Efficiency as Creativity
I'm sure most of us complain bitterly about the price of avgas, but our usual response is to simply fly less. Other factors contribute to that so fuel becomes the easiest and most convenient excuse. At some point, we'll have to decide to fish or cut bait and exit the game entirely, I suppose. But there is a third option and that's to fly a more efficient aircraft. In my travels and in interviews, I broach this subject often because as a skinflint—also known as a cheap bastard—it interests me. But I'm always surprised that most owners I know don't give a whit about aircraft fuel mileage.
So I'm right at home here in Ajdovscina in Slovenia where Russ Niles and I are visiting with Pipistrel Aircraft. The company's founder, Ivo Boscarol, has staked out the hyper-efficient side of flight and just as most of the rest of the industry hasn't even given lip service to efficient flight—exceptions are Diamond, Rotax and Thielert—Pipistrel is just the reverse. The first item in its design brief is the most speed for the least fuel. That's why it has won the NASA Green Flight Challenge going away for a couple of years. On Saturday, we got a look at one of their airplanes, the Virus SW, and collected some flight data and impressions.
First the name. It's a bit of an inside joke, says Taja Boscoral, Ivo's energetic and impressively able daughter. Some years ago, when the company was having great success selling its airplanes, would-be customers came back from demo flights with smiles and the staff joked that they had caught the Pipistrel virus. The name stuck and, well, there you are. I'm not sure it would be my first choice for an airplane name because for an English speaker, the word connotes either a trashed computer or forced visits to the lav. But the Virus is a lot more pleasant than that. Once you've flown it, you won't think about what it's called, other than blazingly fast.
It's a Euro ultralight that is, in fact, ultralight. The empty weight is around 655 pounds (298 kg) with a useful load of between 390 (177 kg) and more than 600 pounds (272 kg), depending the country. The version I flew had a Rotax 912 at 100 HP and standard fuel of 100 liters or 26 gallons. I'll cut right to the performance numbers. At a high-elevation field in the Slovenian mountains on a near standard day, the Virus SW had no problem bolting off the runway into a 1200 FPM climb. At 7500 feet, it was boring along at a true airspeed of more than 140 knots on about 3.2 to 3.5 GPH. Give up 10 knots and you can whittle the fuel burn down to 2.5 GPH. That works out to 45 to 52 MPG--about what we're getting tooling around in our little FIAT 500, but at three times the speed.
Nothing is for free, of course, and for that reason, people who don't care about mileage or efficiency may resonate with the Virus. It's smallish in the cabin and a bit tight. Headroom is adequate but not generous. Same with the baggage compartment. The seats are functional and spare. At every turn, components are small and lightened, albeit superbly crafted. The systems are simple and well designed. For instance, most Rotax installations have carb heat, but Pipistrel simply routed the induction air through the water radiator and eliminated the need for carb heat. True, it loses some power due to higher induction temperature but Ivo Boscarol says the airplane has more power than it needs anyway so it can afford the compromise.
The Virus makes its numbers because aerodynamically, it's slicker than snot on a door knob. In the pattern, viewed from the ground, it looks like some sort of alien rocket. On final, it doesn't want to slow down, so it has both full-span flaperons and the sort of top-wing spoilers you see in gliders. And you need to work them both to get a satisfyingly short landing without a bunch of float. (In cruise, the SW gets some drag credit by setting the flaperons to -5 degrees.) It takes a little skill to fly it well, but it's an inviting challenge.
In short, this is not just another LSA. It's an example of extreme engineering dominated by one goal: efficiency. But practicality hasn't been thrown out the door. It shows both what's possible and what you have to give up in luxury, weight and size to achieve it. One problem with new LSAs is that they carry a high price tag but are often short on utility. In other words, are you willing to spend $140,000 for a hangar toy you fly locally once a week? Or do you want to fly somewhere in the thing? A 100-knot LSA makes trips doable—just. A 140-knot airplane burning 3 GPH makes them more attractive, just don't plan on taking the family dog and a steamer trunk.
Here in Slovenia, where car gas is $8 a gallon, the club members can scoot off to Venice or Florence and back and have gas to spare. In other words, despite the high cost of fuel and the regulatory burden, airplanes like this, especially in group ownership, make flying affordable. We never seem to hear people complain about high fuel costs here because efficiency is baked into the culture. Energy conservation isn't seen as punitive, as is sometimes the case in the U.S., but just a fact of daily life. In the hotel room where I'm writing, for example, the door key goes into a slot to energize the room's electrics. You can't leave without turning out the lights. This sort of thing is common here. The Pipistrel factory is self-sufficient with solar and passive energy design.
As Pipistrel gets more attention—which it will—and as gas gets more expensive—which it already has—look for this sort of design thinking to percolate into other aircraft. You'll see a lot of it in Pipistrel's soon-to-be four-place certified airplane, the Panthera. Keep on eye on that airplane. It could be a paradigm shift.