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Goldberg Extra mods

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Goldberg Extra mods

Old 04-03-2002, 02:05 AM
  #1  
beedriver
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Default Goldberg Extra mods

I am modifing a Golberg Extra 300 to become a 330. I am rebuilding the tailgroup with airfoiled horizontal and vertical stabs and control surfaces. Elevators will be MUCH larger and counterballanced. The BIG question is; Will these mods effect the CG, and if so how do I calculate the new CG. And, should the incidence of the horiz. stab remain at 0 deg? Plane will be powered by a K&B Aero 100.

Ideas?

Thanks for any input,

Walt
Old 04-03-2002, 08:37 PM
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transmission_dr
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Default Goldberg Extra mods

Walt,

The mods that you are making will probably add weight to the tail group, so you will need to rebalance the model. The required CG is determined by the wing air foil and the resultant center of lift, NOT by the tail group configuration. For stable flight in most aircraft, the cg must be in front of the center of lift. You would rebalance using the SAME CG as recommended by the manufacturer as a starting point. From there you can shift the cg as desired to change flight characteristics, the further aft, the more unstabel in pitch the aircraft will be. Too far aft and it will not be controllable. I would stay with zero incindence for the horizontal stabilizer.

My 2 cents,

Jerry
Old 04-07-2002, 07:52 PM
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TerrellFlyer
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Default Goldberg Extra mods

I've been flying the C.G. 300 with the tail group mod. incindence stayed the same, changed landing gear and moved landing gear forward as far as possible,added flying wires to tail end ,at this time I'm flying 1" behind cg, have 30% exp on low rate 70% on high for elevator 30% on high for other flying controls,transmission_dr is correct be very careful on moving cg,it can bite you fastlike .120 4s o.s.in mine ,lots fun.JOHN

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