Having demonstrated with the Me.163B Komet "V6" that the twin chambered motor was a workable design, the new interceptor was pushed forward. Almost exactly as Messerschmitts had done with the Messerschmitt Me.163C, when Junkers received the designs for the new model, Professor Heinrich Hertel decided that the best way to eliminate some of irrational aspects of the aircraft and produce a much better aircraft for production was a rework.

The Technical Department of the RLM were pushing for the completion of the project, so there was a limit to the alterations which could be undertaken at Dessau.

One of the most distinctive features of the new Junkers design was to install a pressurised cabin, and cut down the aft fuselage decking to produce a high visibility teardrop canopy for all round vision. The fuselage was now built in three sections, the forward unit carrying the pressurised cabin, pilot armour and of course the sophisticated, retractable, nosewheel for the tricycle undercarriage.

The centre section carried the fuel tanks, armament and main wheel wells, with the aft section detachable for servicing the motor and combustion chambers. Walterwerke had taken the lessons learned from the HWK 109-509.B and had produced the final version of their twin chambered design, the HWK 109-509.C.

Hertel's reworking led to the Junkers works redesignating the new aircraft the Junkers Ju.248, and the V1 prototype was rolled out for testing in August 1944. To prove the airframe, successful gliding trials were conducted, the Ju.248 being towed aloft behind a Junkers Ju.188.

The Messerschmitt Me.263

William Green writes that in September 1944, the Walter 109-509.C motor was fitted to the airframe and flight trials were sufficient to prompt the acceptance of the design for large scale production.

At this point, the RLM decided that the production type number should revert to Messerschmitt's and so the new type was known as the Messerschmitt Me.263, maintaining its lineage from the Messerschmitt stable.

Discussion.

From an initial scepticism when the original Lippisch delta winged prototypes had flown, Germany in 1945 was staking almost everything on a small number of radical jet and rocket powered designs, and the Me.263 was to be one of them.

Certainly the service record of the Messerschmitt Me.163 had not proved it to be a superior aircraft to the many conventional designs developed over the war years. But beyond the statistics of the demonstrable kill rate, were mixed other factors which were influencing policy at the RLM. Certainly the faith which was placed in the impact of the rocket "wonder" weapons was one part of the equation, but equally manufacture from less strategic materials, and a reliance on non-conventional propellants also played a significant part in moving these projects forward. The Allies had been bombing gasoline manufacturing plants for many months and even though quantities were not at ideal levels, unlike conventional fuels, peroxide and acid propellants were at least available.

The Walter 109-509.C power plant was well forward in development, but as usual with Walter's advanced designs, and in common with other rocket projects, was still not in production when the newly redesignated Me.263 airframes were being built for testing.

On balance, the probability is that airframe was tested in flight. The pictures shown here are the most commonly published, the Me.263 V1 with the upper wing surfaces tufted with threads for analysing airflow over the wings; which was probably done in flight.

One very interesting thing to note about the Me.263 picture here, is that it clearly seems to show a motor fitted. There are visible combustion chamber openings, with twin fuel dump pipes - the pipes must be part of the motor, not the airframe. So if the tufted-wing Me.263 V1 (set up for airflow and therefore flight testing) has the motor fitted, it could have flown under power. This is quite a conundrum.

However, Dressel and Griehl remark that the first batch of Walter 109-509.C motors received did not match the design specification and were too long to be fitted in the Me.263 airframe. The Me.263 required lengthening by 5 cm. A Junkers factory report of March 1945 says that at that time, there were still insufficient working parts for the undercarriage and the motor.

Beeton, usually thorough in his reporting, is clear that the 109-509.C was not flown.

The photographs of the Me.263 showing the Walter motor fitted may have been a trial fit, may have been mocked up for propoganda purposes, or may have been mocked up to provide details for a report.

For a further discussion of the Walter HWK 109-509.C motor, follow this link, and for a more detailed look at a preserved HWK 109-509.C, follow this link.

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