Strength Tests by Towing in Water: Description of an Economical Method Used in Germany Before and During the War

A strength testing method formerly used in Germany is described. Aircraft components were towed under water in a large tank so that loads were produced on the specimen equivalent to those realized under actual flight conditions. Advantages of the method were that no special means for transmitting forces to the specimen were needed and that all changes of the air loads resulting from elastic deformation were automatically included in the applied loading. Particulars arc given about tests made on cabin hoods, tail planes and on one wing. Future possibilities of testing whole aircraft and of conducting research into the effects of clastic deformations on stabilitity characteristics are discussed. The limitations of the method arc given, especially with regard to the absence of compressibility effects. The opinion is advanced that despite these limitations further development of such testing methods should be considered.