Type: High endurance experimental, reconnaissance aircraft
Number built: Three prototypes
Before the outbreak of the Second World War, the Luftwaffe (Eng. German Air Force) was undergoing a massive expansion. Numerous new aircraft designs were either being introduced into service or undergoing testing, with many being integrated into the military for various roles. A number of newly developed aircraft were also primarily used for evaluation and experimentation, and, there were also several designs created specifically to set records. One such aircraft, the Me 261, was built specifically at the request of Adolf Hitler to set long-range records. Due to its specialized role, and the fact that it was not initially ordered by the Luftwaffe, only three prototypes of the Me 261 were built.
The rather obscure Me 261 long-range transport and recconaissance aircraft. Source: alternathistory.ru
History
With the rise of Nazis in Germany, substantial financial resources were allocated to military projects. The Luftwaffe was founded, and saw massive expansion and the introduction of new aircraft designs. However, not all these designs were intended for pure military service. Some projects were mainly aimed at experimentation, and among these were aircraft designed solely to showcase technological advancements and break world records. This trend was quite common in the years leading up to the outbreak of the Second World War in Europe. For example, the Messerschmitt Me 209 was created to set a world speed record, with little to no concerns made over a possible military application.
Speed was not the only record to be pursued, there were others, such as long-range flight. This particular challenge fascinated Hitler, who in 1937, initiated the development of a long-range monoplane. Aside from the many things that might be learned from the experiment, Hitler envisioned this aircraft undertaking the long-range flight from Berlin to Tokyo for the 1940 Olympic Games, carrying the Olympic Torch from Germany over Asia. To meet this requirement, the initial requirements specified that the aircraft needed to have an operational range of over 13,000 km.
The Reichsluftfahrtministerium (RLM), or German Air Ministry, selected the Messerschmitt company for this task. Despite being a relatively small enterprise at the time, Messerschmitt had achieved great success with the Bf 109, one of the best fighters of its era. The official contract was signed on the 18th March, 1938. Under the designation P.1064, Messerschmitt presented a proposal to Hitler for a new aircraft. This aircraft was to be operated by a crew of five within a rather cramped, and elongated fuselage. Due to the aircraft’s specific role, the fuel load was prioritized over crew comfort. Hitler approved the proposal and ordered the construction of three prototypes. The project was subsequently renamed Me 261. Due to Hitler’s keen interest, the aircraft was nicknamed Adolfine by its crew.
In 1939, work began on the three Me 261 prototypes. Despite Hitler’s ambitions, the Me 261 was given low priority, and construction proceeded slowly, and anticipating a war with Poland, work on these aircraft was halted. However, recognizing its potential for long-range reconnaissance and the valuable information it could provide, work resumed in 1940.
The first prototype, Me 261 V1 (BJ-CP or BC-CP, depending on the sources), was flight-tested by Karl Baur in December 1940. The following year, the second prototype, Me 261 V2 (BJ-CQ), was tested. The V2 featured a glazed observation dome on the dorsal fuselage, replacing the rear dome used on the V1. The construction of the third prototype, Me 261 V3 (BJ-CR), faced delays and only completed its test flight in 1943. This version was distinct from the earlier prototypes, featuring a larger crew capacity of seven and being powered by two 2,950 hp DB 610 engines. On the 16th April, 1943, Karl Baur conducted a ten-hour test flight with the V3.
The last of the Me 261 was the V3 prototype, which was powered by stronger engines. Source: airpages.ru
Technical characteristics
Unfortunately, since the Me 161 did not progress beyond the prototype stage. It was designed as an all-metal, long-range transport and later as a reconnaissance aircraft. The fuselage was slim but cramped, made of metal, and covered in duralumin.
The wings of the Me 261 were constructed using a metal frame with a single spar. They were then covered with flush-riveted, stressed-skin metal panels. Notably, the section of the wing closest to the fuselage had a thick profile, which tapered to the wingtips. This design was intentional, as it allowed for a large fuel storage area. The aircraft also featured a twin-rudder tail at the rear.
For its long-range flight operations, the Me 261 had a crew of five: a pilot, co-pilot, radio operator, navigator, and flight engineer. The pilot and copilot sat side-by-side in the cockpit with the radio operator in a central compartment, and the flight engineer and navigator seated in the rearmost compartment, where the aircraft’s bunks were also located.
The first two prototypes were powered by twin 2,700 hp DB 606A/B twenty-four-cylinder engines. These engines were essentially two twelve-cylinder DB 601 engines coupled together to drive a single shaft, requiring two separate radiators and oil coolers. Each DB 606A/B engine was housed within a large nacelle and used four-blade propellers with a diameter of 4.6 meters.
The Me 261 DB 606A/B twenty-four-cylinder engine consisted of two coupled twelve-cylinder DB 601 engines. They worked well on the He 261 and no major issue was reported with it. Source: oldmachinepress.com
Despite frequent mentions of the aircraft being overburdened, sources do not specify a consistent maximum takeoff weight. Additionally, the total fuel capacity is also unspecified. Depending on the sources, the operational range varies from 11,000 to 13,200 km.
To accommodate the aircraft’s weight, it required large-diameter landing wheels that could retract up to 90 degrees into the wings. In addition to these, it had a fully retractable tail wheel retracted towards the front of the aircraft.
The Me 261 was designed as an all-metal, long-range transport and later as a reconnaissance aircraft source: WikipediaThe first two prototypes were powered by twin 2,700 hp DB 606A/B twenty-four-cylinder engines. To cope with their weight, it was provided with two large-diameter landing wheels. Source: planehistoria.comSide view of the second prototype. Source: alternathistory.ru
Fate
Despite demonstrating some potential for long-range reconnaissance, the Me 261 was ultimately rejected from service due to the additional equipment requirements that would have further strained its already overburdened airframe, thereby compromising its flight performance. Despite its cancellation, the V3 prototype (and possibly the other two prototypes) saw operational use as reconnaissance aircraft during the war. In July or April of 1943, the V3 suffered an accident during landing that heavily damaged its landing gear. Although repaired and returned to service, the V3 was eventually scrapped by order of the RLM.
The V1 aircraft was lost during an Allied bombing raid on the Rechlin test center in September 1944, while the V2 was captured by the Allies at the same location in April 1945. Neither prototype survived the war; the captured V2 was scrapped a few weeks after its capture.
The V3 aircraft was damaged during a landing accident but was repaired and put back into service. Source: www.destinationsjourney.comThe V2 was captured by the Allies and was eventually scraped. Source: planehistoria.com
Conclusion
The Me 261 was an aircraft that was not ordered by the Luftwaffe as a military aircraft and thus received low priority. Despite its initial potential for use as a reconnaissance aircraft, it quickly became evident that it would not be feasible for adoption in this role due to its considerable weight. Ultimately, only three were built, and none of them survived the war.
Me 261 V3 Specifications
Wingspans
26.9 m / 88 ft 1 in
Length
16.7 m / 54 ft 9 in
Height
4.72 m / 15 ft 5 in
Wing Area
76 m² / 817.8 ft²
Engine
Two 2,950 hp DB 610 engines
Endurance
24 hours and 36 minutes
Maximum Speed
620 km/h / 385mph
Cruising speed
400 km/h / 248 mph
Range
11,000 km / 6,831 miles
Maximum Service Ceiling
8,250 m / 27,060 ft
Crew
1 pilot
Armament
None
Illustration
Credits
Article written by Marko P.
Edited by Henry H.
Illustration by Oussama Mohamed “Godzilla”
Source:
D. Herwig and H. Rode (2000) Luftwaffe Secret Projects Strategic Bombers 1935 to 1945, Midland Publishing
D. Nesić (2008) Naoružanje Drugog Svetsko Rata-Nemačka. Beograd
D. Monday (2006) The Hamlyn Concise Guide To Axis Aircraft OF World War II, Bounty Books.
J. R. Smith and A. L. Kay (1972) German Aircraft of the WW2, Putnam
B. C.Wheeler, German Fighters of WWII, Aeroplane Special
R. Jackson (2005) Infamous Aircraft, Pen and Sword
M. Griehl () X-planes German Luftwaffe prototypes 1930-1940, Frontline Book
W. Green (1970) Warplanes of the Third Reich, Doubleday & Company
Italy (1932)
Experimental Aircraft – One Prototype Built
In the history of aviation, there have been many projects that on paper promised outstanding flight capabilities, or offered other technical advantages. The time before the Second World War saw aviation advance at a breakneck pace, and is well known for such experiments. The so-called Stipa-Caproni was one such project, being an intriguing, and somewhat bizarre, experimental aircraft designed by Italian aeronautical engineer Luigi Stipa, and built by Caproni during the interwar period. It was characterized by its tubular fuselage, hence earning it the nickname Flying Barrel.
The unique design Stripa-Caproni experimental aircraft. Source: Wiki
History
In 1927 a young Italian aircraft engineer Luigi Stipa began working on an unusual tube-shaped aircraft. Like many other aviation enthusiasts, Stipa was very interested in how aircraft could achieve better performance through exploring unorthodox construction methods. Thanks to his studies in thermodynamics, he was aware of the so-called Venturi effect, named after Italian physicist Giovanni Battista Venturi. In essence, this effect describes the reduction of fluid pressure and increasing velocity when it’s moving through a cylinder of decreased diameter. In theory, using this principle, a special type of aircraft could be created that could achieve significantly higher speeds than the conventional models of the time. Stipa theorized that for this purpose, such an aircraft would have to have a tube-shaped fuselage with the engine being positioned near the front. After finding it theoretically possible, he moved forward to test if the Venturi effect could be implemented in his airplane concept. For this purpose, he began a series of different tests inside a wing tunnel, carried out at the Aerodynamic Laboratory in Rome, from 1928 to 1931. The main focus of this testing period was to find the adequate shape, and leading edges, of the tube-shaped fuselage. This also included finding the right position of the engine, its position inside that tube, and the ideal propeller rotation speed. Following a series of wind tunnel tests, Stipa concluded that it was possible to build a full-scale prototype by using a single tube-shaped fuselage.
Luigi Stipa in his younger years. Source: Wiki
At the end of his research, he concluded that such a project was viable and set the task of building a working prototype. To gain interest in his project, he wrote about his work in the Rivista Aeronautica journal in 1931, and even built a small working replica. The next logical step was to write to the Italian Minister of Aviation, in the hope of getting approval for the realization of his project. Luckily for Stipa, his work came to the attention of General Luigi Crocco, the Air Ministry’s director. Stipa’s work was well received and the project received a green light. To test the concept, a working prototype had to be constructed. It is important to note, that both Stipa and the Italian Air Ministry were aware that this project was merely to test his theories, and would not entail any further development of the prototype. In addition, both were aware that Stipa’s proposed principle was only practical on larger aircraft types.
For this purpose, the prototype was to be powered by a small 120-hp engine. The reason behind this decision lay in the fact that this aircraft was primarily built for evaluation and academic purposes. The Italian Air Ministry was not quite willing to invest huge monetary resources in it, beyond those necessary for the construction of the working prototype.
To help build the test aircraft, the Caproni aircraft manufacturer from Milan Taliedo was chosen. It was designated as Stipa-Caproni (sometimes referred to as Caproni-Stipa) referring to its designer and constructor. The prototype was built quickly and was ready for testing in October 1932.
It is perhaps a little surprising that such an unusual design would receive the necessary support for its realization. However, the exploration of new and unorthodox ideas in aviation was very popular in pre-war Europe. During the 1930s, Italy led the way in this aspect, perhaps even more than other countries, testing many unorthodox designs. What’s more, the Italian Fascist regime even encouraged different and unusual projects like this one, although many of them did not produce any meaningful results.
The Stipa-Caproni prototype was used for testing during 1932 and 1933. Source: en.topwar.ru
Technical specification
The Stipa-Caproni was a two-seater, mixed-construction aircraft, designed to have the simplest and thus cheapest fuselage. Its fuselage consisted of a tube which internally consisted of two large wooden round-shaped rings at the nose, followed by a series of similar but smaller rings. All of them were then connected with horizontal ribs which in turn were covered in fabric. The outer wooden rings served as the foundation, on which the wing and the cockpit would be connected. The fuselage design was, in effect, a large tube shaped airfoil.
A close-up view of the Stipa-Caproni internal fuselage construction. The two larger wooden rings serve as a base to which wings and the cockpit would be attached. Source: www.thevintagenews.com
The wings were mounted centrally on each side of the fuselage. These had a simple wooden construction, and were covered in fabric. They were also connected to the fuselage through metal bracing wires, which as a consequence increased the aircraft’s drag.
To the rear, a fairly large tail assembly was placed. During the design work of this aircraft, Stipa intentionally placed the rear control surfaces as close to the slipstream as possible. He hoped that this arrangement would greatly improve the aircraft’s handling and maneuverability.
On top of the fuselage, an elevated two-seat cockpit was placed. These were top-open with a small windshield placed in front of each position. There were also a pair of small doors that opened on the left side to give access to the seats.
The 120-hp de Havilland Gypsy III engine was placed inside this fuselage. It was centrally positioned and suspended using several steel bars that held it strongly in place. This was necessary to do so, as a weaker mounting could potentially endanger the aircraft during flight. The engine propeller was the almost the same diameter as the tube-shaped fuselage.
Given its overall design, and the position of the propellers inside the fuselage, the landing wheels were small and quite close to the ground. It consisted of three fixed road wheels. Two larger on the front and one smaller on the rear. Initially, wheel fairings were used but at some point, and for unclear reasons, these were removed.
A front view of the unusual engine installation. The engine itself was held in place by several metal bars. Source: WikiIt was provided with a small and fixed three-wheel landing gear. Source: en.topwar.ru
Testing and Final Fate
With this project approved, a prototype was constructed and air tested in October 1932 at the experimental field at Monte Celio near Rome. Despite its odd design, the prototype was able to take to the sky without any major problems. Furthermore, it made several successful flights around Taliedo and Guidnia. It was even presented to the Italian Air Force for future test flights. During this period the aircraft was jokingly nicknamed Flying Barrel or Aereo Botte (Eng. Wooden wine barrel aircraft) or Aereo Barile (Eng. Fuel-Barrel aircraft).
