The Horten H.IV is a German tailless flying wing glider in which the pilot was to lie in a prone position to reduce the frontal area, and hence drag.
It was designed by Reimar and Walter Horten in Göttingen.
They were flown in a number of unofficial competitions in Germany during World War II.
Test pilot Captain Eric Brown describes flying a Horten IV at RAE Farnborough in May 1947 towed by a Fieseler Storch.
[1] The H.IV was allocated the RLM ID number 8-251 and by inference Horten Ho 251 though this was little used in practice.