The American Helicopter XH-26 Jet Jeep was an extremely compact single-occupant helicopter developed by the American Helicopter division of the Fairchild Engine and Airplane Corp. It was designed to fulfill a U.S. Air Force brief which called for a collapsible, air-droppable, easily assembled helicopter which could be used for observation, liaison and reconnaissance missions.
The aircraft was requested by the military in 1951, and by 1952 the first test flights had been successfully accomplished.
The XH-26 Jet Jeep was constructed primarily from aluminium, although the tail section was formed from fiberglass. The interior was extremely basic and small, with just enough room for the single pilot. The bubble-shaped side windows provided a little extra elbow room, and could also be removed if required. There was no ballistic protection for the pilot, and no armaments were provided either.
Unlike a conventional helicopter, the XH-26 Jet Jeep was not powered by an internal engine. Instead two small pulse jet engines were used, one mounted on the tip of each rotor. This simple design meant the helicopter was extremely light, as each engine only weighed 16 lbs. In addition, because the two jet engines produced no torque forces on the helicopter, it could use a very small tail rotor, further reducing weight.
Another benefit of the helicopter was the fact the pulse jets could be started extremely quickly and did not require pre-warming, and as a result the XH-26 Jet Jeep could be airborne within 30 seconds of start-up. The jets were started using an integrated compressed air system.
The name “Jet Jeep” was applied to the helicopter for good reason. Firstly it was designed to fit in a special 5x5x14 ft container which could fit comfortably within a trailer towed by a regular quarter-ton military Jeep. And secondly, for logistical reasons, it was designed to run on the same regular gasoline used in Jeeps and most other military land vehicles.
To prove its versatility, the XH-26 Jet Jeep could also be delivered by air in kit form to inhospitable terrain. It was so simple to put together, that it took two men just 20 minutes to build.
Both the U.S. Army and USAF evaluated the American Helicopter XH-26 Jet Jeep, and in total five prototypes were built. In most aspects the aircraft was up to the job and did what it was asked to do. It was sturdy for its size, fairly easy to fly, simple to put together, had a respectable top speed of 80 mph, and a 2 hour endurance – which would have been enough for most missions envisaged for the helicopter.
In the end however, the innovative engines proved to be the Jet Jeep’s downfall. They were considered to be too loud for practical use. In addition rising development costs started to worry military planners and the project was eventually canceled.
One surviving example of the helicopter still exists and is held in the Presidential Gallery section of the Wright-Patterson Air Force Base museum.