The weight of the aircraft during these flights was 800 kg (1,874 lb), while the calculated wing loading was 44,73 kg/m² (9,16 lb sq.ft.). The maximum speed achieved was 133 km/h (83 mph), and it needed 40 minutes to climb at a height of 3, 000 m. It needed an 800 m long airfield to be able to take to the sky.
The Stipa-Caproni during one of many test flights. Source: www.historynet.com
Despite Stipa’s hopes that the position and shape of the tail control surfaces would improve its mobility, several problems were noted by the test pilots. Firstly the elevator worked very well, which ironically proved to be a major problem. Even with a slight movement of the command control stick by the pilots, the aircraft could prove very sensitive to elevator inputs. On the other hand, the rudder controls were quite stiff, as a consequence the pilot had to use considerable force in order to use it effectively. Analyzing this problem showed that the rudder’s large surface area was to blame for its stiff control. But besides the two problems, the aircraft was reported to be easy to fly when being used in a gliding flight. These defects were of a more or less technical nature, which were not necessarily irremediable through further development of the overall design.
The design of the rear tail assembly proved somewhat problematic. Specifically, the elevator control was overly sensitive while the rudder was quite the opposite. Source: en.topwar.ru
The final results of evaluation flights showed that the Stipa-Caproni does not have any particularly great advantages compared to other more standard aircraft designs. In addition, Stipa-Caproni’s overall aircraft shape offered limited space within the fuselage for passengers or payload.
As Stipa predicted from the start, his principles would not offer any major advantage over a standard smaller-dimension aircraft. The real application of the Stipa-Caproni design was only feasible on larger aircraft. Stipa hoped that his further research would enable him to construct large aircraft powered by two to three tube-shaped engine mounts. Unfortunately for him, after a series of test flights during 1932 and 1933 the interest in his work died out. It was briefly used in various Italian aviation propaganda publications before being scrapped in 1939.
Despite being in general an unimpressive design, the French showed interest in it. Particularly the company ANF Lex Maureaux, which went so far as to acquire a license for the design in 1935. According to initial plans, a two-engine variant was to be built for testing and evaluation. The project did not go beyond basic work was later canceled.
Lastly, an interesting fact is that many people considered Stipa-Caproni to design some sort of proto-jet engine. Whether this was the case or not, Stipa felt his work was overlooked, and according to some sources, he remained bitter throughout his life until he died in the early 1990s.
Stipa hoped that with more resources he would be able to test his principle on a much larger scale, but ultimately nothing came of it. Source: L. Stipa, Stipa Monoplane with Venturi Fuselage
Replica
In 1996, aviation enthusiast Guido Zuccoli began working on a smaller replica of this aircraft. However, the death of Zuccoli in a landing accident caused a delay in the replica’s final delivery. It was finally completed in 2001 when numerous small flights were achieved. The aircraft, powered by a 72 hp Simonini racing engine, managed to achieve a flight distance of 600 m (1,968 ft). After that, the aircraft replica was stored as an exhibit at the Zuccoli Collection at Toowoomba, in Australia.
A smaller-scale replica was built and flight-tested in 2001. Source: www.uasvison.com
Conclusion
The Stipa-Caproni represented an intended for the purpose of testing his new concepts in practice. While surely an interesting and unusual concept, Stipa-Caproni’s overall design was not that practical in reality, offering little improvement over a standard aircraft design of similar dimensions.
Stipa-Caproni Specifications
Wingspans
14.3 m / 46 ft 10 in
Length
6.04 m / 19 ft 10 in
Height
3.2 m / 10 ft 7 in
Wing Area
19 m² / 204 ft²
Engine
One 120 hp (89.5 kW) De Havilland Gipsy III
Empty Weight
595 kg / lbs
Maximum Take-off Weight
850 kg / 1,874 lbs
Maximum Speed
133 km/h / 83 mph
Landing Speed
68 km/h / 42 mph
Climbing speed to 3,000 m
40 min
Maximum Service Ceiling
3,700 m / ft
Crew
1 to 2 pilots
Armament
None
Illustration
Credits
Written by Marko P.
Edited by Henry H. & Ed J.
Illustration by Godzilla
Source:
J. Thompson (1963) Italian Civil and Military Aircraft 1930-1945, Aero Publisher
R. Giacomelli, (1933) The Stipa-Caproni Monoplane, Aircraft Engineering and Aerospace Technology, Vol. 5
D. Nesic (2008) Naoružanje Drugog Svetsko Rata-Italija
L. Salari, Caproni Storia della nascitadell’ industria aeronautica
M Taylor, The Wolrd Strangest Aircraft, Metro Books
O. E. Lancaster (1959) Jet Propulsion Engines, Princeton University Press
L. Stipa (1933) Stipa Monoplane with Venturi Fuselage, Technical Memorandums Nation Advisory Committee For Aeronautics No.753
An artistic drawing of what this unusual aircraft might have looked like source: www.nevingtonwarmuseum.com
The German military industries during the Second World War are often seen as highly developed, and producing highly sophisticated, superior weaponry to that used by the Allies. The reality is quite different, as they began to implement the mass use of slave labor and were chronically short of several key resources. Regardless, bright engineering minds and desperation led to the introduction of a series of new technologies, some being the first of their kind. The German aviation industry was credited with creating some advanced and innovative, but ultimately scarce aircraft designs such as the Me 262 jet fighter. With this reputation, many theories on German hyper-advanced, secretive aircraft projects began to spread after the war. Among them, was the theory that they had created a series of supersonic, flying saucers.
The Myth of German Technological Superiority
In the decades after the Second World War ended, in media and popular culture, German military technology and industry were often presented as significantly superior to the Allies. This is perhaps the most obvious when mentioning the German Wunderwaffe (Eng. wonder-weapon). These weapons ranged from flying bombs, ballistic missiles, jet engines, and super-heavy tanks. In essence, from the German perspective, the Wunderwaffe presented any weapon that would help them turn the tide of the war. Probably the best examples that were used in greater numbers were the V-2 rockets and the Me 262 jet fighter. In the case of the V-2, these were used en masse to bomb targets in Great Britain and continental Europe. Descending at a speed of nearly 6000 km/h, they could not be tracked and struck without warning. The Me 262 was able to achieve speed far superior to that of ordinary piston-powered aircraft., and with its armament of four 3 cm cannons, it could easily take down heavy Allied bombers.
Before we go any further we must discuss the history and truthfulness of these wonder weapons and their origin. It is important to point out that the German war industry prior to and during the war struggled with numerous industrial shortcomings. It was unable to produce enough quantities of weapons and materiel to satisfy the German Army’s demands. This can be best seen in the pre-war tank production when during the invasion of Poland, only a limited number of modern Panzer III and IV were available. The lack of anything better forced the German armored formation to rely on the weaker Panzer I and II tanks. The effective heavy tanks, such as Tigers, due to their complexity and price, were built in limited numbers. Even the Panther, of which some 6,000 were built, which was much cheaper and easier to build, could never be produced in such numbers to fully replace older designs. The Army itself, while generally portrayed to be highly motorized, was actually heavily dependent on horses for the transportation of artillery and supplies.
Regarding the term Wunderwaffe, it is almost entirely associated with German propaganda. The term was more actively used when the war began to turn bad for the Germans, especially after defeats like the one at Stalingrad. In theory, any weapon or vehicle could be categorized as a Wunderwaffe. Ranging from an assault rifle to a jet-powered aircraft. Some were just paper projects or simple proposals that were intended to enter production but they actually never did.
Now the question would be were these weapons truly superior to the Allied ones? A simple answer is no, but every single of these Wunderwaffe had pros and cons, so making a simple conclusion about their effectiveness and use would revive extensive research and work that is beyond this article. But we can briefly consider the effectiveness of the two previously mentioned weapons systems, the V-2 and the Me 262. While the V-2 was quite advanced for its day, it was plagued with many problems. The reliability of the rockets was not guaranteed with some of them exploding during take-offs. Precision was their weakest point, and by late 1944, when they were used en mass, the Germans simply lacked the means to observe their effectiveness against targets in Great Britain and could not correct the aim of the rockets. The Me 262 was also far from perfect, given the technological novelty of many of its components, it too suffered from poor reliability. Both weapons were also introduced too late to have any real impact on the war.
The first mass-produced jet fighter in the world was the Me 262. Source: Wiki
The Germans lost the war, which obviously showed that the concept of the Wunderwaffe was just a desperate attempt to increase the morale of its people and to fight the ever-increasing fear of a possible defeat. But despite it, these weapons continued to tickle the imagination in modern-day culture. To some extent, some mysteries would emerge after the war, that were either fabricated or were to some extent real. The probably best-known, and most infamous is the German flying disc project which employed the unusual circular wing design.
A Brief History of Circular Wing Design
While the circular wing design may be seen often wrongly connected to the unidentified flying object its actual origin is more earthly in nature and goes way back to the 18th century. One of the first recorded proposals for using a circular wing design to create a flying contraption was presented by Swedish scientist and philosopher Emanuel Swedenborg. He published his work in a scientific journal in 1716, but his proposal ultimately led nowhere. Nearly two centuries later in 1871 when French inventor Alphonse Penaur tested his own flying model. Encouraged by this success in the following years he began working on a new aircraft design that was to have elliptical wings and be powered by two smaller steam engines. But he committed suicide in 1880 and never fully implemented this new project. In the 1910s a wealthy weaver, Cedric Lee and his friend George. T. Richards began working on a circular wing glider. After a series of flight tests, they noticed that the glider had a good overall flying performance. Inspired by this success, they hired an engineer, James Radley, to help them build their new propeller-driven circular-wing aircraft in 1913. This aircraft also performed well during its test flight, but during the landing, the engine stopped and the aircraft crashed. While the pilot was unharmed the aircraft was a complete loss. Both Cedric Lee and George. T. Richards continued working on improving their design, but after a few more crash landings, they gave up on their project. In the 1940s, the American Army and Navy experimented with using a few different semi-disc wing designs These were the Boeing B.390 and the XF5U-1. While boths were surely interesting aircraft, their overall design proved to be a failure and none would be accepted for service.
Cedric Lee and George. T. Richards incomplete experimental circular-wing aircraft. Source: B.Rose and T. Buttler Secret project Flying Saucer AircraftThe Boeing B.390 design, while being a much simpler design than the XF5U-1, proved to be an unsuccessful design. Source: B.Rose and T. Buttler Secret project Flying Saucer Aircraft
The Flying Disc Project
The history of German flying disc projects is rather poorly documented, and in many cases, outright fabricated. They were allegedly related to German attempts to develop a vertical take-off and landing (VTOL) aircraft. It is surrounded by a veil of secrecy, and quackery, and probably that is the main reason why it is often connected to mythical or even supernatural origins. It is worth mentioning that the sources regarding these developments are quite unreliable, as they are mostly based on stories told by eyewitnesses and individuals. The reliability of these eyewitnesses and individuals should be taken with a great grain of salt. We must take into account that many of the written sources were made decades after the alleged events occurred. Another vital point to consider is the reliability of the main individuals that were allegedly involved in such projects. One such person was Rudolph Schriever, who after the war, gave an account of his reputed involvement in the development of a secret flying disc aircraft.
According to his story, the German Reichsluftfahrtministerium RLM (Ministry of Aviation) appointed a young aircraft design engineer and pilot, Rudolph Schriever, to work at the Heinkel-Rostock design office. In reality, he had no verifiable claims to German military service, relating to aviation or otherwise, and his only known employment was for the US Army as a truck driver after the war. It’s also not quite clear, but in some sources there is a mention of a certain Otto Habermohl, supposedly also involved from the start. Not to be beaten out by Schriever, there is not only any evidence for his credentials, but he doesn’t seem to have existed at all.
At that time, different engineers wanted to solve the issue of reducing the space needed to launch and recover aircraft. One solution was to launch an aircraft directly, and vertically into the sky. In this case, such aircraft would not need a long runway and instead could take to the sky from a single launching point. But this concept, while tested over the years, was never successfully implemented during the war.
Schriever claims to have approached this problem with a somewhat unusual solution. He made plans using a disc-shaped aircraft powered by jet engines using the so-called Coanda effect. This effect was named after the Romanian Henri Marie Coanda, an aerodynamic engineer. He discovered that when using a jet stream that is applied tangentially against a convex surface it creates a lift force that could be further increased by circulation. Schiriever claimed to have presented his idea to Ernst Heinkel, who was said to have liked the concept. This supposedly led to the start of work on a small prototype. He claims that after some work, the prototype was completed in early 1941. This prototype received the simple V1 designation without any prefix for the aircraft type. This should not be confused with the V1 flying bomb, as the V stands for Versuchs (experimental or trial model) which was quite commonly used by the Germans especially in the aviation industry to describe experimental or pre-production models. This prototype supposedly consisted of a disc-shaped wing design powered by an electrical rotary fan, no power source is given.
In 1942, this prototype was allegedly flight tested. No precise information about its overall performance exists. The assembly of this prototype named V2 was said to have begun in nearly 1943. By that point, Schriever claimed that some design work was moved from Germany to occupied Czechoslovakia. Škoda factories near Prague are assumed to have provided assistance to this project, though he did not specify in his testimony. A few other companies were also mentioned to be to some extent involved in this project, this includes Junkers, Wilhelm Gustloff, and Kieler Leichtbau. The fate of the V2 prototype is not clear.
