Tag Archives: radar

Junkers Ju 88G

Nazi flag Nazi Germany (1943)
Night fighter – Approximately 2,520 Built

A Ju 88G-1 in transit. [Boiten]
Developed from converted fighter versions of the Ju 88A-4 medium bomber, the Ju 88G would take up a growing role in the German night fighter force, as it saw its greatest successes in the Spring of 1944, and its decline in the Autumn of that same year. While built mostly as a result of the German aviation industry’s failure to produce a new specialized night fighter design, the Ju 88G would nonetheless prove to be a valuable asset, one that far exceeded the capabilities of its predecessors and was well suited for mass production.

Hunting in the Dark: 1943

1943 was a year of highs and lows for the Luftwaffe’s night fighter force, one that saw their tactics change considerably to match those of RAF’s Bomber Command. The year started with the Luftwaffe continuing the heavy use of its long standing fixed network of defensive ‘Himmelbett’ cells. These contained searchlights, radar, and night fighters that coordinated to bring down raiders. This chain of defenses stretched across the low countries through northern Germany in a network known more broadly as the ‘Kammhuber line’, named after its architect and initial commander of the German night fighter force, Josef Kammhuber. However the British would develop tactics to shatter this line and employ countermeasures to blind the radars used both by flak and fighter directors, and night fighters. 

They employed what became known as the ‘bomber stream’, deploying their aircraft in a long and narrow formation in order to penetrate as few of the Luftwaffe’s defensive boxes as possible. It was a simple but effective tactic, a night fighter could only intercept so many planes, and the cells were quickly overwhelmed. When they coupled this tactic with radar reflecting chaff, which they called ‘window’, the result was the near total collapse of the German air defenses during the July raid against the city of Hamburg. With German radar scopes clouded by the resulting interference, they were unable to direct gun laying radar for their anti-aircraft guns, and night fighters could not be vectored onto their targets, much less find anything using their on-board radar systems. Virtually defenseless and in the grips of a hot, dry summer, Hamburg suffered a level of destruction eclipsed only by the raid on Dresden when the war was coming to a close.

The Himmelbett system provided expansive coverage but could easily be overwhelmed by a concentrated stream of enemy aircraft. [Price]
The Luftwaffe’s disaster over Hamburg forced them to reform their strategy and develop new detection systems that would be unaffected by the newest RAF countermeasures. Kammhuber was sacked, though not exclusively as a result of the raid, and a new system of night fighter control was to be the primary means of nightly strategic air defense. Instead of the heavy focus on the fixed Himmelbett boxes, night fighters would be assembled over beacons before being directed towards bomber streams. This would ensure there would be no bottlenecks and would allow the full strength of the night fighter force to, as it was hoped, be brought against the enemy in mass. They would also employ new equipment, modifying their Wurzburg radars, used for fire and aircraft direction, with a chaff discriminating device, and replacing the older Lichtenstein (B/C) aerial search radars with the new SN-2.

In the winter of 1943, Bomber Command set out to try and knock Germany out of the war. They launched a series of large-scale raids against major industrial cities and the capital, with Sir Arthur Harris, its C-in-C, believing he could end the war without the need for a costly invasion of the continent (Overy 339). The Luftwaffe’s new weapons and tactics would quickly prove their worth during what later became known as the ‘first Battle of Berlin’. Bomber Command held that a loss rate of 5% represented “acceptable losses” and significantly higher values could spell trouble for continuous operations (Brown 309). Between August and November of 1943, the casualty rates during the “1st Battle of Berlin” sat at 7.6-7.9%, figures which would climb slowly over the following months (Overy 342). However, while most Luftwaffe planners were enthusiastic about the new air defense methods, they would have to confront a growing concern in the service: they were reliant on considerably dated night fighter designs.

 

The Search for a New Design

Left to right: Ta 154, He 219, Ju 188. [avionslegendaires.net & Wikipedia]
Throughout much of 1943, the night fighting mission was taken up mostly by variants of the Bf 110, followed by the Ju 88, and in much smaller numbers the Do 217 and He 219. In order to address the lack of a mass produced, specialized night fighter design, three new proposals were introduced. The first being the Ta 154 “Moskito,” a wooden, dedicated night fighter design which hoped to capture the same success as the British aircraft which bore the same name. The second, the He 219, was a specialized night fighter design championed by the very man who had devised the Himmelbett system, Josef Kammhuber. Lastly the Ju 188, a bomber that at the time still lacked a night fighter version, was proposed for conversion (Aders 72).

The Ta 154, despite high hopes for the project, never came to fruition as a result of its troubled development. The He 219 was sidelined by Generalflugzeugmeister (Chief of Procurement and Supply) Erhard Milch, who opposed increasing the number of specialized airframes in favor of mass production of multipurpose designs (Cooper 265). To make matters worse for the project a number of technical issues prolonged development, the aircraft took around 90,000 hours to produce, and with comparatively little support from the Luftwaffe, few were built (Cooper 325). The aircraft would, however, still be employed with the Luftwaffe, but in limited service. The Ju 188 design that likely would have received Milch’s support simply never materialized. 

With the failure to find a new design, it was clear that the brunt of future night fighting would fall on existing designs, in particular the Ju 88. In early 1943, it was on this design that hopes were placed for a high performance, specialized night fighter that would become available to the Luftwaffe the following year (Cooper 266).

The Old 88

Left to right: Ju 88A-4, Ju 88C-6, Ju 88R, Ju 88G-1. [Asisbiz]
Originally entering service as a medium/dive bomber in 1939, the Ju 88A was a state of the art, if somewhat conservative, design that was exceedingly versatile and easily modifiable. The airframe was sturdy, aerodynamically clean, and modular, with many components capable of being modified without necessitating major revisions to its overall design. This is perhaps nowhere more evident than the self-enclosed combined engine-radiator assemblies that allowed the powerplant and its associated cooling systems to be easily removed or replaced via connecting plates and brackets (Medcalf 106, 107, 191).

Not long after its teething period subsided, the Ju 88 proved itself in a number of roles and was employed as a night fighter early in the war, as some bombers were converted to Zerstorer (long range fighter/ground attack aircraft) at Luftwaffe workshops. Several of these aircraft were subsequently handed off to night fighter squadrons by the end of 1941, the first set with their dive brakes still equipped (Aders 31). However, by the end of 1941, small quantities of serial-built Ju 88C fighters were being delivered, with a larger production run following in the subsequent years. The type would eventually take up a growing position in the night fighter force (Medcalf 166, 178). Owing to their origins as converted aircraft, the Ju 88C-6 series retained virtually the same airframe as their bomber counterparts, with some minor alterations. The bombardier and their equipment were removed and an armament of three 7.92 mm MG17’s, a 20mm MG 151/20, and a pair of 20mm  MG FF cannons were installed in the nose of the aircraft and in the “gondola” beneath the nose that would have otherwise carried the bombsight and ventral gunner (Medalf 319).

The night fighting capabilities of the C-6 were good but its shortcomings were becoming more apparent as the war progressed. By early 1943, it was considered relatively slow and this was particularly worrying in the face of the RAF’s growing use of the Mosquito as a bomber and pathfinder, an aircraft which no German night fighter in service was able to effectively intercept. When flying at high speeds and altitudes, catching these aircraft was often more a matter of good fortune than anything else. In mid 1943, an interim design known as the Ju 88R was introduced in the hopes of alleviating some of the deficiencies of the preceding series. Despite remaining very capable in the anti-heavy bomber role, it had no hope of intercepting the Mosquito. While the Ju 88R proved to be significantly faster thanks to the use of the much more powerful BMW 801 engines over the older Jumo 211Js, it still failed to fulfill the anti-Mosquito role that its planners hoped to achieve. 

  While the aircraft offered greater performance and was favored by pilots, it was still very much a simple conversion, much like the C series it was supplementing, and it was clear additional modifications were necessary to better realize the airframe’s potential. In particular, its greater engine power meant the aircraft could reach higher speeds, but that power also enabled the aircraft to exceed the limits to which the rudder was effective (Aders 73). However, despite the disappointments of the year and the failure to secure a brand-new night fighter design, the hope that a new model of specialized Ju 88 would be entering service was soon realized.

Gustav

The Ju 88G would provide the Luftwaffe with a high performance night fighter that also allowed them to consolidate existing production lines. [Asisbiz]
By the end of 1943, work on the new night fighter was complete and the Luftwaffe was preparing to receive the first planes by the end of the year. The new Ju 88G-1 was developed as the successor to the previous C and R series night fighters, both consolidating production and vastly improving performance. 

