I am wondering if a specially shaped can will produce any lift as it moves through the air.

Please reference the drawing below:

enter image description here

This drawing is showing a hollow can that has been cut so that it will have one side that is higher than the rest of the can. The top of the can is open while the bottom of it is sealed with a plate. This higher side of the can will be moving into the wind as the can travels forward. The can will not be angled, the bottom of the can will remain parallel to the the air flow. Also, the can will be made of a very stiff material so that the higher side of it will not bend backwards.

I believe what will happen is that the air flowing over and around this higher side will lower the air pressure inside of the can and the higher air pressure located below the can will be pushing up on it thus creating lift. I'm pretty sure that this is what should occur, yet I'm asking this question to get verification on it because I am not an engineer and I have a limited knowledge of aerodynamics.


To keep the can held firmly in a vertical position so that it doesn't topple over in the wind and to keep it perpendicular to the ground, it could be attached to a side of a car like how a car's side mirror is attached.

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    $\begingroup$ How would you stabilize the can? It will not maintain this orientation but topple over when moving, so any vertical force will equally point up and down. $\endgroup$ Aug 22, 2020 at 18:50
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    $\begingroup$ @PeterKämpf, well, the can will need to be attached to the body of a vehicle/aircraft. It could be fastened to the side of a car like a side mirror, with the bottom plate of the can parallel with the ground. I will point this out in an Edit section. $\endgroup$
    – user52106
    Aug 22, 2020 at 19:13

2 Answers 2


Any body that is asymmetrical w.r.t. the flow field will produce lift, possibly negative, but certainly not zero. To estimate the sign and magnitude of the lift, this body is simple enough to just build and try from a moving car, instead of theorizing or running a CFD simulation.


Notice you are bending the air to either side, rather than up or down. Air will easily enter the top and disrupt the lower pressure pocket. At higher airspeeds momentum mv may carry top flow past the interior enough for some vacuum to form, but you will do much better with a curved ramp on top to "throw air away" from the surface, allowing a stable lower pressure area to form above the object. As seen with hollow cup data, coefficient of drag will be very high.

This design is vaugely reminiscent of Kline Fogelman wings, but with such a low aspect, it would be a very poor lifter. Give it a try, but most likely you'll be kicking this can down the road.

  • $\begingroup$ thanks for the answer. I understand that this design will produce very little lift, but building a new type of lifter/wing is not what I'm interested in. I just wanted to know if it would produce any lift at all. I asked this simply out of scientific curiosity. Also, I guess it would be better to have a top plate covering the section of the higher side of the can. $\endgroup$
    – user52106
    Aug 22, 2020 at 19:41
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    $\begingroup$ @user255577 drag would be the major issue. Interestingly, if you placed the can on its side, flattened it a bit, and gave it a little AOA, that might lift much better. $\endgroup$ Aug 22, 2020 at 19:46
  • $\begingroup$ Nice pun at the end! :) $\endgroup$ Aug 22, 2020 at 21:11

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