The testing of the Schriever flying disc was supposedly observed by a group of some 25 eyewitnesses from the Flight school which was stationed near this airfield. One of these eyewitnesses gave testimony to a German aeronautical magazine Flugzeug in 1987. The truth of these claims cannot be completely verified with certainty. If we consider the fact that more than 40 years have passed since this incident to the moment they gave the interview. They reportedly saw a strange disc-shaped aircraft. This aircraft was described as disc-shaped with an estimated diameter between 5 to 6 m with the height of an average man. They also reported that it had an aluminum color. And that while being on the ground held in position by four landing gear legs. It managed to reach a flight of around 300 m of distance at 1 m of height. In the event the witness was not being intentionally misleading, it is likely they saw a helicopter being tested, several designs of which were researched and built during the war.
This piece of equipment is often mentioned to be the Rudolph Schriever demonstrator for the whole concept.It shares a notable resemblance to a torque converter. Source: B.Rose and T. Buttler Secret project Flying Saucer Aircraft
Name of the project
Beside the names given to the prototypes, this whole project appears to not have received any official designation, which was somewhat odd. It is often simply referred to as the Heinkel-BMW or by its name of the inventor Schriever, or even as the Schriever-Habermohl flying disc. Also sometimes it is also referred to as Flugkreisel (Flying top). This article will use the Heinkel-BMW flying disc designation for the sake of simplicity only.
Further Work
By 1944, the whole team that worked on this project was supposedly moved to Czechoslovakia. The entire personnel were not stationed at one facility but instead relocated to various small cities in that occupied country. Allegedly, this was done to avoid any of them being killed in the Allied bombing raids. The main base of operation was said to be the Praha-Kbely Airfield. According to Schriever, by this time, other aircraft design engineers began joining the program. One of them was SS Lieutenant Helmut Zborowski who was then appointed commander of this base. Given his position, Helmut would be most likely directly involved in the project. Others included Dr. Richard Miethe who may have been involved in the German rocket development. He may have been involved in the Peenemunde rocket research center, but his work there was never verified and so far no connection has been proven. Lastly, there was Klaus Habermohl and surprisingly an Italian, Dr. Giuseppe Belluzzo, who specialized in the work of turbines. The involvement of these two in the supposed project is unclear. Dr. Giuseppe Belluzzo claimed after the war that he was involved in the disc-shaped aircraft project but there is no proof of this. Klaus Habermohl is another strange person that allegedly worked on this project. What is bizarre is that no actual proof was ever found that this was a real person that existed. Lastly, the role of Joseph Andreas Epp, who was an engineer, was a supposed consultant to the Heinkel-BMW flying disc program. After the war, he claimed to have greatly influenced the German disc-shaped aircraft project, but if this is true, or was just an attempt to gain fame are unknown, the latter option seems more possible.
Schierver claimed that, together this team decided to proceed and built a third,even larger aircraft. The necessary component for the aircraft was to be supplied by Heinkel while Bayerische Motoren Werke AG – BMW was to have been responsible for providing the necessary engines. During the construction of the V3 prototype, one member of the team proposed using an experimental radial flow gas turbine engine which was adopted. The V3 was said to have been completed in the autumn of 1944. It was said to be almost double the size of the previous prototype with a diameter ranging from 12.2 to 15.1 m. No specific model of jet engine was mentioned. Supposedly, this aircraft was capable of achieving subsonic speed and could take off vertically.
Alleged drawing of the V3 prototype, note there are a few slightly different drawings of this alleged prototype. Source: www.nevingtonwarmuseum.com
As the war was by this point obviously lost, the Germans tried to delay the inevitable, and out of desperation, the SS became more involved in Wunderwaffe projects. This flying disc was said to be one of them, with their supposed involvement helping to add another layer of esotericism. Supposedly, soon the new V7 prototype was under construction. The fate of the V4, V5, and V6 prototypes is unknown. The last prototype, the V7 was reportedly designed to be larger than its predecessor by having a diameter of 18.3 to 21.3 m. This prototype was to be powered by gas turbine engines, from the start. At some point the work on the prototype was supposedly taken over by Richard Miethe.
Technical characteristics
Given the general obscurity and poor source materials, the precise construction of this bizarre aircraft is unknown. The available information should be regarded as illegitimate as it is technically incorrect, extremely inconsistent, and often fantastical.
The aircraft itself was envisioned as a circular-rotary wing design likely made of metal and powered by several smaller jet engines. It consisted of a centrally positioned crew cabin, which was surrounded by a large rotary wing assembly, resembling a huge fan. These were surrounded by a huge likely metal ring. What holds this ring in place is not clear according to a few drawings of it that exist.
The V7 had a diameter of 18.3 to 21.3 m. To provide stability it is often suggested that this aircraft received a stabilizing fin added close to the central cockpit. The central cockpit appears to be hemispherical and was fully glazed, providing the crew with a good upper all-around view. The lower view would be greatly restricted by the large rotary wing and present extreme difficulty in landing. How they would resolve this issue is not clear. It is possible that at the bottom of the cockpit, additional windows were to have been added. The crew consisted of two to three crew members whose roles were not specified.
Beneath the large rotary wings, at least four jet engines were to be used to power the whole assembly. These provided lift during take-off and landing. Allegedly, horizontal flight could be achieved by adding additional engines possibly connected to the lower part of the cockpit unit. Several different possibilities could have been used for this project. Ranging from Jumo 004, Jumo 211/b, BMW 003 engines, Walter HWK109 rocket engine, or the Argus pulsejet. Its alleged maximum speed achieved was 1,200 km/h or up to 2,000 km/h at a height of 12,400 m. Given its nature, and that none of the engines would have sufficient performance for supersonic flight, both numbers seem unrealistic, to say the least. Even in Rudolph Schriever’s own testimony after the war, he claimed that the prototype only managed to achieve some basic flights. There is no record that any kind of armament was tested on this aircraft.
The Fate of the Project
Like most parts of this aircraft, its final fate is unknown. Hard to verify, and often absurd claims, mention that it climbed to heights of 12.200 m or managed to reach supersonic speed. Given that it was supposedly in its early development phase when the previously mentioned test flight was made, it is dubious that such a flight was possible even with all of the other issues.
The V7 was said to have been destroyed by the Germans to prevent its capture. Or the Germans failed in this and the Soviets managed to capture it, with no evidence existing in either case. There was also said to be a V8 prototype that was under construction by the war’s end. Another interesting but unconfirmed information is that some members of the team who worked on this flying disc including Richard Miethe actually managed to surrender to the Western Allies. This seems unlikely and was possibly fabricated by Miethe, who was known to have been involved in some different conspiracy theories, so his background is also not verifiable.
The alleged photograph was taken by Joseph Andreas Epp while he was driving toward the Prag airport in (possibly August) 1944. The part of the picture to the right is the same photograph that just increased in size and focused on the aircraft itself. Source: H. Stevens, Hitler Flying Saucers
Ironically, the Germans actually managed to develop and built in small series a rocket-propelled VTOL aircraft, the Ba 349. While quite an unusual design, it was a real, and more practical aircraft in contrast to fictitious flying disc projects. By the time it was flight tested in March 1945, it proved to be a failure.
The experimental and unusual rocked-powered Ba 349 Source: Wiki
Production
After the war, Joseph Andreas Epp claimed that at least 15 various prototypes were built and tested by the Germans. This number also includes another similar project that runs parallel to the alleged Heinkel-BMW project.
V1 – Small prototype model
V2 – Second prototype whose fate is unknown
V3 – Tested in late 1944
V4-6 – Possibly paper projects
V7 – Larger fully operational prototype
V8 – Alleged improved V7 prototype
Is the whole story actually True?
Not surprisingly the entire story about Rudolph Schriever’s work is in all likelihood, a complete fabrication. Author, G. Rendall (UFOs Before Roswell) gives a quite detailed account of the Schriever’s involvement, or better said, lack thereof in the German flying disc program.
The connection between Schriever and the Luftwaffe is not clear. While he is often described as having the title Flugkapitan (Flight Captain) this was not an official military rank but instead an honorary title given to civilian test pilots for their service. This usually includes testing a prototype aircraft and testing newly built planes. Schriever, allegedly thanks to his idea of a flying disc, and pilot skill was said to be summoned to Heinkel. In reality, there is no evidence to support this, neither him being an engineer nor a test pilot. His first public appearance and general mention of his flying disc project occurred when he gave an interview to the Der Spiegel news magazine on the 30th of March 1950.
Schriever may have been influenced to come up with his story by the Italian post-war flying disc stories. In the late 1940s Italian engineers showed great interest in designing similar aircraft. One engineer Francesco de Beaumont proposed a disk-shaped aircraft design powered by four jet engines. Another engineer Giuseppe Belluzzo in his own story given to the magazine Il Giornale d’Italia, was he mentioned Italian and German flying disc development.
Francesco de Beaumont proposed a disk-shaped aircraft proposal. Source: B.Rose and T. Buttler Secret project Flying Saucer AircraftA drawing of the Rudolph Schriever flying disc was published in the German newspaper Der Spiegel in March 1950 Source: H. Stevens, Hitler Flying Saucers
In any case, according to Schriever’s interview, he allegedly became involved in the flying disc program in 1942. Quite interesting is the fact that according to Schriever’s own words, this aircraft was successfully flight-tested. He continued to work on this project up to the end of the war when he had to flee with the whole documentation and plans. He set up a small workshop and the documents were stored there. In 1948 he claimed that they had been stolen by an unspecified foreign agency and never found. Despite claiming to be involved in the secret flying disc program as an engineer, Schriever after the war worked as a simple truck driver. As there is no proof of the Heinkel-BMW flying disc, the whole story seems like a fabrication invented by Schriever. As in his later interview, he claimed to be involved in other projects; it is likely that he was seeking attention possibly from the Allies or simply just bored during a time when Germany was undergoing a slow, painful recovery. To add to the likelihood of the latter, at that time German engineers were highly in demand by the Allies and the Soviets. The US army even organized special operations to bring many German scientists to America, yet Schriver’s claims of the disc aircraft were completely ignored. If being recruited was Schriever’s intention, he failed in that regard. In the end, Schriever’s story ended with his death in 1953, as reported by the German Newspaper, Deutsche Illustrierte
The Real German Circular-wing aircraft
As it is often the case, the reality is often quite disappointing for those who believe in the extraterrestrial and esoteric origins of German flying source projects. Likely the only circular-wing design that reached some operational level was the Arthur Sack Sack AS-6. While even this aircraft had a rather obscure history, it is known that one prototype was completed and tested. Given that this was mostly a one-man project built using salvaged components, it should not come as a surprise that it led nowhere. During testing, the aircraft failed to take off and after a number of improvements, attempts to fly the aircraft were eventually discarded. The only prototype would be destroyed in an Allied bombing raid. The Horten Ho 229 could technically also be classified as a flying disc aircraft, though by any technical definition, it is a flying wing. Despite some effort put into its development, it remained at the prototype stage. There were many other projects but few went beyond a mock-up stage.
While Arthur Sack’s work was never implemented in mass production, his unusual design was often mistakenly taken as some advanced and secret German World War II project, which ironically, it never was. Source: all-aero.comThe unusual Sack AS-6 circular-wing aircraft. Source: alkeeins.blogspot.comFew prototypes of the unusual Horten Ho 229 were built and tested during the end of the war. Source: www.ww2-weapons.comFocke-Wulf wooden mock-up of a VTOL aircraft that has some resemblance with a flying disc. Source: B.Rose and T. Buttler Secret project Flying Saucer Aircraft
Conclusion
Based on the few available information what conclusion could be made regarding this unusual design? Given its supposed secrecy and some element of Wunderwaffe allure, there is no doubt that the project is by all indications, fictional. Given the fact that the Germans allegedly spent years developing such aircraft but did not advance beyond the prototype stage, probably an indicator that the whole concept was likely flawed if it existed in the first place.
In the case of Rudolph Schriever’s work, it is quite certain that his entire involvement in such design was purely made-up after the war. Why he would do so is unclear. It is possible that he tried to get the attention of the Allies. In this regard, he failed, as the Allies probably saw,if they ever bothered in the first place, that the whole story was fake and invented from the start. It is much more likely that Rudolph Schriever simply wanted to do a publicity stunt, as he was probably extremely bored being a truck driver in post-war Germany. In the end, it’s likely that Rudolph Schriever never suspected that his story would have gone so far, being propelled by the flying saucer craze of the 1950s.
Alleged Heinkel-BMW V7 Specifications
Wingspans
18.3 to 21.3 m
Engine
Multiple unspecified jet engines
Maximum Speed
1.200 to 2.000 km/h / 745 to 1240 mph
Maximum Service Ceiling
12.400 m
Crew
2 to 3
Armament
None
Illustration
Artist impersonation of the Heinkel-BMW Flying disc
Credits
Article written by Marko P.
Edited by Henry H.
Ported by Henry H.
Illustrated by Medicman 11
Source:
D. Nesić (2008) Naoružanje Drugog Svetsko Rata-Nemačka. Beograd.
R. Ford (2000) German Secret Weapons of WWII, MBI
B.Rose and T. Buttler (2006) Secret project Flying Saucer Aircraft, Midland
J. R. Smith and A. L. Kay (1972) German Aircraft of the WW2, Putnam
H. Stevens, Hitler Flying Saucers. Adventures Unlimited Press
M. Fitzgerald (2018) Hitler Secret Weapons Of Mass Destruction, Arcturus
G. Rendall (2021) UfOs Before Roswell, Graeme Rendall
The slightly smaller PG-3 used eight jet engines and kept the wings off the Princess without changing them too drastically. Here it is seen carrying the S-II stage. [allaboutguppys.com]The Aero Spacelines PG-2 was an oversize cargo aircraft with an extremely large cargo hold, designed to airlift the first and second stages of the Saturn V rocket from their factories to Cape Canaveral, Florida, for final assembly. To save on costs, the aircraft would use components from existing aircraft, and most interestingly would use several key components from the British Saunders Roe Princess flying boat, hence the nickname “Princess Guppy”. Unfortunately, due to opposition from Congress, and the deterioration of the Princess aircraft, none of the type would be built.
