The problem with V-22 Osprey

The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor 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.

Its first flight was in 1989, and since entering service in 2007, it has had 11 crashes. Although the number of crashes seems to be very low compared to the number of flights and missions over the more than 15 years it has been in service, any crashes involving a large number of losses of life and equipment warrant a more detailed investigation into the circumstances of the collision and the design of the aircraft. All these crashes occurred during landing or low-altitude flights when the rotors were tilted at almost a 90-degree angle.

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

The aircraft is susceptible to sudden imbalance during landing. It 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 sufficient 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 the laws of physics and two cases of unusual design: combining a helicopter with a fixed-wing aircraft and the location of the engine. 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 underneath, facilitating easier lift. In helicopter mode, the V-22 pushes the air against the wing at a 90-degree angle, creating turbulence and low pressure under the wing, making it unstable and harder to control during landing. The wing blocks about 20% of the 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 connected through a gearbox and shaft to both rotors fixed at the end of each wing. The wings should tilt with the rotors at the fuselage, not at the end where they are.

Although the V-22 is a competent and strategic aircraft and a great asset to the Defense, over-engineering and poor design are the main contributors to these crashes and loss of life.