Aviation Week – “Flying Humvees” being designed by AAI and Lockheed Martin have made it through to the second phase of DARPA’s Transformer (TX) program – but the sheer scale of the challenges in producing a fly-drive tactical vehicle is becoming clear.
Transformer is not simply a roadable aircraft – it is a four-seat vehicle that must be able to drive off-road, survive small-arms fire, and rapidly reconfigure into an aircraft that can take off and land vertically and be flown without pilot training.
Phase 2 of the Transformer program is heading for preliminary design reviews at the end of the third quarter of fiscal 2012, after which DARPA will decide whether to select one team to proceed into Phase 3, which would culminate in prototype ground and flight demonstrations in mid-fiscal 2015.
Cost is also a challenge, with DARPA aiming for around $1 million a copy compared with $400,000 for a Humvee and $4 million for light helicopter.
The Terrafugia Transition roadable has a base cost of $279,000 The flying humvee will be able to have a jump takeoff without runway which can enable door to door commuter flying.
AAI’s TX 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
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.
Darpa wants the Transformer to do a lot. It’s got to take off — vertically — and be flyable by non-pilots. It’s got to both be armored enough to handle small arms fire and fuel-efficient enough to carry up to 1,000 pounds of freight for 250 miles on a single tank of gas. (Which is why AAI’s design, pictured above, incorporates a diesel engine.) And it’s got to seat four troops.
And to be a spoilsport: It’s difficult to imagine a military problem that the Transformer actually solves.
I would note that if the specifications can be achieved then the vehicle would enable civilian flying cars for commuting inside of cities. It would expand the number of small civilian flying vehicles from 200,000 for the entire USA to perhaps a few million. A civilian version would not need to be bullet proof.
Robotic air taxis could be deployed in some moderate volume of a few thousand per year by 2020.
A network of pocket airport infrastructure necessary to realize this model would cost only a fraction of the cost of adding lanes to the existing freeways, which typically cost $20M per mile. These cost savings are even more impressive when compared to subsidized transit systems, as evidenced by the recent cost of a Bay Area Rapid Transit extension that cost $161M per mile.
The great promise of GQ V/ESTOL aircraft as a transportation solution is that they can complement commercial air travel by restoring its door-to-door trip speeds, by eliminating ground travel delays. The Green Flight Challenge program can efficiently promote such transformative aircraft as a path toward a potentially enormous new market. GFC can trump the Innovator’s Dilemma that afflicts civil aviation today.