Walter HWK 109-509.B
B-Powered Komets
Walter HWK 109-509.C

The largest thrust that the Walter motor had been developed to deliver was 1750kg for the "A-2". Rocket motor designers always have a desire to produce a motor with increased thrust. However, for a rocket motor as the principal source of motive power for aircraft, increased thrust was of secondary importance against increased endurance. At only a few minutes under power, the Me.163 "Komet" rocket interceptor had a severely limited endurance; quite a handicap under combat conditions.

For propeller driven aircraft, a way to increase endurance is greater fuel load; but the rate at which rockets consume their propellants, means this proposition is not possible without a radical airframe redesign. Although the Walter team had produced an innovative multi-stage motor, rockets have their optimum efficiency at maximum design thrust. Therefore, instead of throttling back the main combustion chamber, Walters decided on an auxilliary combustion chamber for their motor - a lower thrust chamber which would consume less propellant, but would develop sufficient thrust for cruising flight. This would enable the pilot to "throttle back" the main combustion chamber once at height, and by running on the auxilliary chamber pursue (or evade) an enemy, or cover greater distances with a lower fuel consumption.

At the close of hostilities, Walterwerke had been working for some time on dual-chambered motors as one of their major projects. They seem to have taken a very pragmatic approach to the problem, by modifying their existing design to test the principal systems required for the additional thrust unit, in an HWK 109-509.B, before launching work on a major new unit, the HWK 109-509.C.


"Model-B" Discussion.

[Messerschmitt Me.163B V6]

Having studied a substantial part of the current literature on the subject of the Komet, I find that there is what appears to be a significant disparity or even error which has become accepted currency in describing the motors of Me.163 Komets. A number of respected authors describe the standard production Komet as being powered by the "Walter 109-509.B" motor.

Taking the nomenclature which is quite clearly described in original Walterwerke documents, the HWK 109-509.B is a dual chambered development motor. There is no evidence for any Me.163 in operational service using any motor other than the standard HWK 109-509.A-1.

How the model "B" designation, has entered currency is difficult to pin down. I would be interested to hear if anyone can pinpoint a reason. I can imagine that service units might have a service name for the motor, which has been picked up from surviving German records and found its way into the literature. Maybe front-line units used an unknown (to me) reference which is clearly shown in Staffel records. For my own part, German documents which I have found, both from Walterwerke itself, and other sources (Junkers for example) appear to follow the Walter 109-509.A-1, 109-509.C series numbers. It does not seem logical that Staffel servicing personnel would use Walterwerke's manual, and then have their own names/numbers.

So where does Me.163 Komet's "109-509.B" standard motor come from? Has an original author made a mistake in nomenclature, maybe taking the Komet model number in error, and this mistake has been picked up by other writers conducting incomplete research, and reproduced as a standard "fact"?

In the closing stages of the war, making sense of interrogations and captured documents was difficult, made more so by central Reichsluftministerium orders subsequently modified in the field, and the differences between standard manuals and accepted practice on squadron service. Mistakes by intelligence officers at this time were not uncommon. Quite often the definitive summary documents were not produced until 1946 or 1947. Someone concentrating on very early reports, or not taking a variety of sources for their research material can reproduce significant errors - it is our job to try and sort these out.

Web Master Shamus Reddin   [SR Logo]
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