Design question

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Well-Known Member
Jul 23, 2002
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I am trying to design a boost glider (piggy back type). My question is, how do you calculate or adjust for the drag so that the model stays stable through impulse. This might sound crude, but can you basically eyeball it? What I mean is, assuming everything else is correct.if insure that the drag signiture is the same on both sides of the sustainer, is this enough?

This could lead to a kitted product...moderators, please move if I put this in the wrong spot.


Well-Known Member
Feb 22, 2003
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If you look at the Quest Shuttle Intrepid, the only area that has a "mirror image " is the larger vertical fins on the rear of the Sustainer, with a single large solid fin underneath.

It seems to me that the piggybacked glider in this case actually seems to stabilize the sustainer until apogee. I say that because looking at my finished Intrepid, the outer vertical fins of the glider mirror those on the sustainer's outer rear edge.

Is it enough to ensure the drag signature is the same on both sides of the sustainer ?

I'm betting that the glider does indeed help to ensure stable flight, so the obvious answer is to build a test vehicle, launch it without the glider and see how she reacts. If shes stable without, then odds are she will be stable with.

Again though, I'm guessing here and don't have any proof that this theroy is any more than pure hyperbole. This is a very good question, and one that needs more investigation.

Please keep us posted on your findings. 8)