The Ju 88V-58 was the primary prototype for the Ju 88G-1 and first flew in June of 1943 (Aders 258). It sat between the older Ju 88R series aircraft and the later Ju 88G in design and appearance, using the same basic airframe as the Ju 88R and its BMW 801 power plants. However, it also incorporated the vertical stabilizer designed for the Ju 188, used a new narrower, low drag canopy from previous fighter models, and removed the “gondola” which carried a portion of the aircraft’s armament in previous models (Aders 132; Medcalf 191, 192). The armament was significantly improved with the addition of a mid-fuselage gun pod which mounted four MG 151/20 20 mm cannons, making use of the space otherwise taken up by bombing gear, with another pair of cannons installed in the nose of the aircraft. However, the nose mounted pair were removed later on due to issues regarding the muzzle flash of the guns affecting the pilot’s vision, a resulting shift in the aircraft’s center of gravity, and interference with nose mounted radar aerials (Medcalf 191). 

After this series of changes to the aircraft’s fuselage, armament, and the subsequent addition of an SN-2c radar, the Ju 88G went into production. 6 pre-production Ju 88G-0 aircraft and 13 Ju 88G-1s were completed by the end of 1943 (Medcalf 178). The production switch between the previous Ju 88R and 88C models to the G was relatively smooth, with the first three aircraft delivered to the Luftwaffe in January of 1944. Production and deliveries of the new model increased sharply over the following weeks thanks to the aircraft sharing most of its components with older models (Aders 129). Mass production was carried out rapidly, with 12 planes completed a month later in January, roughly doubling the next month, and rising to 247 aircraft in June, before gradually falling as the production of its successor, the G-6, began to supersede it (Medcalf 240).

The Ju 88G-1 went into production with an offensive armament of four forward facing 20 mm MG 151/20 cannons in a pod mounted ventrally near the center of the aircraft. Upward facing cannons in the fuselage, in a configuration referred to as ‘Schräge Musik’, were often installed later at field workshops. These upward facing weapons were of particular use against British bombers, which had forgone ventral defensive guns. This armament was a marked improvement over the three 20 mm cannons and three MG 17 7.92 mm machine guns carried by the preceding C6 and R series (Medcalf 319). 

The aircraft was powered by the much more powerful BMW 801 G-2 engines producing 1740 PS, a huge boost up from the Jumo 211J, 1410 PS, on the Ju 88C-6. This allowed the aircraft to reach 537 km/h at an altitude of 6.2 km, quite a considerable improvement over the Ju 88C-6’s 470 km/h at 4.8 km (Junkers Flugzeug und Motorenwerke 7, 12, Medcalf 319). The engines were unchanged from that of the previous Ju 88R model, though it was able to make better use of them thanks to the enlarged vertical stabilizer which granted better control and stability at high speed.

G-6 

The G-6 would incorporate more powerful engines and standardize several common modifications made to the previous model.  [albumwar2]
To build on the success and production base of the first design, work began on a successor. Retaining the same airframe, the G-6 would be powered by the Junkers Jumo 213 A-1 and would standardize the use of equipment commonly added to the G-1 at Luftwaffe workshops. To this end several new prototypes were produced, these being Ju 88V-108, V-109 which included the MW50 boost system, and Ju 88V-111 which served as a production prototype (Medcalf 192). 

The aircraft carried with it several key improvements over the initial model. It was faster, better armed, and possessed a more advanced set of electronic warfare equipment. However, it’s top speed is difficult to ascertain given the limited number of sources on the aircraft. It was able to achieve 554 km/h (344 mph) at 6km (19685 ft) without the use of the MW50 boost system, and after the war Royal Navy test pilot Eric Brown was able to reach a top speed of 644km/h (400mph) at an altitude of 9,145 meters in tests (30,000ft) (Medcalf 319, Eric Brown 195). In all likelihood, this was a testing aircraft that was using either Jumo 213E or 213F engines, as 9km was well above the full throttle height of the Jumo 213A. Alternatively, some of these engines may have made their way into very late production G-6 aircraft.

The new standardized equipment included an upward firing pair of 20 mm cannons, the FuG 350 Naxos Z radar detector, and they would later be the first night fighters to be equipped with the new SN-2R and Naxos ZR tail warning equipment. They also carried the new Neptun radars for twin engine fighter use and were the only aircraft that made use of the SN-3 and Berlin search radars (Medcalf 319, 324; Aders 181)

The SN-2R was a rearward facing radar aerial added to the SN-2d search radar sets that would warn the crew of pursuers. It helped to significantly improve survivability along with the new Naxos ZR, which could now warn the crew of enemy night fighter radar emissions. These systems quickly showed their worth. Ju 88G-6’s fared better in the presence of enemy night fighters than the He 219’s and Bf 110’s, which lacked standardized tail warning equipment (Aders 181). 

Late G-6’s were also equipped with the FuG 120A Bernhardine. This device was intended to make use of a nationwide network of high powered transmitters that would have been unjammable by the RAF’s electronic warfare equipment. The system would provide the altitude of a bomber stream, its location on a grid map, its course, strength, and the recipient night fighter’s bearing from the ground station. All of this information was relayed in coded messages by means of a teleprinter in the cockpit of the night fighter. It was mostly foolproof, but the system was not fully operational by the war’s end (Medcalf 325; Price 237, 238).

Pilot’s Remarks and General Flight Characteristics

As with the rest of the Ju 88’s in the night fighter service, the plane had the ergonomics and handling characteristics that were so sought after by pilots. The sorties they faced by this point of the war were as long as two hours and as such undemanding flight characteristics were a crucial feature of any night fighter (Aders 23). Stability, well balanced controls and the ability to fly well on one engine were crucial factors, and having them made the Ju 88G a highly rated aircraft among the force (Aders 31, 132). Its reinforced airframe also came in useful, as its earlier use as a dive-bomber required a high tolerance for g-forces that made it capable of pulling off hard maneuvers without risk of damaging the airframe in the process. The addition of the Ju 188’s vertical stabilizer also improved handling markedly, as the newer design provided much smooth rudder controls over the previous version, which had ones unchanged from older bomber models and were quite stiff once the aircraft was brought up to speed (Medcalf 304).

Ju 88G-1 flown by Roland Beamont. [asisbiz.com]
The G-1 handled exceedingly well, with controls that were well balanced and responsive. Praise for the Gustav’s handling could even be found outside the ranks of the Luftwaffe, as Roland Beamont, an RAF fighter pilot and post war test pilot, had a chance to take one up and evaluate how it performed at RAF Tangmere in the summer of 1945. Beamont found the aircraft undemanding, with gentle controls and that, on landing, the aircraft “could be steered on the approach as gently and responsively as any fighter”. Equally as important, he found the aircraft needed very little adjustment in the air, with only very minor trimming of control surfaces needed for smooth operation in regular flight. In a rare chance, he even found an opportunity to have a mock battle with another RAF pilot, Bob Braham, flying a DeHavilland Mosquito. Beamont found the 88 was able to hold its ground for some time, but eventually letting up when he began to reach the limits of the unfamiliar plane so low to the ground and in the wake of Bob’s plane, which promptly outmaneuvered him.

Despite his praise for the aircraft’s flight characteristics, he felt the structural cockpit framework was very restrictive of the pilot’s vision. In a summary of his first flight and a second on July 16th, he claimed “It has remained in my rating as one of the best heavy piston-engined twins of all time and a very pleasant flying experience.” (Medcalf 294, 295). Much like Beamont, most Luftwaffe pilots were very satisfied with the aircraft (Aders 132).

Famed Royal Navy pilot Capt. Erik ‘Winkle’ Brown would also be among the few allied pilots to have the opportunity to fly both the G-1, and subsequent G-6 model. Capt. Brown felt the aircraft possessed largely the same excellent handling characteristics as the Ju 88A-5 he’d flown prior. He praised the aircraft for its easy ground handling, thanks to its excellent brakes, it’s good handling during climbs, and light controls at cruising speed (Brown 190).

Capt. Brown would spend more time with the G-6 and was able to put one through more demanding tests. Having previously flown several versions of the Ju 88, Brown was particularly impressed by the aforementioned high speeds achieved by a Ju 88G-6 (Werk-nr 621965) he’d flown in tests. The aircraft remained in line with his general, glowing remarks over the Ju 88. “It was a pilot’s airplane, first and last, it demanded a reasonable degree of skill in handling and it responded splendidly when such skill was applied. There was a number of very good German aircraft but, with the exception of the Fw 190, none aroused my profound admiration as did the Junkers ‘eighty-eight’ (Brown 195).” 

Perhaps the simplest but greatest advantage the aircraft had in night fighting was in the close proximity of the crewmembers, which allowed them easy communication in the event of intercom failure or emergency. It also allowed the pilot to be seated beside their radar operator, with the flight engineer seated directly behind him, an ideal arrangement providing both easy communication and good situational awareness, which became a necessity as bomber streams became the hunting grounds for RAF night fighters (Aders 132).

While it inherited the benefits of the original design, it also had its flaws, the most obvious of which was the poor visibility due to the bars of the reinforced cockpit frame, and the troublesome landing gear which had a tendency to buckle if the aircraft was brought down too hard (Medcalf 75). The landing gear was a hydraulically actuated set that rotated 90 degrees so that the wheels would lie flat within their nacelles. This greatly reduced drag, as the shallower landing gear bays contributed far less to the frontal area of the plane, but they could be broken in forced landings or careless flying. These types of accidents were typically handled by the airfield ground staff, though handing off the plane to a recovery and salvage battalion could prove necessary in the event of a forced landing or a particularly bad accident (Medcalf 62).

