Centre of lift help??

Question

is centre of lift is the term used to find the net lift produced. is it 25%of the chord line length. i could not find any inofrmation about it. is there other name for it.

Answer 1

Yes center of pressure is what you're looking for. It is located as a percentage of mean aerodynamic cord, MAC, as you say and 25% could be about right for a given aircraft although newer super critical wings will have the center of pressure located somewhat aft of that. Center of pressure moves for and aft with aircraft speed as well and can result in Mach tuck at extreme speeds. A mach trim devise will prevent this.

Answer 2

The center-of-pressure concept assumes that an airfoil produces a single force, lift, and that the lift causes the moment. Since the measured moment of many airfoils is constant, this concept implies that the moment-arm must increase, that the lift moves rearward, as the angle of attack (AOA) and the lift decrease.

    d = M / L

where lift, L, replaces force, F.

This implies that as the AOA is decreased toward the point of zero lift, a point is reached where the lift is actually behind the trailing edge, and ultimately goes to infinity as the lift becomes zero. (What happens when lift becomes negative, as in inverted flight? Does is move ahead of the leading edge?)

Answer 3

I "think" you might mean the centre of gravity. The CofG is a point within an object ( auto, truck, aircraft,) which is a point of balance within the object. If you were to support a auto at its center of gravity it would be perfectly balanced. Adding just a pound of weight to front or back or either side would cause it to tip. Hence, the lower the CofG of an auto the more resistance it has to rollover.

Answer 4

Perhaps center of pressure.  As the explanation above talks about CG, the Center of Pressure is in the mean aerodynamic chord where the sum total of lift produced is acting in a direction toward the top of the lifting surface.