- #1
MotoMike
- 30
- 2
Hello
Over the past year I've taken up the hobby of RC model airplane flying. During that time I've had many discussions with fellow modelers about lift. I've additionally read a bit about it as well. Most explanations I see like to explain it on Bernoulli's principle. That the wing construction being such that the flat bottom provides a shorter distance for the air to travel. that the air passing over the rounded top must go faster to get to the trailing edge at the same time. this more rapid flow results in lower pressure on top and there in comes the lift.
Some things that occur to me is that not all wings are flat bottomed. In modeling many, especially the higher performance models, have symetrical wings which would result in zero lift at an attack angle of zero. I can see that increasing the angle of attack would cause the flow on top to again have to take a longer path and again bournoulli's principle would again be an explanation.
One thing about bernoulis principle that I have trouble with is "why must the air traveling over the top exit the trailing edge at the same time as the air traveling over the bottom of the wing?"
I keep having this image of the wing advancing on the air and since air has a density it will offer resistance, that the wing will compress it and climb up on top of it. I am told by some that it does not work this way and by some that it does but the effect is minimal.
I also consider that just about any angle of attack above the horizontal will result in some of the air being forced downard which in my mind would push the wing in the opposite direction that is to say up and a bit forward.
Can someone discuss lift here with an eye towards helping the nerdy layman grasping the principles? I did search the forum but couldn't find a thread on point.
Regards,
Mike
Over the past year I've taken up the hobby of RC model airplane flying. During that time I've had many discussions with fellow modelers about lift. I've additionally read a bit about it as well. Most explanations I see like to explain it on Bernoulli's principle. That the wing construction being such that the flat bottom provides a shorter distance for the air to travel. that the air passing over the rounded top must go faster to get to the trailing edge at the same time. this more rapid flow results in lower pressure on top and there in comes the lift.
Some things that occur to me is that not all wings are flat bottomed. In modeling many, especially the higher performance models, have symetrical wings which would result in zero lift at an attack angle of zero. I can see that increasing the angle of attack would cause the flow on top to again have to take a longer path and again bournoulli's principle would again be an explanation.
One thing about bernoulis principle that I have trouble with is "why must the air traveling over the top exit the trailing edge at the same time as the air traveling over the bottom of the wing?"
I keep having this image of the wing advancing on the air and since air has a density it will offer resistance, that the wing will compress it and climb up on top of it. I am told by some that it does not work this way and by some that it does but the effect is minimal.
I also consider that just about any angle of attack above the horizontal will result in some of the air being forced downard which in my mind would push the wing in the opposite direction that is to say up and a bit forward.
Can someone discuss lift here with an eye towards helping the nerdy layman grasping the principles? I did search the forum but couldn't find a thread on point.
Regards,
Mike