By Nathan Pfau, Army Flier Staff WriterJanuary 25, 2018
FORT RUCKER, Ala. -- Long before the V-22 Osprey took on the challenge of vertical flight, another aircraft attempted to defy gravity by combining the versatility of a helicopter with the speed of an airplane.
The Ryan VZ-3 Vertiplane is the newest addition to the U.S. Army Aviation Museum's showroom, and is the only one in the world, and if it looks a little odd, that's because it was designed for more than just conventional flight, according to Bob Barlow, former Aviator and U.S. Army Aviation Museum volunteer.
The Vertiplane was designed to fill the need for a versatile aircraft that could fill the needs of an ever-changing battlefield, said Barlow.
"They felt that ground warfare was evolving, and were thinking more about speed and mobility on the battlefield, and ways to get that," he said. "The helicopter was great, but this concept was in line with the same quest for the versatility of a helicopter but the speed of an airplane."
The single-seat Vertiplane was built as a technology demonstrator in 1957 and took its first flight Dec. 29, 1958.
Although the name of the aircraft implies that it's a vertical-lift aircraft, the plane could only in fact achieve short take-off lift, which it could accomplish with about a 20-foot rollout, said Barlow, and did so by employing deflected slipstream technology.
The aircraft itself looks mostly like a standard airplane, aside from its shorter wing span and tips that point directly downward, but when the pilot wished to engage near-vertical lift, he or she could do so by using the controls to deploy double-slotted flaps that would move downward to almost a 90-degree angle to create channel that forced the airflow from the propellers downward.
"When they were ready for takeoff and had the engines going, the flaps would come down and be presented to the slipstream," said Barlow. "The slipstream from the propeller would hit these flaps, be deflected downward and would create a cushion of air to allow the aircraft to lift off (nearly) vertically, and likewise when it was landing."
Once the pilot was at a stable altitude and airspeed, the flaps would retract and fully became an airplane, he added.
Another notable feature of the aircraft is its high tail wing and rudder, which was designed that way to keep it out of the turbulence created by the deflected slipstream system. The aircraft also employed a stabilizer that utilized exhaust air, almost like vectored thrust, out of the rear of the aircraft to give the pilot more control over the aircraft, especially in pitch and yaw, said Barlow.
The Army did a total of 21 test flights with the Vertiplane before handing it off to NASA for further testing. Although the concept was good, it was not without its problems.
"What they found out was that it was very good at short take offs. It could get off the ground in something less than 30 feet, but the problem was, when the aircraft was at very low speed or at a hover, you have this propeller pushing its slipstream against its slotted back, and what that did as the air hit that, it would hit the ground and come back around and get re-ingested by the propellers, which caused sort of a feedback loop," said Barlow. "That caused the propeller to lose authority and the aircraft would nose down. It was never so severe that it was liable to cause a crash -- the pilot was able to arrest that motion -- but it was something they couldn't solve and there was no way around it. It was an inconvenience and it was one that would limit further development."
Although only one Vertiplane was ever built, Barlow said that aircraft like it add to the body of knowledge that leads to further development of aircraft like the Harrier or the Osprey.
"Although the Osprey is a different aircraft and a different concept, it needs to pay homage to these early pioneers because it showed them what was possible. They took the best of several concepts and combined it into one that works," he said. "The bottom line is that this was a technology they tried to keep in concept with what they envisioned the battlefield of the future would be. They needed speed, mobility and flexibility, and this was another way to try to get that."