NASA and the Transportation Problem
The S-II stage of the Saturn V. [James Vaughan- Flickr]The race to the moon in the 1960s between the United States and Soviet Union introduced a number of challenges upon the growing aerospace industry. The task at hand was one of the biggest endeavors in human history, requiring manpower, materials, logistics, training, and calculations never used before to achieve such a tremendous goal. In America, the Apollo program was well underway, composed of the Apollo spacecraft and the massive Saturn V rocket it would be launched from. The Saturn V (at this point called the Saturn C-5), was a multistage launch platform with 3 different stages. Logistically, there was a problem with its design. The Saturn V was meant to be assembled and launched from Cape Canaveral in Florida, but the first and second stages of the rocket were assembled in completely different states. The first stage, S-IC, was assembled in New Orleans by Boeing, while the second stage, S-II, was produced on the opposite end of the country in California by North American Aviation. This created a massive challenge regarding transportation. The two stages were massive in size, each having a diameter of 33 ft (10 m). The first stage had a length of 138 ft (42 m) while the second stage had a length of 83 ft (24.9 m). Transporting these two components was a major issue, as almost nothing could quickly move these to Cape Canaveral. This led to NASA deciding to use an aircraft to transport the 1st and 2nd stages. However, this brought on yet another problem. At the time, no aircraft then in service could carry such a large and ungainly cargo, leading several aircraft companies to propose concept aircrafts to complete such a task. Due to the nature of the challenge, the proposals often were unorthodox in their design to accommodate the large load. One company, however, was formed deliberately to fill NASA’s airlifting needs.
An example of Aero Spacelines’ other work, the Super Guppy. These aircraft would transport the 3rd stage of the Saturn V.
Aero Spacelines was formed in 1960 by Jack M. Conroy with NASA as their main customer in mind. Jack, being a former Air Force and commercial pilot, knew of their transportation issue regarding rocket components even before the Saturn V rocket, beginning with their previous multistage rocket designs. He proposed using modified Boeing 377 Stratocruiser airliners with large overhead cargo holds to carry these rocket components from their manufacturers to their assembly points. The first of his “Guppy” designs as they were called, the Pregnant Guppy, first flew in 1962 and was awarded contract work for NASA as an airlifter. The Pregnant Guppy was still too small, however, to carry the large 1st and 2nd stages of the Saturn V, and so a larger design began to be drawn up. An early study was done with an entirely new fuselage using B-36 wings and control surfaces to save on parts. This design would have a cargo hold with a diameter of 40 ft (12.2 m), allowing it to carry both boosters. Little is known of this design outside of this but it would be quickly changed on January 30th, 1964 when John M. Conroy announced Aero Spacelines would design a new oversized load airlifter based on the Saunders Roe Princess.
The Saunders Roe Princess: A Dead Dream Revived.
The Saunders-Roe Princess in flight. The size of the aircraft is evident in this photo. [Tom Wigley – Flickr]The Saunders Roe Princess was the biggest flying boat design built in Britain, and the biggest all metal flying boat ever built. Originally designed as an innovative transatlantic passenger liner, it would first fly in August of 1952. However the Princess encountered two major issues. The ten Proteus engines used were underpowered, causing performance to suffer. On a more pressing matter, the Princess found itself being quickly outdated as it was developed. With the arrival of the De Havilland Comet, the world’s first jet powered airliner, in the same year as the Princess, it was quickly shown that piston-engine airliners, let alone floatplanes, was a dying breed of travel. Jet aircraft could fly faster, smoother, and further than piston engine airliners, and the Princess couldn’t find buyers because of this change in the market. In addition, the amount of airfields left in Britain after the Second World War nullified the benefits of flying boats and their lack of need for airfields. A single Princess would be built and tested, with two more being completed, but not flown, when the program was ended. The three Princesses were put into storage, cocooned away in hopes that a buyer would eventually come and save them.
Over the years several interested parties would look at the Princesses but no deal ever came to fruition. The three airframes would sit in storage for a decade (1954-1964) when they came to the attention of Jack M. Conroy. Interestingly, this wouldn’t be the first time the US considered acquiring the three aircraft, as the Navy had once proposed to convert the three into flying nuclear-powered test beds, but this plan never progressed past a few models and drawings. At the time, Conroy was still working on his booster carrier concept using B-36 components, but the large design of the Princess gave him an idea. Instead of the B-36, Conroy had the idea of reusing the same parts from the Princess. The plans were quickly reworked and came to be known as the PG-2 Princess Guppy. The PG-2 would reuse the wings from the Princess but had several enhancements. Instead of using the ten Proteus engines, these would be swapped out for six Rolls-Royce Tyne turboprop engines. The Tyne engines were originally planned for the Princess during its development, but the engines weren’t ready and couldn’t be used by the time the Princess was built. Now a decade later, the engine was fully operational and ready. The wing length would also be stretched to 40 feet (16.2 m), and the cargo hold would have a 38 foot (11.6 m) minimum diameter and a length of 100 feet (30.5 m). This reduction in length would no longer allow the aircraft to carry the S-IC booster. Maximum cargo capacity would be up to 200,000Ib (104,600 Kg). The aircraft would be reworked once again later in 1964 as the PG-3. The PG-3 would be reduced in size to some degree. The Princess wings would no longer be lengthened to save on costs, and the Tyne engines would no longer be used on the PG-3, instead they’d be replaced by jet engines. A total of eight jet engines would be used on this design, with 4 pairs of engines being used on B-52H engine pods. Other than wing design, the rear of the aircraft was also changed, with the fuselage not angling upward and instead being more of a straight point.
Aero Spacelines had full intentions of seeing this project through, and eventually a representative of the company was sent to inspect the three Princesses at their storage facility. However, a terrible revelation was discovered upon inspection. At some point, maintenance on the three Princesses in storage was stopped, and so they were left to rot for nearly a decade. Being near the sea and exposed to the elements, the three aircraft had deteriorated to such an extent they would no longer be usable. With this discovery, Aero Spacelines had to unfortunately cancel the project and the three Princesses were scrapped. Work on a large carrier was halted for Aero Spacelines and they focused on their smaller Super Guppy aircraft instead, which carried the 3rd stage of the Saturn V.
Design
The Aero Spacelines PG-2 concept. Note the modified wings and tail empennage off the Saunders-Roe Princess [allaboutguppys.com]The Aero Spacelines PG-2 was a large oversized cargo aircraft designed to carry the first and second stages of the Saturn V rocket. To do so, it would have a very large fuselage to accommodate the rocket stages. The aircraft would have an all metal fuselage that was 200ft (61 m) in length. The lower section of the fuselage contained the huge cargo bay for the rocket stages. On the original plan this section had a diameter of 40 feet (16.2 m) but was shortened to 38 feet (11.6 m) on the PG-2. Cargo was loaded into the aircraft by means of a ramp. The cargo bay had a large clamshell door in front of the aircraft. Landing gear was divided into six pairs of wheels on the underside. Two pairs of wheels were closer to the front of the aircraft while the remaining four were towards the rear. The cockpit and crew section was located above the cargo bay in the aircraft. The cockpit itself bears a striking resemblance to the cockpit section of the Douglas C-133. A crew of 3 to 4 was expected for operations. Initially, the wings would be reused from the Convair B-36 bomber. The engines for this version were never specified. On the PG-2, it was decided at this point that the wings of the Saunders-Roe Princess would be used over for the B-36’s. The wings would be lengthened an additional 40 feet in total for stabilization. The Princess’ original ten Proteus engines would be replaced with six Rolls Royce Tyne engines to improve performance. The tail section of the PG-2 would also be reused from the Princess.
The PG-2 would be reworked into the PG-3 design. The overall proportions were diminished to save on labor. The specifications of this version are relatively unknown aside from one or two estimates based on promotional images. The cargo bay was to remain the same in length. The cockpit section and most of the fuselage remain unchanged aside from the rear. The rear of the fuselage no longer tapered upward and instead transitioned straight back into a cone shape. The tail section of the aircraft remained in the same location but was now supported by a large support to accommodate the height difference of the rear of the aircraft. The wings of the PG-3 remove the 40ft (16.2 m) extension off of the Princess wings and keep the original length. The six Tyne engines were removed in favor of eight jet engines. These engines would be paired together in four B-52 engine pods on the wings. The jet engine intended for use isn’t stated but it’s likely they were Pratt and Whitney TF33 engines. Promotional art also depicts the PG-3 having wingtip mounted fuel tanks.
Conclusion
The final result of the transportation issue. The S-IC and S-II boosters would be transported via barge from their factories to assebmly. Here the S-II booster is carried by the barge Poseidon. [Wiki]With the cancellation of the Princess Guppy, Aero Spacelines moved on to other means to assist NASA regarding transportation, however they weren’t the only company to offer an aircraft design to carry the larger rocket stages. Several other companies had offered proposals to NASA for the same function, such as Convair and Fairchild. Many of these designs reused existing aircraft as their base or for parts to save on costs. None of these would come to fruition either. Despite reusing components from existing aircraft, many members of Congress found building a new aircraft for this role unnecessary for the amount of funding it needed. Instead it was decided that the 1st and 2nd stages would continue to be transported to Cape Canaveral via barge. For the 2nd stage, this was a very long journey that involved going through the Panama Canal to reach Florida. Despite being time consuming, this method was one Congress found cost effective. No oversized aircraft proposals would be built aside from Aero Spacelines’ own Super Guppy design, which was used to transport the 3rd stage of the rocket, and one of which is still in service to this day by NASA.
The Princess Guppy was a well researched design using prior knowledge of Aero Spacelines’ Pregnant Guppy. The design would have brought back to life a decade-old dream but unfortunately it was crushed due to negligence. Had it been built, it would be questionable if the aircraft would even be airworthy. The immense size of the fuselage and the small amount of engines in comparison to said size could have prevented the aircraft from even lifting off. Regardless, none of the types were built.
Variants
Early Design (PG-1?) – The first design of the booster carrying aircraft reused components of the Convair B-36 bomber. It would have a large cargo hold to carry the oversized load.
PG-2 – Second design of the booster carrier. The PG-2 Princess Guppy would use the modified wings and tail components of the Saunders-Roe Princess and would be powered by six Rolls Royce Tyne engines.
PG-3 – Reduced size version to lessen the work needed to build the aircraft. It was powered by 8 jet engines in B-52H engine pods. The Princess’ wing returns to its normal size for this version.
Operators
United States of America – The Princess Guppy was designed specifically to be used by NASA for the transport of the first and second stages of the Saturn V rocket. None were be built.
Aero-Spacelines PG-2 specifications
Wingspan
259.8 ft / 79.2 m
Length
200 ft / 61 m
Height
86 ft / 26.2 m
Wing Area
6328 ft² / 587.8 m²
Engine
6 x 4,616 hp (3,442 kW) Rolls Royce Tyne RTy.12 turboprop engines
Propeller
6 x De Havilland 4-blade propellers
Powerplant Ratings
Horsepower output
Altitude
Take Off
5730 hp
Sea Level
Weights
Useful
250,000 lb / 113398 kg
Minimum Flying Weight
180,000 lb / 81646.6 kg
Maximum Take Off
430,000 lb / 195044.7 kg
Maximum Landing
400,000 lb / 181436.9 kg
Crew
3 to 4
Gallery
Artist Concept of the PG-2 by Godzilla
Credits
Written by Medicman
Edited by Henry H. & Ed J.
Illustrations by Godzilla
Sources
COX, G. (2019). AMERICAN SECRET PROJECTS 3 : u.s. airlifters since 1962. Place of publication not identified: CRECY PUB.
Keeshen, J. & Hess, A. (2013). Secret US proposals of the Cold War : radical concepts in military aircraft. Manchester North Branch, MN: Crécy Publishing Limited,Distributed in the USA by Specialty Press.
Romania (1934) Training and Reconnaissance Aircraft – None Built
Cutout view of the IAR-H.S.300. Note the turret with the machine gun, camera and tandem controls. [Dan Antoniu]The establishment of I.A.R. (Industria Aeronautică Română) at Brașov in 1925 was a huge step forward for Romanian industry, and more importantly, the A.R.R. (Aeronautica Regală Română) Romania’s Royal Air Force. However, with the turn of the decade and rapid development of military aircraft around the world, Romanian aircraft factories, which also included S.E.T. (Societatea pentru Exploatări Tehnice) and the new I.C.A.R. (Întreprinderea de Construcții Aeronautice Românești), were lagging behind in terms of equipment and production facilities. This led to a variety of issues which pushed IAR into bankruptcy. The IAR H.S.300 was IAR’s last attempt at creating an aircraft for the ARR before drastic changes were made, both in terms of the plant’s management and the air force’s requirements and needs.
Development
With the deteriorating stability in 1930s Europe, Romania’s M.A.N. (Ministerul Apărării Naționale, Eng: Ministry of Defense) decided that all of its future aircraft had to be of all-metal construction. This caused a lot of issues with the national aircraft manufacturers, which simply did not have the equipment and facilities to produce all-metal aircraft. Similar issues plagued all Romanian industries even during the Second World War.
Between 1930 and 1933, IAR developed several competent fighter aircraft designs, but none were accepted into service due to their construction, which was part metal, part wood. This would force IAR into bankruptcy. Only a small order of 20 IAR-14 fighters was placed in early 1933, under clandestine conditions, directly from the Romanian high command to the factory.
One of the 20 IAR-14 monoplane fighters produced by IAR for the ARR in 1933. It came as a very much needed show of support to the factory, which was hemorrhaging money. [All the World’s Aircraft]Things changed, however, in 1934, when the leadership at IAR requested an investigation from the Romanian Senate. They accused the MAN of not respecting the previously signed contract, ordering 100 aircraft and 150 engines per year, and buying foreign aircraft instead. In a meeting, a MAN representative responded to the allegations with the following:
“The majority of countries on the world stage have, starting from 1930, begun to equip their own air forces with planes built entirely out of metal, offering much better performance. This also being the policy of the Ministry of Equipment of the Romanian Air Force, taking into consideration the international situation, which is deteriorating swiftly, as long as the IAR factory will continue to only build aircraft from wood or mixed wood-metal, we are not interested, and will continue to rely on imports!”
