On 27 August 1939 the Heinkel He 178 became the first aircraft to take to the skies powered entirely by a turbojet engine, twenty months before the first flight by a British jet aircraft.
The engine used to power the He 178 was designed by Dr Hans Joachim Pahst von Ohain of Göttingen University. In March 1936 he and his assistance were hired by Ernst Heinkel, and began work at Heinkel's Marienche airfield. Their first engine, the HeS 1, was ready for bench tests in September 1937, and produced a thrust of 550lb (250kg), using hydrogen as fuel. The HeS 2 probably never progressed beyond the design stage, but by March 1938 the petrol-fuelled HeS 3 was ready for bench-tests, and produced 1,100lb (500kg) of controllable thrust.
The first flight tests of the HeS 3 were made by suspending it below the fuselage of a Heinkel He 118. These continued until the engine burnt out, and the knowledge gained was used to produce the HeS 3b.
Von Ohain continued to design new jet engines, and by the end of the war he had produced the He S11A, which by early 1945 was being manufactured for use in the Arado Ar 234, Messerschmitt Me 262 and Heinkel He 162.
While the HeS 3 was being tested under the He 118 the airframe for the He 178 itself was under development. The result was a shoulder-wing monoplane, with a duralumin monocoque fuselage with a circular cross-section. The air intake was in the nose, the engine was mounted towards the centre of the aircraft, just behind the fuel tank, and the thrust produced was directed down a long tailpipe that emerged at the rear of the fuselage.
The He 178 first took to the air on 24 August 1939, when it left the runway for a short time, but its first proper maiden flight came on 27 August 1939. This flight was only a partial success, as the engine was badly damaged by a bird strike soon after take-off, but the test pilot, Erich Warsitz, still had time to make a circuit of the airfield and land safely without power.
The second test flight didn't come until 1 November 1939. The engine had been modified to produce the HeS 6, which produced 1,300lb of thrust, giving the aircraft a top speed of 373mph. This second flight was observed by a number of senior figures in the Luftwaffe and German Air Ministry, including Udet, Milch and Lucht, but despite the aircraft's obvious high speed there was very little official interest until the end of the year. The German Air Ministry had its own jet engine development section, and wasn't interested in private developments, at least until the then head of the department moved on.
His successor was more encouraging, but even then work on the single engined He 178 soon came to a halt. Heinkel produced a design for the V2, which would have had a retractable undercarriage and new wings, but this aircraft probably never flew. Instead work moved onto twin engined aircraft, with the Heinkel He 280 and Messerschmitt Me 262.
The first flight of the He 178 came almost exactly one year ahead of that of the second jet aircraft, the Caproni-Campini C.C.2, and twenty months ahead of that of the second turbojet aircraft, the Gloster E.28/29, which took to the air on 15 May 1941. Fortunately the Germans failed to take advantage of this lead, focusing instead on short-term projects and the production of existing types.
Engine: Heinkel HeS 3 on maiden flight, HeS 6
Power: 1,100lb then 1,300lb
Wing span: 23ft 3 ½ in
Length: 24ft 6 ½ in
Height: 6ft 10 5/8 in
Empty weight: 3,565lb
Loaded weight: 4,396lb
Max Speed: 373 mph with HeS 6
Cruising Speed: 360mph at sea level