Saturday, 14 November 2015

Heinkel He219, Design and development of Uhu. Part 4. German Dzib -Compiler-

Design and development

The first six months of the war against Great Britain, which broke out on 3rd September 1939, made the Luftwaffe high command realize that it was in dire need of a modern, fast, long-range reconnaissance aircraft, capable of reconnoitring over British territory. The aircraft hitherto used to perform that role were modified Heinkel He 111s and Junkers Ju 88s, the Luftwaffe’s standard bombers pressed into service as scouts. Their dedicated crews, manning aircraft so vulnerable to interception, could only hope that their luck would hold out.
Their mounts were too slow to outrun Hurricanes or Spitfires, and their defensive armament was too weak to keep fighters at bay.
Revi 16 B sight with additional control levers led behind the armour plate to the cockpit. [Visualisation 3D Marek Ryś]

 On 28th April 1940 the construction department of Heinkel Werke at Rostock-Marienehe presented to the RLM (Reichsluftfahrt Ministerium)2 a project for a fast, single-engined reconnaissance aircraft, designed as a private venture by the Heinkel firm.
The project was clearly inspired by an RLM circular letter, which pointed out the lack of a purpose-built reconnaissance machine in the Luftwaffe’s inventory, and the difficulty of fulfilling that role with other aircraft not designed for the purpose.
A new, custom-designed aircraft such as the RLM was interested in would not have to compromise its speed and operational ceiling due to bomb-carrying capabilities.

On 30th September and 1st October 1940 RLM officials held a first round of talks with the Heinkel company, represented by Robert Lusser, the executive manager, assisted by Mr Ebert and Mr Meschkat. On that occasion the Heinkel representatives presented blueprints of a reconnaissance aircraft designated P 1055, which was based on an earlier design known as the Heinkel He 119.

The aircraft had a wing area of 42 m2, and its maximum speed was 750 kph. Its calculated maximum range was 4,000 km, at a take-off weight of 12,600 kg. One interesting innovation was the possibility of interchanging the outer wing sections, which made it possible to alter the wing area from 35 m2 to 45 m2. So as to arouse more interest in the RLM’s officials, provision was made for the aircraft to carry bombs on external racks, designed by Ernst Heinkel Flugzeugwerke. The payload was, interchangeably, a single 1,800 kg bomb or two 1,000 kg bombs. The crew of two would be seated in a pressurized cockpit.

The RLM evinced a vivid interest in the project, hinting at the possibility of signing a formal contract for the aircraft’s construction in the nearest future. However, they emphasized that the machine’s speed was its most important

asset. For this reason the RLM wanted the aircraft to be fitted with a turbo supercharged Daimler-Benz DB 613 engine, which was expected to be ready in 1941. This powerplant consisted of two coupled DB 603 inline engines connected via a gearbox to one driveshaft, fitted with superchargers and methanol-water emergency boost, which was expected to give a maximum power output of 3,500 hp.

A lively exchange of correspondence between the Heinkel design bureau and the RLM followed the meeting. The proposed bomber variant impressed the representatives of the latter. Still, they considered the aircraft’s planned defensive armament, which consisted of fixed, forward firing guns, inadequate. Some bitter lessons had been learned during the Battle of Britain, during which whole formations of He 111s had been decimated because of their poor defensive armament and the large, glazed surfaces of their front sections, which made their crews even more vulnerable. Although Lusser was convinced that the P 1055, with its superior speed, would outdistance enemy interceptors, von Pfistermeister, another manager at Heinkel, was far less optimistic:

“Our timetable schedules the P 1055 prototype’s maiden flight for the end of 1942. Assuming that the first serial production aircraft will be delivered to operational units in October 1944, four years will have elapsed from now. Unlike you, I don’t believe we can still count on the P 1055’s advantage of speed being maintained at that time. Perhaps a jet-propelled fighter, capable of speeds higher than the 750 kph expected of the P 1055, will be constructed in the meantime. Personally, I hope that it will be a Heinkel-designed fighter, probably the 280. Either way, the P 1055 will need a strong defensive armament, just like today’s bombers.

