Getting 45 MPG at 207 MPH .... can you pulse and glide an airplane?

[jamesqf]

Originally Posted by dcb

...with the right engine combo, you should be able to cruise @ 90mpg at 103mph and 180mpg at 52mph?

Well, except for the fact that IIRC the stall speed's about 65 mph :-)

Would narrow wheels and direct drive, instead of wings and a propeller help or hurt mpg?

Some of the mpg improvement probably comes from cruising at higher altitudes* - around 12,000 ft or up to 18,000 with oxygen - where the air is much thinner, so drag is less. I don't know how induced drag from lift would compare to tire drag, but the low frontal area is about the same as the VW 1L car.

* And that's boring. Flying's more fun when you come back with bits of sagebrush in the gear :-)

[winkosmosis]

Originally Posted by Bicycle Bob

That's the shape of the landing gear mount, in a situation where it works OK.

What do you mean? Why would the nose be pointed for the landing gear?

[bestclimb]

as you increase your speed you are reducing induced drag, but you can get going fast enough that induced drag is a very small portion of your total drag.

There are situations where you can increase speed and reduce power.
Like near stall, when there is not much air moving over the aircraft, so the parasitic drag is very low but you are dragging the wing through the air with the bottom facing the apparent wind.

[MetroMPG]

Originally Posted by winkosmosis

Well lookey here, a pointy nose.

We need to get this man a dead horse and something to beat it with.

[vielecustoms]

another efficient homebuilt plane
Dragonfly FAQ - Dave Morris

[Bicycle Bob]

Oh, that's a big one. The root of this line of development was the Quickie Q1, a single place design with the front wheels on the canard wingtips. It originally flew on 22 HP. Quickie Files
The Windrose motor glider is probably more the way to go if one wants to do gliding, though. Many sailplanes could easily carry a small motor - many of the best ones carry ballast. The records are over 1,000 Miles on Zero gallons, but you don't get to choose the route on those flights. There is a proposal to tether two sailplanes together, to work as kites on the differential in wind speed with altitude. That would give more options, but usually mostly downwind, like a square-rigged ship.

[vielecustoms]

Originally Posted by Bicycle Bob

Oh, that's a big one. The root of this line of development was the Quickie Q1, a single place design with the front wheels on the canard wingtips. It originally flew on 22 HP.

I think that was what I was thinking of. I remember thinking I like that design and if I ever had space, time and money I'd build one of those or a culp special (I like the culp's classic look)

[orange4boy]

Originally Posted by vielecustoms

another efficient homebuilt plane
Dragonfly FAQ - Dave Morris

Fuel Capacity: 15 gallons
Fuel Consumption: 3.4gph at 165 mph TAS
Range: 500 miles with 30min reserve at 165 mph or 840 miles with 30min reserve at 130 mph

That's 48 mpg at cruise! Sweet

[Clev]

A friend of mine has a Piper Cherokee (840 statue mile range on 36 gallons, which I take to be about 23 mpg at a cruise speed of 124 mph.) Because it's carbureted, there's a lot of fiddling with the mixture to get it to run properly at various temperatures and altitudes. I would imagine that it would be a little more efficient (and a lot cleaner) if it were fuel injected.

Still 23 mpg at 124 mph is about the same as my Saturn gets at 83 mph. Not too terrible for the speed. :-)

[Lazarus]

You can pulse and glide this one. It's a G109B motor glider. Not near as fast but once you get up you can feather the propeller and ride the air currents until you need to fire the engine up again. They're comfortable and quite fun to fly.