During the same period, IAR developed a handful of new aircraft, one of them being a reconnaissance, observation, and training monoplane which was proposed directly to the S.S.A. (Subsecretariatul de Stat al Aerului). The blueprints and design specifications of the aircraft were discovered by Giorge Ciocoș at the Pitești archives.
IAR-22 trainer, which is what documents claim the H.S.300 was based on [Istoria Aviației Române]IAR-23, which also has a vast amount of similarities to the H.S.300. [Airwar]The plane was directly based on the IAR-22 trainer according to the factory documents, but a close analysis shows that it borrows details from several IAR aircraft, such as the empennage, which is borrowed from the IAR-23. Several other dimensions are the same as the IAR-23, such as the tailplane. It is entirely possible that the IAR-23, which was developed in March of 1934, served as a basis or inspiration for the IAR-H.S.300, as it was developed only 4 months later, in July 1934. Curiously, the documents continue to claim that the project was based on the IAR-22, stating that the wings are from the IAR-22, while a simple comparison of drawings or photos clearly shows that they are from the IAR-23. Additionally, the wings are identical to the IAR-21, which had undergone static testing in August of 1932.
Design & Construction
In the IAR documents, the aircraft is never officially given a name, instead titled as “IAR plane for training of reconnaissance and observation equipped with Hispano Suiza 300 hp engine.” Hence, it was given the unofficial moniker IAR-H.S. 300, referencing the engine. There are 7 documents detailing the layout and construction of the aircraft, with an additional 5 schemes and drawings showing the dimensions and design.
Structural side view of the IAR-H.S.300 [Dan Antoniu]The IAR-H.S.300 was a rather small monoplane, with a wingspan of 12 meters, and a total length of 8.45 meters. Empty, the plane would weigh 989 kg, and 1,420 kg fully equipped with radio and other onboard equipment.
The wing would be made entirely out of spruce, consisting of the central frame, with a length of 3 meters, and the wings themselves, at 4.5 meters each. The wings would be built upon two wooden spars, and the wing shape made from plywood. The longerons were attached to the rest of the aircraft frame via duralumin 90 degree braces. The leading edge and central portion were wrapped with plywood, while the trailing edge and flaps were covered with cloth. The horizontal stabilizers were also of wooden construction and wrapped with cloth.
Top view of the IAR-H.S.300 with measurements. Note the shape of the wings. [Dan Antoniu]In terms of the frame, it was made out of 4 spruce longerons, attached to each other via diagonal wooden supports. The attaching points were out of duralumin, and fastened with rivets. The fuselage that wrapped around the body was made out of sheet metal in the front and around the engine, plywood around the center and cloth on the tail. The elevator had a duralumin frame, but was covered with cloth, while the vertical stabilizer was made entirely out of duralumin construction and wrapped with cloth.
Frontal view of the IAR-H.S.300, showing its wooden propeller. [Dan Antoniu]The landing gear was conventional, consisting of two wheels with brakes and shock absorbers. It was fixed and reinforced with a diagonal truss. Total weight of the landing gear would be 65 kg.
As for fuel reserves, the aircraft would’ve had two fuel tanks, one in each wing, with a capacity of 115 liters each (230 total) but there was the possibility to increase it up to 500 liters total. The oil tank had a capacity of 18 liters.
Clear side view of the IAR-H.S.300. [Dan Antoniu]As mentioned previously, the engine was a Hispano Suiza 8Fb, a 18,5 L V-8. It had between 312 to 320 horsepower at normal power, and a maximum of 337. Typical revolutions per minute were 1,800 rpm and max was 2,100 rpm. Total weight was 275 kg. First variants were developed in 1914 and would be one of the most used engines by the Entente Powers during the First World War, which Romania was a part of, but later variants remained widely used throughout the 1920s and 30s. This powerplant would theoretically allow the IAR to reach a top speed of 238 km/h at 2,000 meters. Max ground speed was 245 km/h. Landing speed was to be 92 km/h. Range was 750 km with the 230 liter configuration. Time to altitude of 3000 meters was 8 min and 30 seconds.
The Hispano Suiza 8Fb V-8 engine. [Wiki]
Crew and Equipment
As a typical observation and training aircraft, there were two seats in the plane, both equipped with steering controls. The pilot is seated directly above the wings, in an open cockpit. He sat low in the plane’s body, with only his head protruding, protected by a small windshield.
The second aviator sat right behind the wings, higher up than the pilot for better visibility. He sat in a rotating turret that had a machine gun equipped, what type is unspecified. Below him were three drums, with 100 rounds each (300 total). A standard A.T.R. 4 radio was also available. The photo camera was positioned behind the turret, but could be operated from within the turret. Although the turret allowed for enough space to maneuver comfortably, the crewmans parachute was placed in a shelf behind him, for more efficient mobility.
Faith
Ultimately, the S.S.A. rejected the IAR-H.S.300. While the Air Force did need new observation and training aircraft, its method of construction and materials used were not accepted by the MAN and MAM (Ministerul Aerului și Marinei). Despite this, the plane seemed to be adequate for its role and time, with modern radio and photography devices, a turret and a respectable engine. Had IAR been able to produce a prototype and offer improvements, such as a fully enclosed cockpit, it would have been a competitive aircraft in its role. Unfortunately, IAR was bankrupt and unable to promote its designs.
IAR-27 light bomber and reconnaissance aircraft, built in the years prior to the war, more or less out of desperation. [Airwar]The salvation of IAR came in 1936, when Poland became the only supplier to grant Romania production licenses. M.A.N. purchased licenses for the production of the Polish PZL-11 and PZL-24 aircraft, which had full metal fuselages, and were decent aircraft for their time. This required vast investments into the IAR factory, for the tooling and production facilities, and also the personnel and design bureau.
However in 1938, with war knocking at Europe’s door, the M.A.N. equipped the Romanian Air Force with whatever the factories could produce, such as the IAR-37, IAR-38, and IAR-39, which likely wouldn’t have been produced if the IAR-H.S.300 had been pushed into service and upgraded, as they were also reconnaissance and light bomber aircraft. These aircraft did not prove to be a significant upgrade, and were also built out of a combination of metal and wood, but circumstances forced M.A.N. to buy them regardless.
Conclusion
The IAR-H.S.300 was a small reconnaissance and training aircraft developed as a last ditch attempt by IAR for the Romanian Air Force. However due to its construction consisting of part metal, part wood combined with the Romanian Ministry of Defence’s reluctance to accept such planes, the project died quickly. In the end, the Romanian Air Force was forced to purchase mixed construction wood-metal planes from IAR, due to the mounting hostilities of late 30s Europe.
Acronyms and Translations
I.A.R. (Industria Aeronautică Română) Eng: Romanian Aeronautic Industry
A.R.R. (Aeronautica Regală Română) Eng: Royal Romanian air force
S.E.T. (Societatea pentru Exploatări Tehnice) Eng: Technical Exploitation Society
I.C.A.R. (Întreprinderea de Construcții Aeronautice Românești) Eng: Romanian Aeronautics Construction Company
M.A.N. (Ministerul Apărării Naționale, Eng: Ministry of Defence
S.S.A. (Subsecretariatul de Stat al Aerului) Eng: State Subsecretary of Air
MAM (Ministerul Aerului și Marinei) Eng: Ministry of Air and Navy
IAR H.S. 300 Specifications
Wingspans
12 m / 39 ft 4 in
Length
8.45 m / 27 ft 9 in
Wing Area
21.9 m² / 71.9 ft²
Engine
Hispano Suiza 8Fb V-8, 312 hp
Empty Weight
989 kg / 2,180 lb
Maximum Takeoff Weight
1,429 kg / 3,150 lb
Fuel Capacity
230 liters / 60.75 gal
Maximum Speed
238 kph / 147 mph
Time to Altitude
3,000 meters / 9,840 feet – 8 min 30 sec
4,000 meters / 13,120 feet – 13 min 0 sec
5,000 meters / 16,400 feet – 19 min 10 sec
Range
750 km / 466 miles
Crew
1 Pilot & 1 Radio Operator/Photographer
Armament
Single Machine Gun (Unspecified) 3x 100 Round Drum Magazines
Gallery
Artist Conception of IAR HS.300 – Illustration by Godzilla
Credits
Written by Pavel Alexe
Edited by Henry H., Ed Jackson, & Stan Lucian
Illustration by Godzilla
Special thanks to Dan Antoniu and Eng. L. C. Tascau
Nazi Germany (1944)
Parasite Interceptor – None Built
Artist’s depiction of the Sombold So 344 firing off its nose rocket. [Heinz Rodes]The Sombold So 344 was a highly specialized interceptor designed by Heinz G. Sombold to attack Allied bomber formations over Germany in 1944. The way the aircraft would attack, however, would be extremely unconventional. Being deployed from a bomber mothership, the So 344 would fly towards an approaching bomber formation and launch its entire nose cone, which was a 400 kg (882 Ib) rocket, at the enemy bombers in an attempt to destroy as many as possible. From there, the So 344 could either attack the remaining bombers or return to base and land on a skid. Work went as far as wind tunnel models for the aircraft but none would be built.
History
Towards the end of the Second World War, Germany found itself at odds on an almost daily basis against the threat of Allied bombers. While pre-existing aircraft were used to defend Germany from this threat, more and more proposals for aircraft designed to deal with enemy bombers began to emerge. A number of these projects would use extremely unorthodox or downright strange methods to attempt to destroy enemy bombers. These ranged from carrying specialized weapons to even ramming the bomber. These projects were often small in design and were made of widely available materials, like wood, to save on production costs, reserving the more important material for mainline aircraft. An aircraft produced in small numbers that followed this formula was the Bachem Ba 349 “Natter”. Although not used operationally, the Ba 349 was a small bomber interceptor that would not require an airstrip to take off. Instead, it would be launched vertically from a launch rail. After taking off, the Ba 349 would approach the Allied bombers and attack them with a salvo of rockets in the nose. With its ammo depleted, the pilot would then eject from the aircraft, with the aircraft’s engine section parachuting down and being recovered for reuse. The nose would break off for the pilot to deploy the rockets under the cone. The Ba 349 is the most well known of these projects, but many would never leave the drawing board. Many of these aircraft designs were created by large companies but a handful came from individual engineers. One such design, the Sombold So 344, would approach the destruction of enemy bombers in an entirely different, almost ludicrous way.
3-way view of the So 344 [Luft46.com]The Sombold So 344 was the idea of Heinz G. Sombold of the Bley Ingenieurbüro (Engineering Office). Bley Segelflugzeug was a sailplane manufacturer located in Naumburg, Germany. During the 1930s, they became popular for their various sailplane designs, like the Kormoran and Motor-Kondor designs. Heinz G. Sombold was an engineer at Bley. He began working on the So 344 in late 1943 and his aircraft incorporated many features of the sailplanes built by the company. At the time, the craft was only designed as a parasite escort fighter and armed with two machine guns. On January 22nd of 1944 however, Sombold would drastically change the design and purpose of the aircraft. From here, the aircraft would be designed for the destruction of enemy bombers. To fit this new role, it would use a very unorthodox weapon. The nosecone of the So 344 was a rocket filled with 400 kg (880 Ib) of explosives that could be launched by the pilot at enemy aircraft. Sombold envisioned his aircraft using its nosecone rocket against close formations of bombers, where multiple aircraft could be destroyed with one well placed explosive. American bombers would often fly in combat box formations, where the bombers would fly close together to maximize the defensive capabilities of their guns. This allowed the bombers to have ample protection from enemy interceptors, as the approaching craft would come under fire from most of the aircraft in said formation. There were earlier weapons deployed by the Germans to try and damage the closely packed formations, like the BR 21, but none would be as huge a payload as the Sombold’s nose rocket.
Rear view of the wind tunnel model
Design work on the So 344 continued through 1944, even going as far as having a ⅕ scale wind tunnel model being made and tested at the Bley facility. By 1945, work on the project was cut off, as the Bley facility had to be abandoned due to the encroaching warfront. No further work was done on the Sombold So 344 and Sombold’s fate is unknown. No other designs by Sombold are known to have existed. The 344 designation was later used for the Ruhrstahl X-4, or RK 344, air-to-air missile system.
At the top of this image is the photo of the claimed nosecone of a Sombold So 344. In actuality it is a nose section of a Wasserfall SAM. [Lower: Wiki][Upper: Luftwaffe Secret Projects 17]A photo has circulated in several books, as well online, that claims a nosecone of the So 344 was built and discovered by the Allies at the end of the war. However, this photo actually depicts the nose section of a Wasserfall surface-to-air missile. The nose of the Wasserfall easily could be confused for that of the Sombold’s, as its shape is semi-similar and both have four stabilizing fins. No So 344 was built.
Design
Photo of the 1/5 wind tunnel model of the Sombold So 344
The Sombold So 344 was a single man special attack aircraft. It was to have a short, tubular body of wooden construction. For ease of transport, the aircraft could be split into two sections. The cockpit would be located at the rear of the body, directly in front of the vertical stabilizer. The aircraft would have conventional control surfaces on its wings and stabilizers. At the ends of the horizontal stabilizers were two angled vertical stabilizers. The wings would be mid-set. For its powerplant, the So 344 would use a Walter 509 bi-fuel rocket engine. To conserve fuel, the aircraft would be deployed via bomber mothership. Once deployed, it would have around 25 minutes of fuel. To land, the So 344 would have a rounded ski built into the body, similar to how the sailplanes Bley created would land.
For its main armament, the So 344 had a massive unguided rocket as its nose cone. The nose would contain 880 Ibs (400 kg) of explosive Acetol. The rocket was triggered via a proximity fuse. For stabilization, four fins would be placed on the nose. Additionally, the So 344 would have two forward machineguns to either defend itself or attack other bombers once its payload was released.
