# Lift generated by a wing mostly on the top surface or bottom surface and why ?

• Lift generated by a wing mostly on the top surface or bottom surface and why ?

Answer #1 | 22/12 2013 05:40
Half on each.
Answer #2 | 22/12 2013 06:18
Without the top surface lowering the air pressure above the wing, there would be no 'push' under the wing from the higher air pressure below it. It's a team effort but the bottom of the wing would do nothing if the profile of the top did not do its job. On balance, I'd say lift comes from the top surface.
Answer #3 | 22/12 2013 05:58
To be technical about it, it is on the bottom. The wing is lifted by air pressure (no air, no lift) and the air pressure under the wing is greater than the air pressure above it.
Answer #4 | 22/12 2013 12:43
Your book is correct. It is the result of the Bernoulli Principle which states that the pressure of a fluid varies inversely with its pressure. In other words the faster the flow, the lower the pressure. The increased airflow over the cambered upper surface results in a drastic drop in air pressure causing the air pressure below to push the wing up. In essence, the wing has a "suction" on top that pulls the wing up.
Answer #5 | 22/12 2013 16:31
Both. Or neither. It's the DIFFERENCE in pressure between the upper and lower surface that creates the lift.
Answer #6 | 23/12 2013 20:59
I see a lot of answers trying to explain the effect with the minor theories of newton, Bernoulli's or any other here. But the exact lift effect is called the "Coanda Effect" which is mentioned in none of the science texts. at least not in India. This effect makes a body stick to the high pressure flow of fluid. Meaning when an aircraft wing is designed, the flow of air is faster on the upper side and slower flow in the under side. So the faster flow creates lesser pressure and slow flow creates higher pressure. High pressure under the wing means the air pressure under the wing pushes the wing upwards. So basically its the Coanda effect in action. After this u can apply newton's third law and Bernoulli's principle to see the reactions to this effect. If there is a lift due to high pressure, it also creates a drag. this is as per newton;s third law. If the high pressure created under the wing pushes the wing upwards and the drag creates the wing to move forward to the low pressure area when the front side of wing is lifted slightly to avoid the drag. this is in accordance to the Bernoulli's principle. so basically its a mix of all these effects that makes and aircraft fly as it does, and done right, it can also allow the aircraft to fly upside down (Inverted). This can be seen in modern jet fighters in action. So basically u need to get understanding of the Coanda Effect more than any other.
Answer #7 | 23/12 2013 16:03
I see the "Newton, not Bernoulli" camp is out in force. Well, in truth, those who have studied the problem in depth ought to be aware that it's neither Newton nor Bernoulli but Euler who should be mentioned. For the record: the common explanation given in some texts, that air over the upper surface must flow faster and therefore reduces pressure, is wrong. But that fact does not make Newton the winner. In practice, both Newton and Bernoulli equations, when correctly applied, are satisfied by the behavior of air flow around the wing. For a fuller explanation (if you can stand it) see the link below. Either way, what we think of as 'lift' is generated on the underside of the wing.
Answer #8 | 23/12 2013 05:15
From the top of the surface !!