CG on EDGE 540 is VERY SENSITVE
04-29-2004, 11:53 AM
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CG on EDGE 540 is VERY SENSITVE
I have a scrtch built profile Edge 540. It is powered by a .15 and has a 40" WS.
Someone on RCU caluculated the CG for me and I used it in balancing the plane.
The plane with full 2 oz. tank flies fine but whern the tank is near empty it gets real sensitive
on the elevator and also requires elevator trim adjustment. Is this just a CG problem?
If I move up the CG will there be any other bad tendencies?
Someone on RCU caluculated the CG for me and I used it in balancing the plane.
The plane with full 2 oz. tank flies fine but whern the tank is near empty it gets real sensitive
on the elevator and also requires elevator trim adjustment. Is this just a CG problem?
If I move up the CG will there be any other bad tendencies?
04-29-2004, 12:49 PM
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RE: CG on EDGE 540 is VERY SENSITVE
It sounds like it may be related. Try doing a dive test. Trim for hands off level flight at about 1/4 throttle. Dive at a 40 or so degree angle. Then release the elevator stick. With positive stability the model will slowly pull up the nose. If it's dead neutral it'll keep diving on the same line. If it's behind the neutral point it'll tend to nose down to a steeper dive. Do the same test with a full tank and a close to empty one. The elevator trim for level flight will change between the fuel load.
Other factors.... 3D models DO fly on the ragged edge so they can hover and 3D easier. That makes them twitchy in the extreme. To compensate you can program in more exponential and also fly slower. Control response is greatly affected by flying speed. A totallly unstable model can still be flown at very slow speeds even if the pilot would be totally overwhelmed if it was flying a bit faster. The key is complete throttle management.
Other factors.... 3D models DO fly on the ragged edge so they can hover and 3D easier. That makes them twitchy in the extreme. To compensate you can program in more exponential and also fly slower. Control response is greatly affected by flying speed. A totallly unstable model can still be flown at very slow speeds even if the pilot would be totally overwhelmed if it was flying a bit faster. The key is complete throttle management.
