Most Efficient Homebuilt Airplane?

Question

I work at an avionics shop. One of our customers told me about the plane he was building, a two seater which he claimed could get 3gph at 150mph on a Rotax engine and 87 octane fuel. I don't remember what the name of it was, and I haven't seen him since. I've read some impressive numbers on Vans and Mustang II, but this is beyond anything I've ever heard. Is it possible these numbers are accurate? If so, what kind of plane might he be building?

Answer 1

Check out the Nemesis NXT.  

www.nemesisnxt.com

www.relentlessairracing.com

Super fast, super slippery.  Throttle back and cruise at altitude at outrageous speeds.  

Lancair's are quite efficient as well.

Answer 2

Might be a Rutan aircraft.

The Varieze can do 150MPH on about 4GPH with an old Continental O-200.  The original had a VW engine.

http://www.airventuremuseum.org/images/c...

A Quickie can do about the same speed with a 64HP engine (would probably be about 3GPH).

http://en.wikipedia.org/wiki/Image:Rutan...

Answer 3

A Zodiac XL won't do _quite_ that well, but at 24 gallons of fuel capacity, for a 656 statute mile range, it's not far off. Cruise speed is 155 MPH @ 8,000 ft at 75% cruise with Rotax 912S (100 hp, 4 cyl). Some Zenith models that fly a bit slower do a bit better on fuel economy, but the XL is still cruising at a fuel economy of about 27.7 mpg.