2 x 1,940 hp.ea.
46 ft. 3 in.
38 ft. 5 in.
Other than jump jets, before the AW609 produced by AgustaWestland and other tilt rotor aircraft were invented, only aircraft using main rotor blades and propellers have been able to land and take off like a helicopter and fly at higher speeds like a fixed wing airplane.
Bell Helicopter started developing the AW609, along with Boeing, in 1996. When Boeing left the partnership two years later, AgustaWestland became Bell’s partner in the project. In late 2011 Bell Helicopter left the entire project to AgustaWestland.
The AW609 has a pressurized cabin, comes with an all glass cockpit including three digital displays, full instrument flight capability, computerized flight data diagnostics, weather radar, GPS, an emergency locator transmitter, and the latest avionics. It is said to be easier to fly than its larger cousin, with an easy transition from vertical to horizontal flight, and it is capable of autorotation.
The aircraft’s cabin remains relatively quiet, even while the rotors are turning at cruising speeds, due to their placement at the wing tips.
The 26 foot diameter counter rotating propellers of the AW609 act like helicopter rotors when in their up position. They make vertical take offs and landings possible. When the pilot rotates the propellers to their forward position, they act like any other airplane propellers, pulling the 16,800 lb. aircraft through the air at a maximum cruise speed of 316 mph. The AW 609 can fly higher than most helicopters; up to 25,000 feet.
The Pratt & Whitney engines of the AW609 produce 1,940 h.p each. They are coupled to gear boxes that permit 95 degrees of rotation. The extra five degrees of rotation from straight up provides some rearward movement. Each engine is capable of operating independently.
The pitch of each propeller is controlled by a specially modified swashplate with a linked engine command system so that both propellers will react simultaneously. The AW609 avionics, electrical, structural, and control systems are engineered for ease of maintenance and reliability.
The AW609 uses fly-by-wire controls. Pilots control the AW609 with a cyclic center stick. Collective control is with a power lever. Conventional pedals with toe brakes control yaw. There is neither the rudder of a conventional aircraft, nor the tail rotor of a helicopter. Rather, the pedals change the pitch of the aircraft’s blades adding thrust or reducing thrust to each propeller independently to provide rotational forces.
Takeoff is done by rotating a switch on top of the power lever that controls engine tilt. A single click forward moves the engines upward to an 87 degrees angle. The brakes are held as power is increased to avoid ground movement. The aircraft is climbed quickly to over 15 feet of altitude to get out of ground effect. While in ground effect, the effect of the rotors down wash on the aircraft’s wings causes instability around its roll axis.
The foot pedals will rotate the AW609 just like they will in any helicopter while in hover. Further tilting the engines forward to a 75 degree angle will climb the aircraft, similar to a helicopter.
A Limiting Airspeed Indicator displays the amount of power available at various engine tilt settings. The more forward the engines are tilted towards level flight, the more power available will be shown on the LAI. If safe forward speed is in danger of being exceeded, a stick shaker will engage. However, the pilot has final control over the speed of the aircraft.
The AW609 will be using the lift from its wings for flight at engine angles from 45 degrees to zero degrees. Automated flaperons move up and down as aircraft speed changes.
Flying the AW609 while “on its wings” is similar to flying a conventional airplane. You use the stick for climbing and rolling, and the pedals for yaw control.
For landing or hovering from forward flight, the engines can be tilted back to 90 degrees. Forward speed will be quickly reduced, like extending the flaps and speed brakes on a conventional aircraft. But, the aircraft will remain at its flight level until descent is desired.
You can autorotate the AW609. In an engine-out emergency, given sufficient air speed an altitude, the aircraft can be glided while looking for a safe place to set down. Then the engine rotation switch is pulled back to set the engine angles at 95 degrees. That will make the aircraft assume a slightly nose down attitude, facilitating downward visibility.
A typical landing approach from a 1,000 foot altitude with an air speed of 230 mph involves setting engine tilt on downwind to 75 degrees. The aircraft will quickly slow to a desired approach speed of about 140 mph. During final approach the engines can be slowly rotated until the AW609 slows to about 55 mph. For flare the engines are tilted slightly rearward until zero air speed is attained. Then the engines can be rotated further up for a helicopter like touch down.
To taxi the AW609, the engines are rotated slightly forward to about 87 degrees while power is increased just enough to attain a forward roll. Steering is done by differential braking of the rudder peddles. Ground handling of the aircraft takes some practice to master, but can be easily accomplished.
AugustaWestland intends to market the AW609 for both military and civil use. In the military role, it can perform much the same as its larger cousin, the Osprey, but with the lower overall costs of a smaller aircraft. The U.S. Marine Corps is even considering the AW609 as a potential helicopter escort. The AW609 may find use with the U.S. Coast Guard for search and rescue or maritime patrol missions.
AgustaWestland feels that their AW609 is a logical choice to take the place of executive fixed-wing aircraft as well as helicopters. In the civilian role, the AW609 can be configured with up to nine passenger seats. It can fly at the same speed as many executive propeller driven transports, yet land where there are no runways. Its has the potential of being used by law enforcement, and operators of off shore oil rig transports.
Observers remark that the AW609 is much more quiet than a similar sized helicopter during horizontal flight. However, noise increases greatly when the aircraft is in its vertical take off and landing mode.
AgustaWestland anticipate initial sales of some 60 AW609 aircraft and hope to sell over 450 aircraft in what is expected to be a 20 year production cycle. While AgustaWestland has not disclosed the exact price of the AW609, it is thought to sell for about US$25 million.
To date three prototypes have been built with one more under construction. On Oct. 30, 2015 the second built AW609 broke up during flight resulting in the total loss of the aircraft and its crew of two.
The AW609 should receive FAA certification in 2020 with production and deliveries commencing thereafter.