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When I was a kid I used to make small balsa-wood gliders who's wings were completely flat, and with no angle of attack. They flew OK, which has always made me w

When I was a kid I used to make small balsa-wood gliders who's wings were completely flat, and with no angle of attack. They flew OK, which has always made me wonder about both Bernoulli and Newton in this regard.

euroderf 1y ago
Did they fly basically the same when chucked upside-down ? There's that stabilizer to complicate things.
- zabzonk 1y ago
  > Did they fly basically the same when chucked upside-down ? sadly, never occurred to me to try. > There's that stabilizer to complicate things. True, getting the tailplane right is kind of key to a successful aircraft. but these would have been basically the same as the wings. so they may have provided some lift, and so some down-pitch?
  - nostrademons 1y ago
    I tried, and yes, an inverted balsa-wood glider will still fly. Actually just tried right now with a styrofoam glider, upside-down, and it's fine. Marginally less range than when flying right-side-up, but it's a very small difference. I suspect that what's going on is that the center-of-gravity interacts with the center-of-lift to create a slight angle of attack regardless of what orientation the plane itself has. Then there is some unknown feedback loop that keeps that angle of attack from getting too large and stalling. It's not unlimited - if you make a paper airplane whose wings are too far forward or center of gravity is too far back, it will still stall - but it keeps most reasonable planes moving forward rather than down.
    - zabzonk 1y ago
      Yeah, I agree it must have something to do with the forces on the model. I loved playing with these things way back when (1960s) - the most frightening one was a model attached to a jetex rocket engine https://en.wikipedia.org/wiki/Jetex https://en.wikipedia.org/wiki/Jetex which after taking off immediately immolated itself, which I suppose is par for rocket powered aircraft, of any size.
gus_massa 1y ago
> no angle of attack You probably need to film the plane and nave an accurate horizontal reference to ensure the wing is perfectly horizontal. (Disclaimer: I only made paper planes, but I never filmed them.)

euroderf 1y ago

Did they fly basically the same when chucked upside-down ? There's that stabilizer to complicate things.

zabzonk 1y ago
> Did they fly basically the same when chucked upside-down ? sadly, never occurred to me to try. > There's that stabilizer to complicate things. True, getting the tailplane right is kind of key to a successful aircraft. but these would have been basically the same as the wings. so they may have provided some lift, and so some down-pitch?
- nostrademons 1y ago
  I tried, and yes, an inverted balsa-wood glider will still fly. Actually just tried right now with a styrofoam glider, upside-down, and it's fine. Marginally less range than when flying right-side-up, but it's a very small difference. I suspect that what's going on is that the center-of-gravity interacts with the center-of-lift to create a slight angle of attack regardless of what orientation the plane itself has. Then there is some unknown feedback loop that keeps that angle of attack from getting too large and stalling. It's not unlimited - if you make a paper airplane whose wings are too far forward or center of gravity is too far back, it will still stall - but it keeps most reasonable planes moving forward rather than down.
  - zabzonk 1y ago
    Yeah, I agree it must have something to do with the forces on the model. I loved playing with these things way back when (1960s) - the most frightening one was a model attached to a jetex rocket engine https://en.wikipedia.org/wiki/Jetex https://en.wikipedia.org/wiki/Jetex which after taking off immediately immolated itself, which I suppose is par for rocket powered aircraft, of any size.

gus_massa 1y ago

> no angle of attack You probably need to film the plane and nave an accurate horizontal reference to ensure the wing is perfectly horizontal. (Disclaimer: I only made paper planes, but I never filmed them.)