Having designed the V-22 Osprey and the V-280 Valor, Bell Helicopters sits at the forefront of tiltrotor design, but not all tiltrotors need to be manned. One of Bell’s most eye-catching concepts it is working on is the unmanned V-247 Vigilant. It is increasingly becoming evident that tiltrotor aircraft are the future of US military rotary aircraft. (The US Navy is also reportedly considering a tiltrotor design to replace its aging fleet of MH-60 Seahawk helicopters).