posted 05-10- 07:08 PM
This is part of the FM document I'm working on. THere's more too this but I haven't typed it yet 
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First, if you think of the CG as a lever this is what can happen. We put 100 lbs one foot away from the CG towards the nose. How much do you have to put 2 feet behind the CG to balance the aircraft? 100 lbs- wrong. Since this weight is twice as far from the CG, it only talks HALF the weight to balance it. Ever seen a teeter totter where a big kid sits halfway up his side while the littl kid sits all the way at his end? They can still go up and down. The lever principle is why.Now besides balance how does this affect flight characteristics. Well, it's simple.
Take a 1 pound piece of pipe, fill the length with 4 pounds of concrete and swing it in an arc. Try to stop it. Now take a one pound piece of pipe of the same length and put a four pound lead weight on the end of it. Swing that in an arc and try to stop it. Get the picture?
You can have a plane balanced perfectly. The CG is right where it should be (here's a tip from Tailslide. The CG usually is even with the midpoint of any bomb mounts). You take the plane up and pull hard on the stick, but not too hard. To your suprise, the thing goes into a spin like a wagon wheel and you can't pull out. Typically, you have too much weight concentrated in the end of the tail.
A quick note, don't think puling all the weight to near the center will solve your headaches. Now you have a plane that responds like a dog. Some of that weight out near the ends is used to HELP the plane turn or roll.
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Which end does the propeller thingy go on?
(Formerly posted as Da Jug head)
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posted 05-10- 07:08 PM
