Heinkel He 219

Design & Development

Development and production of the He 219 was protracted and tortuous, due to political rivalries between Josef Kammhuber, commander of the German night fighter forces, Ernst Heinkel, the manufacturer and Erhard Milch, responsible for aircraft construction in the Reichsluftfahrtministerium (RLM — the German Aviation Ministry). The aircraft was also complicated and expensive to build; these factors further limited the number of aircraft produced.

When engineer Robert Lusser returned to Heinkel from Messerschmitt, he began work on a new high-speed bomber project called P.1055. This was an advanced design with a pressurized cockpit, twin ejection seats (the first to be planned for use in any combat aircraft), tricycle landing gear — featuring a nose gear that rotated its main strut through 90° during retraction (quickly orienting the nosewheel into the required horizontal position for stowage within the nose, only at the very end of the retraction cycle) to fit flat within the forward fuselage, and remotely controlled, side mounted FDSL 131 defensive gun turrets similar to those used by the Messerschmitt Me 210. Power was to be provided by two of the potentially troublesome, dual-crankcase DB 610 "power system" engines then under development, weighing on the order of about 1–​1⁄2 tonnes apiece, producing (2,200 kW/2,950 hp) each, delivering excellent performance with a top speed of approximately 750 km/h (470 mph) and a 4,000 km (2,500 mi) range with a 2,000 kg (4,410 lb) bomb load.

The RLM rejected the design in August 1940 as too complex and risky. Lusser quickly offered four versions of the fighter with various wingspans and engine choices in order to balance performance and risk. At the same time, he offered the P.1056, a night fighter with four 20 mm cannon in the wings and fuselage. The RLM rejected all of these on the same grounds in 1941. Heinkel was furious and fired Lusser on the spot.

About the same time as Lusser was designing the P.1055, Kammhuber had started looking for an aircraft for his rapidly growing night fighter force. Heinkel quickly re-designed the P.1055 for this role as the P.1060. This design was similar in layout but somewhat smaller and powered by two of the largest displacement (at 44.5 litres/2,700 cu. in.) single-block liquid-cooled aviation engines placed in mass production in Germany, the DB 603 inverted V12 engine. As designed by Heinkel, these engines' nacelle accommodations featured annular radiators similar to the ones on the Jumo 211-powered Junkers Ju 88A, but considerably more streamlined in appearance, and which, after later refinement to their design, were likely to have been unitized as a Heinkel-specific Kraftei engine unit-packaging design. Nearly identical-appearance nacelles, complete with matching annular radiators, were also used on the four prototype He 177B prototype airframes built in 1943-44, and the six ordered prototypes of Heinkel's He 274 high-altitude strategic bombers with added turbochargers. The early DB 603 subtypes had poor altitude performance, which was a problem for Heinkel's short-winged design, but Daimler had a new "G" subtype of the DB 603 powerplant meant to produce 1,400 kW (1,900 PS) take-off power apiece under development to remedy the problem. Heinkel was sure he had a winner and sent the design off to the RLM in January 1942, while he funded the first prototype himself. The RLM again rejected the He 219, in favour of new Ju 88- and Me 210-based designs.

Construction of the prototype started in February 1942 but suffered a serious setback in March, when Daimler said that the DB 603G engine would not be ready in time. Instead, they would deliver a 603A engine with a new gear ratio to the propellers, as the DB 603C with the choice of using four-blade propellers, as the similarly-powered Fw 190C high-altitude fighter prototypes were already starting to use into early 1943, with the DB 603. DB 603 engines did not arrive until August 1942 and the prototype did not fly until 6 November 1942. When Kammhuber saw the prototype on the 19 November, he was so impressed that he immediately ordered it into production over Milch's objections. Milch—who had rejected the He 219 in January—was enraged.

Stability problems with the aircraft were noted but Heinkel overcame these by offering a cash prize to engineers who could correct them. Further changes were made to the armament during the development of the prototype He 219V-series. The dorsal rear defensive guns—mounted atop the fuselage and firing directly rearward from a fixed, internally mounted, rear-facing dorsal "step" position, at a point just aft of the wing trailing edge — were removed due to their ineffectiveness. The forward-firing armament complement of the aircraft was increased to two Mauser MG 151/20 20 mm autocannon in the wing roots, inboard of the propeller arcs to avoid the need for gun synchronizers, with four more MG 151/20 autocannon mounted in the ventral fuselage tray, which had originally ended in a rearwards-facing "step" similar to and located directly under the deleted rear dorsal "step" — this rearwards-facing feature was also deleted for similar reasons. The A-0 model featured a bulletproof shield, that could be raised in the front interior cockpit, hiding the entire bottom portion of the windscreen, providing temporary pilot protection and leaving a sighting slot by which the gunsight could be aimed at a bomber. Production prototypes were then ordered as the He 219 A-0 and quickly progressed to the point where V7, V8 and V9 were handed over to operational units in June 1943 for testing.