Lichtenstein SN-2

Early combined SN-2 with the wide-angle attachment; compared to a later model on Ju 88G. These large aerials came to be known as the ‘Hirschgeweih’(stag antlers). [Bauer, Rod’s Warbirds]
Perhaps the most important feature of the Ju 88G, its radar, was easily the weakest point of the aircraft in comparison to its contemporaries in foreign service. Unlike the British or Americans, the Germans lacked any major production of centimeter band search radars, forcing them to rely on meter band types. In practical terms, the meter band radar carried with it several major disadvantages, the most evident and visible of which were the large aerial antennas which protruded from the aircraft’s fuselage and created significant drag. In tests by the Luftwaffe’s Rechlin test pilots, it was found that the Lichtenstein (B/C) decreased the maximum speed of a Bf-110 by 39.9 km/h (Aders 44). Another major disadvantage was its inferior ability to cut through ground clutter, leading to very poor performance at lower altitudes and making it useless near ground level (Aders 163, 200). 

The standard Ju 88G-1 was equipped with the Lichtenstein SN-2c, also designated as FuG 220. This airborne radar set was designed by Telefunken for naval service and originally rejected by the Luftwaffe earlier in the war. Its initial rejection was based on its extreme minimum range of 750 meters, which meant that any target would disappear off the scopes long before the pilot would be able to see it (Aders 79, 80). Its later adoption was a matter of the previous air search radar having a relatively short maximum range, and that the SN-2 would be unaffected by the chaff that made the previous sets useless (Brown 309). However, due to the shortcomings of the original SN-2, the device was coupled with a simplified version of the older Lichtenstein  FuG-212 radar to track targets within the large minimum range of the new system.  The resulting set up required the use of 5 radar scopes and was an exceedingly cumbersome display, with three scopes devoted to the older Lichtenstein set and two for the SN-2 (Price 196). 

The two scope SN-2c display, the “peaks” represent radar contacts. Left is azimuth and range, right is elevation. The range demarcations are 2 km for both sides, the radar will not display contacts beyond the 5th demarcation.[Bauer]
The SN-2 carried by the 88G was an improved model which had its minimum range decreased to an acceptable distance, allowing it to drop the excess equipment for the far simpler SN-2c, which required only two scopes (Aders 122). The system had a frequency range of 73/82/91 MHz, a power output of 2.5 kW, an instrumented range of 8km, a minimum range of 300 m, a search angle with an azimuth of 120 degrees, an elevation of 100 degrees, and a total weight of 70 kg. While the system had a maximum instrumented range of 8km, its practical detection range was tied to the altitude at which it was operating and the size of the target. For example, if searching for a heavy bomber traveling at the same altitude, and with the maximum antenna aperture towards the Earth being roughly 30 degrees, and at an operating altitude of 5km, the slant range of the radar can be placed roughly at the system’s maximum range of 8km (Bauer 12, 13). This range increases or decreases correspondingly with the altitude of the aircraft or its target, with the device being virtually useless near ground level.

 One SN-2c was eventually recovered by the RAF when an inexperienced crew landed their plane at RAF Woodbridge as a result of a navigation failure, which allowed the British to develop both effective chaff and electronic jamming countermeasures for it (Price 221). This same aircraft would be the one given such a good review by Roland Beamont, its registration code being 4R+UR. 

The SN-2 would see further development even as its usefulness declined in the face of widespread jamming and chaff which targeted its operating bands. The SN-2d was the most immediate development which helped to some degree. Its operating frequencies were shifted to the 37.5-118 MHz dispersal band to make use of its still usable frequencies that were not fully targeted by RAF jamming efforts. It would later be combined with the SN-2R tail warning radar and, very late in the war, made use of low drag ‘morgenstern’ aerials and an aerodynamic nose cone which fit over it (Aders 244). 

Late War and Experimental Radars

Left to right: Fug 218 Neptun, Lichtenstein FuG 220 SN-2 with a low drag array, FuG 240 Berlin with its parabolic antenna set behind a removable nose cone. [Rod’s Warbirds, Asisbiz,ww2aircraft.net]
 The FuG 217/218 Neptun radar sets were developed and built by FFO. These had been initially developed for use in single engine night fighters, but were later adapted for use aboard twin engine aircraft. They were largely a stop gap following the RAF jamming efforts against the SN-2, as any new aerial search radar was months away. These series of radars came in a variety of configurations as they were further developed and pressed into wider service.

 The Neptun 217 V/R was a search radar that could switch between two frequencies between 158 and 187 MHz, had a search angle of 120 degrees, a maximum range of 4 km with a minimum of 400 meters, and a total weight of 35 kg. The subsequent Neptun 218 V/R search radar included four new frequency settings along the same range, had a maximum range of 5km with a minimum of 120 meters, a power output of 30kW, weighed 50kg, and possessed the same search angle as the previous model. Both radars could be mounted in a “stag antler” array with the preceding Neptun 217 V/R also having a “rod” type mounting arrangement, which consisted of individual antennas attached to the airframe. As with the SN-2, tail warning sets were produced which were found in the form of the standalone Neptune 217 R and Neptun 218 R sets, or as a component of the Neptune 217 V/R and Neptun 218 V/R combined search and tail warning radars. (Aders 245, 246).

The FuG 228 SN-3 was developed by Telefunken and was visually similar to the SN-2 but with thicker dipoles. The device operated on a frequency range of 115-148 MHz, had a power output of 20kW, a maximum range of 8km with a minimum of 250m, a search angle with an azimuth of of 120 degrees, an elevation of 100, and a total weight of 95kg. Some sets also made use of a low drag “morningstar ” array that used ¼ and ½-wavelength aerials. 10 sets were delivered for trials and may have been used in combat (Aders 245).

 The FuG 240 Berlin was another radar developed by Telefunken and their last to see operational use during the war, it also being the first and only centimetric aerial search radar to see service with the Luftwaffe. It operated on a wavelength of 9 to 9.3 cm, an output of 15kW, had a maximum range of roughly 9 km, a minimum of 300 m, a search angle of 55 degrees, weighed 180 kg, and had no serious altitude limitations (Aders 246, Holp 10). While only twenty five Berlin sets were delivered to the Luftwaffe they made successful use of them in March of 1945 (Aders 246; Brown 317). While these new devices were free of the heavy jamming the SN-2 faced, they lacked the larger production base of the SN-2 which continued to be fitted to new night fighters until the end of the war.

Passive Sensors

While the SN-2 radar was somewhat mediocre, this deficiency was offset by other devices that were often installed aboard which could supplement it, these being the FuG 227 Flensburg and FuG 350 Naxos Z. Developed by Telefunken, Naxos was able to detect the emissions of British H2S ground mapping radar and other devices with frequencies in the centimeter band. This would enable a night fighter equipped with the system to home in on RAF aircraft that were using ground mapping radar to direct bomber streams to their targets. The Naxos Z set was capable of detecting emissions at up to 50 km, enabling them to find pathfinders or simply other bombers in the stream as the ground mapping radar became more commonplace among the aircraft of Bomber Command (Price 176, Medcalf 325). Subsequent models would expand the reception band to allow the device to detect British centimetric aerial intercept radar and combine the system with tail warning equipment to alert aircrews to the presence of British, and later American, night fighters, with the series working within the 2500 mHz to 3750 mHz band (Medcalf 325). These included the Naxos-ZR, used exclusively in Ju 88s, with the aerial contained within the fuselage, the Naxos ZX, which further increased the detectable frequency ranges, and the Naxos RX, which was a version of the previous type which coupled it with tail warning equipment (Aders 248, 249). This was solely a directional sensor and would give the operator the azimuth of the target, but not its altitude or range. 

Naxos indicator, each notch represents a detected emission [Bauer]
Flensburg was another passive device, this one made by Siemens. While Naxos detected the emissions from RAF ground mapping radar, Flensburg picked up the tail warning radar of RAF bombers, a device codenamed Monica. With later versions operating on a tunable frequency band of 80 mHz to 230 mHz, it allowed aircraft equipped with it to detect virtually all bombers traveling within a stream should their rear warning radar be active (Medcalf 325). Among the captured pieces of equipment in Ju 88G [4R+UR], this was evaluated by the RAF and found to be an exceedingly useful tool for detecting and closing in on their bombers. The aircraft with the device was evaluated by Wing Commander Derek Jackson in a series of tests with both a single RAF Lancaster bomber and a small group of five planes flying over a considerable distance. He found that, in both cases, he was able to home in on the bombers with the Flensburg device alone from as far as 130 miles away without any issues even when the aircraft were in close formation, where there was hope that several of the tail warning radars operating closely together might have confused the device (Price 222). 

