Heinkel He 178 V1

06/30/2010. Remarks by Johan Visschedijk: "The events which led to the world's first flight by an aircraft powered solely by a turbojet began when Ernst Heinkel employed Dr. Hans Joachim Pabst von Ohain and his assistant Max Hahn in March 1936. Von Ohain had been conducting pioneering experiments on jet propulsion at Gottingen University and continued to do so in a secret shed at Heinkel's Marienehe airfield.

By September 1937, the first demonstration turbojet, the HeS 1, was bench-running (albeit somewhat uncontrollably and only on hydrogen) to give a thrust of about 551 lb (250 kg) and it resembled in principle Frank Whittle's early patents although it was in no way influenced by them. It is unlikely that an HeS 2 design was built, but, by March 1938, the HeS 3 design was bench-running at a thrust of about 1,102 lb (500 kg) and had made the further advances of being controllable and of running on petrol.

The HeS 3 engine used an axial-flow impeller and a centrifugal compressor. Some of the air from this compressor passed forward into a reverse-flow annular combustion chamber while some went rearwards to mix with the combustion gases before entering the turbine. The radial inflow turbine was of similar configuration to the compressor and the whole engine had a somewhat large diameter for its size, due to the compressor and combustion chamber arrangement. Maximum rotor speed was 13,000 rpm and the weight was 794 lb (360 kg).

Flight tests began with this engine suspended beneath a Heinkel He 118, and, at the same time, the design began of the He 178 to be powered by the HeS 3 for more extensive experiments. The HeS 3 made many flights beneath the He 118 until the turbine burned out but, by that time, much had been learned and an improved engine (though of similar performance) was ready. The decision was made to install the new engine, the HeS 3b, in the He 178 airframe which was nearing completion in the same secret hangar as the He 176.

The He 178 was a shoulder-wing monoplane with the pilot's cockpit well forward of the wing leading edge. The wings were largely of wooden construction, had moderate dihedral, an equi-taper planform, and large in-board trailing edge flaps. The HeS 3b engine was installed in the duralumin monocoque fuselage with its forward end roughly on a level with the wing trailing edge, and air was drawn from a nose intake through a duct which curved beneath the pilot's seat and then up to the engine; the tailpipe was of considerable length, being about one third of the aircraft's total length. The single petrol tank was immediately behind the cockpit, and the tail wheel-type landing gear retracted into the fuselage.

The date when taxiing trials with the He 178 began is uncertain, but, with Flugkapitiin Erich Warsitz at the controls, the aircraft made a short hop along the runway on August 24, 1939. The first true flight followed three days later, August 27, when Warsitz circled Marienehe airfield, but this flight was marred because the landing gear could not be induced to retract and the engine cut out soon after take off when a bird was sucked into the intake. However, a safe power-off landing was made.

The flight occurred exactly one year before the first flight of the Italian Caproni-Campini C.C.2, which used a much cruder ducted-fan jet system but was, nevertheless, the world's second jet aircraft to fly. Not until more than 20 months after the He 178 flight, did the first serious competitor appear when, on May 15, 1941, the Gloster E.28/39 first flew with a turbojet born out of Whittle's work.

Up until the completion of the He 178's first flight, this jet project had been kept strictly as a private venture, but from that time every effort was made to interest the RLM. It was not, however, until November 1, 1939, that Udet, Milch, Lucht and others were induced to witness a flight of the He 178 at Marienehe. One reason for this long delay in making only the second flight was that once war had started the order had been given to concentrate on normal aircraft production and experimental work was slowed down.

Nevertheless, time had been found to make modifications to the HeS 3b engine which resulted in the HeS 6, giving a thrust of 1,301 lb (590 kg) at 13,300 rpm but with a weight of 926 lb (420 kg). This was the engine used on the second flight, but the performance was rather poor because of the lower power-to-weight and power-to-diameter ratios of the engine and defects in the airframe, the most noteworthy of which was the directional instability above a certain speed and the fact that the landing gear still refused to retract. The He 178 only flew at about 373 mph (600 kmh) maximum but Dr von Ohain believed that his HeS 6 engine could have pushed it up to about 434 mph (700 kmh) if the airframe defects alone had been remedied.

Although the demonstration in November had received a cool reception, the period of official disinterest in Heinkel's turbojet development was coming to an end by the late autumn of 1939. Up until that time, the turbojet program instituted by the technical department of the RLM saw no place for engine development in an airframe company. This policy was largely that of Hans A. Mauch (who headed the jet engine development section of the Technisches Amt, Technical Department) but, when he left the RLM at the end of 1939, Helmut Schelp moved into a more influential position and he approved the backing of Heinkel's turbojet program.

By this time, the work at Heinkel was expanding to explore various types of turbojet engine, but no attempt was made to continue development of the He 178 because the problems encountered with a fuselage-mounted engine were considered too great at that stage. Instead, attention turned to the development of a fighter with wing-mounted turbojet engines, the He 280. The He 178 was finally dispatched to the Berlin Air Museum where it was destroyed in a 1943 bombing raid.

The pictured aircraft is a replica."