Part II in my stealth chronology also goes back to the Germans. The Kriegsmarine started with stealth materials for the new Electroboats Types XXI and XXIII. The rubberized material was Opanol used to defeat sonar by absorbing it. Another material Tarnmatte was used to stealth the Schnorkel and worked fine. When the Luftwaffe heard of this concept, they wanted it for their Next Gen jet fighter aircraft and so Horten was tasked with making the world's first stealth fighter based on the Ho-IX flying wing. Flying wings as a configuration are already stealthy b/c radar waves tend to pass over them. What the Hortens did was make the aircraft largely out of wood and then added a filler of sawdust and charcoal in a resin matrix. The engine inlets and wing leading edges meanwhile would be covered with anti-radar stealth paint and the production machine, the Go-229 would feature dielectric panels to absorb or scatter radar. The plane was tested at Gottingen and flew under power on Feb 14, 1945. GEMA, an electronic firm, also got into the stealth game with crystals stemming from crystalline radar research. Another use was to affix the crystals to a test plane for radar diffraction and that led to 4 test flights of a modified Weihe. That led to a design by DFS known as the "Black Diamond" but before any work could be done the Soviets got the plans and later Professor Ufimtsev wrote a book on Radar Diffraction Through Use of Geometric Shapes. That was aquired by the CIA in the 1970s and is the origin of the faceted F-117- NOT any US ingenuity at all. The USAF had previously used primitive RAM on a Windecker Eagle in '72 but the Germans had already done that with the Ho-IX in 1945. The semi-stealthiness of the SR-71 was purely accidental due to necessity. During WW2, the USN tried visual stealth by mounting a lighting system on a patrol aircraft to blend into the sky during daylight hours. It was hoped to come out of the sun and attack a U-boat. It failed as the lighting system was electrically flawed. "Project Yehudi"...