Model HZ-1 Flying Platform

Information on the De Lackner Aerocycle is provided courtesy of the Army Transportation Museum at Fort Eustis, Virginia. -- Editor

De Lackner Helicopter Company, Mount Vernon, New York.
Single engine VTOL (vertical take off and landing) research vehicle

Developed privately by the De Lackner Helicopter Company of Mount Vernon, New York, this single engine research vehicle was the first of several one-man flying machines evaluated by the Army during the late 1950s.

The Aerocycle was powered by a four-cylinder, water-cooled 43hp Mercury Outboard motor located on a circular platform just above the two belt-driven, counter-rotating fifteen foot rotor blades.   With a top speed of more than 70 mph, it was faster than others evaluated by the Army.  The landing gear consisted of a single large air bag placed directly beneath the rotor blades, augmented by four smaller air bags fixed to outrigger bars.  This was ultimately abandoned in favor of helicopter-type metal skids.

The test pilot for this Aerocycle was then Captain Selmer Sundby, an experienced pilot with six years of experience and more than 1500 hours in fixed and rotary winged aircraft.  Designed to require only about twenty minutes of instruction before actual flight, Sundby said, "...  it only took me one flight to realize that a non-flyer would have considerable difficulty operating it."   Standing to the rear of the center pedestal, secured by safety belts,  the pilot used the motorcycle-like handle bars to turn, varying the speed of the rotor blades thereby changing torque.  Directional control was made by leaning in the desired direction of travel.  Lift was obtained by increasing rotor blade rpms.

Captain Sundby made many flights with this Aerocycle, some only seconds long and one almost 43 minutes long.   "I had two accidents while testing this machine - one in free flight from about 40 feet in the air, doing 30-35 mph, and another during tethered flight, " said Sundby.  "Both accidents were similar in that the counter rotating blades flexed and collided, shattering the blades.  This resulted in immediate loss of lift and control."   Further studies could not pinpoint the exact speed or conditions that caused the blades to flex, and eventually the concept was abandoned.

Of the original twelve ordered by the Army, this is the only one remaining in existence.  For his efforts, Colonel Sundby was awarded the Distinguished Flying Cross by the Chief of Staff of the Army in 1958.