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Glider c of g

Vertigo

Junior Member
#1
Hi all,

I've recently made a glider out of cardboard. It is just meant to be thrown, but the problem is that it is really tail heavy and I don't know how I should change it to fix this. More specifically, should I move the wing forwards to move the wings forward to transfer weight, or should I move them backwards to put the c of g behind the center of pressure? Preferably, i would not like to add any additional weights to it to change the c of g. Any help would be greatly appreciated.
 

g828

Stickman
#2
I would move the wing back. If I remember correctly moving the wings back would allow the CG in front of the CP which would allow the glider to be stable.
If that doesn't work, pictures would be nice as well :).
 

Vertigo

Junior Member
#3
thanks for the reply!! i will try moving the wing slot backwards. unfortunately the picture file of the glider is too large, but i have an exact CAD model that it was cut from. Screen Shot 2013-04-01 at 11.16.47 PM.png
 

Attachments

zev

lumpy member
#5
before moving the wing around, I would suggest moving the electronics as far forward as possible.

EDIT: idiot idiot me. its a glider! still, you can move the battery.
 

pgerts

Old age member
Mentor
#6
I have not seen any glider without the need of some "lead" in the nose.
Cardboard seems heavy compared to "normal" building materials but if your plane is built up then cardboard might be OK.
 

Vertigo

Junior Member
#7
i am currently using cardboard just for prototyping, however i plan to use balsa wood for the final version
 
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Vertigo

Junior Member
#8
i don't have any batteries since i don't have plans of attaching any control surfaces to it. i just wanna get a good glide ratio
 

zev

lumpy member
#10
usually they say the COG should be about 33% behind the leading edge of the wing… a good place to start anyway.
 

pgerts

Old age member
Mentor
#11
I assume that 33% is good for a fighter or trainer.
A soarer might be good a little more aft.
The red line on the picture seems way to far back.