Operations
The So 344 would be carried to an approaching bomber formation via a modified bomber mothership. Once deployed, the aircraft would move in an arc towards the bombers, coming in downwards at them from at least 3,300 ft (1,000 m) above. This height would protect the So 344 from defensive fire during its dive. When the aircraft was lined up with a group of bombers, the pilot would launch the nosecone into the middle of the formation. Given the close proximity of the bombers in formation and the explosive threshold of the nosecone, it was predicted the resulting explosion would be able to take down several bombers in one attack. After launching its nosecone, the So 344 would have some fuel left and could continue to attack the remaining bombers with two machine guns on the aircraft. When fuel was low, the aircraft would return to base via gliding, like the Messerschmitt Me 163B rocket interceptor. Once near an airfield, it used a large ski to land.
Conclusion
The So 344 was a very strange way of approaching the bomber problem over Germany late in the war. The logic behind it was not too far fetched. The aforementioned Ba 349 Natter followed a similar attack plan, approaching the bombers and firing off a salvo of rockets before the pilot bailed from the craft. A project like the So 344 was not new to Germany by that point in the war and, like most of its contemporary designs, was not produced.
Had it been produced, the So 344 would have been a very niche aircraft. The fact that the aircraft had a single shot from its rocket payload made accuracy extremely important. The aircraft also would have been a prime target for Allied escort fighters once it ran out of fuel. A bomber would also need to be modified to carry the So 344 and would be a prime target for the escort fighters once the attacker was launched. The nature of the aircraft has led it to wrongly be named a “suicide attacker” by many postwar books on the subject. In some instances, the craft is also incorrectly listed as being a ramming aircraft. It is likely the aircraft would not have impacted the war very much.
Variants
Sombold So 344 (1943)– Original planned fighter version. Armed with two machine guns or heavier armament. None were built
Sombold So 344 (1944)– The Sombold So 344 attack aircraft. Armed with a nosecone rocket which would be fired at enemy bomber formations. None were built.
Operators
Nazi Germany – The Sombold So 344 was designed for the Luftwaffe to use against Allied bombers over Germany. None of the type would be built.
Sombold So 344 Specifications
Wingspan
18 ft 8 in / 5.7 m
Length
22 ft 11 in / 7 m
Height
7 ft 1 in / 2.2 m
Wing Area
64.58 ft² / 6 m²
Engine
Walter 509 Bifuel rocket engine
Weight
2,976 Ib / 1,350 kg
Flight Time
25 minutes
Crew
1 pilot
Armament
2x machine guns
1x 880 Ib (400 kg) Nose Rocket
Gallery
Artist’s Concept of a completed So 344 with striped nosecone – By Ed Jackson
Video
Credits
Article by Marko P.
Edited by Henry H. and Stan L.
Illustration by Ed Jackson
Herwig, D. & Rode, H. (2003). Luftwaffe Secret Projects: Ground Attack & Special Purpose Aircraft. Hinckley, England: Midland Pub.
Germany (1944)
Experimental VTOL Fighter – Paper Project
The bizarre looking Focke-Wulf Triebflügel fighter design. [luft46.com]During the war, German aviation engineers proposed a large number of different aircraft designs. These ranged from more or less orthodox designs to hopelessly overcomplicated, radical, or even impractical designs. One such project was a private venture of Focke-Wulf, generally known as the Triebflügel. The aircraft was to use a Rotary Wing design in order to give it the necessary lift. Given the late start of the project, in 1944, and the worsening war situation for Germany, the aircraft would never leave the drawing board and would remain only a proposal.
History
During the war, the Luftwaffe possessed some of the best aircraft designs and technology of the time. While huge investments and major advancements were made in piston engine aircraft development, there was also interest in newer and more exotic technologies that were also being developed at the time, such as rocket and jet propulsion. As an alternative to standard piston engine aircraft, the Germans began developing jet and rocket engines, which enabled them to build and put to use more advanced aircraft powered by these. These were used in small numbers and far too late to have any real impact on the war. It is generally less known that they also showed interest in the development of ramjet engines.
Ramjets were basically modified jet engines which had a specially designed front nozzle. Their role was to help compress air which would be mixed with fuel to create thrust but without an axial or centrifugal compressor. While this is, at least in theory, much simpler to build than a standard jet engine, it can not function during take-off. Thus, an auxiliary power plant was needed. It should, however, be noted that this was not new technology and, in fact, had existed since 1913, when a French engineer by the name of Rene Lorin patented such an engine. Due to a lack of necessary materials, it was not possible to build a fully operational prototype at that time, and it would take decades before a properly built ramjet could be completed. In Germany, work on such engines was mostly carried out by Hellmuth Walter during the 1930s. While his initial work was promising, he eventually gave up on its development and switched to a rocket engine insead. The first working prototype was built and tested by the German Research Center for Gliding (Deutsche Forschungsinstitut für Segelflug– DFS) during 1942. The first working prototype was tested by mounting the engine on a Dornier Do 17 and, later, a Dornier Do 217.
The Dornier Do 217 was equipped with experimental ramjets during trials. [tanks45.tripod.com]The Focke-Wulf company, ever keen on new technology, showed interest in ramjet development during 1941. Two years later, Focke-Wulf set up a new research station at Bad Eilsen with the aim of improving already existing ramjet engines. The project was undertaken under the supervision of Otto Ernst Pabst. The initial work looked promising, as the ramjets could be made much cheaper than jet engines, and could offer excellent overall flying performance. For this reason, Focke-Wulf initiated the development of fighter aircraft designs to be equipped with this engine. Two of these designs were the Strahlrohr Jäger and the Triebflügel. The Strahlrohr had a more conventional design (although using the word conventional in this project has a loose meaning at best). However, in the case of the Triebflügel, all known and traditional aircraft design theory was in essence thrown out the window. It was intended to take off vertically and initially be powered by an auxiliary engine. Upon reaching sufficient height, the three ramjets on the tips of the three wings would power up and rotate the entire wing assembly. It was hoped that, by using cheaper materials and low grade fuel, the Triebflügel could be easily mass-produced.
A model of the Triebflügel. This is how it may have looked if completed. [Wiki]
The Name
Given that these ramjet powered fighter projects were more a private venture than a specially requested military design, they were not given any standard Luftwaffe designation. The Triebflügel Flugzeug name, depending on the sources, can be translated as power-wing, gliding, or even as thrust wing aircraft. This article will refer to it as the Triebflügel for the sake of simplicity.
Technical Characteristics
Given that the Triebflügel never left the drawing board, not much is known about its overall characteristics. It was designed as an all-metal, vertical take-off, rotary wing fighter aircraft. In regard to the fuselage, there is little to almost no information about its overall construction. Based on the available drawings of it, it would have been divided into several different sections. The front nose section consisted of the pilot, cockpit, and an armament section for cannons and ammunition, which were placed behind him. Approximately at the centre of the aircraft, a rotary collar was placed around that section of the fuselage. Behind it, the main storage for fuel would be located. And at the end of the fuselage, four tail fins were placed.
A drawing of the Triebflügel’s interior. [luft46.com]This aircraft was to have an unusual and radical three wing design. The wings were connected to the fuselage while small ramjets was placed on their tips. Thanks to the rotary collar, the wings were able to rotate a full 360o around the fuselage. Their pitch could be adjusted depending on the flight situation. For additional stability during flight, the tail fins had trailing edges installed. The pilot would control the flying speed of the aircraft by changing the pitch. Once sufficient speed was achieved (some 240 to 320 km/h (150 to 200 mph)), the three ramjets were to be activated. The total diameter of the rotating wings was 11.5 m (37 ft 8 in) and had an area of 16.5 m² (176.5 ft²).
This unusual aircraft was to be powered by three ramjets which were able to deliver some 840 kg (1,1850 lb) of thrust each. Thanks to ramjet development achieved by Otto Pabst, these had a diameter of 68 cm (2.7 ft), with a length of less than 30 cm (0.98 ft). The fuel for this aircraft was to be hydrogen gas or some other low grade fuel. The estimated maximum speed that could be achieved with these engines was 1,000 km/h (621 mph). The main disadvantage of the ramjets, however, was that they could not be used during take-off, so an auxiliary engine had to be used instead. While not specifying the precise type, at least three different engines (including jet, rocket, or ordinary piston driven engines) were proposed.
In the fuselage nose, the pilot cockpit was placed. From there the pilot was provided with an overall good view of the surroundings. The main issue with this cockpit design wass the insufficient rear view during vertical landing.
Close up view of the Triebflügel landing gear assembly. [Secret Jets of the Third Reich]The landing gear consisted of four smaller and one larger wheels. Smaller wheels were placed on the four fin stabilizers, while the large one was placed in the middle of the rear part of the fuselage. The larger center positioned wheel was meant to hold the whole weight of the aircraft, while the smaller ones were meant to provide additional stability. Each wheel was enclosed in a protective ball shaped cover that would be closed during flight, possibly to provide better aerodynamic properties. It may also have served to protect the wheels from any potential damage, as landing with one of these would have been highly problematic. Interestingly enough, all five landing wheels were retractable, despite their odd positioning.
The armament would have consisted of two 3 cm (1.18 in) MK 103s with 100 rounds of ammunition and two 2 cm (0.78 in) MG 151s with 250 rounds. The cannons were placed on the side of the aircraft’s nose. The spare ammunition containers were positioned behind the pilot’s seat.
Final Fate
Despite its futuristic appearance and the alleged cheap building materials that would have been used in its construction, no Triebflügel was ever built. A small wooden wind tunnel model was built and tested by the end of the war. During this testing, it was noted that the aircraft could potentially reach speeds up to 0.9 Mach, slightly less than 1,000 km/h. The documents for this aircraft were captured by the Americans at the end of the war. The Americans initially showed interest in the concept and continued experimenting and developing it for sometime after.
In Modern Culture
The Triebflügel taking off in the movie. [marvelcinematicuniverse.fandom.com]Interestingly, the Triebflügel was used as an escape aircraft for the villain Red Skull in the 2011 Captain America: The First Avenger movie.
Conclusion
The Triebflügel’s overall design was unusual to say the least. It was a completely new concept of how to bring an aircraft to the sky. On paper and according to Focke-Wulf’s engineers that were interrogated by Allied Intelligence after the war, the Triebflügel offered a number of advantages over the more orthodox designs. The whole aircraft was to be built using cheap materials, could achieve great speeds, and did not need a large airfield to take-off, etc. In reality, this aircraft would have been simply too complicated to build and use at that time. For example, the pilot could only effectively control the aircraft if the whole rotary wing system worked perfectly. If one (or more) of the ramjets failed to work properly, the pilot would most likely have to bail out, as he would not have had any sort of control over the aircraft. The landing process was also most likely very dangerous for the pilot, especially given the lack of rear view and the uncomfortable and difficult position that the pilot needed to be in order to be able to see the rear part of the aircraft.
The main question regarding the overall Triebflügel design is if it would have been capable of successfully performing any kind of flight. Especially given its radical, untested and overcomplicated design, this was a big question mark. While there exist some rough estimation of its alleged flight performances, it is also quite dubious if these could be achieved in reality. The whole Triebflügel project never really gained any real interest from the Luftwaffe, and it is highly likely that it was even presented to them. It was, most probably, only a Focke-Wulf private venture.
Triebflügel Estimated Specifications
Rotating Wing diameter
37 ft 8 in / 11.5 m
Length
30 ft / 9.15 m
Wing Area
176.5 ft² / 16.5 m²
Engine
Three Ramjets with 840 kg (1,1850 lb) of thrust each
Empty Weight
7,056 lbs / 3,200 kg
Maximum Takeoff Weight
11,410 lbs / 5,175 kg
Climb Rate to 8 km
In 1 minute 8 seconds
Maximum Speed
621 mph / 1,000 km/h
Cruising speed
522 mph / 840 km/h
Range
1,490 miles / 2,400 km
Maximum Service Ceiling
45,920 ft / 14,000 m
Crew
1 pilot
Armament
Two 3 cm MK 103 (1.18 in) and two 2 cm (0.78 in) MG 151 cannons
Gallery
A rendition of how the Triebflugel may have looked had it been built. Illustration by Pavel ‘Carpaticus’ Alexe.
Credits
Article by Marko P.
Duško N. (2008) Naoružanje Drugog Svetsko Rata-Nemačka. Beograd.
D. Sharp (2015) Luftwaffe Secret Jets of the Third Reich, Dan Savage
Jean-Denis G.G. Lepage (2009) Aircraft of the Luftwaffe 1935-1945, McFarland and Company
J.R. Smith and A. L. Kay (1972) German Aircraft of the Second World War, Putham
United States of America (1953)
Long Range Interceptor Proposals [None Built]
Detailed drawing of the N-144, with cutaway section
Born from the Long Range Interceptor program, the first of Northrop’s contenders were three aircraft that had large delta wings and overall similar shapes and designs. The first, the N-126, started as a modified version of Northrop’s F-89D Scorpion fighter but would become its own unique aircraft by 1954. The second, the N-144, was a large four-engine interceptor design that dwarfed current bombers of the time and could carry an impressive arsenal. The third, the N-149, differed the most from its two siblings. It was much smaller and used General Electric engines over Wright engines. The N-144 was the most successful out of the entire program, but would prove to be too costly and a maintenance nightmare if produced. The N-126 and N-149 would also not meet expectations, as did none of the other competitors in the doomed program.