We cannot ignore the possibility, or rather the high probability, of the existence of much faster fighters in the future ...”

uring a subsequent meeting between von Pfistermeister and the RLM’s representative Friebel, more issues concerning the new design were discussed. It was believed that the aircraft would be instrumental in delivering cartographic photographs of certain territories in Africa, the Middle East and the Far East, which at that time were practically blank spots on maps of the world. Friebel made it clear that Heinkel should focus on designing a reconnaissance aircraft, since at that time the Luftwaffe had no use for a bomber based on the P 1055 project. In fact, the aircraft expected to fulfil the role of long-range bomber was another Heinkel design, the He 177 Greif. Furthermore, a Zerstörer (destroyer) variant of the P 1055 was considered redundant in view of the heavy losses suffered over England by the Messerschmitt Bf 110 units.
Details of the left side of the cockpit. From left: BG 25 control panel (for FuG 25 device), ADb-11 switch box (part of FuG 16ZY set) and Revi 16 B sights illumination controller (main and auxiliary for Schräge musik guns, if they were installed). [Visualisation 3D Marek Ryś]
Despite the RLM’s unfavourable stance on the matter, Heinkel did design a Zerstörer variant of the P 1055 on his own initiative, which he presented to the RLM’s representatives on 19th October 1940. The aircraft was to attain a top speed of 745 kph at 6,000 m, and its planned armament consisted of four fixed MG 151 cannons, two in the fuselage and two more in the wings. Mr Christensen of the RLM pointed out that production of such an aircraft would make sense only if its maximum speed matched that of enemy fighters. For the time being it was decided to continue developing the P 1055 as a reconnaissance aircraft, whilst a possible Zerstörer variant would be designated the P 1056.
Only a few days later, on 24th October 1940, another conference was held to discuss new aircraft projects under development. Ernst Heinkel presented drawings of his reconnaissance P 1055. The aircraft was to fly at a top speed of 735 kph (at 6,000 m). Its range was supposed to be 2,000 km at maximum speed, and 4,000 km at cruise speed, whilst its service ceiling was estimated at 9,800 m. The RLM was generally satisfied with the project, although its representatives demanded that several alterations be made. The aircraft’s ceiling was to be increased to 12,500 m through the use of supercharged engines, whereas its armament of two fixed, forward-firing MG 151 cannons was to be enhanced by the installation of a single, remote-controlled MG 151 cannon mounted in the aircraft’s tail. Due to the anticipated threat from enemy interceptors, Heinkel was also required to make provision for two additional, remotely controlled, ventral and dorsal gun stations. The design was to retain the interchangeable outer wing sections, and furthermore be able to make dive runs at up to 30o angles. As it was to operate over the Atlantic, de-icing equipment was also considered indispensable.
Meanwhile, the P 1056 Zerstörer variant being developed in parallel was to reach a top speed of 720 kph at 9,000 m and have range of 2,000 km. The P 1056’s planned armament consisted of two fixed, forward-firing MG 151 cannons, a pair of twin-mounted MG 131 Z machine guns at a dorsal station, and a pair of twin-mounted MG 81 Z machine guns in the ventral position. The RLM ordered that development of the P 1056 should be continued, provided that it could be fitted with at least three gun stations with flexible mounts, which would enable the aircraft to take on the role of an escort fighter, dubbed ‘Begleitigel’.
On 23rd November 1940, Scheibe of the RLM inspected a wooden mock-up of the P 1055. In his report he underlined that the crew arrangement, the available room inside fuselage, and the periscopic gunsights for the remotely controlled weaponry complied with the RLM’s requirements. He further stated that the design could be considered useful not only as a reconnaissance aircraft, but also as a daylight bomber and a destroyer as well. There was enough room in the aircraft’s fuselage for the bomber variant to carry bombs internally. Dr. Robert Lusser suggested that the P 1055 should carry an increased defensive armament consisting of two gun stations in the dorsal and ventral positions, each station to be armed with two twin-mounted machine guns, as well as one or two fixed cannons mounted in the aircraft’s nose.
Heinkel He 219 A-0, believed to be W.Nr. 190 012, W.Nr. 190 012, coded G9+FK, of 2./NJG 1, flown by Hptm. Ernst-Wilhelm Modrow; Venlo, March 1944. Upper surfaces and port wing underside are painted in RLM 76 Lichtblau, whilst starboard wing underside is finished in RLM 22 Schwarz. Upper surfaces additionally stippled with RLM 75 Grauviolett. Code letter ‘F’ red. Note the unit’s emblem in the front part of the fuselage. [Visualisation 3D Marek Ryś]

