Jetset44! Help on camber debate

[Skonkworkstexas]

Guys, throw yer 2cents on this one Steve, if your reading this, I would like your opinion.
This is the hot debate at Marshall Aeromodelers
Undercambered versus other designs
Bernoullis Fluid Principal states " As a Fluid moves over a curved surface, its velocity increases and its pressure decreases".
First of all a principle is not a law. If it was then an undercambered wing would behave as a full symettrical as it is curved on both sides, and would create the same lift with no angle of attack-they would cancel. Applied algebraically Bernoullis could also read this"As a fluid moves over an INVERSELY curved object, its velocity DECREASES and its pressure INCREASES. applied dynamically, the undercambered wing would create much more than a flat bottom, or any wing.
This being said, at a cost of greatly increased cost of induced drag.
when engineers tried supersonic flight they found that turbines don't work well, or possibly at all that way.
The SR71 engine Aerospike was a poor but workable solution.
The notable late Kelly Johnson made it like a huge ice cream cone. As the velocity decreased, the pressure greatly increased and was fed around the engine for Afterburner food-if exceeded several bleed doors would open. If exceeded more the spike would move. Heres the kick-if the spikes electronics, or whatever the control moved wrong, which was common, then UNSTART! The plane would slam. Bet todays electronics would fix that. Anyway overemphasis!!! My Weakness!! Am I right about undercambered wings or wrong. That you have the principal works two ways, but not a solution cause the induced drag sucks? Enjoy this one, cause this is for the club.
Skonk :confused: :)

[banktoturn]

Skonk,

It's not clear from your post exactly what your claim is.

First, you can view the Bernoulli Principle as a law. The Bernoulli Equation correctly predicts the pressure, under the correct conditions, which essentially means attached flow.

The only camber that matters is the camber of the mean line, which is the line down the 'center' of the airfoil (equidistant from the upper and lower surfaces of the airfoil). There is no such thing as an 'undercambered' airfoil. What is often called an 'undercambered' airfoil is an airfoil with enough camber that its lower surface is concave. Airfoils like this do tend to acheive high lift, if they can operate without stalling. They also tend to have higher drag than less cambered airfoils, when operated at the same angle of attack. For the same amount of lift however, they tend to have lower drag than less cambered airfoils, because they can acheive that lift at a lower angle of attack.

banktoturn

[Skonkworkstexas]

Thats what I was trying to find out. Thanks! :D