Throt/ Rud

[Rcmaster199 at aol.com]

Bob, this is exactly how I feel. Why not learn to use the sticks? 
 
On the money with P-Factor (not to be confused with K-factor) and GP  also. 
Slipstream is the key and it could be significantly straightened by doing  
something similar to what Nat has done with the Xpress series of models.  Strakes 
surrounding  the CG help reduce the effects. This is a  design feature tha 
belongs on all pattern models. IMHO
 
MattK
 
 In a message dated 1/27/2005 8:18:27 AM Eastern Standard Time,  
bob at toprudder.com writes:

Ed,
 
I am a very firm believer (no one will convince me otherwise) of  exactly 
what you describe. Slipstream effect is the whole  reason we put right thrust in 
our engines. It has NOTHING to do with torque,  _P-factor_ 
(http://home.earthlink.net/~x-plane/FAQ-Theory-PFactor.html) ,  or _gyroscopic  precession_ 
(http://www.cybercom.net/~copters/aero/gyro.html) .
 
The issue of transitioning from vertical to horizontal (either to  inverted 
or upright) is a gyroscopic precession issue. The best way to counter  that is 
to use lighter weight props turning at lower rpm -- less spinning  mass and 
less gyroscopic effect.
 
P-factor only exists at high angle of attacks, which does not happen in a  
vertical climb. 
 
Torque tries to roll the plane, and some schools of thought are that, to  
counter the torque-induced roll, the left wing has to lift more than the  right, 
causing more induced drag on the left. While this may be true for a lot  of 
planes while taking off, this does not apply to pattern planes in a  vertical 
climb since both wing panels would be fighting the torque  equally.
 
Gyroscopic precession only occurs when the airplane is moving around its  
pitch axis, as when pulling or pushing a corner. It is most noticeable when  the 
airplane is slow, since there is less aerodynamic stabilizing force  available 
from the rudder/fin.  IMHO, no throttle-rudder mix is going to  correct this. 
It might be possible to mix elevator to rudder,  and enable/disable the mix 
based on throttle position.
 
When I flew a Cap21 in pattern, I had to use left rudder when pulling an  
inside corner at the top of square loops. I had to use a TON of right rudder  
when pushing a corner, and this was with about 5 degrees of right  thrust.
 
IMHO, learn to do it with your thumbs. Practice enough and it will become  
automatic. Just my 2CW.
 
Bob R.


Edward Skorepa <edsko at xmission.com>  wrote:

I'm confused too. I know, I know I shouldn't  argue with someone like chip 
but I believe the main reason we're putting  right thrust is an asymmetric 
vertical fin. On most conventional airplanes  the area above thrust line is much 
greater then area below. So, the  spiraling slip stream  will hit the top 
portion of the vertical fin  from the left pushing tail to the right thus right 
thrust. When inverted,  the spiraling slip stream will hit vertical fin from the 
right because  fin is now on the opposite side and  pushes tail to the left. To 
 straighten the flight path, we need now the left thrust which is already  
there. During inverted push ups, why do we need to use left rudder? The  
spiraling slip stream misses completely vertical fin and the right (left  when 
inverted) thrust is causing airplane to yaw left. If you have a big  gasser, turn on 
smoke, do inverted push up and watch where the smoke goes.  However, Chip's 
approach of fixing the inverted push ups problem is  quite interesting and I'll 
try it on my new bird I'm working on right  now.
ed




 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20050127/8f75545a/attachment-0001.html