In 1951 at the request of the Army, the USAF developed the XH-26, a one-man observation helicopter powered by a pulse-jet on the end of each rotor blade. It could be packed into a container to be towed by a regular Jeep and stripped for air dropping, re-assembly taking 20 minutes. Five prototype Jet Jeeps were evaluated and performed well, although the pulse-jets were too loud and cost considerations forced the cancellation of the program

The second of five XH-26 helicopters built. Powered by an American Helicopter XJ49-AH-3 pulsejet on each rotor tip (red cylinder on right side of photo) each producing 35 lbs. of thrust. It performed well but was very noisy and the blade tip motor location precluded engine out autorotations. It was not put into production.

Single-seat helicopter powered by pulse-jet engines on the rotor tips, developed for USAF and US Army. It was designed to be air-droppable for rescue and observation purposes, but not proceeded with although the five prototypes proved to be rugged vehicles. The maker was bought by Fairchild in 1954. Photo from: Wright State University