Unfazed by (or perhaps because of) murmurs from within Bell Helicopter management to the effect that development of the BA609 might be accelerated, Agusta- Westland has released some details of its developmental Erica tilt-wing aircraft (so-called because in the Erica’s case the entire wing is rotated between fixed- and rotary-wing flight).
The central issue between the two designs is whether it’s better to tilt the wing structure along with the engine and prop-rotor, or simply to leave the wing in place and tilt the prop-rotor and engine between the helicopter and airplane modes.
The Bell/Boeing V-22 and Bell/Agusta BA609 both tilt only the nacelles and prop, while AgustaWestland’s design tilts the whole wing, including the prop and nacelle. Some critics of the tiltrotor configuration maintain that the rotor downwash striking the wing at a 90-degree angle creates complex aerodynamics and control problems that only a sophisticated fly-by-wire control system can cope with. The BA609 has FBW, and the Erica will, too.
Initial development costs for Erica are being picked up by the European Union. The Erica will be 6,000 pounds heavier than the BA609, weighing in at 22,000 pounds and featuring four-blade prop-rotors as opposed to the BA609’s three-blade prop-rotors. The AgustaWestland offering will sit atop taller landing gear, allowing a flatter prop-rotor pitch and more airplane-like takeoffs at higher gross weights. Like the BA609, the Erica will have interconnects between its twin turboshaft engines powering both prop-rotors and allowing rotor/airplane transition under single-engine power.