Messerscmitt ME262 - Early Prototypes
Like the Meteor, the ME262 was developed to take advantage of the turbojets military potential. It was initially designed around the Axial Flow BMW003 turbojet with an entirely different layout to the Whittle engine. In the axial flow turbojet air is compressed after entering the front of the engine by a series of compressor stages or fans, in the middle of the engine fuel is added and the mixture ignites, the rapidly expanding gases then pass through a turbine connected to the forward compressor stages before exiting the jet pipe. The design has the advantage of having a much smaller cross-section although it does suffer much more if debris are ingested into the engine.
The Jumo 004 axial flow turbojet engine
As in the case of the Meteor there was a great deal of doubt over how much power the BMW engine would produce, estimates of less than 2,000lbs of thrust forced the designers to a twin-engine configuration as the only way to produce an aircraft capable of sufficient performance while carrying a useful warload. The smaller diameter of the engine however made it possible to suspend the engines below the wings without requiring excessively long main undercarriage legs to achieve ground clearance.
The construction of the first prototype ME262 V1 began in January 1941 and it was ready for flight long before its turbojet engines, early bench tests of these were very dissapointing at just 570lbs of thrust, far too low for practical use. This led to the first prototype V1 being fitted with a conventional 750hp Jumo 210A in the nose driving a wooden propellor in order to flight test the airframe. It was ready for taxi trials on the 17th April 1941 and flew for the first time on the 18th April fitted with a tail wheel rather than the tricycle undercarriage that would be a feature of the later design.
ME262 V1 with Jumo 210 in the nose and BMW003 engines.
The aircraft flew a total of 23 times on piston engine power up until 8th May 1941 when it finally received its pre-production BMW003 engines. The engines were rated at 1085lbs but the first flight was a disaster with both units failing, it was only saved from total loss by the by its piston engine and wooden propellor which allowed a safe landing. The ME262 would not fly again with BMW engines until October 1943 when it was fitted with redesigned BMW003a engines.
The second and third prototypes V2 & V3 were modified to take the Jumo004, this required a nacelle 10% larger in diameter and 16% longer. To counteract this the horizontal stabilizer was enlarged and the wings were swept back. V3 was the first to fly on the 18th July 1942 with Jumo 004AA0 engines of 1,850 lbs thrust, V2 was completed in July 1941 but did not fly until 1st October 1942. The development program was expanded during this time to include two further prototypes and fifteen pre-production aircraft. The last two prototypes V4 & V5 flew on the 15th May 1943 & 26th June respectively, V5 was the first to be fitted with tricyle undercarriage necessitating the main undercarriage to be moved back 3ft in the wing.
ME262 V3 in July 1943, note tailwheel configuration