Category Archives: WW2

World War 2 saw the airplane rise to even greater importance than in the first World War. Air superiority became a crucial component of battlefield operations and air forces were massively expanded during the conflict.The Allied and Axis sides of the war developed enormous war machines, capable of developing and rolling out unprecedented numbers of advanced new military equipment in rapid response to changing conditions on the battlefield, as well keeping up with the technological advances of adversaries.

High altitude bombing raids and night fighting were hallmarks of the War for Europe, whilst aircraft carrier battles pitched the American and Japanese fleets against one another. The technology of the day was pushed to it’s limit with the use of superchargers in aircraft engines, the introduction of radar, and the rapid development of the jet engine by the war’s end.

The period ended as the Nuclear Age and subsequent Cold War were ushered in by the tremendous and tragic blows to Japan’s wearied people.

Vought F4U Corsair

sweden flag USA (1942)
Naval Fighter Plane – 12,571 Built

black-and-white-f4u

The F4U Corsair is another most famous fighter and fighter-bomber of WWII, although it saw action mostly against the Japanese in the Theatre of the Pacific, therefore being primarily used by the US Navy and the Marines. This airplane in particular was specifically designed for aircraft carriers, being a naval aircraft in essence, although initial doubts over its performance on-board an aircraft carriers made it to serve initially as a land-based asset. It saw also action during the Korea War as a ground attack and Close Air Support (CAS) aircraft, and with the French in the Indochina, Algeria, and Suez Canal crisis. It also saw some service in the Atlantic during WWII, mainly with the British Fleet Air Arm, where reportedly provided air cover to the airplanes attacking the battleship Tirpitz, and served in the Indian and Pacific Oceans. The Corsair contributed to change the balance over the skies of the Pacific by shooting down many Mitsubishi A6M Zeros, although not as much as the Grumman F6F Hellcat.

The Corsair is single-seat and single engine fighter/fighter-bomber for day and night-time, featuring a characteristic inverted gull wing (Similar to that of the Junkers Ju-87 Stuka and the Loire-Nieuport 40) and a very long propeller-blade. The development of the Corsair began following a request by the US Navy for twin and single-engine fighters in 1938, with the single-engine required to obtain the maximum speed possible and a stalling speed of no more than 110 km/h (70 mph), and a long range. Interestingly, the initial requirements comprised the aircraft to carry anti-aircraft bombs to be dropped on enemy formations. That same year, Vought – the builder company – was awarded a contract to start with the development of the Corsair.

The Corsair was a pretty advanced aircraft for the times, and this characteristic meant that its development would find several problems that required solution, which in turn, were quite remarkable. Even so, the Corsair required improvements while in service, which does not deny the fact that it was one of the greatest and unique airplanes of the war, let alone a good complement to other aircraft carrier-based fighters and among the best naval fighters in the war.

One of the main features during development was the incorporation of the largest engine available, the Pratt & Whitney R-2800 V-18 Double Wasp of 2250 hp, requiring the installation of a wide three-blade Hamilton propeller. This installation had two visible effects on the design: First, the characteristic shape of the airframe, where the bow is basically the area where the big and long engine is located, almost displacing the cockpit further aft. Second, it yielded speeds of up to 652 km/h (405 mph), making it the first single-engine American design to reach such speed. But the first problems emerged, especially in regards to diving speed that, although achievable, meant considerable damage to control surfaces and access panels, as well as problems with the engine. Spin recovery standards also needed to be revisited.

The wing itself, along with the longitudinal shape, were both a challenge when designing the frame. In regards to the inverted gull wing, it was purposed to make the width and the landing gear as short as possible, benefiting also the minimization of drag, as the anhedral of the center section gave an optimal meeting angle between the wing and the fuselage. Yet the weight of the wing alone neutralized those effects. But it also had the problems when recovering from developed spins, as the shape of the wing interfered with the elevator. It also had problems with the starboard strip, that used drop without warning, requiring the installation of small stall strips on the leading edges. The port wing also had the potential of stalling and dropping in failed landings, which was further dangerous if throttle was abruptly increased in such cases. The inverted gull wing was also a product of solving the problem of the landing gear, as they needed to be tall enough to keep the propeller away from the ground (the same problem the Saab J-21 had). It simply shortened the length of the legs, while the landing gear was able to retract and rote 90° into an enclosed wheel well, maintaining the streamline of the wings.

The Corsair, however, was benefited during its development thanks to the experiences of other air forces when the war sparked in Europe. As a result, the set of 2 X 7.62mm synchronized engine cowling-mount machine guns, and the 2 X 12.7mm wing machine guns was deemed unsuitable, prompting the armament scheme to be modified. Three 12.7mm machine guns were fitted on each wing, increasing the firepower of the Corsair.

redbull-f4u-corsair-and-b25-mitchell
A Corsair and Mitchell bomber, fly together at an airshow.

As it was abovementioned, other problems prevented the Corsair to serve as a carrier-based fighter until 1944, mainly those related to the type of landing required in that type of vessel. Not only the wing-related problems when performing this manoeuvre, but also the location of the cockpit plus the long bow made landings particularly dangerous for new pilots. Furthermore, during landing approaches manoeuvres, the oil from the hydraulic cowl flaps had the tendency to spatter onto the windscreen, compromising visibility, and the oleo struts had bad rebound when landing, making the entire aircraft to bounce upon landing. The top cowl flap down was sealed, while a valve was fitted to the landing gear legs in order to solve the issues, solution that were, on the other hand, implemented by the British firstly. It had its first flight in 1940, entering in service in December 1942 intended as a naval fighter, but these problems delayed its utilization as carrier-borne fighter and the US Navy initially preferring the F6F Hellcat, but it also meant that the Marines would use the Corsair as their main air assets, and it was with this branch that the Corsair began to carve its reputation. It entered in service in the late 1942, where the Marines began to make use of it at the Battle of Guadalcanal and the Solomon Islands, where its first debut was rather disappointing. But once the Marines learned how to maximize the advantages of the Corsair, they began to contest the air supremacy the Japanese had. It also saw extensive action as a fighter-bomber/attacker in the Marshall Islands, Palaus, Iwo Jima and Okinawa.

