Additional Information & Images
AAI's TX (below) is a 7,500lb vehicle with an unpowered rotor for VTOL, a fold-out wing for cruise and a ducted fan for propulsion. A single 1,200shp Honeywell HTS900 turboshaft generates power to drive the four electric wheel motors, spins up the rotor for a "jump" take-off and drives the 56in-diameter ducted fan in forward flight. Ground speed is up to 80mph; flight speed range is 50-155kt; maximum altitude is 10,000ft.
Using Cartercopter's slowed rotor/compound technology, AAI's TX is essentially an autogyro with wings. In forward flight, lift transfers to the wing and the 50ft-diameter rotor slows until it is rotating solely to provide stability. Compared with a conventional helicopter, this reduces rotor drag. Retractable suspension pulls the wheels up into their wells to further reduce drag in flight. To land, the vehicle autorotates, the high-inertia, tip-weighed blades storing enough energy to enable a "zero-roll" touchdown.
Lockheed Martin's TX (below) is a 7,000lb vehicle with ducted fans that tilt from horizontal for VTOL and to vertical for forward flight. The 8.5ft outside-diameter fans are attached to a lifting-body center wing section mounted above the vehicle. This houses a pair of turboshaft engines that drive the fans and has a trailing-edge flap to increase lift at low speed. Flight speed is up to 130kt.
To convert from fly to drive, the outer panels of the 41.5ft-span wing fold inwards against the ducts and the complete wing/fan assembly rotates to lie along the length of the vehicle. A Pratt & Whitney EnduroCore heavy-fuel dual rotary engine then powers the four electric wheel motors. DARPA is aiming for a range - on the ground or in the air - of 250 miles on a tank of gas.
Three main contractors are working on the flying Humvee: Rocketdyne, Lockheed Martin and AAI Corp. Rocketdyne will create the engines and already makes jet and transport plane engines for the Airforce. Lockheed Martin is the largest defense contractor in the country. The main design comes from AAI.
Right now, designs are in the first phases. AAI has a $3 million contract from DARPA to cover feasibility studies, wing studies, propulsion, materials and flight controls. The first prototypes aren't expected until 2013 -- and those prototypes are expected to be partial prototypes. The full development phase is expected to cost $9 million. That's a pretty steep total for just the first phase of the project, which is has a total budget of $40 million.
DARPA aiming for around $1 million a copy compared with $400,000 for a Humvee and $4 million for light helicopter.
From Wikipedia: An AH-64 Apache helicopter costs around $18 million, a V-22 Osprey tiltrotor around $70 million, and a F-35B Lighting II STOVL jet $238 million
Concepts that appear to have not made it into development:
**NOTE: THE FOLLOWING IS NOT PART OF DARPA'S PROJECT**, although it is a flying car concept in development which has proposed military purposes.
The Urban Aeronautics X-Hawk is primarily a troop carrier that can transport small fighting units in areas where the use of helicopters is impractical or impossible. Unlike ground transport in urban environments, X-Hawk is unaffected by IED’s and other potentially lethal threats and can deliver troops to any location with great precision including the capability to deliver them directly into a building at any level through a window. This avoids the use of potentially perilous stairwells.
Edited by Engineer on 4/18/2013 11:53 AM PDT