The problem with V-22 Osprey

The Bell Boeing V-22 Osprey is an American multi-mission, tilt-rotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft.

First flight in 1989 and since entering service from 2007 it has had 11 crashes. Although the number of crashes seem to be very low compared to the number of flights and missions for the more than 15 years in service, but any crashes involving large number of losses of life and equipment would makes it a more detailed investigation into the circumstances of crash and the design of the aircraft. All these crashes occurred during landing or low altitude flights when the rotors were tilted at almost 90-degree angle.

A fixed-wing turboprop aircraft’s native flight motion that allows it and gives lift to the aircraft is when the propellers move air parallel to the wing’s pitch. A helicopter’s native flight motion that allows and gives lift to the aircraft is when the rotors is at 90-degree angle to the fuselage. When these two are designed into one single aircraft the laws of physics clash and become at odds to each other and cause the crash. It is the laws of physics and poor design that causes the problem. The designers of the aircraft thought if they build a helicopter into a fixed-wing aircraft it would serve both needs, and it does to some extent, but during landing the engine thrust and downdraft from the propellers over uneven surface can push the air harder on one side of the aircraft and the low pressure and turbulence under the other wing cause the aircraft it to lose balance.

The aircraft is susceptible to sudden imbalance during landing. The aircraft is not large and heavy enough to withstand those sudden pushes. The Rolls-Royce T406 delivers 6,000 shp (4,470 kW) to each end of the wing and that much power is enough to catapult and tip over the aircraft causing it to lose control.

The problems with the V-22 can be narrowed down to one case of ignoring laws of physics, and two cases of unusual design by combining a helicopter into a fixed-wing aircraft, and the engine location. The wings should not be fixed and must tilt with the rotors when they tilt.

In a fixed-wing aircraft the turboprop engines push the air in-line and parallel to the wing’s pitch allowing the air to travel faster over the wing and slower under helping easier lift. In helicopter mode V-22 pushes the air against the wing at 90-degree angle over the wing and creates turbulence and low pressure under the wing making it unstable and harder to control during landing. The wing blocks about 20% of air that is supposed to push down and lift the aircraft.

The engine should be a single turboshaft engine installed over the wing above the fuselage and through a gearbox and shaft to both rotors fixed at the end of each wing. The wings should tilt with the rotors at fuselage, not at the end where they currently are.

Although V-22 is a very capable and strategic aircraft, a great asset to the military, but over-engineered and poor design are the main contributors to these crashes and loss of lives.