It was the British the ones that solved the operational problems of the Corsair for naval use, as they began to operate with the Corsair in 1944, on-board the HMS Victorious. Those Corsairs saw action as carrier-borne aircraft by supressing Flaks and providing escorts to aircraft performing raids against the Kriegsmarine battleship DKM Tirpitz in three raid operations: Operation Tungsten, Operation Mascot and Operation Goodwood. Later on the British Corsairs were deployed in the Indian Ocean and the Pacific, attacking Japanese targets on April 1944.

The Corsair saw action in post-WWII conflicts such as the Korean War, the Indochina War, among others. Many served with other air forces as surplus or donated aircraft, where it served more than 30 years after WWII was over, when it scored its last air victories and gave an honourable closure to an era past gone. 10 F2G ‘Super’ Corsair series also served as civilian racers after the war.  A total of 12571 Corsairs were built, being in service with the US Navy, the Marines and other air forces from 1942 to 1979, attesting the good quality of the aircraft and its endurance, being produced until 1953. A total of 15,386 Mustangs were built.

Design

The Corsair is a low inverted gull wing fighter, with a single tail and a single engine: Pratt & Whitney R-2800 V-18 Double Wasp of 2250 hp, with a wide propeller fitted as to maximize the power yield. As a result of the size of the engine, the bow or nose of the Corsair is particularly long, which made the cockpit to be located further aft. The relocation and reconfiguration of the armament – which was placed at the wings – and the resulting relocation of the fuel tank in front of the cockpit contributed to its location in the airframe, which in turn had to be elongated.

The wings with their characteristic shape were the result of the need for shortening the legs of the landing gear and for accommodating also a folding wing, while being located also well ahead the pilots’ cockpit, making the Corsair to have a cross shape. This wing design also resulted in the Corsair having remarkable aerodynamics over similar airplanes of its type. The shape of the wing was also beneficial in the sense that the meeting angle between the wing as the fuselage reduced drag and saved the utilization of wing root fairings, although the bent wing tended to neutralize such benefits given its weight. On a similar way to the Saab J 21, the supercharger air intakes, alongside the oil coolers, were placed at the wings, this case on the anhedraled center section of the wings. The combination of the propeller diameter, the engine and the wing’s shape and length – alongside the resulting aerodynamics – made the Corsair the fastest naval aircraft the US had at its disposal. The flaps were changed to a NACA slotted type while the ailerons were increased in span.

The fuselage, mainly the large panels, were made of aluminium and attached to the frames by spot welding, which eliminated the use of rivets. The top and the bottom areas of the outer wings were made out of fabric, as well as the ailerons, the elevators – which were also made of plywood – and the rudder. At the rear an IFF (Identification Friend or Foe) transponder device was installed.

The landing gear consisted typically of two ‘legs’ at the wings and a rear small wheel, with the carrier-based version having also a tail hook for the arresting cable. All of the set was retractable, only that the ‘legs’ at the wings rotated 90° and then swivelled backwards, a trait that common among many US fighters. Noteworthy to remark that the landing gear was hydraulically operated, alongside the cooling flaps, the wing flaps, the wing folding and locking, the arresting gear, the gun charging, and the dive breaks.

The aft cockpit had some interesting features and modifications resulting from the assessed hazards while landing on an aircraft carrier. As this problem was the result of the nose and the location of the same cockpit, a rectangular plexiglass panel was fitted in the lower center section, so to allow the pilot to see below and perform carrier landings with more safety. In addition, armour plates were applied to the canopy area, with the windscreen being a 38mm bullet-proof installed internally and the behind the curved windscreen. To aid the pilot’s rear view, half-elliptical planform transparent panels were placed at each side of the structure right behind the cockpit, yet the view provided was rather limited.

The aft section of the Corsair is also full of noticeable characteristics, with a projecting fuselage tip where the vertical stabilizer is placed, which is large. The horizontal stabilizer is, in turn, placed ‘aft’ of the tail.

The Corsair’s armament was originally a set of two 7.62mm machine guns at the frontal section of the nose, and two 12.7mm machine guns, one at each wing. But as the abovementioned reports from the war in Europe obliged the armament to be modified, the final disposition was of 6 X 12,7mm machineguns at the wings, three on each side.

Death has bent wings.

F4U Climb

The Corsair was the most effective fighter the US Navy and the USMC had from the moment it was introduced and entered combat in the Solomon Islands in 1943. It was appraised by the pilots due to its performance and its capacity to remove the threat posed by the Mitsubishis A6M Zeros, as well as to break Japanese bombing raids. It was also capable of outfling and outfighting any land-based aircraft. It was capable of performing interception, bombing, ground-attack and fighter missions. The Corsair was a fighter that was also an ace-maker, with Kenneth Walsh (21 kills), Gregory “Pappy” Boyington (28 kills) and Joe Foss (26 kills). It was under Boyington lead that his squadron, the “Black Sheep” were the most effective squadron, scoring 97 kills and 103 damaged airplanes on the ground. Noteworthy to remark, the Corsair was also appraised by Admiral Nimitz giving its performance.

As the Corsair was cleared for carrier use, it began to operate on-board USS Essex and USS Bunker Hill. The Corsair also performed dive bombing missions in the Marshal Islands as it dropped more than 90718 kg (200000 lbs) of bombs against Japanese installations. It also took part in combats at China Sea, Okinawa, Iwo Jima, Formosa and the Philippines. It also took part on the Saigon and Tokyo Raids, which were diversionary attacks prior to Okinawa. It was also during Okinawa where they had to operate as fleet air defence against the Kamikaze attacks in the earlier stages of the battle, performing CAS with bombs, rockets and Napalm once the threat was neutralized. They reportedly achieved remarkable feats, like keep flying after ramming an enemy. The Corsairs scored 2140 Japanese airplanes with only 189 Corsairs lost, along with 14 warships and 33 merchants sunk (Saigon raid). These scores earned the Corsair Nimitz’s appraisal and a US government citation, and the builder granted an “E” after the War.

