[NSRCA-discussion] Snap entry in FAI

[Del]

If you are referring to flaps per full scale look at where flaps are located on the wing.  Why are they located there?  To allow and contribute to the loss of lift at root of the wing but to still allow for stability and lifting airflow to continue over the outer wing panels. 
 
At the wing loadings and air speeds our aerobatic models fly at (referring to 2m in this case) at best we can accomplish is to create a high speed wing stall or at least force a snap with massive deflections of our surfaces. 
 
Myself, unless someone can show with wing tunnel studies or tuft video analysis that the wing is truly stalled, I believe many models truly do not have a stalled wing condition. If they did, they would display a change in track that would be easily detectable d/t the AOA and transition to high speed stall. It doesn't occur instantly unless already in or approaching a stalled state. 
 
    Del  
  ----- Original Message ----- 
  From: Bob Richards 
  To: General pattern discussion 
  Sent: Monday, June 30, 2008 8:22 AM
  Subject: Re: [NSRCA-discussion] Snap entry in FAI


        When a wing stalls, it simply means the airflow detaches from the top of the wing. The air is still flowing on the bottom of the wing, the wing is still providing some lift, and the ailerons can still deflect this flow. If this was not the case, a rolling harrier would not be possible. (Shame on me for mentioning 3D flying on a precision aerobatics newslist!! :-)   )



        Deflecting the aileron down will not necessarily cause the wing to stall quicker, in fact as the wing starts to move up (roll rotation) the angle of attack is actually decreased on the rising wing, and increased on the falling wing. This is how one wing panel can be stalled and not the other.



        Besides, if deflecting the trailing edge down causes a wing to stall quicker, I don't think flaps would be a good idea on a landing approach. 



        Bob R



        --- On Mon, 6/30/08, Del <drykert2 at rochester.rr.com> wrote:


          ----- Original Message ----- 
            I would like someone to explain how, if the wing, or one panel, is stalled how the ailerons are continuing to control the direction of rotation. If there is a stalled wing, then it will be the one with the "down" aileron as that wing has the higher incidence angle. This stalled panel would cause a roll contrary to the aileron deflection. This is actually what happens when you get an oeverweight airplane too slow and add some surface deflections. It will snap contrary to the aileron.


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