On 28th November 1940 the RLM officially announced that the P 1055 bomber and reconnaissance aircraft had been included in its production plans for the Luftwaffe. A complete airframe mock-up was expected to be ready by 15th January 1941. Before the mock-up was completed, the RLM demanded more changes to the project. The wing configuration was altered from low wing to mid-wing (that is, the wings were to be mounted approximately half way up the fuselage sides). Besides this, the engine was to be moved forward, ahead of the wing leading edges, in order to ensure easier access and maintenance on the ground. The aircraft was to be fitted with twin, three-bladed, contra-rotating propellers. Since the development of the prototype was reaching its final phase, it was time to allocate an official designation. Being a direct descendant of the He 119 project, the aircraft was duly designated the ‘Heinkel He 219’. 
The modifications demanded by the RLM caused a delay in the construction of a wooden airframe mock-up, which was finally ready for inspection on 4th February 1941. It transpired that the calculated top speed had dropped to 653 – 686 kph (depending on the wing type). The RLM’s representatives agreed on further modifications,

which were intended to confer on the aircraft a maximum speed of about 740 kph. Pursuing the goal of a higher top speed, Heinkel’s designers removed, amongst other things, the Fowler flaps (which slid backwards before hinging downwards) and the spacious bomb bay. In addition, the fuselage width was reduced. (16)

Origin: Ernst Heinkel AG
Type: Night fighter

  He 219A-0 to A-7, He 219B & He 219C
Crew: Two
First Flight:
  He 219V-1 November 15, 1942
Service Delivery:
  Prototypes: November 15, 1942
  He 219A-1: November 1943
Total Production: 268

He 219V-1:
   Model: Daimler-Benz DB 603AS
   Type: Inverted-vee-12 liquid-cooled
   Number: Two    Horsepower: 1,750 hp

   Model: Daimler-Benz DB 603G
   Type: Inverted-vee-12 liquid-cooled
   Number: Two    Horsepower: 1,900 hp

He 219A-6:
   Model: Daimler-Benz DB 603L
   Type: Inverted-vee-12 liquid-cooled
   Number: Two    Horsepower: 1,750 hp

He 219A-7/R2:
   Model: Daimler-Benz DB 603E     Number: Two
   Type: Inverted-vee-12 liquid-cooled
     1,800 hp at 2,700 rpm for takeoff.
     1,900 hp at 5,905 ft. (1,800m).
     1,550 hp at 22,965 ft. (7,000m).

Dimensions: He 219A-7
Span: 60 ft. 8 in. (18.5m)
Length (With Aerials):

  50 ft. 11¾ in. (15.54m)
Height: 13 ft. 5½ in. (4.1m)                          Weights: He 219A-7
Empty: 24,692 lb (11,200 kg)
Loaded: 33,730 lb. (15,200 kg)

Performance: He 219A-7
Maximum speed: 416 mph (670kph)
Initial climb: 1,804 ft (550m)/min

Service ceiling: 41,660 ft (12,700m)
Range: 1,243 miles (2,000km)

He 219V-1
2 x 20mm MG 151/20 Cannon in wing roots.
1 x 13mm MG 131 in rear cockpit.

He 219A-2/R1
2 x 20mm MG 151/20 Cannon in wing roots.
2 or 4 x 20mm MG 151/20 Cannon in belly tray.
2 x 30mm Mk 108 cannon in Shräge Musik mount.

He 219A-7/R1
2 x 30mm Mk 108 Cannon in wing roots.
2 x 20mm MG 151/20 Cannon in belly tray.
2 x 30mm Mk 103 Cannon in belly tray.
2 x 30mm Mk 108 cannon in Shräge Musik mount.
   Ammunition: 100 rounds per gun

He 219A-7/R2
2 x 30mm Mk 108 Cannon in wing roots.
2 x 20mm MG 151/20 Cannon in belly tray.
2 x 30mm Mk 108 Cannon in belly tray.
2 x 30mm Mk 108 Cannon in Shräge Musik mount.
   Ammunition: 100 rounds per gun

The Heinkel He 219 Uhu ("Eagle-Owl") was a night fighter that served 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 an advanced VHF-band intercept radar. It was also the first operational military aircraft in the world 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 upon the strategic bomber offensive of the Royal Air Force; but only 268 of all models were built by the end of the war and these saw only limited service. (17)(18)(19)(20)(21)

FuG-220 Lichtenstein SN-2 Radar
At the end of 1943, the Luftwaffe began to give the improved radars FuG 220 Lichtenstein SN-2, that operated in the greater wavelength of 90 MHz (in the rank under the VHF band of FM of the United States) what towards quite but immune to the electronic interference, but Hirschgeweih required the antennas (red deer horns) that were but great enough that the masts Matratze.
The new antennas produced great aerodynamic drag maximum slow down of the airplanes until in 50 Km/h. First equipment SN-2 had problems with the minimum rank of detection, being this of 500 m, to resolve the problem of pursuit of targets short-distance was made necessary to add a second radar FuG-202 Lichtenstein BC or FuG-212 Lichtenstein C-1 to cover the rank under the 500 M.s, but improvements in the spring of 1944 lead to new versions of SN-2 with lower minimum ranks. This conformation began to be used in night fighter with the Heinkel 219A 5/R4. (22)
The Lichtenstein radar was among the earliest airborne radars available to the Luftwaffe in World War II and the first one utilised exclusively in the air interception role. Developed by Telefunken, it was available in at least four major revisions, designated FuG 202 Lichtenstein B/C, FuG 212 Lichtenstein C-1, FuG 220 Lichtenstein SN-2 and the very rarely used FuG 228 Lichtenstein SN-3. (FuG is short for Funk-Gerät, German "radio set"). The Lichtenstein series remained the only widely deployed airborne interception radar used by the Germans on their night fighters during the war — the competing FuG 216 through 218 Neptun mid-VHF band radar systems were