The Corsair was among the few WWII-era aircraft to serve right into the earlier days of the Cold War, as it took part in low altitude attack fighter-bombing and CAS missions in Korea, as well as heckling the enemy in night missions. It also attacked enemy installations It dropped bombs, Napalms, rockets and cannons the same way as in WWII, being both aircraft and pilots both veterans of that conflict, and operating from WWII aircraft carriers (USS Essex and USS Bon Homme Richard). As tough as it was, it was able to cary alarge payload and remain more time in the combat zone for CAS missions, and even the Corsair even managed to kill a North Korean Mig-15. The Corsair also had a high rate of availability and hard resistance against enemy fire.

One last dogfight over the jungle

F4U in flight

When the 1969 ‘Soccer War’ sparked between Honduras and El Salvador, both nations were having among their air forces inventories some WWII-era fighters, namely F4U/FG-1 and P-51D/TF—51 fighters. These airplanes were to perform the last dogfight between WWII-era (or piston-propelled engine) airplanes, like two medieval knights clad in armour, ready to joust for a last opportunity as to write the last chapter of an era. The morning of the 17th of July, 1969, the encounter was bound to take place. As Honduran Captain Fernando Soto was leading a group of three F4U-5 to strafing missions at the border, one of the Corsairs was attacked by two Salvadorian P-51, with Capt. Soto shooting it down. But there was to be a second encounter between the veteran aircraft, as late on the same day, during a bombing mission alongside another F4U-5, they encountered Salvadorian FG-1. The result was that both FG-1 were shot down, making of Capt. Soto the only “Ace” of the War.

P-51 of the Salvadorian Air Force, piloted by US mercenaries, patrolled the Salvadorian skies and border, looking also for the Honduras Corsairs, with no avail.

Variants

  • F4U-1 (Corsair Mk I)/FG-1 – This was the first production series of the Corsair, being characterized by a ‘bird cage’ canopy and a low seating position, featuring also the definitive abovementioned modifications for the series-production models, including the 6 X 12,7mm machine guns’ configuration. An additional pair of auxiliary fuel tanks were installed in each wing edge A two-seat trainer was built but was not accepted by the US Navy. The Corsairs in service with the Marine Corps did not had folding wing capacity neither they were fitted with an arrester hook but a pneumatic tail wheel, as they were land-based, receiving the designation FG-1 and being built by the Goodyear. Those with the British Fleet Air Arm were denominated Corsair Mk I.
  • F4U-1A (Corsair Mk II) – A post-war denomination introduced to differentiate the mid-to-late production batch. This version – which would be the second production version – would have a new type of canopy, similar to a Malcolm hood type – like that of the Spitfire – and with only two frames. It had a simplified windscreen, which improved visibility overall along with the canopy being taller. That the pilot’s seat was raised 180mm (7 in), in combination with a lengthened tailwheel strut, meant that visibility was also improved, solving the problems posed by the long nose. This is the version that, along canopy modifications, also introduced wing and undercarriage oleo struts modifications, becoming in the US Navy carrier-based version. This version also received a new power plant, the R-2800-8W water-injection engine, and the capacity to carry a center-section fuel drop tank. Goodyear also built a variant of this version, land-based and without folding wing capacities. Those in service with the British had their wings modified – shortened by 2cms/8 in – for use in their carriers, denominated FG-1A.
  • F3A-1 (Corsair Mk III) – Denomination for those built by the Brewster, which none of them reached front-line units as the building both production and quality control were poor, noticeable after having speed restrictions and broken wings (due to poor quality wing fittings).
  • F4U-1B – Unofficial post-war denomination to identify Corsairs modified for Fleet Air Arm use.
  • F4U-1C – Ground attack and fighter version, with the 6 X 12,7mm guns replaced by a set of 4 X 20mm AN/M2 (Hispano-Suiza) cannons thus providing considerable firepower for ground attack missions. Based on the F-4U-1. This version had a remarkable performance in the Battle of Okinawa, as it was introduced in 1945.
  • F4U-1D/FG-1D/F3A-1D (Corsair Mk IV and Mk III) – Ground attack and fighter version, developed and built in parallel to the F4U-1C. It had the new engine fitted in the F4U-1A, yielding speeds of up to 684 km/h (417 mph). It also carried an increased payload of rockets and a twin-rack plumbing for an additional belly drop fuel tank, which increased firepower but also drag. The range was also increased, meaning it could perform long missions. A single piece – Malcolm hood type – canopy was adopted firstly as a standard for this version, then for the following Corsairs. Goodyear and Brewster also produced this version, under denominations FG-1D and F3A-1D, respectively.
  • F4U-1P – Photo-reconnaissance version.
  • XF4U-2 – Nigh-time fighter version fitted with two auxiliary fuel tanks.
  • F4U-2 – Experimental carrier-based night-time fighter. Armed with 5 X 12,7mm guns, with the starboard gun being replaced by an Airborne Intercept radome containing a radar. 32 were modified by Naval Aircraft Factory, ant two more were modified in the front-line. It saw action in the Solomon Islands and in Tarawa.
  • XF4U-3 – Experimental version used to test different engines that never entered into combat. Goodyear also produced some units of this version, denominated FG-3. A single XF4U-3B was produced with some modification, intended to be issued to the British Fleet Air Arm.
  • XF4U-4 – Version with new engine and cowling.
  • F4U-4 – A naval fighter/fighter bomber version, being the last one taking part in WWII, as it was introduced by late 1944. It was powered by a 2100 hp dual-stage-supercharged V18 cylinder engine, with its power boosted to 2450 hp when the cylinders were injected with a water/alcohol mixture. An air scoop was fitted under the nose, while the wing fuel tanks were removed. The propeller was also changed from a three blade to a four blade type. The new engine, the mixture and the new propeller blades allowed the F4U-4 to reach speeds of up to 721 km/h (448 mph) and a better climbing rate (4500 ft/min / 1180 m/min). A flat bulletproof windscreen was also installed, avoiding optical distortions. Versions with wingtip tanks and a six-blade contra-rotating propeller were proposed but ultimately rejected by the US Navy.
  • F4U-4B – Corsair that were set to be delivered for the British Fleet Air Arm, but were confiscated by the US.
  • F4U-4C – A version with an alternate weapons set of 4 X 20mm AN/M2 (Hispano-Suiza) cannon. 300 delivered.
  • F4U-4E/F4U-4N – Night fighters with the starboard wing radar radome. The F4U-4E was equipped with an APS-4 search radar, and the F4U-4N was equipped with an APS-6 search radar. These Corsairs would have an armament of 4 X 20mm AN/M2 (Hispano-Suiza) cannons. These Corsairs served in the Korean War.
  • F4U-4K – Experimental drone version
  • F4U-4P – A photo-reconnaissance version.
  • XF4U-5 – Version with new engine cowling.
  • F4U-5 – A modified version of the F4U-4, introduced in 1945 and aimed at increasing the Corsair’s performance and introduce many of the suggestions issued by the pilots. It was powered with a Pratt & Whitney R-2800-32(E) engine with a two-stage supercharger of 2850 hp. Automatic blower controls, cowl flaps, intercooler doors and oil cooler for the engine were fitted. Spring tabs for the elevators and rudder, a modernized cockpit, a retractable tailwheel, heated cannon bays and pitot head were also fitted. The cowling was lowered two degrees, and the wings were all-metal. 223 units delivered.
  • F4U-5N – A radar equipped version. 214 units delivered.
  • F4U-5NL – A winterized version equipped with rubber de-icing boots on the leading edge of both wings and tail. 72 units delivered and 29 units modified from F4U-5N.
  • F4U-5P – A long range photo-reconnaissance version. 30 units delivered.
  • F4U-6/AU-1 – A re-designated AU-1 (which in turn, was based on a modified F4U-6), which was the ground-attack version in use by the Marine Corps. The AU-1 had extra armour protecting both pilot and fuel tank, as well as extra racks, and the oil coolers relocated inboard to reduce changes of ground fire damage. The supercharger was redesigned for low-altitude operations. Capable of carrying up to 3720kg (8,200lbs) of bombs and of reaching speeds of 383 Km/h (238mph) or 479 Km/h (298mph) when armed with bombs or rockets and with one or two fuel tanks. At empty payload this version could reach speeds of 626 Km/h (389mph). produced in 1952 and retired in 1957, seeing action in the Korea War.
  • F4U-7 – Version based on the AU-1 for service with the French Navy.
  • FG-1E – Goodyear-made Corsairs FG-1 with radar equipment.
  • FG-1K – Goodyear-made Corsairs FG-1 used as drones.
  • FG-3 – A turbosupercharger version from modified FG-1D airframes.
  • FG-4 – Goodyear-made Corsairs F4U-4 that were never delivered.
  • Super Corsairs (F2G-1 / F2G-2) – Versions developed after the war, powered by a Pratt & Whitney R-4360 Was major with 4-row 28-cylinder radial engine and a teardrop/bubble canopy. The F2G-1 had a manual folding wing and a 4,3m (14ft) propellers, the F2G-2 had hydraulic operated folding wings, 4m (13ft) propellers and carrier arresting hooks. Development problems delayed and finally ended further developments, with the F2G-2 becoming racing planes.

