|Nov 09, 2014, 08:58 PM|
United States, WA, Seattle
Joined Aug 2014
Forgive the naive question...I'm new.
I was reading this by G_T:
"The desired CG location is not a constant. As turbulence levels change, the optimal airspeeds change (the more turbulence, the faster, even with no camber changes and even with no ballast added). The optimal CG position changes as well."
...and it made me wonder: Has anybody played with trim ballast under servo control?
What possibilities would it open up in a top-level ship if you could move a couple of grams fore/aft from the CG? Wouldn't it allow for attitude trimming without deflecting any control surfaces?
|Nov 09, 2014, 09:40 PM|
Yes, variable CG has been done in F3B over 15 years ago, by Rolf Decker in Germany, I believe. The weight of and additional servo and the idea to move weights really did not provide an advantage. Decker also experimented with variable aspect ratios during flight and that too dis not give the advantages in flight one might expect.
In general, DLGers have found that if they did not add ballast in the wind that often just adding a penny to the nose helped immensely. Since this is a relatively quick change you could do it, if you desired, between launches.
It is better to know you plane as conditions change and rarely should you be second guessing yourself during a flight window.
|Nov 10, 2014, 05:09 AM|
even tested compressed helium in a steelbowel.
but it seems moving the bowl around did change CG to much
Often, only a tat (1-2g) of lead is enough, to change Cg.
But changing inflight, maybe is a bit too complicated and you'll end up with,bad settings for every kind of wind.
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