meant as a potentially more versatile stopgap system through 1944, until the microwave-based FuG 240 "Berlin" could be mass-produced; the Berlin system was still in testing when the war ended.
By late 1943, the Luftwaffe was starting to deploy the greatly improved FuG 220 Lichtenstein SN-2, operating on a lower frequency of 90 MHz (lower end of the US VHF FM broadcast band) which was far less affected by electronic jamming, but this required the much larger Hirschgeweih(stag's antlers) antennas, with only eight dipole elements, looking like a much-enlarged version of what occupied the forward end of each one of the earlier quadruple Matratze masts. This aerial setup also produced tremendous drag and slowed the operating aircraft by up to 50 km/h (30 mph).
The first SN-2 set had a problem with a huge minimum range of 500 meters, initially requiring the retention of a supplementary B/C or C-1 set with its full set of four Matratze masts, but the alarming drag that full sets of both types of antennas caused, from both radars being installed, later changed the requirement to only a "one-quarter" subset of the earlier Matratze array at the end of a single mast, centrally mounted on the nose of the aircraft when the BC or C-1 UHF radar remained installed. Improvements in early 1944 led to newer SN-2 versions with lower minimum range, which allowed the older UHF radar system to be removed entirely. In July 1944, the newest version of the SN-2 radar fell into Allied hands when a fully equipped Ju 88 G-1, of 7 Staffel/NJG 2, flew the wrong way on a landing beacon and landed in England by accident, with the crew not realising the mistake until it was too late to destroy the radar or IFF gear. This led to successful jamming of several frequency bands of the FuG 220 (I to III, 72, 81 and 90 MHz), and a partial adoption of the use of the low-to-mid

VHF band FuG 216 and 217 Neptun radar — which used eight shorter-length dipoles in the same "stag's antlers" layout for its frequency ranges than the SN-2 did — but several other bands that the SN-2 used were still operational. After the Allied jammings the FuG 220 antenna setup was optimized for the still operational bands, the 90-degree vertical dipole setup was changed to a 45-degree diagonal setup.

Late-war developments
Late in 1944, the Morgenstern (Morningstar) antenna, comprising a doubled set of two Yagi antenna arrays at 90° angles to each other, on a central, forward projecting mast was developed, and used by both the SN-2 and Neptun radar sets. This was just compact enough to fit into the nose of a Ju 88G, and was covered with a rubber-coated, wooden conical radome with the extreme tip of each element barely protruding above the surface. Further development led to the FuG 228 Lichtenstein SN-3 radar set but this saw little to no service.

A 9 cm wavelength system known as FuG 240 Berlin was developed, based on captured examples of the Allies' cavity magnetron technology but saw little to no operational use.

Allied countermeasures
The Allies were able to jam and track the early FuG 202 and 212 sets by Summer 1943. During several months in this period they rendered these sets almost useless by blinding them with 'Window', termed Düppel by the Germans. Fully jamming the SN-2 took longer but was finally accomplished by the Allies following the mistaken landing due to a navigation error of a Ju 88G-1 night fighter from NJG 2at RAF Woodbridge, equipped with both the Flensburg

radar detector and the SN-2 radar on July 13, 1944, compromising both systems to the Allies. (23) Some allied aircraft were then equipped with 'Piperack' which countered the Lichtenstein SN-2 aerial intercept radar. (24) Much more dangerous were Mosquito intruders equipped with a device called Serrate to allow them to track German night fighters by emissions from their Lichtenstein B/C, C-1 or SN-2 sets.
An aerial maneuver known as the 'corkscrew' was developed to remove an attacked heavy bomber from within the 60-degree cone of coverage of an attacking night fighter's Lichtenstein radar. The technique was developed using the same early model UHF-band Lichtenstein-equipped, Ju 88R-1 night fighter that had landed at RAF Dyce in April 1943 by its defecting crew. It was also later flown in tests by the RAF's enemy aircraft evaluation unit, No. 1426 Flight, known colloquially as the 'Rafwaffe'.

Lichtenstein FuG 220 Functional Diagram  (25)

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