Operators

  • f4u-4-vmf-124-13-kenneth-a-walsh-okinawa-06-45_03
    U.S. Navy F4U-4 – VMF 124 No 13 – June 1945
  • United States of America – The Corsair was primarily used by the US Navy and the United States Marine Corps in most of the campaigns of the Pacific War. It started its service at Solomon Island in 1943 as fighter in the hands of the USMC, where three famous Pacific War American Aces marked their scores with Corsairs. It also took part of dive bombing operations in the Marshal Islands, seeing also action in the China Sea, Okinawa, Iwo Jima, Formosa, the Philippines and also in the Tokyo and Saigon Raids. In Okinawa, it became the main defence against Kamikaze attacks. The Korean War brought the Corsairs back given its capacity to carry large and heavy amounts of payload/ordnance, performing ground-attack and CAS missions, used by the USMC. Many were also sold as surplus aircraft, serving in the air forces of Argentina, El Salvador and Honduras.
  • f4u-1f-mk-1-1855-nas-faa-5f-jt150-10-43_03
    Royal Navy F4U-1 (F.Mk.1) 1855 NAS FAA – Oct 1943
  • United Kingdom – 2,012 Corsairs were issued to the British Royal Navy Fleet Air Arm in 1943, where the wings were clipped 8 inches in order to increase storage in the lower carrier decks, being the British Corsairs the first ones to be used in on an aircraft carrier. The Corsair also took part as escort fighter and anti-air defences in three operations – Operation Tungsten, Operation Mascot and Operation Goodwood – against German battleship DKM Tirpitz. In 1944, British Corsairs took part in operations at the Indian and the Pacific Ocean, remarkably used in Java as bombers. It was during Corsair service with the British, that enhancements for carrier operation were made.
  • French Navy F4U-7 - 14F Aeronavale No.133704 - Circa 1956
    French Navy F4U-7 – 14F Aeronavale No.133704 – Circa 1956
  • France – France and its naval air branch or Aéronavale operated with 69 AU-1 and 94 F4U-7s from 1954 to 1964. It was introduced to replace the Supermarine Seafires, Grumman Hellcats, Curtiss Helldivers and SBD Dauntless that equipped the naval air service. They operated from 4 carriers – Arromanches, Dixmude, La Fayette and Bois Belleau – that were part of the French Navy. 4 squadrons – the 14F, 12F, 15F and 10F – were operating with the Corsair, alongside two training squadrons – 10S and 57S. French Corsairs intervened firstly in Indochina, as they were handed by the US (AU-1 Korean War veterans) and where they were well received by French troops and pilots. In Indochina 6 Corsairs lost and 2 pilots dead.
  • The Corsairs also operated in Africa, namely in Algeria, Suez and Tunisia. In Algeria, they provided fire support, bombing, reconnaissance and protection of airborne troops. There were some considerable losses due to accidents and AA fire took place. In Suez, they took part in operations from carriers Arromanches and La Fayette, attacking the Cairo-Almanza airfield with only one loss against 12 planes damaged and 1 damaged of the Egyptians. The last action the French Corsairs saw was in Tunisia, where they provided support to besieged troops at a French airbase after Tunisian independence, attacking also Tunisian troops and vehicles. 3 Corsairs were lost due to the AA. The French reportedly used the Corsairs to experiment with anti-tank missiles, but they were never used. As new carriers and new air naval assets were introduced, the Aéronavale withdrew its Corsairs.
  • f4u-1a-rnzaf-22sqn-49944-1944_03
    Royal New Zealand AF F4U-1A – 22 Sqn 49944 – July 1944
  • New Zealand – The New Zealand air force shifted from the P-40 to the Corsair in 1944, receiving in total 424 airframes as a lend-lease, with 13 squadrons operating it. The RNZAF operated with F4U-1A, F4U-1D and FG-1D, concentrating on attacking the bypassed islands with ground support, escort and air patrols. Only 17 Corsairs were lost, as the Japanese air superiority was, by the time the Corsairs were received, almost neutralized. A squadron equipped with Corsairs served an occupation duty for two years once the Pacific War was over.
  • Argentina – Argentine acquired the day-time and night-time fighter versions of the Corsairs (26 F4U-5/5N/5NL) in 1957, being incorporated to the Argentinian aircraft carrier ARA Independencia. As the abovementioned versions were fitted with Radar, Argentina became the first nation in the region to operate aircraft with radars. They intervened during the 1958 border incidents with Chile, and in the period of 1959-1960, the Corsairs were used as submarine chasers – equipped with depth charges – following the detection of unidentified submarines. They also took part during the political revolt of 1963, being 1964 their last year of operational service during another set of border incidents with Chile. They were withdrawn from service in 1968.
  • Honduras – The Honduras Air Force operated the Corsair from 1956 to 1979, with 19 units. The Honduran Corsairs also took part in the 1969 ‘Soccer War’, where a single Corsair scored three victories against two Salvadorian Corsairs and one Mustang, piloted by Capt. Fernando Soto. These were the only air-to-air victories of the war. The Honduras Corsairs also performed strafing missions at the border. The Corsair that scored those victories is now a war memorial.
  • fg-1d-el-salvador-fas-201-67087-1958_03
    El Salvador Air Force FG-1D – 67087 – Circa 1958
  • El Salvador – The Salvadorian Air Force operated the Corsair from 1957 to 1976, with 25 F4U-/FG-1D. They took part in combats during the 1969 ‘Soccer War’, where took some losses in the hands of the Honduras Air Force operating similar F4U-4 and F4U-5 fighters.
  • Germany – Germany captured only one British Corsair that was forced to land in Norway due to technical issues while taking part in Operation Mascot.
  • Japan – Japan also captured two Corsairs after emergency landings, with one possible tested in flight.

