BrokenChild
01-25-2002, 06:12 AM
Ok, I have herd that the farther the servos are places out on the wings, or the heavier the wings are compared to the fuse, will add a negative effect on the airplanes flying characteristics. True to an extent. I have herd that the amount of rudder under the datum line and above can be devided to give certian effects on mainly high speed and 3D type plaines... Herd the diffrent percentages on diffrent types of models for wing:stab this control surface to another...ect, ect. Would a really light weigh airplane, act funny if all the weight (ie: battery pack and motor) was offest a large amount on the datum line? I mean if most of the airplanes weight was the battery, would this effect the flying abilities? I cant really get this question out, but if you understand, then please reply...
~nate
Richard Miller
01-25-2002, 01:03 PM
Nate,
I think that you've enmeshed in the phenomenon of mass moments of inertia. General rule, if you want a maneuverable airplane, as most of us do, is to keep the mass as close to the intersection of the three major axis as possible. That's what Mr. Sopwith did with the Camel, and exactly for the reason stated.
Imagine the wings represented by a spanwise line. The center of gravity of the mass of the wing half-span will be, let's say, 40% of the distance between the the CG and the tip. This is the L in the L-square, its the length which, multiplied by the mass - that of the half span, gives an indication of the resistance to displacement.
Or, you're holding 10 pounds at arm's length. Arm is 2 feet long. Force needed to displace the weight =X. If you arm were all of a sudden, miraculously 4 feet long the force needed would be 4x, and the response accordingly that much slower.
L [length] -SQUARED!
Got it?
-Richard