Nearly three decades later, a more serious attempt at "invisibility" was tried with the
Horten Ho 229 flying wing fighter-bomber, developed in Germany during the last years of World War 2[
citation needed]. In addition to the aircraft's shape, the majority of the Ho 229's wooden skin was bonded together using carbon-impregnated plywood resins designed with the purported intention of absorbing radar waves. Testing performed in early 2009 by the
Northrop-GrummanCorporation established that this compound, along with the aircraft's shape, would have rendered the Ho 229 virtually invisible to the top-end
HF-band, 20-30 MHz primary signals of Britain's
Chain Home early warning radar, provided the aircraft was traveling at high speed (approximately 550 mph (890 km/h)) at extremely low altitude - 50–100 feet (15–30 m).
[3]
In the closing weeks of World War 2, the US military initiated "
Operation Paperclip", an effort by the
US Army to capture as much advanced German weapons research as possible, and also to deny that research to advancing Soviet troops. A Horten glider and the nearly complete Ho 229 V3 third prototype airframe were secured and sent to Northrop Aviation for evaluation in the United States,
[3] who much later used a flying wing design for the B-2 stealth bomber. During World War 2, Northrop had been commissioned to develop a large wing-only long-range bomber (
XB-35) based on photographs of the Horten's record-setting glider from the 1930s, but their initial designs suffered controllability issues that were not resolved until after the war. Northrop's small one-man prototype (N9M-B) and a Horten wing-only glider are now preserved at the
Chino Air Museum in Southern California.