View Full Version : center of gravity question??

macro heli flyer
04-27-2004, 10:29 PM
should the cg for the heli be exactly in the center rotor shaft, or should it be a little nose heavy.. I read something on that somewhere but cant remeber where... also I have a 2700mh 4cell bat to charge , I have a mrc supper brain charger but the bat says slow charge for 13 hours at 270ma . does that mean .27of an amp? and fast charge at 1350ma my charger onl;y goes to 4.5 amps....

04-28-2004, 06:02 AM
I believe you want the C/G under the rotor shaft. If someone else thinks differently, I'll learn something too! :D

As to the charging rates...

First: 1000mA is 1 Ampere. Or put another way, 1 mA is 1/1000 of an Ampere

To charge at 270 mA is correct at .27 of one Amp

Fast charge of 1350 mA would be to charge at 1.35 Amps

If your charger goes to 4.5 Amps, then it goes to 4500 mA

Your probably have a 4 cell 2700 mAH battery. This means that the battery should be able to supply 2700 mA for an Hour (this is what mAH means, it's MilliAmpere's per Hour). Of course, it should be able to supply more current for less time, or less current for more time. For example, if you had a 5.4 Amp load (or 5400 mA) the battery should be able to last for 30 minutes. You are drawing twice the rated capacity of the battery, so it should last about half the amount of time. It's not a perfectly linear scale, but this should give you the idea.

Does this help at all?

04-28-2004, 07:37 AM
You "can" fly with vertually any CG, but when you start flying inverted you will find that "centered" is best :)

macro heli flyer
04-28-2004, 12:48 PM
:lol: thanks Rich for your imput it really appreciated.. thank god there is sites like this, or eles i would be in big big trouble,, rob.... :glasses2: