AMERICAN HELICOPTER CO. XH-26 JET JEEP
On display at the National Museum of the USAF is this intriguing X-copter. Housed in the Presidential Gallery on a secure part of Wright-Patterson AFB, there are special access requirements.
According to the National Museum of the USAF:
At the request of the U.S. Army in 1951, the U.S. Air Force initiated the development of a one-man, pulsejet-driven helicopter for observation, liaison and reconnaissance purposes. This unarmed helicopter had to be collapsible, capable of aerial delivery to troops in rugged terrain, and assembled quickly with simple tools. The American Helicopter Division of the Fairchild Engine and Airplane Corp. won the design competition and produced the rugged and uncomplicated Model XA-8. Under the military designation XH-26, the aircraft first flew in January 1952.
Constructed of aluminum, except for the aft fuselage which was laminated fiberglass, the XH-26 did not use any gears. Rather than having an internal engine like other helicopters, the Jet Jeep was powered by two 6.75-inch pulsejets on the end of each rotor blade tip. Designed by American Helicopter, each of these pulsejets weighed 16 pounds and produced 35 pounds of thrust. Started with an internal compressed air system, the engines did not have to be warmed up, and the XH-26 could take off in just 30 seconds. Furthermore, since the pulsejets produced no torque like engines on other helicopters, the tiny, belt-driven tail rotor was not used for anti-torque but to improve directional control.
American Helicopter chose the name "Jet Jeep" because the XH-26 would be used like a Jeep in the air, and it could use the same fuel as the Jeep. When collapsed, its 5-foot-by-5-foot-by-14-foot container fit on a trailer towed by the one-quarter ton Jeep. If stripped for air drop, the Jet Jeep weighed less than 300 pounds, and it could be assembled by two men in just 20 minutes.
The Army and USAF evaluated five prototype Jet Jeeps, and they proved to be a rugged aircraft with a top speed of 80 mph and a ceiling of 7,000 feet. However, the pulsejets produced so much noise that the Army found the aircraft unsuitable, and cost considerations forced the cancellation of the program.
Engines: Two American Helicopter AJ-7.5-1 pulsejets
Fuel capacity: 50 gallons
Range: 135 miles
Endurance: Approx. 2 hours
National Museum of the USAF. AMERICAN HELICOPTER CO. XH-26 JET JEEP
. [Web.] Posted 11/8/2011.