Within Four Walls

First printed in the UK magazine called The Royal Magazine #211, May 1916 and reprinted in the magazine called The Armchair Detective in the Winter of 1981. Collected in Donovan of Whitehall.
A couple years before WWI, a German inventor came up with a revolutionary way of steering airplanes. The Germans did not want it because it was not appropriate for their style of planes at the time. He took it to the English and they likewise turned it down. Now years later it is coveted by the RAF but he was deep back in Austria-Hungary. Donovan's job was to find him and get his plans.