V-22 Osprey

The V-22 Osprey is a tiltrotor vertical/short takeoff and landing (VSTOL), multi-mission air-craft developed to fill multi-Service combat operational requirements. The MV-22 will replace the current Marine Corps assault helicopters in the medium lift category (CH-46E and CH-53D), contributing to the dominant maneuver of the Marine landing force, as well as supporting focused logistics in the days following commencement of an amphibious operation. The Air Force variant, the CV-22, will replace the MH-53J and MH-60G and augment the MC-130 fleet in the USSOCOM Special Operations mission. The Air Force requires the CV-22 to provide a long-range VTOL insertion and extraction capability. The tiltrotor design combines the vertical flight capabilities of a helicopter with the speed and range of a turboprop airplane and permits aerial refueling and world-wide self deployment.

http://www.fas.org/man/dod-101/sys/ac/v-22.htm