|06-22-2011, 10:16 AM||#1|
I am: Boolean21
Join Date: Sep 2002
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Principle of Balance
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My apologies if this has been asked before. I did search for CoG and only came up with questions specific to a single airframe.
My general question is: Should the CoG be checked "with" or "without" the plane fueled?
|06-22-2011, 10:24 AM||#2|
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I am: Max P.
Join Date: Feb 2007
Location: Aurora, Ontario
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Re: Principle of Balance
Again the answer is "It depends"
It depends on where the engine and fuel tank are located.
For a tractor type of aircraft, with the gas tank and engine AHEAD of the CG, you always check it with the fuel tank empty. This is because you want to start nose heavy, and then be spot on CG when landing with the tank empty.
For pushers, where the engine and tank are BEHIND the CG, you balance it with the tank FULL, but because all the balance points are backwards, you want spot on CG for take-of and as the plane burns fuel, you get a little more nose-heavy, but nose heavy is safer than tail heavy, which could be disastrous in a pusher as the plane continues to fly and burn fuel
The best way to do it is to have the tank directly on the CG of the plane, so that you never have a CG shift as the fuel is consumed. The problem with that is the engine is usually mounted quite a distance from the CG (Usually.. ) making long fuel lines necessary, and unless you use a pump, can cause all sorts of engine problems due to poor fuel feed.
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