 

F4U-4 Specifications 

Wingspan  12,49 m / 41 ft 0 in
Length  10,27 m / 33 ft 8 in
Height  4,5 m / 14 ft 9 in
Wing Area  29,17 m² / 314 ft²
Engine  1 Pratt & Whitney R-2800-18W 18 cylinder radial engine of 2,250 hp
Propeller Diameter  4,06 m/ 13 ft 4 in
Maximum Take-Off Weight  6149 Kg / 13,556 lb
Empty Weight  4174 kg / 9,202 lb
Loaded Weight  5626 kg / 12,405 lb
Maximum Speed  718 km/h / 446 mph
Range  2511 Km / 1,560 miles
Maximum Service Ceiling  12650 m /41,500 ft
Climb Rate  3050m in 5,1 minutes (22.1 m/s; 4,360 ft/min)
Crew  1 (pilot)
Armament
  • 6 X 12,7mm (0.50 caliber) M2Browning machine guns or 4 X 20mm AN/M2 cannons.
  • Up to 1000 kg (4000 lbs) of bombs.
  • 8 X 127 mm high velocity aircraft rockets.

Gallery

f4u-4-vmf-124-13-kenneth-a-walsh-okinawa-06-45_03
U.S. Navy F4U-4 – VMF 124 No 13 – June 1945
U.S. Navy F4U-1 VMF 123 no. 15 ‘Daphne C’ – July 1943
f4u-1a-vf-17-jolly-rogers-17640-bighog-11-43_03
U.S. Navy F4U-1A – VF-17 17640 ‘Big Hog’ – Nov 1943
U.S. Navy F4U-1D - VMF-451 20141 - Apr 1945
U.S. Navy F4U-1D – VMF-451 20141 – Apr 1945
Royal Canadian Navy FG-1D - 1841 Sqn BuNo 76236 - Aug 1945
Royal Canadian Navy FG-1D – 1841 Sqn BuNo 76236 – Aug 1945
f4u-1a-rnzaf-22sqn-49944-1944_03
Royal New Zealand AF F4U-1A – 22 Sqn 49944 – July 1944
Royal New Zealand AF F4U-1 - No. 21 Sq NZ5315 BuNo 49909 - Jun 1944
Royal New Zealand AF F4U-1 – No. 21 Sq NZ5315 BuNo 49909 – Jun 1944
f4u-1f-mk-1-1855-nas-faa-5f-jt150-10-43_03
Royal Navy F4U-1 (F.Mk.1) 1855 NAS FAA – Oct 1943
French Navy F4U-7 - 14F Aeronavale No.133704 - Circa 1956
French Navy F4U-7 – 14F Aeronavale No.133704 – Circa 1956
fg-1d-el-salvador-fas-201-67087-1958_03
El Salvador Air Force FG-1D – 67087 – Circa 1958

 

 

