High Speed Tunnel and other
Research in Germany
A.Thom, R.A.E., M.A.P.
G.P. Douglas, R.A.E., M.A.P.
CIOS Target Nos. 25/71 & 25/82
A resume is given of information collected during a visit to North Germany, 17th to 29th June 1945. The favourable power factor of German tunnels is attributed to their greater diffuser length. This and the large power available allow them to use a higher density and so a higher Reynolds Number. This is considered to be essential. Much fundamental work has been done on aerofoils, shock waves, boundary layer stability, etc. The large icing tunnel being built at Gottingen (Göttingen) is also described and in an appendix a more detailed description of the Brunswick (LFA Braunschweig, AOB) tunnels is given.
The following notes are the results of a visit to the LFA (Brunswick) and the AFA and KWA at Göttingen. The primary object of the visit was to examine the technique and methods of correction used in the large subsonic tunnels and to find what had been achieved. These matters were also discussed with leading workers from DVL, Berlin.
The effort being put into pure aerodynamic research was very great and substantial progress had been made. The optical equipment especially is noteworthy. The tunnels are all of much larger power than ours. Pressure is not under control and so Reynold's Number cannot be kept constant with varying Mach number - perhaps an unnecessary fefinement if the scale is large enough. The circular section may be desirable but it certainly has some disadvantage. Much can probably be learned by closer study of the German transonic and supersonic tunnels and the measurements of the degree and type of unsteadiness of the larger tunnels. In Brunswick (LFA Braunschweig, AOB) there are full size tunnels of different types which could be used to supply far more information than could ever be obtained from a model... Particulars of some German Tunnels ..
Every tunnel building is provided with a complete workshop and machine shop and in addition there are very large Aero machine and wood-working shops. The main machine shop is elaborately provided with a variety of large planning machines, copying machines etc. The accommodations for staff was on a generous scale and all manner of mechanical helps were provided. Well fitted out dark rooms (please don't think of modern ones for entertainment! But one for handling photos, AOB) were in every building and evidence was not lacking of the extensive photographic equipment which had been in existence.
Keywords: The large 8 m. dia. Brunswick tunnel (No.5 was kept fully occupied by firms tests ...Thus there are the boundary layer tunnels and the cavitation tunnels at Göttingen .. Gothert also considered ..he considered that good agreement had been obtained on tunnelflight comparison up to M = 0.85 on the Me 262 ... Sweepback ..High speed tunnel design .. ... M = 0.95 ... blackage corrections .. allevation .. In the tunnel at Kochel a silica gel screen surrounds the mouth of the tunnel and acts like a heat exchanger ..propeller tests .. Tunnel steadiness .. Sensitive pressure gauge ... treatment by Schlichting .. The Lilienthal Gesellschaft Competitions in 1940 ... Large Icing Tunnel .. Air ducts were provided so that a full size motor could be tested running in the working section under any condition of velocity, pressure or temperature .. Collector and Expansion Cona ... Rotating cylinders are arranged to assist in the expansion at the first bends .. Ice dust apparently Dr. Ritz did not thing that thiis would accumulate in the air or that it would matter ..
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