The earlier prototypes, with four-blade propellers for their DB 603 engines (also used on the Fw 190C prototypes, with the same DB 603 engine) had blunt, compound-curvature metal nose cones also used for production-series He 219A airframes. The initial examples of these nose cones possessed cutouts for their use with the quartet of forward-projecting masts for the Matratze 32-dipole radar antennae on the noses of at least the first five prototypes, used with the early UHF-band Lichtenstein B/C or C-1 radar installation. These early He 219V-series prototype airframes also had cockpit canopies that did not smoothly taper aftwards on their upper profile, as on the later production He 219A-series airframes, but instead ended in a nearly hemispherically-shaped enclosure. The "V4" (fourth) prototype, equipped with the earlier canopy design, had a small degree of internal metal framing within the rearmost hemispherical canopy glazing, apparently for a rear dorsal weapons mount or sighting gear for the deleted fixed "step"-mount rearwards-firing armament. The idea for the rear-facing dorsal and ventral "step" features on the original He 219 fuselage design, for armament emplacement locations was later carried into the May 1943 revised fuselage design, for what became the Heinkel Amerika Bomber design contract competitor, the He 277, for its revised fuselage design to accommodate a tricycle undercarriage. The Heinkel engineering department's Typenblatt general arrangement drawing for a BMW 801E-powered, tricycle-gear He 277 Amerika Bomber design show the early He 219 V-series' rearwards-facing "steps" being inherited by the He 277's revised fuselage design in similar locations on its aft fuselage. The adoption of the pair of He 219 prototype rear-fuselage "step" features relocated the ventral emplacement rearwards by two meters, to provide space for the He 277's nosewheel configuration's seven-meter long bomb bay. The adopted "step" locations provided for the Amerika Bomber's dorsal and ventral, generally rearwards-firing aft fuselage turrets, with each turret placed at the position of the "step" features, being armed with a pair of MG 151/20 cannon apiece.

Milch repeatedly tried to have the He 219 program cancelled and in the process, Kammhuber was removed from office. Production ceased for a time, but was restarted because the new Junkers Ju 388s were taking too long to get into service.

Further developments

The follow-on series to the He 219As in service was to be the He 219B fitted with the new, but troublesome 1,864 kW (2,500 hp) Junkers Jumo 222A/B 24-cylinder engines — a multibank, liquid-cooled inline engine, with six rows of cylinder blocks having four cylinders each—which would have allowed the He 219 to reach 700 km/h (440 mph), each of which were almost the same displacement in their A/B (supercharged) and E/F (supercharged with intercoolers) versions and each only very slightly heavier, compared to the Double Wasp radial engines in the American P-61 night fighter. The He 219B wing was also to have had an increased span of 22.06 m (72.38 ft), for better high altitude performance. The Jumo 222 did not reach production status, with just under 300 examples built in at least three differing displacement sizes. Only a few test machines were ever fitted for the engines; some additional airframes were built with the enlarged wing. These examples were slated to fly with high-altitude versions of the standard DB 603 powerplants in place of the troubled Jumo 222 multibank powerplants, but only one or two test machines ever flew with them.

A further adaptation would have been the He 219C, also intended to use the B-series design's big wing and Jumo 222 powerplants as well as an all-new fuselage of 17.15 m (56.27 ft), with a complete three-man Ju 388J cockpit section forward, converted to accept the He 219A's standard nose gear layout (the Ju 388 itself used the Ju 88's conventional gear design), the Borsig-designed Hecklafette HL 131V "quadmount", hydraulic-powered four-gun manned tail turret intended for later He 177A versions and the He 177B-5, as well as more than one Amerika Bomber strategic bomber design competitor. Day bomber and night fighter versions were proposed and metal was cut for the project but, without the over-1,500-kW output Jumo 222 engines getting out of their strictly experimental status, they never flew.

Paper projects include the very-high-altitude He 219E with a vastly increased wingspan of 28.5 m (93.5 ft) and 1,500 kW (2,000 PS) output rated DB 614 engines, which were apparently a further-uprated version of the never-produced DB 603G inverted V12, capable of the desired 1,491 kW (2,000 hp) power output level that Germany had so much trouble crafting into combat-reliable aviation powerplants.

A more reasonable project was the Hütter Hü 211, a design by Wolfgang Hütter that took a standard He 219 fuselage and tail and added a long-span, high aspect ratio wing of 24.55 m (80.54 ft) to create a fast, high altitude interceptor. Since this design was also meant to be powered by the ill-fated Jumo 222 it never flew, although work continued on two sets of wings until they were destroyed by Allied bombing.

The He 219 was the only piston-engined night fighter capable of facing the British Mosquito on equal terms, given its speed, manoeuvrability and firepower, but it never played a significant role in the war because the industry failed to make it available in sufficient numbers.