Sources

Aviation Publications (1977). Pilots Manual for F4U Corsair., Berger, R (Ed.). Aviones [Flugzeuge, Vicenç Prat, trans.]. Colonia, Alemania: Naumann & Göbel Verlagsgessellschaft mbH., Chant, C (2001). Aviones de la Segunda Guerra Mundial [Aircraft of World War II, Fabian Remo Tamayo & Fernando Tamayo, trans.]. Madrid, Spain: Editorial LIBSAD’Angina, J. (2014). Vought F4U Corsair. Oxford, UK: Osprey Publishing., Gunston, B. (1995). Guía Ilustrada de los Cazas y Aviones de Ataque Aliados de la Segunda Guerra Mundial (II). [An Illustrated Guide to Allied Fighters of World War II, Gearco, trans.]. Barcelona, Spain: Ediciones Folio (Original work published in 1981)., Gustin, E. (n.d.). Chance Vought F4U Corsair. F4UCorsair.com.HISTARMAR (n.d.). Chance-Vought F4U-5 Corsair. Fundación HISTARMAR.Lyford, C., & Tillman, B. (2014). Corsairs vs. Mustangs: The last dogfight. The Flight Journal, 16-24.Marsaly, F., & Bocognano, J. (2002). Les Corsairs de la Royale. Aérostories.org.Rochotte, L. (1999). Les Corsair Français. Net-Marine.Sherman, S. (2012). Vought F4U Corsair. Acepilots.com.The National WWII Museum (n.d.). Airplanes in the Us Freedom Pavilion: The Boeing Center.UTDallas (n.d.). Chance Vought/LTV History.Vought.org. (n.d.). F4U Corsair – WWII Record. Vought.org.Werbaneth, J. P. (2009). His Majesty’s Corsairs. Avalanche Press.Vought F4U Corsair. (2016, September 11). In Wikipedia, The Free Encyclopedia. Images: Black and White F4U by Brian Struble / CC BY 2.0,   F4U in FlightF4U Climb by Airwolfhound / CC BY-SA 2.0, Royal Navy F4U by Tony Hisgett / CC BY 2.0,  Redbull F4U Corsair and B25J Mitchell by Ronnie Macdonald / CC BY 2.0,   Side Profile Views by Ed Jackson – Artbyedo.com, Additional Side Profile Views by Brendan Matsuyama

Saab J 21R - 21463 w/ Gun Pod Side Profile View

Saab 21 / 21R

sweden flag Sweden (1945)
Fighter / Attack Plane – 298 Built

The Saab J 21 is a peculiar airplane, not only because of its advanced features. This fighter in particular is one of the only two airplanes that were initially powered with a piston-propelled engine, then later modified to incorporate a jet engine using the same airframe and implementing very few modifications. This airplane is also the product of Swedish defence concerns and resourcefulness, as Sweden wanted to keep its neutrality and territorial integrity during WWII, electing to develop a domestic fighter program as access to foreign advanced technology was restricted.

Saab J 21A-3 in a Hangar
Saab J 21A-3

A single-seat, single-engine airplane that later became one of the first-generation jet fighters. Its design is a twin-boom tail pusher configuration. It had two longitudinal booms, attached to the main wing but extending backwards from the middle section of each wing, with the main body placed in the middle. Similar to the Lockheed P-38. This design also implements a rear mounted piston engine, otherwise known as a pusher configuration, which made engine modifications easy.

The piston-propelled version, the J 21 – had the engine, a licensed Daimler-Benz DB 605B, simply fitted at the rear of the main body, behind the cockpit and between the longitudinal booms. The jet version – J 21R – was fitted with air in-takes at both sides of the fuselage, having the engine (a De Havilland Goblin 2 and later a Swedish-licensed version, a Flygmotor RM1) located on the same area as the piston-propelled version and elongating the main body. The fuselage section harbouring the engine was also widened. Another modification was that the elevator was placed at the upper area of the double tail plane. The wing in both configurations was a low-wing, being straight until it met the longitudinal booms, changing into a slightly swept wing from the longitudinal boom to the wing tip. It also received wingtip fuel tanks.

The J 21 could develop speeds up to 645 km/h (400,78 mph), while the jet propelled version could develop speeds up to 800 km/h (497 mph), being a fast aircraft in both configurations. Its firepower (J 21) was equally powerful, as it was armed with a 20 mm cannon, either a Bofors or a Hispano-Suiza HS.404, and 2X 13,2mm Bofors machineguns at the nose, with 2X 13,2mm Bofors machineguns in the wings. The J 21R received an even much more considerable firepower, as it featured a 20mm Bofors cannon, 4X 13.2mm M/39A heavy machine guns, a centreline pod with 8X 13.2mm M/39 machineguns, and wing racks for 10X 100mm, 5X 180mm, or 10X 80mm anti-armour rockets.

Saab J 21 Prototype
Prototype in Service

The J 21 was initially developed with the aim of providing Sweden with good air assets to defend its air space and neutrality, and also with the aim of replacing many of the existing airplanes development. The development began in 1939, under the lead of Frid Wänström, having as basis a Bristol Taurus as an engine, yet it fell into a momentary freeze until 1941, when it was resumed. This freeze was due to Saab’s concentration in the Saab B 17 and B 18 bombers. As the configuration resulted problematic for the pilot’s safety when bailing out, many proposed solutions came, such as blowing the propeller, blowing the entire engine or using a “bomb crutch” to throw the pilot away from the airframe. The solution came with the development and implementation of a Bofors ejection seat, which was tested first on ground and in-flight on a SAAB B 17. The nose landing gear wheel was tested on a steel platform attaching the three undercarriage components, with the structure being towed by a truck during the test programme. In 1943 the first flight of the prototype took place, with units entering in service with the Flygvapnet in 1945. Three prototypes were built during the development process. In 1947 the J 21 evolved into de J 21R when it received the De Havilland Goblin jet engine, but as the J 29 Tunnan was introduced, it replaced the J 21 as the main fighter, performing the J 21 instead ground attack missions, thus designated A 21R.

The J 21 was in service with the Flygvapnet from 1945 until 1954, with 298 fighters built from 1945 to 1949. The J 21R was in service with the Flygvapnet from 1950 until 1956, with 60 units built from 1950 to 1952. Three J 21 are preserved as static displays in museums.

Design

Saab 21 R
The jet powered Saab 21 R in flight

The basic design of the J 21/J 21R was a twin-boom tail pusher propeller, making it one of the most radical operational designs of those times. This scheme proved to be beneficial for two important aspects. First, it benefited both pilot view forward and allowed the armament to be concentrated on the nose, meaning that such combination provided a good firing scope and sight, let alone a good firepower and making maintenance services rather easy. Second, it made possible for the aircraft to be updated thus being able to install a jet engine using the same airframe of the piston-propeller engine version, which was basically the basic airframe.

The only drawback of this layout – mainly with the J 21 piston-propelled engine version – was the risk for the pilot to hit the blades when bailing out, as the engine was placed right behind the cockpit. The solution came with one of the first ejection seats in the world, developed by Saab in 1943, being tested on the ground and on-flight and being a SAAB B 17 the testing platform. Another drawback was that, similar as the earlier versions of the Mustang P 51, the rearward view was rather poor, which could be problematic in a dog-fight. The J 21 featured a characteristic wing, as it was roughly strait from the main fuselage to the tail twin-booms, then being slightly swept back from the tail booms to the wingtips.