In all, 250 Flensburg sets were produced, alongside roughly 1,500 Naxos-Z sets, and though only the latter became standard equipment, both saw extensive use among Ju 88 night fighters (Aders 124). These devices proved incredibly successful in combination with SN-2 and, for several months, allowed the German night fighter forces to achieve great operational success. However, they eventually fell behind again one final time after the successful British efforts to counter the Luftwaffe’s sensors and tactics in the months following the landings in France (Brown 319). In the end only Naxos remained the only reliable means of detecting raiders as, unlike Monica, they could not do without their H2S ground mapping radar.

Initial Deployments

Field use of the aircraft began shortly after the delivery of the first pre production aircraft, which were quickly sent out to units equipped with older models of Ju-88s, often being placed into the hands of formation leaders. In this way, its introduction into service was gradual, with the first aircraft already being in the hands of more experienced pilots before more deliveries allowed for the entire unit to transition away from older models. Prior to July of 1944, Gruppe IV of NJG3, II and III of NJG6, and I of NJG7 were supplied with large numbers of G-1s, followed by a gradual supply to NJG2, Gruppe IV of NJG 5, III of NJG3, and NJG100. It should also be noted that these aircraft could be found in the inventories of most units, even those that did not fully transition over fully to their use (Aders 131). 

For the first three months of 1944, the Luftwaffe inventory had only a single digit number of operational G-1s but, by April and May, mass deliveries of the aircraft began, with 179 planes available in May and 419 by July (Aders 272). A total 1,209 Ju 88G-0s and G-1s were delivered to the Luftwaffe between December of 1943 and October of 1944, with the aircraft and its successor, the Ju 88G-6, becoming the mainstay of the German night fighter force for the remainder of the war (Medcalf 178, 240).

Zahme Sau: Winter through Spring

As a heavy radar equipped night fighter, the Ju 88G would serve the Luftwaffe as “Zahme Sau” (Tame Boar) interceptors. They differed from “Wilde Sau” (Wild Boar), in that they were to receive guidance toward enemy bombers from a series of ground based stations in a system known as Y-Control. With information collected from various search radars and passive radio and radar detectors scattered throughout much of Western Europe, ground control operators would direct interceptors toward bomber streams (Price 175, 178).

For much of 1944, a typical mission for a Zahme Sau pilot would go as follows. First, they would take off and head for an assembly point marked by a radio/searchlight beacon. Then, they would wait their turn before receiving radio commands directing them towards a bomber stream. The fighters were led away from the beacons by their formation leaders, but rarely did all a gruppe’s fighters actually reach the target in close order. Lastly, upon reaching the stream, they would attempt to merge with it and then begin to search out targets with on board sensors. In addition to direct guidance, Y-control gave a running commentary on a bomber stream, describing its course and the altitude range the staggered bombers flew at (Aders 102, 103,195). This running commentary was particularly useful later on when night fighters more commonly flew alone and the use of the signal beacons was restricted.

This system would see the effectiveness of the Luftwaffe’s night fighters reach its zenith in the spring. Building upon their successes of the previous winter they would inflict heavy losses on Bomber Command. Between November of 1943 and March of 1944, Bomber Command would lose 1,128 aircraft prior to the temporary withdrawal from large scale operations over Germany. During the raid on Nuremberg in April of 1944, 11.9% of raiders failed to return home in what became the costliest raid of the entire war (Overy 368). Thankfully for the Allies, the Luftwaffe would never see this level of success again, as Bomber Command shifted to support Operation Overlord at the end of May. While Arthur Harris wished to continue his large-scale area bombing campaign over Germany, he would relent to pressures from higher offices and place his forces in support of the coming operation to liberate France. The subsequent raids against various rail yards across coastal France would prove a well needed respite for Bomber Command. The short distance the raiders flew over hostile territory meant that Luftwaffe night fighters had fewer opportunities for interception, and thus Bomber Command’s losses were comparatively light.

RAF Tactics and Changing Fortunes

Avro Lancaster and DeHavilland Mosquito NF MK XVII. [Flickr]
Following Overlord, Bomber Command returned to Germany better equipped and prepared for the challenges ahead. A typical late war Bomber Command heavy raiding force was composed mostly of Lancaster and Halifax heavy bombers which were supported by airborne  radar and radio jammers, night fighters, decoy formations composed of trainee squadrons, and chaff dispersing aircraft. In addition to the aforementioned Lancaster and Halifax, the B-17 and B-24 were also used by both the USAAF and RAF as electronic warfare platforms during these raids, though in much smaller numbers. Several variants of the DeHavilland Mosquito would be used as pathfinders, bombers, and nightfighers. The pathfinders were particularly troublesome as they could outpace any interceptor, save for a night fighter variant of the Me 262 that was introduced near the end of the war. While goals of the heavy bombers were straightforward, the supporting forces’ goal was to disorient Luftwaffe ground controllers and engage their night fighters to reduce operational losses and tie up enemy aircraft (Aders 194, 195).

Locating the stream proved difficult, but if a fighter was to infiltrate it, they were mostly free of electronic interference and would encounter little resistance. While successful infiltration often meant good chances for kills, most night fighters would end up returning to base having expended most of their fuel in the search.

Various derivatives of the FuMG 402 Wasserman radar, a long range early warning and fighter control radar built by Siemens. Later versions were capable of frequency changes within the 1.9-2.5 m, 1.2-1.9 m, and 2.4-4.0 m ranges (Aders 251). [cdvandt]
While the Luftwaffe’s system was still holding steady it soon faced a new challenge, as from December 1943 onward, German night fighter pilots would also have to contend with the long-range Mosquito night fighters of the RAF’s 100 Group. Tasked with supporting bombing raids through offensive action, they operated by seeking out German night fighters over raid targets, at night fighter assembly points, and lastly to seek out enemy aircraft near the stream itself (Sharp & Bowyer 289). 

 By the beginning of May 1944, 100 Group possessed only about a hundred Mosquitos, though the number would grow larger and they would begin to replace their older and less capable aircraft (Sharp & Bowyer 290, 291). In the Autumn of 1944, the Mosquitos began to carry equipment to track German night fighters by activating their Erstling IFF (Identify Friend or Foe System) by mimicking the signals of German search radars. With this new gear and their bolstered numbers, they had tied down much of the Luftwaffe night fighter force by the winter of 1944. Eventually, the Germans left their IFFs off, which made tracking their own planes extremely difficult, and forced them to abandon the use of the assembly beacons which were frequented by the Mosquitos (Aders 196). Understandably, the Mosquito became the source of constant anxiety for Luftwaffe night fighter crews. The Mosquito typically made its appearance during takeoffs, landings, and when the often unsuspecting German night fighters were transiting to and from their targets. Under such circumstances, the use of tail warning and radar detecting equipment aboard the Ju 88G was both an important defensive tool, and a serious morale booster. 

Despite its earlier successes, the Luftwaffe’s night fighter force’s effectiveness began its decline in August of 1944 in the face of general disruptions to their detection and communication capabilities as the Allies deployed radar and radio jammers to the continent (Aders 194, 195, 197). This loss of early warning radar coverage would prove a decisive blow to the Luftwaffe, one that they never recovered from.

Blind and Deaf: Autumn into Winter 

As summer turned to autumn, night fighter bases were increasingly harassed by Allied daylight fighter bombers, which forced the Luftwaffe to disperse their forces to secondary airfields. While these “blindworm” locations were free of prowling Mosquitos and fighter bombers, they were not without their disadvantages. While these fields were well camouflaged, their rough landing fields could be hazardous and they were not cleared for night landings. This forced many night fighters to land at their more well-constructed bases after their nightly sorties and return to the camouflaged fields in the evenings. The result was a rise in losses as the aircraft were occasionally caught by Allied fighters on their flight back. Through late 1944 and into 1945, German night fighter losses were most commonly the result of interception in transit or being hit on the ground. While at first only bases in Belgium and the Netherlands were threatened, Allied fighters would appear in growing numbers over the skies of Western and Southern Germany, as would the recon aircraft that periodically uncovered the “blindworm” bases (Aders 197). 

A Ju 88G caught in transit. [asisbiz.org]
In September of 1944 the night fighter force flew a total of 1,301 sorties against approximately 6,400 enemy aircraft, of which they brought down approximately 76, representing a loss rate of 1.1%. Bomber Command losses had fallen significantly from the 7.5% of the previous year, and from last April’s catastrophic high of 11.9%. As such, Bomber Command losses were once again well below the 5% attrition threshold for continuous operations (Aders 197). 

By the start of winter, the RAF and USAAF had largely succeeded in jamming most of the Luftwaffe’s early warning radars, y-control radio services, and through the use of chaff and jammers, made the standard SN-2 search radar useful only in the hands of experts. This had the overall effects of ensuring the night fighter force was slower to respond in-bound raiders, more likely to be sent against diversionary formations, and that night fighters were far less likely to make contact with the bomber stream after being vectored toward it. By winter, it had become clear for the Luftwaffe that the after hours war over Western Europe had been irrevocably lost.

