Strings explain the bernoulli theory

[facthunter]

Once the plane goes supersonic a whole new set of rules apply. Most of those WW2 fighter wings were laminar flow where the max thickness is well back. They are not as forgiving as the earlier Clark Y etc but these guys were chasing speed. they even hit Mcrit a few times. (Local airspeed supersonic with shock waves. You can see these when they form). You imagine the air does not compress below Mach 1, above that it does. Don't think we will be concerned with it in the RAAus for a while. Nev

 

 

[Neil_S]

I seem to remember my balsa wood gliders flew pretty well with just a thin flat sheet for a wing. The spitfire wing is a very thin section and worked a treat, too. .Kaz

Hi Kaz,

 

Yes - I certainly remember the same, and rubber band powered balsa wood planes too. Also we all know planes can fly upside down, so IMO (unscientific as that may be) the curve more determines the smoothness of the flow of air and where it breaks down relative to the AofA thus assisting the lift, rather than actually providing lift. I could be entirely wrong, but while my plane continues to fly I don't really care......

 

Cheers,

 

Neil

 

 

[kgwilson]

Hi Kaz,Yes - I certainly remember the same, and rubber band powered balsa wood planes too. Also we all know planes can fly upside down, so IMO (unscientific as that may be) the curve more determines the smoothness of the flow of air and where it breaks down relative to the AofA thus assisting the lift, rather than actually providing lift. I could be entirely wrong, but while my plane continues to fly I don't really care......

 

Cheers,

 

Neil

I agree. The aerofoil shape is just an efficient way of getting the wing through the air as has been shown in numerous wind tunnel experiments. Bernoulli & Newton have a bit to do with it. The faster you go though with a high camber wing, more & more drag is generated so by thinning the wing down as the performance of an aircraft increases keeps the drag to a minimum, to the point where the wing becomes almost flat. All this video did was show what happens when the laminar flow detatches at the stall & then all hell breaks loose with some of the bits of cotton being pushed forwards as well as sideways, upwards & every conceivable direction, consistent with a complete breakdown of the air moving across the wing. Wind tunnel experiments show this with smoke as the angle of attack is increased to the stall.

 

 

[facthunter]

If you want to see what really happens, attach manometer tubes to various parts of the section and read off the pressures. A "neutral lift line" for a lifting section is quite negative. Could easily reach 3 or more degrees of negative incidence. Centre of pressure movement is more with these sections than with symmetrical ones. Nev