Original URL: http://www.theregister.co.uk/2010/08/04/transition_redesign/

Terrafugia Transition flying car redesign - first analysis

Crash protection robs lardo pilots of golf clubs

By Lewis Page

Posted in Science, 4th August 2010 12:46 GMT

The Terrafugia Transition - the nearest thing to a flying car expected on the civil market in the near future - has been redesigned following last year's flight tests of a proof-of-concept prototype.

The new, redesigned Transition flying car. Credit: Terrafugia

New and improved ... but it's lost 90lb of payload.

The new design includes some significant changes from the original Transition layout. The nose canard of the proof-of-concept vehicle is gone, and the tail empennage is now an open twin-boom affair rather than the former arrangement in which the twin tails and elevator emerged from a flattened rear fuselage.

The Transition proof-of-concept prototype in flight tests. Credit: Terrafugia

Out with the old. The nose canard is to go and the tail area opens up.

According to Terrafugia, the redesign was required following lessons learned during flight and road tests of the proof-of-concept design. Since then the company has applied for - and been granted - 110lb of extra weight on the design by the Federal Aviation Administration (FAA) while still allowing the Transition to qualify as a "light sport" aircraft. A light-sport pilot's licence is significantly easier and cheaper to obtain than a normal private ticket, and red tape is lessened too.

The firm says that the new design exploits the FAA weight extension to furnish essential road-safety kit including an "energy absorbing crush structure" in the nose and a rigid safety cage for the occupants. Aircraft don't normally feature such things, as they need to be as light as possible - and if they crash, will normally be going significantly faster than a car, tending to make the value of the protective gear moot.

Other "flying cars" have tended to get around this by qualifying not as cars but some other, less restrictive road vehicle class on the ground - for instance as a motorcycle. But the Transition will actually be a car in the eyes of the National Highway and Traffic Safety Administration (NHTSA).

Weigh more than 180lb? No golf clubs or passengers for you, fatty

The road-safety kit could also be useful in flight mode, however. The new Transition is to feature an emergency parachute intended to bring it down safely in the event even of some massive disaster such as the wings coming off.

Forced landing by parachute isn't always that brilliant an idea if it's possible to make a rolling glide landing, especially if there's a strong wind blowing. A glide landing made into wind - the recommended procedure - can often deliver a much lower ground speed on touchdown, meaning a better result for aircraft, passengers and any nearby property.

By contrast, an emergency parachute landing on a blustery day means the aircraft hitting while moving across the ground quite literally like the wind and descending fairly fast to boot. But it demands much less skill from the pilot, and it still works even if the wings, tail and/or controls have fallen off. And a Transition, unlike pretty much any other light aircraft, will offer useful car-style protection which is designed for crashes in this speed range.

Terrafugia "expects the Transition® will prove itself to be one of the safest [Light Sport Aircraft] in the world", says the company.

That's all well and good - but there's a fair bit in the story so far to make prospective Transition buyers think hard.

First and worst, Terrafugia hasn't actually been able to accomplish the redesign within the FAA's extra weight margin. The Transition was originally supposed to offer useful load (that is, allowance for fuel and payload) of 550lb. Even that was a bit tight, as a full tank of unleaded weighs more than 120lb: two hefty occupants wouldn't be able to take any significant luggage on a fully-fuelled takeoff.

Following the redesign, despite the elbow room offered by the feds, useful load has been cut to 460lb, leaving as little as 330lb for passenger, pilot and bags. Terrafugia boldly advertises that the "cargo area holds golf clubs", but this could easily be a matter of 50lb or more: even a moderately-hefty 13 stone (180lb) golfer wishing to take off fully fuelled would probably have to travel solo in order to take his clubs with him.

All in all, for a lot of people, the Transition is beginning to look more like a single-seat rather than a two-seat aircraft, and there may yet be more weight gains on the horizon as the new design is built. Terrafugia might be well advised to simply abandon the struggle to stay within light-sport certification limits and accept that its customers will need normal private pilot's licences: plenty of people have these, after all.

Then there's the awkward fact that Transitions were supposed to be delivered last year, a forecast that has now slipped to "late 2011". Extrapolating from past history it will take Terrafugia three years, not one, to bring delivery day 12 months forward into the present - so actual deliveries could easily be as late as 2013.

Quite apart from disappointing customers, this sort of delay burns up money. Terrafugia says it has an order book of $18m, but that may not be enough to recoup development costs incurred over as much as seven years and two designs - and more orders could be hard to win for a driveable plane that can in many cases only carry one person.

The Transition's many advantages remain, of course: the ability for normal pilots without instrument ratings to simply drive under bad weather and restricted airspace is a unique selling point, as is the joyful prospect of simply landing and driving onward out of the airport gates rather than faffing with hangar or tiedown space, hire cars or taxis etc.

The Transition remains a very cool idea and we here on the Reg flying-car desk wish it well, but we have to say that prospects look less rosy than they did a few years back. ®