While the night fighter force had some success in finding alternatives to their models of the SN-2 air search radars there was no hope of recouping their past successes. Between the chronic fuel shortages, marauding RAF Mosquitos, mounting ground and transit losses, and the compromised performance of most of the Luftwaffe’s ground based radars, the situation had become unsalvageable. Its decline was final, and in February of 1945, the force disintegrated as the Allies took the war into Germany (Aders 201). After almost a year following its greatest successes, the Luftwaffe’s night fighter force finished the war mostly grounded for lack of fuel and as night harassment forces in support of Germany’s depleted and hard pressed army (Aders 206). 

Large numbers of German night fighters were captured as the Allies overran their airfields, many left intact. Lacking flame dampeners or exhaust stains, these planes have likely never been flown. [flickr]

On the Offense

In conjunction with their interception duties, many units equipped with Ju 88Gs would conduct night ground attack operations against Allied forces in France against the Normandy beachhead, and later across the Western front in support of Operation Wacht am Rhein at the end of 1944. 

On the night of August the 2nd, 1944, the first of these operations were carried out against various targets, including the disembarkation area at Avranches and the Normandy bridgehead. The operation code-named ‘Heidelburg’ was conducted by elements of NJG’s 2, 4, and 5.These attacks were conducted without the use of bombs and were regarded by some as absurd due to the extreme danger in conducting low level strafing runs at night, and with only limited preparations being made before the operation (Boiten P4 25). The attacks would be carried out until the night of the tenth with the night fighters taking considerable, but inconsistent, losses. 

On the night of the sixth, one Ju 88G would claim an unusual victory in this period as during their return flight,  Lt. Jung of 6./NJG2. Jung and his R/O Fw. Heidenrech detected and closed in on P-38 of the 370th fighter squadron at around 2:30 near Falaise, which they subsequently downed. Not all the aircraft had the same luck as Jung, as during the same night another Ju 88G of his Gruppe would be brought down by an Allied night fighter. The aircraft proceeded to crash into a Panther tank belonging to the 1st SS Panzer Division, resulting in a two hour traffic jam during that unit’s counter attack on Mortain (Boiten P4, 28). The overall impact these missions had were largely undefinable due to the inability to accurately survey the damage inflicted. 

While infrequent attacks were carried out during the Autumn of 1944, the Luftwaffe’s night fighters would not be committed to any major ground attack operations until the end of the year. On the night of December 17th, several night fighter squadrons would be called upon for night ground attack operations in support of Operation Wacht Am Rhein. This action saw roughly 140 Ju 88’s and Bf 110’s of at least seven Gruppen being committed to what was to become the Battle of the Bulge (Boiten P3, 65). 

This abandoned Ju 88G-6 was modified for ground attack missions, its radar had been removed and racks for bombs had been added. An AB 500 cluster bomb unit lies in the foreground. [Rod’s Warbirds]
These night raids did considerable damage and sowed confusion amongst rear-echelon services, as vehicles initially traveled with undimmed lights and many facilities failed to observe black out conditions. This was especially true against rail and road traffic which, until then, felt safe traveling at night. These mistakes placed otherwise safe trucks, trains, depots, and barracks in the sights of night fighters sent on massed area raids, and armed reconnaissance patrols. These attacks were typically carried out by strafing, and bombing in the case of modified aircraft, which were equipped with ETC 500 bomb racks. During the nightly ground attack operations during the Battle of the Bulge, these modified aircraft typically carried a pair of AB 250 or AB500 cluster bombs which themselves contained either SD-1 and SD-10 anti-personnel submunitions.

These attacks were particularly effective on the odd night with higher visibility. On the night of the 22nd of December, 23 Bf 110G’s and Ju 88G’s belonging to the I. and IV./NJG 6 flew interdiction missions around Metz-Diedenhofen. Owing to the good weather that night they were able to successfully attack several targets, which included some 30 motor vehicles credited as destroyed, and several trains which they attacked north of Metz. They were joined that night by seven aircraft from I.NJG4 which undertook low level strafing attacks, for which they were credited for the destruction of one locomotive, four motor vehicles, and a supply dump. Additionally, they were credited for damaging another locomotive, six motor transport columns, and five single motor vehicles. Losses amongst the night fighters were uncharacteristically light that night, with only Bf 110 G-4 2Z+VK having been lost during the raids (Boiten 73).

Ground crew with an engine heater prepare a Ju 88G-1. [Asisbiz]
The operational conditions during these raids were generally very poor, both a result of the weather, which had infamously grounded most aircraft during the initial stages of the battle, and Allied electronic interference. While the navigational aids and avionics of their aircraft made them effectively all weather capable, the harsh weather and Allied jamming of navigation beacons and radio communications proved serious challenges to Luftwaffe night fighter crews. The difficult nature of the missions themselves made for little improvement, as they typically flew at low altitudes under weather conditions which reduced visibility. The sum of all of these factors made for missions which brought on significantly more fatigue than the typical bomber interception mission.

Throughout the battle, the Ju 88G would prove an exceptional night ground attack aircraft or ‘Nachtschlachter’. With its powerful engines, cannons, large payload, and exceptional de-icing systems, the aircraft could carry out attacks under very harsh winter conditions. Several of these aircraft would have their radar removed and were used exclusively for this mission until the end of the war. A number of former night fighters would even serve with the bomber squadron KG2, with their cannon armament removed, as night attack aircraft (Medcalf Vol.2 618).

The raiders encountered few night fighters as several RAF Mosquito night fighter units had been withdrawn to requip with the new Mosquito NF Mk. XXX. Between the two USAAF squadrons with their P-61’s and the remaining RAF units, there were few Allied night fighters in the area (Aders 200). However, Luftwaffe losses to AAA were high thanks to the advanced centimetric gun-laying radars in use with the US and British armies. In the end the night fighters were able to cause disruptions behind allied lines, but the price paid was steep, with 75 aircraft being lost over 12 nights (Boiten P5 3). 

Operation Gisela:

The Ju 88G would play an exclusive role in the last major Luftwaffe night action of the entire war, in a large-scale intruder mission dubbed Operation Gisela. This operation was likely formulated after Maj. Heinz-Wolfgang Schnaufer discovered that night fighting conditions on the other side of the ‘front’ were far more favorable. He later submitted a proposal to his fighter division to attack Allied bombers over the North sea, where there would be relatively little electronic and chaff interference, and where the bombers would least suspect an attack. However, the CO of the 3rd fighter division would instead propose to attack the bombers at their airfields when they were landing.

In any case the British intelligence services got wind of the plan as was made clear by the broadcasting of the song ‘I dance with Gisela tonight’ over a propaganda station. The attack would be postponed several times until early March, 1945 (Aders 205). 

About 100 Ju 88G’s were dispatched in three waves to follow a bomber stream as it departed for home. Upon reaching their destination the first wave would down twenty two bombers, however the fires from the wrecks would ruin the chances of the subsequent waves. While many bombers were saved by flying to different airfields after being alerted by the flames, eight more were wrecked attempting to land at darkened airstrips. However, the night fighters would face a dangerous return trip as they had to chart a course using dead reckoning and astral navigation due to their signal beacons being jammed (Aders 205). In the end, the night fighters would suffer a similar level of losses to the bombers they were hunting as a result of ground fire, crashes resulting from low level flight, and navigation failures. Operation Gisela would end in failure with no subsequent missions being attempted.

Construction 

Fuselage 

Wing connecting system [Ju 88A-4 Bedieungsvorscrift. [1941], 46]
The Ju 88A-4 was the most widely produced bomber variant and provided the foundations for the C, R, and G types. It was a fairly conventional all metal aircraft in its construction, and, while it pushed few technical boundaries, it was state of the art and versatile. It was primarily made of sheet aluminum fastened by rivets, with cast parts used for load bearing elements. Some use of Elektron magnesium alloy was made to further reduce weight, with sparing use of steel where strength was required, particularly in the landing gear assemblies and fuselage connecting elements. The fuselage cross section was rectangular with rounded corners and clad in large sheet aluminum stampings. It used a semi-monocoque structure made up of formers and bulkheads joined by connectors that ran front to aft, with the outer aluminum skin riveted to both elements, which allowed it to bear some of the structural load. Its structural load factor was 4.5 with a 1.1 multiplier for the first wrinkle, 1.3 for yield, and 1.8 for failure. In service, it proved very sturdy, with Junkers engineers claiming after the war that there had been no reported major structural failures over the service life of the airframe (Medcalf  41,43,73).

Eventually, the construction process had been improved to the point where the fuselage could be built from sub-assemblies that would become the upper and bottom halves of the fuselage. These would then be joined together after the internal components were fitted. Wing construction followed a similar process, making heavy use of sub assemblies, followed by equipment installation, skinning, and painting. An early model Ju 88 took roughly 30,000-man hours to complete. By the end of 1943, this number remained about the same for the Ju 88G-1. While this may seem unimpressive at face value, the night fighter carried an airborne radar system and a much more sophisticated set of avionics (Medcalf 41-43; Adders 183).

