I’ve been playing around with the idea of an aircraft that gets it’s lift both from a wing and lighter-than-air gasses, a kind of cross between a zeppelin and an airplane. I think today it should be possible to build a rigid, airtight wing that could be filled with helium, probably in several separate cells. Are there any problems with this idea that I am overlooking? I’d think you could build a small plane with a proportionally small wingspan, with a really low stall speed.
WAG:
The only problem I can think of is that I’m not sure it would be worth it… you wouldn’t get much lift just from filling the wing with helium. To get enough lift to make it worthwhile, you’d need a huge area to fill with the gas.
Interesting idea, though!
To get any kind of lift from bouyancy you need a huge size and to get any kind of lift from a wing you need speed so both things are incompatible in practical terms. Huge size means huge drag at high speed.
Hmm, how about on a larger scale then? A zeppelin in the shape of a flying wing?
There is no need for helium with a flying wing. There is so much inherent lift in a huge flying wing that it can just coast over wind currents. Helium would be redundant.
Just like putting helium into tires to decrease the weight of a car and increase mileage. You need tires so big that you’d have practical problems driving it.
If you insisted on filling a large enough flying wing with helium, it’d have to be so big that the weight of the internal support to keep the wing from collapsing would keep the wing from flying.
Also, I think tire rubber is too porous for helium. You’d have to refill them more often, since helium atoms are so much smaller than regular atmospheric molecules.
If you can build a rigid airtight wing, why not fill it with vacuum. Or unfill it with vacuum. Or unfill it with everything which would result in a vacuum. Or something.
Whatever the case, a wing with absolutley nothing inside is even lighter than a wing full of helium.
Nature abhors this thread.
Yep, it’s definitely been thought about:
And some say it’s already been done. A few years back, Popular Science’s Area 51 monitors reported something which appeared to be a giant, very slowly moving, stealthily shaped flying wing, presumably a dirigible observation platform. Unfortunately, I can’t find any citations for that.
I just finished reading a book “Air Commando Chronicles” by Col Robert L. Gleason (ret) in it he told a story about an inflatable airplane built by Goodyear called the Inflate-O-Plane. I came in a package and when you pulled the cord it inflated like a life raft. It was supposed to be ejected out the back of a SAC bomber with its own parachute. If this was filled with helium it might have been enough to make a difference.
As for evacuating the hollow structures inside an aircraft we have been doing that for years. Our composite structures have been using vacuum construction since the early 60”s. The vacuum is used the construction technique and I don’t think it makes that much difference in weight.
FWIW some track cyclists to fill tires with helium for reduced weight. They already use lightweight “sew up” tires becasue small reductions in rorating weight make a noticable difference in acceleration.
Mac, Vacuums are not used in composite construction like you think. Vacuum bagging is used to squeeze all the voids out of the laminations but not to keep air out of a hollow honecomb structure. This is actually a common technique for woodworkers to install veneers. The part is placed in a plastic bag and all the air is pumped out. You now have nearly full atmospheric pressure, around 14.7psi, squeezing the stuff inside the bag. For a 24"x48" part that’s equivalent to up to sixteen tons of force.
This might give you an idea of how huge it would have to be:
http://www.info2000.net/~aloomis/darwin.htm
scroll down about 1/3 of the page and check out Larry Walters. This guy attached 45 weather balloons filled with helium to a lawn chair. Each balloon is about 4 ft in diameter when filled. He was floating at an altitude of about 11,000 feet.
And I found a picture of it.
From The Deltoid Pumpkin Seed revisited article in the Princeton Packet:
That link has a picture of the prototype in flight, at a more modest 26 feet long.
See also The Deltoid Pumpkin Seed by John McPhee.
So, the answer to your question is “Yes, someone has built an aircraft like this idea of yours.” Many UFO nutjobs take this idea and run with it and believe that the Aereon company is really not still struggling to put new aircraft designs into production, but is a cover for the fact that the idea was taken by the US Government and now there are 800 foot long Aereon type ships at Area 51. So, if you search for ‘Aereon’ you’ll mainly find UFO site references.
Share and enjoy!
Thanks for the link. I thought it would be possible. 8^)
breaknrun: although the essence of the story in your link is true, you should check out snopes for the full story ie replace Miller with soda, helicopter with snagging power lines after a voluntary descent etc etc