Heinkel He 280

He 280

Picture - Heinkel He-280 V2. Note missing engine cowlings. Early flights were carried out with cowlings removed in order to minimize the risk of fire as a result of dripping fuel.

Role: Fighter
Manufacturer: Heinkel
Designed by: Robert Lusser
First flight: September 22, 1940
Status: Cancelled
Produced: 1940-1943
Number built: 9

The Heinkel He 280 was the first turbojet-powered fighter aircraft in the world. It was inspired by Ernst Heinkel's emphasis on research into high-speed flight and built on the company's experience with the He 178 jet prototype. A combination of technical and political factors led to it being passed over in favor of the Messerschmitt Me 262. Only nine were built and none reached operational status.

Development

The Heinkel company began the He 280 project on its own initiative after the He 178 had been met with indifference from the Reichsluftfahrtministerium ("RLM") (Ger. "Reich Aviation Ministry"). The head designer was Robert Lusser, who began the project under the designation He 180 in late 1939. It had a typical Heinkel fighter fuselage, elliptically-shaped wings and a dihedralled tailplane with twin fins and rudders. The landing gear was of the retractable tricycle type with very little ground clearance. Internally, the He 280 was equipped with a compressed-air powered ejection seat, the first aircraft to carry one.

The first prototype was completed in the summer of 1940, but the HeS 8 intended to power it was running into difficulties. On 22 September 1940, while work on the engine continued, the first prototype started glide tests with ballast hung in place of its engines. It would be another six months before Fritz Schx¤fer would take the second prototype into the air under its own power, on 30 March 1941. The type was then demonstrated to Ernst Udet, head of RLM's development wing, on 5 April, but like its predecessor, it apparently failed to make an impression.

Had Udet approved development, Heinkel would have received the extra funding which they needed. This might have led to a rectification of the problems they were having with the jet engines. This was the case across all jet engine development in Germany; government funding was lacking at the critical stage that of initial development.

A contest flight in 1941 comparing an He 280 with a Focke-Wulf Fw 190 had the He 280 completing four laps of an oval course before the Fw 190 could complete three. Ernst Heinkel designed a smaller jet fighter airframe for the He 280 that was well matched to the lower-thrust jet engines available in 1941. The maximum weight of the He 280 was 4,296 kg (9,470 lb), compared to 7,130 kg (15,720 lb) for the Me 262 (which did not get an adequate thrust engine until late 1944). The He 280 could have gone into production by late 1941 and maintained the air superiority which the Fw 190 had established, and filled the gap between the Fw 190 and Me 262. Initial problems with the HeS 8 engine would have likely been ironed out as production of the fighter began.

Some of the resistance to the He 280 would make little sense today. The tricycle landing gear was considered too frail for grass or dirt airfields which were common at the time especially in Russia and North Africa. The Me 262 was originally designed as a tail-dragger, but this configuration makes it difficult for a jet to become airborne. Test pilots had to tap on the brakes to get the Me 262 tail off the ground while trying to take off. Pioneered on its fifth prototype with fixed gear, and made retractable on the sixth prototype and afterwards, the Me 262 emerged with its redesigned tricycle landing gear.

One benefit of the He 280 which impressed the political leadership was the fact that the jet engines could burn kerosene, which requires much less expense and refining than the high-octane fuel used by piston-engine aircraft. The He 280 might have been more easily "sold" if Heinkel stressed the possibility of using it as an attack aircraft for anti-shipping. While the R4M rockets were not available until 1944, the Germans did develop the Nebelwerfer in 1941, which was a 150 mm (5.9 in) artillery rocket launcher. These tubes could have been mounted underneath the wings of a jet. German pilots complained that bombs dropped by the Me 262 had little chance of hitting their targets. A forward-firing recoilless weapon would have been much more effective.

Had the German government given support to production, the He 280s could conceivably have gone into production earlier in the war and reached the Luftwaffe earlier than was ultimately the case with the Me 262. But it was not to be, as Udet, on that April day in 1941, could not see a need for a plane without propellers, no matter what its future might be.

Over the next year, progress was slow due to the ongoing engine problems. A second engine design, the HeS 30 was also undergoing development, both as an interesting engine in its own right, as well as a potential replacement for the HeS 8. In the meantime, alternative powerplants were considered, including the Argus As 014 pulsejet that famously powered the V-1 flying bomb. (Using as many as eight was proposed.)

By the end of 1943, however, the third prototype was fitted with refined versions of the HeS 8 engine and was ready for its next demonstration. On 22 December, a mock dogfight was staged for RLM officials in which the He 280 was matched against an Fw 190. Here, the jet demonstrated its vastly superior speed. Finally, at this point the RLM became interested and placed an order for 20 pre-production test aircraft, to be followed by 300 production machines.

Engine problems continued to plague the project. In 1942, the RLM had ordered Heinkel to abandon the HeS 8 and HeS 30 to focus all development on a follow-on engine, the HeS 011, a much more advanced (and therefore problematic) design. Meanwhile, the first He 280 prototype had been re-equipped with pulsejets and was towed aloft to test them. Bad weather caused the aircraft to ice up, however, and before the jets could be tested, pilot Helmut Schenk became the first person to put an ejection seat to use. The seat worked perfectly, but the aircraft was lost, and never found.

With the HeS 011 not expected for some time, Heinkel was forced to accept that it would have to use a competitor's engines, and selected the BMW 003. Unfortunately, this engine was also experiencing problems and delays, and in the meantime, the second He 280 prototype was re-engined with Junkers Jumo 004s while the next three airframes were earmarked for the BMW motor (which, in the end, would never be ready before the end of the He 280 project). The Jumo engines were much larger and heavier than the HeS 8 that the plane had been designed for, and while it flew well enough (for the first time on 16 March 1943), it was immediately obvious that this engine would be unsuitable in the long term. The aircraft was slower and generally less efficient than the Me 262.

Less than two weeks later, on 27 March, Erhard Milch cancelled the project. The Jumo 004-powered Me 262 appeared to have most of the qualities of the He 280, but was better matched to its engine. Heinkel was ordered to abandon the He 280 and focus attention on bomber development and construction, something he remained bitter about until his death.

Specifications (He 280 V3)

General characteristics

Crew: 1, pilot
Length: 10.40 m (34 ft 1 in)
Wingspan: 12.20 m (40 ft)
Height: 3.06 m (10 ft)
Wing area: 21.5 m² (233 ft²)
Empty weight: 3,215 kg (7,073 lb)
Loaded weight: 4,280 kg (9,416 lb)
Max takeoff weight: 4,300 kg (9,470 lb)
Powerplant: 2x— Heinkel HeS.8 turbojet, 5.9 kN (1,320 lbf) each

Performance

Maximum speed: 820 km/h (512 mph)
Range: 370 km (230 mi)
Service ceiling: 10,000 m (32,000 ft)
Rate of climb: 1,145 m/min (3,756 ft/min)

Armament

3 x— 20 mm MG 151/20 cannons

"Harbinger of an Era...The Heinkel He 280". Air International, November 1989, Vol 37 No 6. ISSN 0306-5634. pp. 233-241, 260.

Heinkel He 280 Pictures and Heinkel He 280 for Sale.

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Source: WikiPedia