Wings and Stabilizers

The Ju 88’s wings were the heaviest part of the aircraft, comprising much of its total structural weight at over 1200 kg. A pair of massive main spars ran from the root to the wing tip, a rear spar ran across the entire span of the wing to support the flaps and ailerons, and two forward spars ran from the engine nacelles to the fuselage to transfer thrust from the engines and support loads from the landing gear. These spars were joined by relatively few airfoil shaped ribs and stiffened with corrugated aluminum (Medcalf 41-43). The wings were joined to the fuselage by means of four large ball connectors, which made for easy assembly and alignment. (Medcalf 73).

The vertical stabilizer was fixed to the fuselage by means of the same ball-screw connectors as the wings. Installing it was simple, with the rudderless stabilizer being fitted to the fuselage, and the rudder fin being affixed afterwards. The horizontal stabilizers did not use the same fitting system. Instead, they were each inserted into the fuselage by two spars which were then bolted together. This process was virtually the same on both the Ju 88A and the Ju 188, save for the latter having a fin which was 42% larger by area and a rudder which was 68% larger than the previous model (Ju 88A-4 Bedienungsvorschrift-FL Bedienung und Wartung des Flugzeuges; Ju 188E-1(Stand Juni 1943); Medcalf 123). The Ju 88G would incorporate the larger vertical stabilizer from the Ju 188 to improve stability and control at high speed.

Ju 188 vertical stabilizer assembly. [Ju 188E-1(Stand Juni 1943)]
As previously stated, the landing gear could prove troublesome due compromises in its design. During early prototyping, JFM (Junkers Flugzeug- und Motorenwerke) redesigned the landing gear into a single strut that would rotate so that it would lie flat beneath the wing when retracted. While this did remove the frontal area that would have seriously impacted the aircraft’s high speed performance, it came at the cost of added complexity and made for a far less robust landing gear arrangement (Medcalf 74, 75). Differing from earlier series, the Ju 88G’s landing gear frames made use of welded cast steel instead of light weight alloys.

 The G-1 carried a maximum of 2835 liters (620 gallons) of fuel, with the subsequent G-6 likely having a reduced fuel capacity considering its shorter endurance (Report No. 8 / 151).

Engines and De-icing Systems

The Ju 88R’s BMW 801 engines and engine mounting plate. [Wikimedia]
Among the most notable features of the Ju 88 were its use of unitized engine power units and its novel de-icing system. The unitized engine installation incorporated both the engine and associated cooling system into a single module that could be installed or removed from the aircraft relatively quickly, and made storage of components easier. These “kraftei” arrangements existed for the BMW 801 G-2, and, later, Jumo 213 A-1 engines. These engines were fitted with VDM and VS-111 propellers respectively. 

 

Engine Type Arrangement  Bore  Stroke  Displacement  Weight  Maximum Output  Maximum RPM Fuel type
BMW 801 G-2 Radial 14 156 mm 156 mm 41.8 liters 1210 kg 1740 PS 2700 C3, 95 octane
Junkers Jumo 213 A-1 Inverted V-12 150 mm 165 mm 35 liters 820 kg 1775 PS [2100 PS MW50] 3250 B4, 87 octane

(Medcalf 323; Ju 88S-1 Flugzeug Handbuch 3, Smith & Creek 687; Jumo 213 13) 

The aircraft was also equipped with a de-icing mechanism which took in air, ran it through a heat exchanger around the exhaust ejector stacks, drove it through channels in the wings, and then out over the ailerons (Rodert & Jackson). As the BMW 801 had no exhaust stacks compatible with this system, they made use of a petrol-fired heater to supply air to the de-icing system on the Ju 88G-1 (Report No. 8 / 151).

On left: Exhaust stack heat exchanger. On Right: the wing channel flow area. [Rodert & Jackson]

Cockpit

 The crew arrangement on all Ju 88 models would set the entire crew within the canopy and in close contact with one another. The bombardier ,or radar operator, sat to the pilot’s right, a flight engineer/gunner at the pilot’s back, and a ventral gunner sat beside the flight engineer or in a prone position inside the “gondola”, where his weapon was located. Aboard the Ju 88G, the ventral gunner’s position had been omitted with the removal of the gondola, however the positions of the other crew members remained largely unchanged. While these close quarters arrangements were somewhat claustrophobic, they ensured easy communication between the pilot and the rest of the crew at all times. It also made for a much simpler bail out procedure, as half the canopy would detach and allow for a quick escape for all aboard. In the Ju 88G, the crew entered the aircraft through a hatch below the cockpit.

Ju 88G-1 instrument panel. The cables for the radar display are on the right. [albumwar2]
The Ju 88G’s cockpit differed heavily from previous fighter versions as a result of added instrumentation and alterations to some of the aircraft’s existing controls. Among the new additions were ammunition counters with space for representing up to six guns, and a Zeiss Revi C.12/D gunsight. This sight differed from previous sets by its new elevation controls and its lack of an anti-glare shield. The front of the canopy was protected by a 10mm armor plate, with the windscreen itself being comprised of four panes of armored glass. The three in front of the pilot were electrically heated to prevent frost formation (Report No. 8 / 151). Work was also done to revise the controls to bring them more in line with other Luftwaffe fighters, perhaps most usefully by the addition of an automatic engine control system and manual propeller pitch control switches being added to the throttles (Brown 194).

Armament

The gunpod of the Ju 88G. [Asisbiz, Ju 88 G-1 Schusswaffenlage Bedienungsvorschrift-Wa]
The aircraft’s initial armament consisted of four Mg 151/20 cannons and a defensive MG 131. The cannons were mounted in a ventral pod between the aircraft’s wings and supplied by ammunition belts that occupied the space used as a bomb bay on bomber variants of the airframe. The ammunition belts were loaded with an equal proportion of high explosive ‘mine-shot’, armor piercing, and general purpose high explosive shells. The single 13 mm MG 131 was placed at the rear of the canopy within an armored glass mount and supplied with 500 rounds of armor piercing and high explosive shells in equal proportion (Ju 88G-1 Schusswaffenlage Bedienungsvorschrift-Wa). An armament of upward firing 20mm cannons, being either the MG FF or MG 151/20, were often installed at Luftwaffe field workshops prior to their inclusion to the design in the production run of the G-6 model.

In addition to its cannons, the aircraft could mount ETC 500 underwing racks for bombs and fuel tanks. These racks could each support bombs weighing over 1000kg, though bomb loads in service were light compared to those carried by bomber variants of the Ju 88. These were universal pylons that were added to existing aircraft, an alteration that was fairly simple given the design commonalities with the older Ju 88A-4, and newer Ju 88S medium bombers.

Avionics

In addition to its complement of detection devices, the aircraft carried a variety of tools to aid in navigation and ground direction. Ju 88G’s were typically equipped with the following devices: FuB1 2 (Blind approach receiver), Fug 10P (radio set), FuG 25 (IFF), FuG 101 (Radio altimeter), and the FuG 16zy (radio set).

The FuB1 2 was a blind landing system that guided the aircraft onto a runway by way of two radio beacons placed at 300 m and 3000 m away from one end of the airstrip. It was a tunable device so that airfields could possess separate frequencies between 30 and 33.3 mHz. The aircraft itself carried the Eb1 2 beacon receiver, the Eb1 3F beam receiver, the FBG 2 remote tuner, the AFN 2 approach indicator, the U8 power supply unit, and either a mast or flush antenna (Medcalf 324). 

The FuG 10P was a radio developed by Telefunken and was coupled with the Pielgeräte 6 radio direction finder. The device consisted of numerous transmitters and receivers capable of operating at various ranges. One pair, E10 L and EZ 6, operated at between 150-1200kHz, and another, S10 K and E10 K, between 3-6mHz. Other components included the U10/S and U10/E power supply units, and the fixed antenna loading unit AAC 2. Numerous versions existed and made use of various other components. Much of this system was later removed during the production run of the Ju 88G-6 (Medcalf 324).

The FuG 25 “Erstling” was an IFF system manufactured by GEMA that would respond with coded impulses to the ground-based Wurzburg, Freya, and Gemse radar systems up to a range of 100 km. The receiver operated on a frequency of 125 mHz and the transmitter at 160 mHz. The entire unit was contained within the SE 25A unit, with the BG 25A control box in the radio operator’s station (Medcalf 324).

FuG 101 was a radio altimeter designed by Siemens/LGW with a maximum range of 150-170 m and operated on a frequency of 375 mHz at 1.5 kW. Accuracy was within 2 m and the entire system weighed 16 kg. It consisted of the S 101A transmitter, E 101A receiver, U 101 power supply unit, and the pilot’s panel indicator (Medcalf 325). 

