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E-Flite Mystique 2.9m ARF
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Dec 03, 2012
, 09:41 AM
Joined Jan 2007
Originally Posted by
Tail heavy as compared to the specs or tail heavy based on how it flies? In general, tail heavy is bad, but that is based on how it flies, not on specs.
SETTING THE CG
This has been mentioned before but is worth repeating. The starting CG setting on most gliders is a recommendation, not a law. That CG setting should get you safely into the sky. Then you tune.
My experience with most gliders is that the "stock" CG is a bit more forward than I prefer. But I still start from that point. It is best to work the CG back, over many flights, to get the best trim. What will work for me may be too rearward for you.
People post their CG settings, but if it is rearward of the stock CG, and you are not an experienced glider pilot, you may not want to start that far back. Just a thought.
I have flown gliders of very accomplished pilots were the CG is so far back I found it hard to fly the glider, but they loved it there. I have flown other contest gliders where the aircraft seemed nose heavy to me, but they beat me with that glider every day of the week because that is what worked for them.
Start with the specs, but leave room to adjust, usually rearward. If you put lead in the nose or tail to get the stock CG, leave some of it as easily removeable so you can tune the CG based on flight performance or based on your personal preferences.
If you are set up for electric flight and have several battery packs, weigh them. If your battery pack is not right on the CG, you may need to strap on some lead to even them out.
Guys, to save you some time I did a lot of C of G testing. Furthest back I ran was 122mm, and furthest forward was 117. 120mm seem ideal for me. As for the position on the wing being a long way back, it's not back that far, it's around 28% of AMC, remember it's a swept back wing, wing sweep effects the physical position of the C of G.
Camber settings. Speed 1mm up. Cruse level TE, Thermal 3.5mm down. Again lots of testing was done to obtain these settings.