The LRI Competition
At the start of the Cold War, it was realized that if a Third World War would ever happen, defending the mainland United States from airborne threats would be a top priority. ICBMs and nuclear missiles are the go-to threat everyone imagines when they think of the Cold War, but these wouldn’t be operational until the late 1950’s. In the early years, nuclear weapons would be deployed by strategic bombers and these would be the major threat. Intercepting these long range aircraft would be of the utmost importance if the war went hot in the 1950’s. Developing an aircraft able to reach these bombers and destroy them led to the creation of the modern interceptor. Most countries had begun developing an interceptor of their own. At the forefront was the United States Long Range Interceptor program (LRI). This program originated in early 1952, with Major General L.P. Whitten of the Northeast Air Command noticing that a capable aircraft would be able to takeoff and intercept enemy bombers using the warning time of the Semi-Automatic Ground Environment (SAGE) system, which was an integrated defense network of SAM, radar and fighters across the US and Canada, able to intercept enemy bombers well before they were able to reach the United States. Although the idea was put out, no official requirements for the idea came about until December of 1953, when the Air Council put out extremely demanding needs. The aircraft would need to be airborne in two minutes from getting the scramble alert. Maximum speed would be Mach 1.7 with a range of 1,000 nm (1,850 km). Combat ceiling would be 60,000 ft (18,000 m) with a climb rate of 500 ft/min (150 m/min). The aircraft would be minimally armed with forty-eight 2.75 inch rockets, eight GAR-1A Falcon AAMs or three unguided nuclear rockets. This requirement became known as Weapon System WS-202A. Most companies developed submissions, but McDonnell and Northrop had an early start with a long range interceptor design being conceived very early on, well before an official requirement had been requested. Northrop had three aircraft designs that would fit the requirement for WS-202A; the N-126, N-144 and N-149. All three were visually similar to each other and shared concepts and equipment with one another.
Northrop N-126: The Delta Scorpion
Bottom view of the N-126 Delta Scorpion model [US Secret Fighter Projects]The first of the designs Northrop submitted was the N-126 Delta Scorpion. This aircraft actually began development months before an official requirement was put out. The design was submitted in February of 1953 and was essentially a Northrop F-89D Scorpion modified with a new delta wing design and Wright YJ67 engines. The aircraft received a performance review sometime in 1953 along with McDonnell’s two-seat version of the F-101 Voodoo. Neither design was chosen for production. The N-126 did show promise, as it came close to meeting the very first requirements and it was supported by the Air Defense Command. However, the predicted first flight in twenty-one months was a bit too optimistic and the design was disliked by the United States Air Force Headquarters, as it didn’t exactly meet requirements compared to the F-101 variant. Northrop pushed this early design and adamantly tried to acquire production.
Front quarter view of the N-126 Delta Scorpion model [US Secret Fighter Projects]They were quick to begin working on an improved design that would be longer and yield better results. It took over fifty concept designs before they found a suitable improvement. The aircraft itself no longer resembled the F-89D Scorpion it got its name from, but the name would stick until the end of the project. This new design was submitted in August of 1954. The N-126 was now much sleeker, with a forty-five degree delta wing and two underwing Wright J67-W-1 engines (Allison J71-A-11 engines were a weaker alternative choice). The delta wings all three projects used provided lower weight than generic straight wings and minimized drag. The trailing edge of the wing would have a split speed brake on the outer surface, an aileron located in the middle and a feature on the inboard section only referred to as an “altitude flap”. For the landing gear, a bicycle configuration with two wheels on each gear would be mounted directly under the aircraft, with a smaller landing gear being placed under the wings.
For armament, the aircraft would use the required eight Falcon AAMs and forty-eight rockets being mounted in a 20 ft weapon bay. Four external hardpoints would allow extra ordnance to be carried, such as bombs or extra missiles. Alternative loadouts included any combination of four AIR-2A unguided nuclear rockets, six Sidewinders, or two Sparrow guided missiles. The N-126 would use the Hughes E-9A fire control system, one of the few remnants carried over from the F-89. The E-9A would be linked to a long-range search radar that would have a range of 100 nm (185 km). For fuel, one large internal tank and two smaller tanks in the wings would hold 4,844 gal (22,025 l). Extra drop tanks could be mounted under the wings and offer an additional 1,600 gal (7,275 lit). For its predicted mission, the N-126 would be able to launch and engage enemy bombers twenty-seven minutes after scramble. Northrop expected a prototype would be ready for a first flight by June of 1957.
Northrop N-144: The Monstrous Interceptor
Color photo of the N-144 model [US Secret Fighter Projects]The N-144 was the second design Northrop submitted. It was made to offer the best results in regard to the WS-202A requirements. It resembled the N-126 but was much larger and had four J67 engines. The N-144 dwarfed its siblings, competitors, and even several current bombers of the time. With a wingspan of 78 ft and a length of 103 ft, this was no small aircraft. In comparison, the Convair B-58 supersonic bomber had a wingspan of 56 ft and a length of 96 ft (interesting to note, a plan to convert the B-58 into a long range interceptor was proposed).
Its appearance wasn’t the only thing carried over from the N-126. The E-9A fire control system, its accompanying scanner, and its landing gear design (now with four wheels on the main gear) were all reused in the N-144. The N-144 also had a forty-five degree delta wing like the N-126. The N-126 and N-144 would both have their engines on pylons on the wings. This configuration allowed much more powerful engines to be used and a simpler intake system compared to having the engines be built into the body, not to mention the layout being much safer in the event of a fire.
Top down view of the N-144 model. Note the 45 degree delta wing [US Secret Fighter Projects]The N-144 utilized many features that would directly improve the aerodynamics of the aircraft. The aircraft would have low wing loading which would increase its cruise altitude and improve takeoff and landings. The addition of a horizontal tail, which isn’t often seen in delta wing designs, gave the N-144 improved handling and stability over designs that lacked the horizontal tail (see the Convair F-102 Delta Dagger for example). When the aircraft would be supersonic, the wing would have a chord flap that would retract into the wing to reduce drag. Area ruling was a feature involving tapering the center of the fuselage which would reduce drag while the aircraft was flying at supersonic speeds. Most current delta wing designs utilized area ruling, but none of Northrop’s interceptors surprisingly did. Northrop ruled that the advantages would only affect supersonic flight, and not provide anything useful during subsonic flight. Having no area rule also made the aircraft simpler in design and easier to produce. Northrop’s studies into the delta wing expected to see performance increase as time went on, with more modifications and better engines being used on the N-144 if it went into production. With these expected improvements, Northrop theorized a 14% improvement in top speed and service ceiling.
Frontal view of the massive N-144 model. The size of its engine pods are evident. [US Secret Fighter Projects]For armament, the N-144 would still utilize the standard eight Falcon AAMs and forty-eight rockets, but could also carry twelve Falcon AAMs, six AIR-2A Genie (Ding Dong) rockets, 452 2.75 in FFAR rockets or 782 2 in (5.1 cm) rockets internally in any order. External hardpoints could also be fixed for carrying bombs or more ordnance. For fuel, a large fuel tank would be in the wings and fuselage and could carry 6,910 gal (31,419 l) of fuel. Given the size of the aircraft, Northrop advertised that it could be used in alternative roles.
Northrop N-149: The Opposite End
Model of the N-149. The additional fuel tanks can be seen. [US Secret Fighter Projects]The N-149 was the third and final design submitted by Northrop for WS-202A. Submitted in July of 1954, the N-149 was almost the polar opposite of the N-144. Instead of opting for raw power and utilizing four engines, the N-149 was meant to be the smallest option available while still performing just as well as its competitors. In comparison, the N-126 would be 85 ft (25.9 m)long with a wingspan of 62 ft (19 m), while the N-149 would be 70 ft (21.5 m) long with a wingspan of 50 ft (15.5 m). This size decrease would save cost, space and fuel consumption. The N-149 used the same wing layout as the previous entries and would also retain the E-9A fire control system and accompanying radar. Given the advancements of the N-144’s wings, it is likely the N-149 would also benefit from them as well. The N-149 did not use Wright J67 jet engines like the N-126 and N-144, but would instead use General Electric J79 engines. These engines were longer than the J67 but would benefit the aircraft, given its small size, to achieve the required speed and rate of climb. The bicycle landing gear with outer wing gear was once again used, but now with two wheels on each gear like the N-126. The armament for the N-149 was less than its predecessors, but it would make up for weapons in the amount able to be built. Once again, eight Falcon AAMs and forty-eight 2.75in rockets were standard, but alternative armaments would be a single Sparrow AAM, four Sidewinder AAMs, another 105 2.75 in rockets or 270 2 in rockets. Additional armament could be mounted on four external hardpoints like the N-126 and N-144, however, two of these would be taken up by external fuel tanks. These tanks would be 600 gal (2,730 l). The majority of the fuel would be in a large tank that spanned the fuselage and into the wings and would carry 2,050 gal (9,320 l) of fuel. Northrop expected a first flight of the aircraft by the summer of 1957.
The Program Concludes
Detailed drawing of the N-149 with cutaway
Although Northrop is the center of this article, Boeing, Douglas, Lockheed, Martin, McDonnell, North American, Chance-Vought, Grumman and Convair all submitted designs. When the assessment of all the designs was completed, it was concluded that none of the proposals exactly met up the set requirements. The N-144, however, came the closest to meeting the specification. After assessment, the N-144 had a predicted speed of Mach 1.76, a combat ceiling of 58,500 ft (17,800 m) and a combat range of 1,015 nm (1,880 km).
McDonnell’s design came close, as it could go faster and reach the same altitude, but its range was much less compared to the N-144. Materials Command was not too keen of the N-144 and it is obvious why. The cost, production and maintenance of it would be tremendous. Given its four engines, the aircraft would require much more maintenance compared to its two-engine competitors. Producing such a large aircraft would be extremely costly given its size and engine count. The best option for performance would also be the worst option considering its cost.
Its siblings didn’t meet the specifications as well. No reason was put out as to why the N-126 failed the competition, but given the state of the program, it can easily be assumed it didn’t meet either the range, speed, or altitude requirements. The N-149 did have a specified reason for its rejection, though. After taking off at full power and reaching its maximum height, it would only offer 20 minutes of flight, with 5 minutes at full power for combat. Having your aircraft destroy as many bombers before reaching their target is necessary and only 5 minutes wouldn’t be sufficient to fulfill its duty. Ultimately, WS-202A wouldn’t produce any aircraft. The requirements had gone too high, and the companies wouldn’t be able to produce a cost effective aircraft in time that would meet the expected specifications. The program would go on to become the new LRI-X program in October of 1954, and Northrop would be one of three companies tasked with creating a new interceptor, which their Delta-Wing trio would surely influence in a number of ways.
Variants
Northrop N-126 (February 1953) – The 1953 N-126 Delta Scorpion was an improvement upon the F-89D Scorpion by having a delta wing and YJ67 engines.
Northrop N-126 (1954) – The 1954 version of the N-126 no longer resembled the F-89 but was now longer and more streamlined.
Northrop N-144 – The N-144 would be the second design submitted to the LRI competition. It was much larger than the other two submissions and would utilize four engines.
Northrop N-149 – The N-149 was the smallest of the three designs and was meant to be the best performing for its size. It looked visually similar to the N-126 but would carry slightly less ordnance and utilize Gen Elec XJ79-GE-1 jet engines over the Wright J67-W-1s.
Operators
United States of America – All three designs would have been operated by the United States Air Force had they been constructed.
Northrop N-126 – Artist Impression of the Delta Scorpion in USAF Prototype StageNorthrop N-144 – Artist Impression of the N-144 the in Late Prototype StageNorthrop N-149 – Artist Impression of the N-149 in service with the 171 Fighter Interceptor Squadron, Michigan, circa 1960s
3-Way drawing of the N-126 Delta Scorpion [US Secret Fighter Projects]3-Way drawing of the N-149 [US Secret Fighter Projects]Underside quarter view of the N-126 model [US Secret Fighter Projects]
3 view drawing of the N-126 Delta ScorpionA photo of the N-126 Delta Scorpion in wind tunnel testing
3-Way drawing of the N-149 [US Secret Fighter Projects]Colored photo of the N-149 model. Note the tail has been slightly damaged. [US Secret Fighter Projects]Rear view of the N-149 model. Damage to the tail is evident here. [American Secret Projects: Fighters & Interceptors, 1945-1978]Credits
An alternate side view of the Fw 190 mit DB 609 model. [Falko Bormann]The Focke-Wulf Fw 190 mit DB 609 was a 1942 design venture to provide the Luftwaffe with a successor to the Fw 190 and its troublesome BMW 801 radial engine. Intended, to mount the envisioned experimental 16-cylinder Daimler-Benz DB 609 engine to produce around 2,600 hp (later 3,400 hp), the new power plant would have required a drastic redesign to the forward section of the Fw 190 as well as parts of the fuselage. In the end, the Fw 190 mit DB 609 was canceled due to flaws with the design and Daimler-Benz’s cancellation of the DB 609 project. Similar to many of the other designs produced in 1942, the Fw 190 mit DB 609 remained a paper design only, although an airframe was provided for the intent of mounting and testing the engine. Obscure in nature and short-lived, much of the project’s specifications and estimated performance are unknown.
History
The original blueprint illustration of the Fw 190 mit DB 609. [War Thunder Forums]The Focke-Wulf Fw 190 Würger (Shrike) was one of Nazi Germany’s most iconic fighters of the Second World War. First introduced in August of 1941, the Fw 190 gave contemporary Allied fighters a run for their money and proved to be a relatively successful design. However, the air-cooled 14-cylinder BMW 801 radial engine which powered the Fw 190 proved to be troublesome at times. The BMW 801’s cooling system was inadequate, which caused overheating and production of fumes, which would leak into the cockpit and could suffocate the pilot. Despite the relatively successful introduction of the Fw 190, it was not known if the Reichsluftfahrtministerium (RLM / Ministry of Aviation) would make further orders for the aircraft. However, the spring of 1942 was a prosperous time for the Focke-Wulf firm and assured the Fw 190’s future. The RLM put in orders for large quantities of Fw 190, which in turn boosted the firm’s budget. As such, designers at the Bremen-based Focke-Wulf firm initiated a design venture to produce a successor for the Fw 190 by replacing the troublesome BMW 801 engine with more advanced engines being developed by BMW and Daimler-Benz.