The wing was purposed with acquiring laminar flow as far as possible. In regards to the aerodynamics, it was required the airframe to reduce minimum drag and engine cooling drag, so the oil and liquid coolers, along with the duct system for the engine, inside the airfoil contour between the fuselage and the tail booms. Considering the tail boom design, the horizontal elevator was placed between the tail sections, connecting them. The landing gear, meanwhile, was of tricycle configuration and long, which made the J 21 to be a tall aircraft so to keep the propeller away from the ground. The rear gear retracted into the tail booms behind the rear wing spar, but this forced the fuel tank to be placed in the wing centre section. The frontal wheel was located at the nose.

The engine was a Daimler-Benz DB 605B inverted V12 of 1475 hp, which gave the airplane speeds of maximum 645 km/h (400,78 mph), but as the engines were received in poor conditions, improvements and overhauling were required. As a result of the power provided by this engine and the aerodynamic characteristics, the J 21 was deemed good, as it had excellent handling, benign stall characteristics and tight turning circle. The armament also gave this fighter good firing power, with the Swedish pilots being able to compare it with the Mustang P 51D (Sweden received a good number of them) and considering they were a good match for it. But the main drawbacks were that at medium and high altitudes performance tended to decrease, the rearward view was poor, and the controls were heavy to operate, increasing tiring during combat.

The armament of the J 21 consisted of a 20 mm cannon, either a Bofors or a Hispano-Suiza HS.404, and 2X 13,2mm Bofors machineguns at the nose, with 2X 13,2mm Bofors machineguns in the wings. The J 21A-3 was able of carrying unguided rockets (2X 180mm or 8X 80/145mm) and bombs (600kg, 500kg, 250kg or 4X 50Kg).

Saab 21 Cockpit

After World War II, the jet engine technology was becoming the mainstream propulsion system, and the Flygvapnet wanted to catch up and incorporate such technology into its assets. As the development of a new jet propelled fighter would take some time, the J 21 was chosen to be the platform for using an airframe in use with the new technologies back then. As a result, the J 21R was developed and introduced, with the first prototype taking flight in 1947 and then entering service in 1950. This ‘new’ fighter required some structural changes so to cope with the new power plant, like up to 50% of its airframe. First, the main body was slightly prolonged ant widened, so to allow the De Havilland Goblin 2/Flygmotor RM1 engine (that allowed speeds of 800 km/h) and the air intakes, located at each side of the fuselage. In addition, the stabilizer was moved upwards top to the fin, so to allow the engine flow, requiring the tails to be redesigned. The wing leading edge was mover forward and made sharper. Airbrakes were introduced, one upward and other downward flaps placed on the outer wing’s trailing edge. Given the increased speed, the ejection seats were properly modified so to enable ejections at subsonic speeds. And as the propeller was removed, the landing gear was shortened in turn, reducing the height of the airplane. Fuel tanks were fitted in the middle wing and the wingtips, which increased the fuel volume.

The J 21R received an enhanced firing power, as the standard 20mm cannon/4X 13,2mm M/39A heavy machineguns set was added with a centreline external pod carrying 8 additional 13,2mm M/39 heavy machineguns. In addition, the J 21R was fitted with wing racks allowing the airplane to carry 10X 100mm or 5X 180 Bofors rockets, or 10X 80mm anti-armour rockets.

Materializing ‘Armed Neutrality’

The J 21 is, like the J 29 Tunnan, the product of Sweden’s concerns about its own security during WWII, especially in the light of Germany’s invasions of Norway and Denmark in 1940, which were neutral nations by the time. As Sweden considered that its existing air assets wouldn’t be able to successfully contribute to the defence, given their obsolete condition, it considered that new aircraft were necessary. As with the J 29, Sweden faced some problems when trying to acquire some technology due to the restrictions imposed by the conflict, although by sheer luck it was able to receive the Daimler-Benz DB 605B engine, as Germany was trying to hamper the delivery. These circumstances decided the Swedish government to undertake a local rearmament programme and implement a policy of ‘armed neutrality’ to secure the nation’s neutrality. The focus was placed on the development and fabrication of advanced aircraft. As the same concerns prevailed after World War II and into the very earlier days of the Cold War, it was deemed that the resulting technologies from the War needed to be exploited and incorporated, having in mind Sweden to catch up with the newly developed technologies, especially in regards of propulsion. The Saab J 21 became the platform for the Flygvapnet to make the transition from piston-propeller engine to jet engine, while at the same time providing the country with a locally built jet engine fighter, while newer and more advanced aircraft were put into service.

A feat of Swedish Nytänkande

The fact that the J 21 was used as a basis for an almost new jet powered engine fighter is a product of Sweden’s innovative thinking and also of its capacities – out of need, in part – of working with existing resources at the point of maximizing them. While the J 29 Tunnan has the honour of being the first jet fighter exclusively built for that purpose, it is the J 21 the very first jet engine fighter the Flygvapnet operated with, being amongst the very few designs, if not the only one, in being successfully modified as it received two different types of power plants. And while the J 29 Tunnan displaced the J 21 as a fighter, it was able to operate as a good ground attack aircraft until 1956, making this airplane born in the World War II, an early Cold Warrior and the basis for Sweden’s jet fighter industry and operationalization. It simply meant a huge step for the Swedish Air Industry, let alone its Air Force.

