GF7 car design could legally hit 550 mph – in the sky
May 28, 2014
Greg Brown and Dave Fawcett are working on an design that they hope will yield something we've spent decades waiting for – a flying jet-propelled car. A sleek cross between a business jet with a luxury automobile, the GF7 drives on electric motors while on the ground, then can extend wings and use a 3,500-lb thrust jet engine to fly to 38,000 ft (12,000 m) and speeds of 550 mph (885 km/h). The (obvious) catch: if this ambitious project does get of the ground, it won't come cheap.
One thing that 21st century life seems to lack is a good selection of flying cars. For those of us growing up in the 1960s, TV shows about life after the year 2000 featured wonderful inventions – space ships, pocket flip telephones, and of course flying cars. Here we are 50 years later and flying cars have yet to become a commercial reality. I’m not the only person who feels a little let down, and some of those people are hard at working designing real flying cars.
This latest venture really takes the concept into Gerry Anderson Supercar territory by inventing a jet-propelled flying car that would be capable of speeds over 550 mph in the air, and highway speeds on the ground. This effort is still at its early stages, and frankly, the concept is a very big reach, but we did want to share the team's progress with you.
The principles behind the project are designer Greg Brown, and engineer Dave Fawcett, who are based in Napa, California. Fawcett, of Airboss Aerospace, has engineered many aircraft, including the Viper, the Maverick and Javelin jets. The objective of the GF7 project is to create a four-passenger single-engine, reliable, and simple-to-operate flying car that can operate on both the freeways and the airways.
Brown told us in an interview that all flying cars are expensive. The team's betting that people who can afford one probably don’t want to be driving a go-cart with a super-light chassis and a small engine. So the pair have created a vehicle with the comforts of a luxury sedan, fast cruising speeds and full car performance. They decided to go all the way to a jet-propelled flying car with a turbine engine in the 3,500 pound thrust class (at 375 mph, one pound of thrust equals one horsepower).
The original vehicle concept was a two-seat, bubble canopy, tandem design (one seat behind the other), but Brown says no one liked the concept except fighter pilots like himself. The GF7 design has a basic folding wing, and is propelled on the ground by an all-electric 50 kWh battery pack that is recharged by the jet engine during flight. The anticipated road performance is 100 mph (160 km/h) top speed with a 0-60 mph time of 7-12 seconds, depending on fuel load.
Based on similar performance of electric vehicles they hope to reach 80-120 miles (129-193 km) of driving per charge, which should be adequate considering the myriad of small airports around metro areas. For those needing more distance driving, they did not rule out the possibility of installing a small auxiliary power unit to extend the driving range into the hundreds of miles. This eliminates the need for a separate, heavy internal combustion engine for ground operation.
The wheels and tires will retract into the fuselage in flight for streamlining. The delta wing span is 23 ft (7 m), which lends itself to high cruising airspeed while providing a smoother ride in turbulence, and with full span flaps provides a stable approach for landing. Twin vertical tails support a wide horizontal stabilizer in the back.
"The more we got into the systems the more we realized how complimentary they were," said Brown. "You can save jet fuel by using the electric motor to drive to the runway and start the turbine engine when you need it. The high torque electric motors assist the jet to accelerate for take-off reducing take-off roll – it will be like an afterburner take-off. Four wheels braking with large road tires reduces stopping distance, and the ample battery power makes for an excellent backup to support environmental and avionics systems in the air. To top it off, the turbine engine produces plenty of extra electrical capacity to charge the batteries."
Brown told us that he and Austin Meyer, a software engineer and designer of the VP-400 and Xavian avionics, were seeking to make the aircraft as easy to operate as an iPhone, but still be a fully IFR (Instrument Flight Rules)-certified and pressurized at 8 PSI, allowing for cruising altitudes up to 39,000 ft (12,000 m).
“The GF7 is designed to get above [the FAA rule of] 10,000 feet and the 250 knot (450 km/h) speed restrictions quickly, then accelerate rapidly to 350 knots indicated airspeed, and stay fast all the way to the destination," Brown told us. "It’s about achieving high speed and connecting cities in a regional area such as San Jose, Las Vegas, and LA or Dallas, Houston, and Austin. The GF7 is designed for short legs, so we are targeting cruising altitudes below 28,000 ft (8,500 m)."
The GF7, despite its looks, is a conventional aircraft. It would need a runway 2,500 ft (760 m) long for takeoff and landing. Approach and landing speeds should be around 90-110 knots (166-203 km/h). Cruising speeds would be between 0.75 and 0.82 Mach, and 350 knots indicated airspeed, which equates to a true airspeed of 550 mph at 25,000 ft. Expected range on a full tank is 700-1,000 miles (up to 1,600 km), depending on the flight profile.
The team hopes to have a flying prototype completed in about four years. There is no getting around the estimated selling price, which will be between US$3-5 million. This price range is around that of other jet aircraft of similar capability, such as the Eclipse 550, which sells for around $2.9 million.
Would there be a market for such a high end machine? First of all, the technical challenges of putting such a complex aircraft in a road-worthy package is daunting. Next, how do you get car insurance on a three-million-dollar vehicle? Other flying car teams, with the possible exception of those at Terrafugia, have fallen short in execution – and this jet-powered car will take a lot of capital investment to become a reality.
"The GF7 can increase the size of the region a person can influence in a day without the dependence on a team of support personnel," claimed Brown. "It saves time by flying fast and eliminating delays resulting from startup, shutdown, transferring to a ground vehicle and backtracking to a waiting airplane. With a GF7 there is no need for travel coordinators, or a staff of pilots and drivers at the ready. You don’t need to pay for airport services, a rental car, or aircraft tie-downs, which also means you can avoid busy airports."
"You can fly with jet reliability, over bad weather, and in leather-appointed luxury to airports with no services and have all the conveniences of a car when you get there," he continued. "For the private jet owner, when you want to fly your plane, you don’t have to spend a half-hour hauling your aircraft out of the hangar. You leave from your house and go to whatever airport you want and get airborne. Airports become high speed on/off ramps. The GF7 is about independence, and removing barriers to flight, in a fast, comfortable and reliable aircraft."
The developers suggest that their customers would emerge from the thousands of regional business managers who regularly travel between city clusters, and anyone who needs to operate at airports that don’t offer ground transportation.
Of course, it’s also for anyone who loves to fly ... and has deep pockets.
"We’re going to make an aircraft that delivers an amazing flying experience," enthused Brown.