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Old 15th Nov 2007, 15:13
  #16 (permalink)  
Pugilistic Animus
 
Join Date: Dec 2006
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Mark1234: there are 3 possible limiting factors which may limit or define max theoretical turning performance, they are:

1. The airfoil's ability to produce maximum lift---

Assuming a steady state process where L=W, since the maximum weight ever to be carried by a wing is the weight that it carries at the stall Vs.

Lmax = Clmax *QS=1/2rhoVsqrd*S--- And ---

W[at stall] =Clmax 1/2rhoVssqrd*S ---therefore---

g max or n [g=n] max = Lmax/Wmax...divide eq. 1, by 2 and all cancels except the 'V' terms, therefore nmax= [V/Vs]sqrd...so you now have now the max load factor possible: a stall at 2 vs will pull 4m*g or 4 W or 4 'g'---

a stall at 4*Vs creates load factors of 16g etc, etc...



2. The operating strength limitations: this is the upper limit of the load factors that will not hurt the airframe: Va again

From above pt.1--- you can derive that Va = Vs*sqrt n


3. Thrust or power limits ---

This defines the ability to maintain altitude.


As far as stall speed in a turn remember that n = L/W =1/Cos phi; phi = b= stall speed increase with bank angle is derived by recording that---
--- stall speed increases with W or g can be derived from Vs2/Vs1=sqrtW2/W1, so you may write that Vs[phi] =Vs*sqrt[n]

Lastly, as a hint to understand the web site---- remember that y =sin Theta, and X =cos theta, and sin /cos =Tan and Tan= opposite side length/ adjacent, or y/x


and for interest:

Rate of turn =1091Tan [phi] / V

and

increase in stall speed Vs with flaps is given, by

Vsf = sqrt*CLmax [clean] / Clmax [w/flaps]

BTW: turn radius at stall speed is infinite as you implied already--impossible!


math stuff on this site can be very cumbersome




Intruder: I was timed out at 2.00 am and couldn't repost I'll get back to you soon!

Last edited by Pugilistic Animus; 18th Nov 2007 at 19:00. Reason: clean up equations: and syntax
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