Sunday, 8 November 2015

Night Eyes of the Luftwaffe. Heinkel He219 Uhu. Part 1. German Dzib-Compiler-

The Heinkel HE 219 Uhu “Eagle-Owl”, was a night fighter that server with the German Luftwaffe in the later stages of World War II.
A relatively sophisticated design, the He 219 possessed a variety of innovations, including Lichtenstein SN-2 advanced VHF-band intercept radar, also used on the Ju 88G and Bf 110G night fighters. It was also the first operational military aircraft to be equipped with ejection seats and the first operational German World War II-era aircraft with tricycle landing gear. Had the Uhu been available in quantity, it might have had a significant effect on the strategic night bombing offensive of the Royal Air Force but only 294 of all models were built by the end of the war and these saw only limited service. (1)

There have been countless occasions when superior combat aircraft have been created because the engineering team was able to get on with the job and do it in the best and most efficient way. Obvious examples are the de Havilland Mosquito, General Dynamics F-16 and another was the Heinkel He 219. Designed as a versatile multi-role aircraft, it was finally developed purely for night-fighting and then criticised because it was so specialised.

Ernst Heinkel AG was one of the largest aircraft firms in Hitler's Germany, and it was certainly the most experienced in producing combat aircraft. In mid-1940 the Rostock-Marienehe head office had surplus design capacity, and this was put to use in creating a number of projects, one of which was Projekt 1064. This was a Kampf-Zerstörer, literally a war-destroyer but meaning a multi-role fighter, attack, reconnaissance and even torpedo aircraft. It incorporated many new features, including a tandem-seat pressurised cockpit in a rather serpent-like nose, a shoulder-high wing, giant underslung engine nacelles housing twin-wheel main units of a tricycle landing gear, twin tail fins and remotely-controlled defensive gun barbettes.

