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Old Oct 12, 2012, 08:41 AM
bwill6 is offline
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United States, CA, Tehachapi
Joined Jun 2011
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Originally Posted by GaryO View Post
For those of you who say it's the CG that effects the climb, do a simple test. Add 10 g to the nose and throw. The plane climbs the same. The glide of course will be effected by the weight.

Now add some up elevator. The glide will smooth out, the throw will go over the top.

It's the elevator that controls the climb. If not, then our pre set would move the cg.

Agghhh. It's sort of like chicken and egg.

I'm surprised that Phil Barnes hasn't chimed in by now.


Sorry, it's a completely un-necessary post.
I can tell you with absolute certainty that a more forward CG causes pitch up on launch IF THE ELEVATOR IS TRIMMED FOR A FLAT GLIDE AT NORMAL SPEEDS. Yes, the theory is sound. Yes, I have experienced it. 1 year ago I was flying DLG with a TX that was incapable of programming a launch preset. I was able to make up for it by using a more forward CG. I often had to manually give slight down elevator at about half to three quarters of the way up the climb to keep it from going inverted, but it worked. Once I got a better transmitter, I moved the CG back to where I really liked to fly it and I set up a launch preset. With the elevator trimmed for a flat glide, the DLG would go straight in whatever direction I pointed it on launch. I didn't measure it, but my launches seemed to be higher, too. Note that that last statement was purely subjective. My perception of higher launches could be completely false. However, CG certainly did affect the behavior of the plane on launch.

If your momentary switch is on the wrong side and you don't feel like doing surgery on your TX to move it, you can do like I did and use a rubber band to hold the switch you use in the off position. I still use this method today. Just make sure you change the rubber band frequently. I've had one break, leaving the launch preset turned on during launch (it'd been on there for like 3 months). Scared the bejeezes out of me.

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