Variants of the J 21

  • J 21A-1 – Fighter version and the very first production series of the J 21. It featured the armament configuration of the 20mm Hispano-Suiza HS.404 cannon and the 13,2mm Bofors/Colt heavy machine guns. In service until 1949. 54 delivered.
  • J 21A-2 – Fighter version and the second and third production series, featuring enhanced avionics and incorporating a Bofors 20mm gun, with the other armament being the same. It was also equipped with further direction horizon instruments. In service until 1953-1954. 124 delivered.
  • J/A 21A-3 – Fighter/fighter-bomber version based from modified J 21A-2 airframes. It was equipped with a SAAB BT9 bomb aiming sight and two RATO (Rocket-Assisted Take-off) devices, armed with unguided rockets (2X 180mm or 8X 80/145mm) and bombs (600kg, 500kg, 250kg or 4X 50Kg). 119 delivered.
  • J 21B – A planned version to be armed with 3X 20mm guns at the nose, a radar in the starboard room, improved aerodynamics and better engines (A Daimler-Benz DB 605E/Rolls-Royce Griffon). It was also intended to feature a pressurized cockpit and a bubble canopy. Cancelled

Variants of the J 21R

  • J 21RA / A 21RA – First production series powered by a De Havilland Goblin engine. Later reconfigured into ground attack airplanes (A 21RA). Fitted with wingtip fuel tanks to increase the operational range and endurance. Operated until 1953. 30 delivered.
  • J 21RB / A 21RB – Second production series powered by a Swedish-license made De Havilland Goblin (RM1). It was also reconfigured later into a ground attack airplane (A 21RB), with the nose heavy machineguns changed to a 12.7mm caliber. Fitted with wingtip fuel tanks to increase the operational range and endurance. Operated until 1956. 30 delivered.

Operators

  • Sweden -The Flygvapnet operated the J21 a time roughly after the end of World War II. It operated with 54 fighters of the J 21A-1 version, 124 The J 21 fighters of the J 21A-2 version, and 119 fighter/bombers of the J 21A-3 version. The J 21 was in service between 1945 and 1954, with X units: F9 Goteborg, F15 Soderhamn, F12 Kalmar, F6 Karlsborg and F7 Såtenäs. In addition, the Flygvapnet operated with 30 fighters of the J 21RA version, and 30 fighters of the J 21RB version. Both were later on modified into ground attack airplanes, being denominated as a result A 21RA and A 21RB. The J 21R was in service from 1950 to 1956, with three units: The F10 Ängelholm, the F7 Såtenäs, and the F17 Kallinge. Three J 21 remain today as museum exhibitions in Sweden.

 

 

21 Specifications

Wingspan  11,6 m / 38 ft 0 in
Length  10,44 m / 34 ft 3,02 in
Height  3,97 m / 13 ft 0 in
Wing Area  22.2 m² / 238,87 ft²
Engine  1 Daimler-Benz (SFA) DB 605B inverted V12 of 1475 hp
Maximum Take-Off Weight  4431 Kg / 9,768.6 lb
Empty Weight  3250 kg / 7,165 lb
Loaded Weight  4150 kg / 9,149 lb
Maximum Speed  645 km/h / 400,78 mph
Range  750 Km / 466 miles
Maximum Service Ceiling  11000 m /36,090 ft
Climb Rate  15 m/s (2,950 ft/min)
Crew 1 (pilot)
Armament
  • 1 X 20 mm Hispano-Suiza HS.404 or a Bofors cannon located at the nose.
  • 2 X 13,2 mm Bofors (Colt) heavy machine guns located at the nose.
  • 2 X 13,2 mm Bofors (Colt) heavy machine guns located at the wings.
  • The J 21A-3 fighter/bomber version could carry also 2 X 180mm, or 8X 80/145mm rockets; and 600kg, 500kg, 250kg or 4X 50Kg bombs

 

21R Specifications

Wingspan  11,37 m / 37 ft 4 in
Length  10,45 m / 34 ft 3 in
Height  2,90 m / 9 ft 8 in
Wing Area  22.3 m² / 260,0 ft²
Engine  1 De Havilland Goblin 2 Turbojet (Svenska Flygmotor RM2B Turbojet)
Maximum Take-Off Weight  5000 Kg / 1,0230 lb
Empty Weight  3200 kg / 7,055 lb
Loaded Weight  N/A
Maximum Speed  800 km/h / 497 mph
Range  720 Km / 450 miles
Maximum Service Ceiling  12000 m /39,400 ft
Climb Rate  17.1 m/s (3,366.1 ft/min)
Crew  1 (pilot)
Armament
  • 1 X 20 mm Bofors cannon located at the nose.
  • 4 X 13,2 mm M/39 heavy machine guns located at the nose, later changed to 12.7mm caliber.
  • 8 X 13,2 mm M/39 heavy machine guns on a centreline pod.
  • Wing racks allowing 10X 100mm, 5X 180mm, or 10X 80mm anti-armour rockets.

Gallery

Saab J 21A-1 - Prototype
Saab J 21A-1 – Prototype
Saab A 21A-3 - 21364
Saab A 21A-3 – 21364
J 21R - Prototype
Saab J 21R – Prototype
Saab A 21R Trainer - 21455 Side Profile View
Saab A 21R Trainer – 21455
Saab J 21R - 21463 w/ Gun Pod Side Profile View
Saab J 21R – 21463 w/ Gun Pod

Saab A 21A-3 Converted J21R Converted J21R 2

Saab 21 R
The jet powered Saab 21 R in flight
Saab J 21 in Service
Saab J 21 in Service
Saab J 21 Prototype
Prototype in Service
Saab J 21A-3 in a Hangar
Saab J 21A-3
Saab 21 Cockpit
Saab 21 Cockpit
Saab 21R - Flightline
Saab 21R – Flightline

Sources

Chant, C. (2001). Aviones de la Segunda Guerra Mundial [Aircraft of World War II, Fabian Remo Tamayo & Fernando Tamayo, trans.]. Madrid, Spain: Editorial LIBSASharpe, M. (2001). Jets de Ataque y Defensa [Attack and Interceptor Jets, Macarena Rojo, trans.]. Madrid, Spain: Editorial LIBSAGoebel, G. (2014). The SAAB J 21 & J 21R. Air Vectors.Frederiksson, U. (2000). Saab J 21/A 21/A 21R. x-plane.org,  Aviastar.org (n.d.). Aircraft Profile #138. Saab J.21A & R.Aviastar.org (n.d.). Saab 21R. 1947.NGO valka.cz. (2015). Saab J 21R.Saab. (n.d.). 1940’s.SAAB 21. (2016, June 23). In Wikipedia, The Free Encyclopedia.Saab 21R. (2016, June 8). In Wikipedia, The Free Encyclopedia., Images: Converted J 21R, Converted J 21R 2Saab A 21A-3 – Alan Wilson / CC BY-SA 2.0, Side Profile Views by Ed Jackson – Artbyedo.com