inboard or outboard

[Gavin D]

Hello all

I have a model that gives the c of g position as measured at the wing tip if I translate this measurment to the fusalage and balanced it there will get the same results as if it was balanced at the tips, the wing is tapered

Gav

[Don Fry]

Yes that is fine, take a line from the tip banance points, and that line represents the balance point anywhere on the line.

[Bill_B]

It annoys me when ARTF kits give the wing tip as a measurement for CG, it's just a right pain as quite often a straight line can't be taken from wing tip to wing tip as the canopy, or fuselage is in the way.

[Steve T]

With you on that one, trying to gauge the line without actually marking the model, in the end I gave up and stuck little c of g stickers near the fuselage, but sometimes retracts mess that up, I don't like to balance at wingtip, I made a frame from a base and nice 'almost' pointy dowels.

 

Edited By Steve T on 19/01/2015 13:26:08

[Gavin D]

Thank's for the replys guys. Tried that Donald and the model balances ok at both points

Gav

[Peter Jenkins]

Don't forget guys, that the manufacturer's CG position can be wrong! Best to err on the safe side for the first flight ie. a more forward CG than published and see how it flies. Don't be afraid of moving the CG around until the aircraft flies well. If it's twitchy then keep moving the CG forward by small amounts until the aircraft feels nice and solid but not overly stable. If it's very stable and a bit nose heavy, move the CG aft by small amounts until the aircraft flies the way you'd like it to - nice a stable but nicely manoeuvrable.

CG position is the most powerful trimming tool available to us modellers. Don't forget to use it to check out if your aircraft is flying as well as it might - but do it a little bit at a time!