The design was just what the Luftwaffe really needed, but long term planning at the Ob.d.L. (Luftwaffe high command) was conspicuously absent. Instead, Projekt 1064 was looked at unfavourably because it used so many radical innovations. The 'American' idea of nosewheel gear was scorned, and Heinkel even had the temerity to pick the Daimler-Benz DB 603 engine, a big and powerful unit that, like the Heinkel project, had never been requested officially, and thus was itself under a cloud. Projekt 1064 was filed away and forgotten.
Fighting a lone battle to build up the Luftwaffe's vital night fighter force was the harassed General der Nachtjägd, Josef Kammhuber. He consistently failed in his efforts to get a truly advanced night-fighter designed for the job, but eventually he managed to gain an interview with Hitler. He left the room with 'special powers' enabling him to overrule his opponents, and as a result in October 1941 Projekt 1064 became the He 219, with a development contract.Kammhuber had been impressed by the potential of this design on a visit to Rostock, and considered it could be the night-fighter he was seeking. At the same time, Focke-Wulf received a contract for a night-fighter which became the Ta 154, dubbed 'Moskito' because of its wooden construction but it never entered widespread
A group of Heinkel He 219 Uhu "Owls" at Fliegerhorst Grove (Karup Airfield) in Denmark in May 1945 shortly after the German surrender. The tail rudders were removed to make the aircraft unflyable.
Few changes were made to the Heinkel design, which retained its twin 13 mm (0.51 in) MG 131 barbettes above and below the rear fuselage and also the 4,409 lbs (2000 kg) bomb load. Forward firing armament was to comprise two 15 mm MG 151/15 cannon in the wingroots and a ventral installation of two 20 mm MG 151/20s or a large 30 mm MK 103 cannon. The basic aircraft was a clean and efficient stressed-skin design, with powerful slotted flaps (oftendescribed incorrectly as Fowler-type). The engines had circular radiators giving the appearance of radials, and a retractable ladder was provided for access to the lofty cockpit, where pilot and radar observer sat back-to-back with amn excellent all round view. A 13 mm (0.51 in) MG 131 was provided for rear defence. In the centre fuselage were three tanks housing 2600 litres (572 Imperial gallons).
The He 219 V1 (first prototype) made its maiden flight on 15 November 1942, and demonstrated outstanding handling and performance. The only real problem was poor yaw/roll stability, rectified in the third aircraft by enlarging the tail and extending the rear fuselage. There then began a process of development and tinkering with the armament and equipment that became so complex that today it is impossible to unravel. Even during the war, the RLM (air ministry) asked whether the profusion of types and designations could be simplified. The prototypes flew with a recorded 29 different variations of armament, while the plans for a manufacturing programme were thrown into disarray by repeated air raids on Rostock in March and April 1942, which twice destroyed virtually all the He 219 drawings. These attacks prompted Heinkel to plan for production at Vienna-Schwechat, fuselages being supplied from Mielec in Poland; continued bitter opposition, led by Generalfeldmarschall Erhard Milch, repeatedly delayed any production of what any impartial observer must have concluded was an outstanding aircraft.
Back in August 1942, Kammhuber had urged Heinkel to think in terms of a complete operational Gruppe (wing) by 1 April 1943, but at that date the sum total of He 219s was five prototypes. In the fIrst week of 1943 the third prototype He 219 was flown in mock combat against a Junkers Ju 188 (a type favoured as a night-fighter by Milch), leading to a highly biased RLM report which put in all the He 219's faults and omitted the enthusiastic comments of test pilots. It even suggested the Messerschmitt Bf 110 as an alternative to the new fighter. Nevertheless, later in that month Heinkel did receive the first production contract, for 127 aircraft.
On 25 March 1943 came a more detailed fly-off between an He 219 (probably the V4, with FuG 212 Lichtenstein C-1 radar), flown by the Gruppenkommandeur of I/NJG 1, Major Werner Streib, and a Ju 88S and a Dornier Do 217N. The Dornier soon withdrew, but the Junkers was flown by a pilot as famous as Streib, Oberst Wiktor von Lossberg of the technical staff. Brilliant as von Lossberg was, he had to concede defeat to the He 219, which by this time was becoming known as the Uhu (owl). The initial pre-series He 219A-O was delivered from late May 1943 in He 219A-0/Rl and R2 sub-types, respectively with the belly tray housing four MK 108s or four MK 103s. Both guns were of 30-mm calibre, but the MK 108 was a compact low-velocity weapon weighing 130 lbs (59 kg), while the MK 103 was a massive gun weighing 320 lbs (145 kg) and having tremendous power. Wing guns usually remained MG 151/20s. The pilot had a two-pronged control column, partly to ease the choice of either hand and partly to carry more switches and triggers. Guns were fired by the right hand, the top button firing the fuselage guns and the front trigger those in the wings. A further addition in at least one He 219A-0 was a compressed-air ejection seat for both occupants, the first in service in the world. There was an MF radio wire from the cockpit mast to each fin, but these were no real problem in emergency escape, and Heinkel was in fact looking ahead to the time when the He 219 would be jet-propelled. This also explained his original choice of nosewheel-type landing gear.