As such, the Focke-Wulf firm produced several drawings in late 1942 which saw the Fw 190 mounting experimental engines. The designs are as follows:
Drawing Number
Project Title
10 10 05-201
Fw 190 mit BMW P. 8028
10 10 05-202
Fw 190 mit BMW 801 J
10 10 05-203
Fw 190 mit DB 609
10 13 141-02
Fw 190 mit DB 623 A
10 13 141-16
Fw 190 mit DB 614
11 19 05-502
Fw 190 mit BMW P. 8011
Unknown
Fw 190 mit DB 603
Unknown
Fw 190 Strahljäger
In order to provide a suitable testbed for these engines, Fw 190 V19 (Werknummer 0042, rebuilt from a Fw 190 A-1) was allocated for engine installation tests. Curiously enough, Fw 190 V19 would be later be redesigned for the “Falcon” wing design which saw a drastic redesign of the wing to a swept, bent design. Conversion to this wing type was meant to take place on February 16, 1944 but this would never occur. Nonetheless, Fw 190 V19 would maintain the regular wings for engine testing.
A closeup of the Fw 190 mit DB 609 model’s cockpit and fuselage section, highlighting the supercharger radiator’s placement. [Falko Bormann]Although the Fw 190 mit DB 609 showed potential, there were several problems which plagued the design. For one, the rather heavy and bulky engine severely affected the aircraft’s center of gravity. As such, the engine’s radiators had to be moved down the fuselage behind the cockpit. The engine also would have put too much stress on the landing gears which could potentially result in a fatal crash if landing conditions were rough. On top of the airframe design issues, the intricate design of the engine also proved a problem for the Daimler-Benz designers, who would terminate the DB 609 (and its subprojects) in April 1943. As such, the Fw 190 mit 609 project would be dropped as well without the experimental engine ever being mounted on V19. Many of the other designs produced by Focke-Wulf in 1942 would also meet the same fate, for more or less similar reasons.
Due to the short-lived conceptual nature of the design, detailed specifications and estimated performance do not appear to have survived. As such, much of the aircraft’s intricate details and specifications are unknown. One could only hope that, in the near future, more details of the Fw 190 mit DB 609 and it’s contemporary designs will surface.
Design
A model of the Fw 190 mit DB 609 in a hypothetical livery with a drop tank. [Falko Bormann]The Focke-Wulf Fw 190 mit DB 609 was a 1942 project to produce a successor to the Fw 190 by replacing the troublesome BMW 801 engine with more promising experimental engines being developed at the time. As the name of the project suggests, this design would have seen the implementation of a Daimler-Benz DB 609 V16 engine. The Daimler-Benz DB 609 was a development of the company’s DB 603 engine. Unlike its predecessor, the DB 609 would have 16 cylinders in contrast to the former’s 12 cylinders. The DB 609’s output was estimated by Daimler-Benz designers to be approximately 2,600 to 2,660 hp, though it would later be upped to 3,400 hp. The benefits of this engine were the ability to function normally upright and inverted, but the bulky engine design required a drastic redesign of the engine cowl and parts of the fuselage. The cowl would have been extended to accommodate the DB 609 engine, the length of which would have measured at 115 in / 2,935 mm compared to the BMW 801’s 79 in / 2,006 mm length.
According to the official blueprints for the Fw 190 mit DB 609, the two large radiators intakes required for the engine’s supercharger were moved to the cockpit’s rear, on the side of the fuselage. This was done to pull the center of gravity back, as placing them in the front would make the aircraft too nose heavy. The placement of the supercharger radiators is similar to that of the American Republic P-47 Thunderbolt. It would appear that internet sources claim the radiator placement was nicknamed the Hamsterbacken (Hamster Cheeks), but it is unknown whether or not this was an official nickname.
Fw 190 V19 (Werknummer 0042), which was intended to mount and test the DB 609 engine, was rebuilt from a Fw 190 A-1, but it is unknown which variant precisely the hypothetical production variant would be based upon. Armament wise, the official project blueprints show two 7.92x57mm Mauser MG 17 machine guns mounted on top the engine cowl. What appears to be a 20x82mm Mauser MG 151/20 cannon would be installed in the engine hub and would fire out through the propellers. It is unknown what wing armament (if any) the Fw 190 mit DB 609 would have had.
Due to the rather short-lived and conceptual nature of the Fw 190 mit DB 609, not many of the plane’s specifications are unknown. Performance estimations do not appear to be available, nor are aircraft dimensions.
Operators
Nazi Germany – The Focke-Wulf Fw 190 mit DB 609 was intended to be a successor to the Fw 190. However, development was dropped due to various problems with the design and engine.
Gallery
Artist Concept of the Fw 109 with the DB 609 Engine [Ed Jackson]A retouched blueprint of the Fw 190 mit DB 609. [Heinz J. Nowarra]Credits
Primary Sources
Fw 190 mit DB 609 (Drawing. No. 10 10 05-203). (1942). Bremen: Focke-Wulf Flugzeugbau AG.
Nazi Germany (1942)
Jet Fighter Concept – None Built
An official blueprint showing the Fw 190 Strahljäger’s design and estimated performance. (Die Deutsche Luftrüstung 1933-1945: Vol. 2)
The Fw 190 Strahljäger (Jet Fighter) was a conceptual turbojet fighter and the Focke-Wulf Flugzeugbau firm’s first attempt to design a jet-powered fighter. First mentioned in a report dated November 5, 1942, the Fw 190 Strahljager would have seen the BMW 801 radial engine replaced by a Focke-Wulf T.1 turbojet engine capable of producing 1,300 lb / 600 kg of thrust at most. Short-lived and canceled mere months after its conceptualization, the Fw 190 Strahljäger is quite mysterious in many aspects, such as how the engine would have performed while mounted. Unfortunately, due to the unique nature of the design, the Fw 190 Strahljäger has been the victim of falsification and malicious misinformation. One of the most popular claims on this aircraft was that it was built. This is almost assuredly false, as no primary sources support this claim. A photo does exist which purports to show a Fw 190 with the jet engine, but this photo is definitely a fake as there are too many discrepancies and questionable content, such as the plastic model looking landing gear. Nonetheless, the Fw 190 Strahljäger is quite an interesting design from 1942 that shows Focke-Wulf’s attempts to remedy the powerplant issues of their Fw 190.
History
When first fielded in August of 1941, the Focke-Wulf Fw 190 Würger (Shrike) made a positive impression with Luftwaffe pilots. Seemingly equal or superior to most contemporary Allied fighters, the Fw 190 gained a fearsome reputation among the Allied pilots, who at first did not even realize the Fw 190 was a new aircraft model. Despite the success of the Fw 190, there were several problems with the aircraft’s design. For one, the air-cooled 14-cylinder BMW 801 radial engine which powered the aircraft was prone to overheating due to inadequate cooling systems and, as a result, would produce fumes which would seep into the cockpit and suffocate the pilot. This issue was somewhat addressed in subsequent production variants, but the problem was never snuffed out. In an attempt to address this issue, the Bremen-based Focke-Wulf firm began to look into the possibility of changing the powerplant. However, it was not until late 1942 that the firm launched several design ventures for a new design. In the spring of 1942, the Focke-Wulf firm received a considerable amount of funds from production orders for the Fw 190 by the Reichsluftfahrtministerium (RLM / Ministry of Aviation). The goal of the design venture was to provide a successor to the Fw 190 by replacing the BMW 801 with more promising engines being developed at the time.
A colored official blueprint showing the Fw 190 Strahljäger’s design and estimated performance. Note the large “Ungültig” on the document, which means “Invalid”. (Doktor_Junkers)
One of the designs which resulted from this venture was the Fw 190 Strahljäger (jet fighter), a curious design that first appeared in documents on November 5, 1942. This design explored the feasibility of replacing the BMW 801 with a Focke-Wulf designed turbojet engine. Even before 1942, the Focke-Wulf firm looked into the possibility of replacing the BWM 801 with a turbojet. Dr. Otto Pabst, a Focke-Wulf engineer, told British officials after the war that he attempted to design a jet engine which would be used for the Fw 200 Condor bomber before the Second World War started. The report which entails his interview states: “Dr. Pabst had also worked on a gas turbine engine to be constructed by Focke-Wulf, which consisted of a double entry radial compressor and a single stage axial flow turbine with a single annular burner chamber which was expected to produce 600 kg (1,300 lb) thrust at 11 km (7 mi) or 2 kg (4 lb) thrust at sea level.“ The 4 lb / 2kg thrust at sea level is likely an error by the document author, and the more realistic thrust would be 440 lb / 200 kg. The engine in question was the Focke-Wulf T.1, and this same engine was envisioned to power the Fw 190 Strahljäger.
Much of the Fw 190 Strahljäger’s developmental history is unknown due to poor documentation and the project’s short lifespan. It would appear that the Fw 190 Strahljäger was designed with the intent of making the turbojet nose easily adaptable to standard Fw 190 airframes. Surprisingly, estimated performance graphs on the Fw 190 Strahljäger exist and demonstrate improvement over the standard Fw 190 A variant. Despite this, however, the Fw 190 Strahljäger’s top speed was lower than the Heinkel firm’s He 280 jet fighter and the Messerschmitt firm’s Me 262 fighter. As such, the Reichsluftfahrtministerium decided that the project was not worth pursuing and priority was given to the other firm’s jet fighter programmes. As such, the Fw 190 Strahljäger project would come to an end either in very late 1942 or early 1943, after only two or three months of development time. The original intent to replace the BMW 801 with a turbojet failed, and the Fw 190 program would evolve to utilize improved and reliable conventional reciprocating engines and propellers.
Fact or Fiction? – Author’s Analysis
With the mysterious and unique nature of the Fw 190 Strahljäger design, several online publications from recent times have made several claims about the project, with the most important being that a Fw 190 was actually converted to test the turbojet. This claim is certainly false, as primary documentation and credible historians show that the project did not even make it past the drawing stage. Although the Focke-Wulf firm could have easily taken a factory fresh Fw 190 off of the production lines to test this, just because they could does not mean they did.
A fake photo of the Fw 190 Strahljäger. Several discrepancies in this photo gives away it’s doctored nature. (greyfalcon.us)
There does exist a photo which claims to be evidence that a Fw 190 Strahljäger was built, but there are several discrepancies which suggest that it is fake. For one, the landing gear seems rather plastic, and the shadows are questionable. The shadow of the main wing suggests it is evening or morning and the sun is off to the left, while the shadow from the tailplane is projected as if the sun is behind the plane. Furthermore, it appears that two Werfer-Granate 21 rocket launchers are hung beneath the wing. If a hypothetical aircraft was converted to test the engine, it would make no sense for it to retain the launchers especially when it takes little time to remove them. Lastly, it seems that the nose exhaust is at the wrong angle relative to the fuselage. In conclusion, this appears to be a photo of a model which has been bleached to give the black and white effect. FotoForensics (used to detect photoshopped images) does not appear to suggest that the photo was modified, but this could possibly be due to the image not being the original one.
Other than that, a curious nomenclature which has surfaced in recent times suggests the turbojet-powered Fw 190 would be called the Fw 190 TL (TurboLader Strahltriebwerk – Turbocharger Jet Engine). However, this claim is questionable as official documents only state the name was “Fw 190 Strahljäger”. This can possibly be chalked up to misinformation.
Design
A diagram showing the turbojet engine in detail, along with some of the statistics of the aircraft. (Projekt ’46)
The Fw 190 Strahljäger was a 1942 project to mate a Focke-Wulf designed turbojet engine with a standard Fw 190 A airframe. According to credible secondary sources and an interview with former Focke-Wulf engineer Otto Pabst, the engine which would power the Fw 190 Strahljäger “consisted of a double entry radial compressor and a single stage axial flow turbine with a single annular burner chamber which was expected to produce 600 kg (1,322 lb) thrust at 11 km (6.8 mi) or 2 kg (4 lb) thrust at sea level”. As mentioned earlier, the 4 lb / 2 kg thrust was likely an error and the actual engine would produce 440 lb / 200 kg of thrust at sea level. The engine was the Focke-Wulf T.1 turbojet. The exhaust of the turbojet would be passed through a ring-shaped outlet between the engine and the fuselage. The exhaust passed through the side and bottom, but not the cockpit on the top. The engine would be accompanied by 370 gal / 1,400 l fuel, which the engine uses at 309 gal / 1,170 l per hour. This would give the Fw 190 Strahljäger a total flight time of 1.2 hours or 72 minutes.
A postwar Allied report which shows the Fw 190 Strahljäger’s blueprint. (Author’s Collection)
The Fw 190 Strahljäger’s armaments consisted of two 7.92x57mm Rheinmetall-Borsig MG 17 machine guns mounted on the engine cowl and two 20x82mm Mauser MG 151/20 cannons, one in each wing. It is unknown whether or not the aircraft would have been able to carry ordinance.
Official graphs of the Fw 190 Strahljäger’s estimated performance exist. Some fundamental specifications are listed in the Specifications Table below.
Operators
Nazi Germany – The Fw 190 Strahljäger was intended to replace the Fw 190’s troublesome BMW 801 engine, but the design did not go into production due to several factors.
Focke-Wulf Fw 190 Strahljäger*
* – Information taken from “Das Focke-Wulf Strahltriebwerk wird an die vorhandene Zelle Fw 190 angebout” published in 1942 by the Focke-Wulf Flugzeugbau AG and “Luftwaffe: Secret Jets of the Third Reich” published in 2015 by Dan Sharp
Wingspan
34 ft 5.78 in / 10.51 m
Wing Area
197 ft² / 18.3 m²
Engine
1x single stage axial flow turbine Focke-Wulf T.1 turbojet
Engine Ratings
4 lb / 2 kg at Sea Level*
1,300 lb / 600 kg at 7 mi / 11 km
* – Likely an error in the document, the more realistic thrust would be 440 lb / 200 kg
Nazi Germany (1938)
Italy (1932)
United States of America (1953)
