CG location vs total weight

[Del K. Rykert]

Hi Xavier..
    Remember that elevator controls speed and throttle controls elevation.  The speed component is what need to be addressed to keep the wing from stalling more so in the 2# heavier plane. Pitch control is going to take much less elevator/drag input the more the CG is moved back.  If you truly want to make a pattern airplane 2# heavier than it needs to be I guess I am missing the fundamentals of why we normally strive so hard to keep our competition aircraft as light as possible. Speed is a factor that has to be increased for a heavier aircraft to stay in the air as wing loading is higher. C.G. I believe is primarily a factor within realistic flight parameters that different pilots choose to fly at different places to get the track and feel from their aircraft, not a component of carrying more weight. 
    I suspect this is part of your weight lifting project?
 
                         del 
               NSRCA - 473
 
  ----- Original Message ----- 
  From: Xavier Mouraux 
  To: discussion at nsrca.org 
  Sent: Monday, March 29, 2004 8:23 PM
  Subject: CG location vs total weight


  Hello all,

  I am trying to clarify an idea about CG location for different weight of a same airplane. 

  Goals: 
  Minimize the effect of elevator trim /stab incidence on level flight, inverted flight and verticals.
  The airplanes need to fly at the same speed independent of its weight or the qty of fuel.

  Questions:
  Could it be that a heavier plane need a CG more AFT than the same plane with a lower weight to "set" in the proper angle of attack ?
  Could it be useful to locate the tank so the CG move FWD as the fuel is burned ?
  What about CG recommendation on plan or from other pilots with same plane but different weight ?
  How much change in angle of attack is required on a pattern plane for a 2lb difference in weight to fly at the same speed ?
  What would be the effect on elevator sensitivity ?
  Am I going too far ?

  Any opinion ?

  Xavier
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