Centre of Gravity Jig - design suggestions please

[wgt40w]

Can I have some practical design suggestions for a c of g jig to use on a Trex 600 Electric - please.

Was thinking of using the 'hooks' from 2 metal coat hangers, spaced apart suitably for the flybar, fixed to a piece of wood that could be laid across two back-to-back chairs / or hanging from the shed roof beams.

[xygax]

How..

do yo u check the CoG on a FBL... ! there would seem to be a vital componant missing .... a flybar !

[sacko]

Pull the heli up by the grips, so the blades are against you.

If the nose goes toward the floor, its nose heavy..

[pgkevet]

..or a roller under the skids..or if you're really as anal as mate Ivan you pull the head, drill a hole in a wall or chunk of timber..shove the main shaft in it and teeter the whole thing!!!

[ModelGuard.Com]

best way is to clamp the head in a vice with the main shaft horizontal. Then undo the lower jesus bolt and remove. This method is the most accurate of all. If you dont beleive me then try this experiment.

get the heli perfectly balanced using the hang method or skids bar method, then place a one pound coin on the tail end of the heli and note how much difference this makes, it will tip the heli by probably 2-3 cm

try this with the clamp head method and the tail will drop by a good 10-20 cms


Edit.. just noticed the last two posts say the same thing, removing the lower jesus bolt enables the heli to move freely and not bind on the motor.

[wgt40w]

Somehow I don't fancy trying some of these suggestions.

[Steve]

Get a little bubble stuck on the tail boom with blue-tac with the heli on a flat table, and adjust the blue-tac so that the bubble is in the middle.

Then put the grips across the the heli (assuming it's flybarless) and use two pieces of thin slotted between the head block and the blade grip on each side to pick it up off the table and watch the bubble move, or not move with any luck.

Same technique with a flybarred heli, except you don't need the wires. Just pick it up by the flybar.

Much easier than lifting the whole heli onto its side or taking the head off. Keeps the heli flat on its skids and less prone to being dropped.

Even simpler - don't bother with the bubble and just eyeball the skids against the table surface when the heli is lifted a few mm off.

[wgt40w]

Thanks Steve - your suggestion will be acted on (yes it has a flybar)

[Steve]

You could even set up the bubble on the head button so that it doesn't affect the balance of the heli, not that it really does anyway. But just for peace of mind.