Initial deliveries went to I/NJG 1 at Venlo, on the Dutch frontier, where Streib determined to show what the type could do. It had C-1 radar, the intermediate set that followed FuG 202, and used the same group of small dipole aerials tuned to the 490 MHz frequency, but with two displays showing a direct view and a plan. The first combat mission was flown by Streib himself with backseater Pischer on the night of 11/12 June 1943 in He 219A-0 G9+FB. The mission was an epic, for the Uhu shot down five RAF heavy bombers. On returning, however, Streib totally misjudged the approach because of a misted windscreen. Seeing the dim runway lights at the last moment he selected full flap at too high a speed; the circuits shorted and the flaps blew back under the air load. The aircraft hit the ground so hard it broke up, but both men walked away without a scratch.On hearing this, Milch said, "Yes, but perhaps Streib would have shot down just as many had he been flying another type of aircraft." But over the next 10 days these immature machines, in just six more sorties, destroyed another 20 RAF bombers, including six Mosquitoes. No Mosquito had ever before been intercepted at night, and not even Milch could ignore this achievement. The main trouble was that, despite having an assembly line at Schwechat, another about to start deliveries at Marienehe and a third being set up at the vast plant at Oranienburg (on tapering off of He 111 production), Heinkel's huge network of plants simply could not deliver He 219s. This was partly because of the fantastic profusion of sub-variants, many of them launched to meet official criticisms. It was also because of shortages of critical parts, notably engines. Whereas the basic plan was for 100 aircraft to be delivered monthly, actual acceptances hardly ever exceeded 12 per month.Subsequent He 219 sub-types are listed separately. Few of these attained production status, although features that did become standard included longer nacelles housing extra fuel, removal of the rear gun (except on the three-seat He 219A-5/R4), installation of the powerful FuG 220 Lichtenstein SN-2 radar with huge Hirschgeweih (stag's antlers) dipole aerial array, FuG 220 tail-warning radar, the ejection seat and, not least, the schräge Musik (literally 'slanting music', or jazz) armament. This scheme dated from 1941, having been proposed by armament engineers at Tarnewitz and tested by an NJG Experte, Oberleutnant Rudolf Schoenert. The idea was that oblique upward firing guns could be brought to bear accurately in a no-deflection shot by formating below and slightly behind the enemy bomber, using, a special upward looking sight. The scheme was made possible by the amazing fact that British heavy bombers not only had not one gun firing downwards but also not one window from which a formatting night-fighter could be seen. The usual schräge Musik installation in the He 219 comprised two MK 108s each with 100 rounds, fixed aft of the fuselage tanks at an angle of 65°.
By mid-1944, the RLM officials who had time to think about the matter realised that the campaign against the Uhu had been misguided. Milch himself had gone, production being henceforth a series of massive dictates by civilian Albert Speer. One of these, the Notprogramm (emergency programme) of 1 November 1944, virtually halted all aircraft manufacture except that of jets and single-engined fighters. Thus, the He 219 never did become the massive programme that should have been possible. The He 219 never equipped any unit except I/NJG 1 (ones and twos reached II/NJG 1, NJGr 10, Erg./JG 2 and NJSt 'Finnland' and 'Norwegen', but the numbers were trivial). By June 1944, I/NJG 1 had 20 Uhus, almost all of the current production He 219A-2 and He 219A-5 types. By this time RAF Mosquitoes were making themselves felt not only as pathfinders and bombers but also as intruders, and the number of He 219s that failed to return from night sorties climbed significantly. Previous attrition had been very low, although I/NJG 1 lost three Kommandeure in succession in 1944, two of them having been killed in mid-air collisions.In January 1945, I/NJG 1's establishment was up to 64 aircraft, and total deliveries of all versions reached 268, plus about 20 development aircraft modified to acceptable operational standard by field units and a further six (not on any official documents) which were assembled and put into action by I/NJG 1 from replacement components and spares. So, how does one assess this controversial aircraft? There is no doubt it was a 1940 design of exceptional merit which could in a more ordered society have been developed for many roles with telling effect, as was the UK's Mosquito. The mass of sub-types merely diluted the main production effort, and the consistent failure of Daimler-Benz and Junkers to deliver the hoped for engines killed the advanced versions that would have kept the He 219 in front. As for the aircraft itself opinions are divided.
According to Gebhard Aders (author of Geschichte der deutschen Nachtjägd), the He 219 "never achieved the values given in its manual. With almost full tanks and full armament, the He 219 could not get above 26,247 ft (8000 m). With Lichtenstein and flame dampers, the maximum speed fell to about 311 mph (500 km/h) at this height." On the other hand, he states "The 219 was the only German night-fighter that could still climb on one engine, and even go round again for another landing attempt," a belief echoed by many former Uhu pilots. Yet that greatest of test pilots, Captain E. M. 'Winkle' Brown, who flew several captured He 219s, wrote in Air International that the type was "somewhat overrated... It suffered from what is perhaps the nastiest characteristic that any twin-engined aircraft can have, that being it was underpowered. This defect makes take-off a critical manoeuvre in the event of an engine failing, and a landing with one engine out can be equally critical. There certainly could be no overshooting with the He 219 in that condition."
This marginal performance is the more remarkable when it is remembered that the DB 603 was the largest of the inverted V-12 engines used by the Luftwaffe, with a cubic capacity 65 per cent greater than that of the Merlin. The problem lay squarely in the growth of systems and equipment with which the Uhu was packed, so that a typical He 219A-7 version weighed more empty than any Ju 88 night-fighter, and more than a fully-loaded Mosquito. (2)