CG Centre of Gravity

ZACATTACK wrote: When your setting up your CG on your control line plane....it should be done with an empty gas tank, no wing weights in place and your motor installed. Is this correct?? Am I looking for an level aircraft? Should it rotate forward a touch? Any help on this you guys are familiar with is greatly appreciated.

Empty tank, yes, everything else installed, yes,including things like tip weights.
The model should be in a ready-to-fly state, don't add anything after you have checked the CG (unless you need to add weight to correct the CG)
Check the correct position for the CG from the plan, the model should balance level if supported at the indicated point.
If the CG is FORWARD of the correct point the model will fly but be less responsive to the controls, if it's BEHIND the correct point the model can easily be so unstable as to be uncontrollable. So, nose heavy, OK within reason, tail heavy, no.

Wilf

Hello Lew, if this is in regards to your latest build, I would make it nose heavy for the first flight. A nose heavy combat wing gets to fly another day while a tail heavy wing is uncontrollable and will ultimately leads to a crash. Another good piece of advice is only put enough fuel into the tank to get it running on initial flight and release even if it's only for a few laps.

I'm not sure how you installed the engine, but in the event you used blind nuts you could install longer engine bolts and attach weights to one of the screws temporarily. My initial flights, I try to balance the plane about 1/3 of the chord. This is generally if not right on where the first lead out guide exits. In the event you balance there, the end result usually lands you nose heavy and is a good starting place.

This is a thin winged plane and needs speed. Keep in mind, a wing is going to fly all over the place until the speed gets up and this could take half a lap. The tendency to overcontrol at this point must be eliminated. All controls should be slowed to their max. meaning pushrod in the furthest hole on the control horn from center line of pivot. A handle with a close line spacing as well. The plane will initially fly like a brick but all of these can be adjusted out on the succeeding flights. Ken

So you guys are saying to complete the monokote add the necessary wing tip weight recommended by the plans and then check the CG ???

ZACATTACK wrote: So you guys are saying to complete the monokote add the necessary wing tip weight recommended by the plans and then check the CG ???

Yep Lew, cover it and do it fully ready to go minus fuel.

Absolutely, what they said. Balance it in a ready-to-fly condition, minus fuel. I like mine to rock nose down a tad rather than hang level. That's how I fly all of my planes. I usually press a couple of tiny fingernail marks in the wingtips for checking balance. You can't see them but you can find them and hold it securely with your fingernails to check. That might be weird.

Thanks Guys!!

RknRusty wrote:Absolutely, what they said. Balance it in a ready-to-fly condition, minus fuel. I like mine to rock nose down a tad rather than hang level. That's how I fly all of my planes. I usually press a couple of tiny fingernail marks in the wingtips for checking balance. You can't see them but you can find them and hold it securely with your fingernails to check. That might be weird.

Hey! Whatever works. I usually use pins pushed in a good bit at the CG point and balance it with them resting across 2 bricks.

cribbs74 wrote:

RknRusty wrote:Absolutely, what they said. Balance it in a ready-to-fly condition, minus fuel. I like mine to rock nose down a tad rather than hang level. That's how I fly all of my planes. I usually press a couple of tiny fingernail marks in the wingtips for checking balance. You can't see them but you can find them and hold it securely with your fingernails to check. That might be weird.

Hey! Whatever works. I usually use pins pushed in a good bit at the CG point and balance it with them resting across 2 bricks.

I use pins too in the shop, but if I'm making field adjustments, I have ready made notches to hold it for a quick check in case I want to adjust it. My marks are less than a millimeter deep on the underside of the wingtip so it's easy to find and hold while I see how she hangs.