The FuG 16zy “Ludwig” was a radio manufactured by Lorenz and used for fighter control and directional homing, operating on a frequency range of 38.5 to 42.3 MHz. In Ju 88 night fighters it usually accompanied the Fug 10P radio gear which sat just below the defensive machine gun at the rear of the canopy. It could be set to different frequencies for the Y-control communication system: Gruppenbefehlswelle [between aircraft in formation], Nachischerung und Flugsicherung [between the pilot and the ground control unit], and Reichsjagerwelle [running battle commentary] (Aders 242). It was composed of the S16 Z Tx transceiver, E16 Z and U17 power supply systems, and the loop phasing unit ZWG 16 along with the antenna (Medcalf 324).

The FuG 120A ‘Bernhardine’ was a radio positioning device designed by Siemens to provide navigational assistance and bomber stream intercept information to night fighters by means of a teleprinter in the aircraft’s cockpit. It was intended to overhaul the night fighter force’s air to ground communication infrastructure which faced significant signals interference from the RAF, but the war ended before it entered large scale service. Aircraft could be directed over a range of 400km with position bearings accurate within .5 degrees from ground stations (Medcalf 325, Price 238, 239).

Emergency Equipment

The emergency equipment carried by the Ju 88G. [Ju 88S-1 Flugzeug Handbuch]
The Ju 88G would share the same emergency gear as the Ju 88S, this being stowed in a compartment at rear of the fuselage. The largest items of the set were an inflatable raft and an emergency radio beacon, with the contents of the entire compartment being sealed in a waterproof cloak (Ju 88S-1 Flugzeug Handbuch 64).

Production

Junkers Flugzeug und Motorenwerke AG was the sole manufacturer of the Ju 88G and, as was the case with most late war German aircraft, production was conducted at major plants in conjunction with dispersal facilities. The primary production facility for the Gustav was at Bernburg, with two dispersal plants at Fritzlar and Langensalza, each of which would eventually be able to assemble 75 aircraft every month, these being half the capacity of the main Bernburg plant (Medcalf 241, 247).

As with all major fighter projects at the time, large-scale mobilization of labor and material resources was managed by the Jagerstab, an office which built direct links with the RLM (Reichsluftfahrtministerium, the German Air Ministry), regional government officials, and industrialists in order to marshal resources for expanding fighter production. The office was created in response to increasing Allied raids against Germany’s aviation industries and the growing disparity in numbers, which began to strongly favor the Allies as they built up their forces in anticipation for the landings in France. The office was headed by Albert Speer, Minister of Armaments and War production, and aided by Erhard Milch, Generalluftzeugmeister (Air Master General). In spite of the rapidly deteriorating wartime conditions facing all German industries, the office was successful in boosting production, but relied on desperate and illegal measures (Medcalf 229,232). In the fall of 1944, a minimum 72-hour work week was standard, as was the use of forced labor under conditions that were especially poor at the dispersal sites. The acceptance of rebuilt and used parts became ever more commonplace. This, however, did little to offset the clear superiority of the Allies in the air after the Summer of 1944 (Medcalf 247).

Up until April of 1944, the aircraft was built in parallel with decreasing numbers of Ju 88C-6 and Ju 88R, as production at Bernburg transitioned over to the Gustav. Production of the Ju 88G-1 ceased in October as the factories shifted over to the Ju 88G-6 (Medcalf 240). The Bernburg plant was hit twice by the USAAF’s Eight Air Force in February of 1944, which resulted in total stoppages for only a few days, after which production quickly resumed. However, there was a projected loss of over a hundred aircraft per month compared to the averages of the previous year, with a full recovery requiring several months (Medcalf 229).

 

Ju 88 Production January  February  March April May June  July August September October November  December
1943 13 (+6 pre-production)
1944 12 26 47 169 209 247 239 143 88 10
5* 14* 138* 189* 222* 308* 178*
1945 168* 35* 19*

 

Ju 88G-6 production*

Ju 88G-0 Werk Nummern: 710401 through 710406

Ju 88G-1 Werk Nummern: 710407 through 714911

Ju 88G-6 Werk Nummern: 620018 through 623998

Ju 88G-7 Werk Nummern: 240123 through 240125 (~3 built)

Ju 88G-10 Werk Nummern: 460053 through 460162 (~30 built, converted to mistel air to ground weapons)

Variants:

G-0: Preproduction aircraft, the same as G-1

G-1: Production night fighter, powered by BMW 801 G-2 engines 

G-2: Proposed zerstorer, powered by the Jumo 213A, was to carry a single MG 131, four MG 15’s, and two MK 103’s. No radar.


G-3: Proposed night fighter, powered by DB 603, same armament as the G-1

G-4: Proposed night fighter, powered by Jumo 213A, with GM-1 boost system

G-5: Proposed night fighter, powered by Jumo 213A

G-6: Production night fighter, powered by Jumo 213A

G-7: The same as G-6 except with Jumo 213E engines with three speed, two stage intercooled superchargers. Output: 1726 HP (1750 PS) unboosted, 2022 HP (2050 PS) with boost at 3250 RPM. Weight: 28,946 lbs (13,130 kg). Speed:  650 km/h at 7.9 km. Experimental.

G-10: Same as G-6 but with an extended fuselage.

(Medcalf 319, 178, 240; Green 448-482; Smith & Creek 687)

Conclusion:

Only a handful of Berlin centimeter band radars would enter service with the Luftwaffe near the end of the war. The system improved the aircraft’s performance across the board, lacking the drag inducing aerials of the SN-2, and it was untroubled by allied jamming or the altitude limitations of older systems. [wikimedia]
The Ju 88G would prove a valuable asset to the Luftwaffe’s night fighter forces through its zenith, in the spring of 1944,  until its collapse nearly a year later. From a production standpoint the aircraft was phenomenal. It made use of existing supply chains and components from Ju 88 variants that had long been in service prior to its introduction, allowing for a near seamless transition into mass production. In terms of its performance, the initial model would prove exceptional, being far faster and easier to fly than the existing night fighter workhorses, the aging Bf 110G and Ju 88C. The subsequent G-6 model would prove to be even more impressive with the addition of more powerful engines and standardized tail warning equipment.

While the aircraft did have its downsides and couldn’t solve every problem the night fighter service faced, it effectively fulfilled its purpose, and became the most numerous night fighter model in German service by the war’s end.

Specification Charts:

Classification Aircraft type Engine Engine output  Loaded weight Range Maximum Speed 
Bomber Ju 88A-4 Jumo 211J 2×1400 PS (2x 1380 hp) 14000 kg, 30864lbs  2430 km, 1510 mi 440 km/h (5.5 km), 273mph (18044ft)
Zerstorer/Night fighter Ju 88C-6 Jumo 211J 2×1400 PS (2x 1380 hp) 470 km/h (4.8 km), 292mph (15748ft)
Zerstorer/Night fighter Ju 88R-2 BMW 801D 2×1740 PS (2×1716 hp) 3450 km, 2144 mi  550 km/h (6.2km), 341 mph (20341ft)
Night fighter Ju 88G-1 BMW 801G 2×1740 PS (2×1716 hp) 12005 kg, 26466lbs 2870 km, 1783 mi 537 km/h (6.2km), 333mph (20341ft)
Night fighter Ju 88G-6 Jumo 213A 2x 1775 PS [2100 PS], (2×1750 hp [2071 hp]) 12300 kg, 27116lbs ~2400km, 1491 mi 554 km/h (6.0km), 344mph (19685ft)

(Medcalf 323, 319, 320; Smith & Creek 687)

*only the G series was tested with radar and exhaust flash hiders fitted, when equipped with these devices the C and R series flew at values lower than the ones presented on this chart

[] denotes performance with the MW50 boost system

Ju 88G-1  (Ju 88G-6) Specification
Engine BMW 801 G-2 (Jumo 213 A-1)
Engine Output 2×1740 PS (2x 1774PS [MW50: 2100PS]) : 2×1706 hp (2×1750 hp [2071 hp])
Empty Weight 8846 kg (9000kg) : 19502 lbs (19842 lbs)
Loaded Weight 12,005 kg (12300kg) : 26466 lbs (27117 lbs)
Maximum Range 2870 km (~2400 km) : 1784 mi  (~1490 mi)
Maximum Endurance 4 hours 35 minutes (3 hours 45 minutes)
Maximum Speed [at altitude] 537 km/h [6.2 km] : 333mph [20341ft] 
Armament 4xMG 151/20 , 1xMG 131 (4xMG151/20, 2xMG 151/20, 1x MG 131)
Crew 1 Pilot, 1 Radar Operator, 1 Flight Engineer/Gunner
Dimensions
Length 14.5 m : 47′6 7/8” 
Wingspan 20.08 m : 65′11″ 
Wing Area 54.5 m2 : 586.6 ft2 

(Ju 88 G-2, G-6, S-3, T-3 Bedienungsvorschrift-Fl 66, 69 Part II; Ju 88G-1,R-2, S-1,T-1 Bedienungsvorschrift-Fl 49, 53 part II; Report No. 8 / 151: Junkers Ju 88 G-1 Night Fighter 2; Medcalf 323, 319, 320)

*Top speeds reflect only the initial production models and do not take into account any boost systems.

BMW 801 G-2 Low supercharger gear (January 1944) At Height Output RPM Manifold Pressure
Maximum power (3 minutes) 0.9 km 1740 PS 2700 1.42 ata
Combat power (30 minutes) 1.1 km 1540 PS 2400 1.32 ata
Maximum continuous 1.6 km 1385 PS 2300 1.20 ata
Low power, greatest efficiency 2.2 km 1070 PS 2100 1.10 ata
Low power 2.3 km 980 PS 2000 1.05 ata
BMW 801 G-2 High supercharger gear (January 1944) At Height Output RPM Manifold Pressure
Maximum power (3 minutes) 6.0 km 1440 PS 2700 1.30 ata
Combat power (30 minutes) 5.6 km 1320 PS 2400 1.32 ara
Maximum continuous 5.8 km 1180 PS 2300 1.20 ata
Low power, greatest efficiency 5.7 km 990 PS 2100 1.10 ata
Low power 5.7 km 905 PS 2000 1.05 ata

Engine rated for C3 ~95 octane fuels

(Ju 88S-1 Flugzeug Handbuch 3)

 

Radar System Practical Maximum range Minimum range Search angle-azimuth Search angle-elevation Frequency Output Array Other notes
FuG 220  Lichtenstein SN-2c & SN-2d  8km (instrumented)

Altitude dependent 

300m 120 degrees 100 degrees 73/82/91 MHz later changed to 37.5-118 MHz dispersal band 2.5kW Stag antler (Hirschgeweih), few examples of low drag morningstar array (Morgenstern) SN-2d had a narrower beam width, was combined with tail warning radar, and performed better against jamming. Standard production radar for the Ju 88G.
FuG 217 Neptun V/R Altitude dependent 400m 120 degrees Two click stop frequencies of 158 amd 187 MHz Rod or stag antler FuG 217R was the tail warning radar component
FuG 218 Neptun  V/R Altitude dependent 120m 120 degrees Six click stop frequencies between 158-187 MHz stag antler  FuG 218R was the tail warning component
FuG 228 Lichtenstein SN-3 Altitude dependent 250m 120 degrees 100 degrees 115-148 MHz 20kW Stag antler, morningstar ten sets built
FuG 240/1 Berlin N-1a ~9km 300m 55 degrees 9-9.3cm (3,250-3,330 MHz) 15kW Parabolic antenna 25 sets built, 10 delivered for service, 1945

 

This chart is only for operational and experimental radar usage aboard the Ju 88G, it does not include earlier radars or specialized sets designed for other aircraft. 

*The morgenstern (eng. morningstar) aerial is often misidentified as a separate search radar or exclusive to either the SN-2d or SN-3, it is a low drag aerial arrangement compatible with either device.

~ Sources disagree

(Aders 244-246; Holp 10)

Gallery

Illustrations by Ed Jackson

Ju 88G-1
Ju 88G-1 [4R+UR], 7. Staffel/NJG2 flown by Hans Mackle, WNr. 712273. This is a relatively early production Ju 88G equipped with an FuG 220 SN-2c search radar and a FuG 227 Flensburg radar detector.
Ju 88G-6 [C9+AC], Stab II./NJG5 Hans Leickhardt, 1944. This late production G6 used a rare “morningstar” low drag array for its SN-2d combined search and tail warning radar set. While the SN-2’s faced considerable jamming and chaff interference, the series still was still improved upon, focusing on its still usable bands and developing more aerodynamically efficient antennas. This plane was also equipped with a Naxos radar detected which was installed within the fairing over the cockpit.
Ju 88G-1 [2Z+HM], 4. Staffel/NJG6 Aschaffenburg, Germany 1945. While this is a relatively early production Ju 88G it was later refitted with the SN-2d as can be seen from the angle on the nose mounted dipoles and the tail warning array. This aircraft also received a pair of upward firing cannons and a Naxos radar detector.
Junkers Ju 88G-6 [C9+AR], 6. Staffel/NJG5 Dubendorf, Switzerland, 1945. A late war Ju 88G-6 equipped with a FuG 218 G/R Neptun combined search and tail warning radar set, and while it lacks the fairing typically used for installing the Naxos radar detector there was by this point a fuselage mounted model designed for the Ju 88G. Unlike the SN-2R, the FuG 218R tail warning radar sits at the top of the vertical stabilizer rather than below it.
Junkers Ju 88G-6 [4R+EP], 6. Staffel/NJG2 Fritzlar 1945. This aircraft is a good example of the lax camouflage regulations for the Luftwaffe’s night fighters. While aircraft were delivered in white-grey liveries the air and ground crews were free to devise their own patterns.
Ju 88G-6 [C9+HB], 1. Staffel/NJG5, 1945. This aircraft was equipped with an extremely rare FuG 240 Berlin centimeter band search radar. While it presented many major improvements over previous Luftwaffe aerial search radars, only a few were delivered near the end of the war. The radar’s parabolic antenna sits behind the wooden nose cone which created far less drag compared to the ‘antlers’ that were used by the older meter band radars. This aircraft and others that carry late war radar sets are typically misidentified as Ju 88G-7’s. Due to the overlap between that type and very late production G-6’s, identifying them can only be done through their Werk-Nummer.
With its nose mounted Mg 151/20, Hptm. Johannes Strassner’s Ju 88G had perhaps the most peculiar Schräge Musik arrangement of any night fighter. (Boiten P4 30) [Asisbiz]
One of the most obvious differences between the Gustav and other Ju 88 fighters was the removal of the nose mounted weapons to a ventral pod, where muzzle flashes would not disturb the pilot, and the empty area that once served as a bomb bay would offer a much larger capacity for ammunition. Also visible here is the larger vertical stabilizer. [warbirdphotographs.com]
A Flensburg aerial, one of several mounted to a Ju 88G [asisbiz.com]
The capture of a Ju 88G-1 proved to be one the most valuable Allied intelligence coups of the war and, for the Germans, a source of endless trouble. [i.pinimg.com]
Many of the Luftwaffe’s ‘blindworm’ makeshift airfields were later overrun by allied forces, here American personnel inspect Ju 88G-6’s and Bf 110G-4’s hidden in a forest clearing. [SmallScaleArt]
Despite its growing obsolescence and degraded performance in the face of RAF jamming efforts, the SN-2 saw continued development. Its last versions used morningstar aerials encased within wooden nosecones to reduce drag.[Asisbiz]

A restored Ju 88G-1 fuselage in the Berlin Technikmuseum. (http://3.bp.blogspot.com/-eWzHzdTpJNo/TVqQOv6IFHI/AAAAAAAACVI/gvX4yAaLL_0/w1200-h630-p-k-no-nu/ju88berlin0.jpg )

Primary Sources

  • Air Intelligence 2 (g) Inspection of Crashed or Captured Enemy Aircraft Report Serial No. 242 dated 16th July 1944 Report No. 8 / 151: Junkers Ju 88 G-1 Night Fighter. 1944.
  • Fw-190 A-5/A-6 Flugzeug-Handbuch (Stand August 1943). Der Reichsminister der Luftfahrt und Oberbefehlshaber der Luftwaffe, Berlin. December 8, 1943.
  • Handbuch fur die Flugmotoren BMW 801 MA-BMW 801 ML-BMW 801C und BMW 801D Baureihen 1 und 2. BMW Flugmotorenbau-Gessellschaft m.b.H. Munich. May, 1942.
  • Junkers Flugmotor Jumo 213 A-1 u. C-0. Junkers Flugzeug und Motorenwerke Aktiengesellschaft, Dessau. December, 1943.
  • Ju 88S-1 Flugzeug Handbuch. Junkers Flugzeug und Motorenwerke A.G., Dessau. 1944.
  • Ju 88A-4 Bedienungsvorschrift-FL Bedienung und Wartung des Flugzeuges. Der Reichsminister der Luftfahrt und Oberbefehlshaber der Luftwaffe, Berlin. July 19, 1941.
  • Ju 188E-1 (Stand Juni 1943). Junkers Flugzeug und Motorenwerke Aktiengesellschaft, Dessau. June 1, 1943.
  • Ju 88G-1 Schusswaffenlage Bedienungsvorschrift-Wa (Stand Oktober 1943). Der Reichsminister der Luftfahrt und Oberbefehlshaber der Luftwaffe, Berlin. November, 1943.
  • Ju 88 G-1,R-2, S-1,T-1 Bedienungsvorschrift-Fl (Stand November 1943). Der Reichsminister der Luftfahrt und Oberbefehlshaber der Luftwaffe, Berlin. December 1, 1943.
  • Ju 88 G-2, G-6, S-3, T-3 Bedienungsvorschrift-Fl (Stand September 1944). 1944.
  • Rodert, L. A., & Jackson, R. (1942). A DESCRIPTION OF THE Ju 88 AIRPLANE ANTI-ICING EQUIPMENT (Tech.). Moffett Field, CA: NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS. 1942.

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Credits

  • Article written by Henry H.
  • Edited by Stan L. and Ed J.
  • Ported by Ed J.
  • Illustrations by Ed Jackson