I got around to looking at the manual and the C.G again tonight on my Great Planes Super Sportster 60 after noticing the other day that it wasn't as far forward as it was before I covered it...

If I look at the manual, it says that the acceptable range is 30% - 36% of the total wing chord. For the 60 size, measured total wing chord is about 11.3" or so. This would make the balance range between 3.3" and 4.1" (manual says between 3.3125 and 4.0625). Without the battery/receiver mounted in the plane, I measure my C.G. at 4" back from the leading edge.

This being the case (just barely falling within the acceptable range) without the battery and receiver in, would you just mount the battery and receiver as far forward as possible (basically at the leading edge of the wing) and then call it good? By that I mean not mounting additional weight up front??? I know that the C.G will move a tad more forward just from the batter and receiver, but it really doesn't move it that much in mine.

The manual would suggest that the position is fine, but it also says to reduce the elevator throw to 3/8" U/D.... well, my elevator throw is as small as possible and nearly double that. (I do know another person with a SS60 that has nearly an inch U/D and I think nearly the same C.G location - but I didn't actually measure it on his). Another note if it makes a difference is that his weighs about 7.5 lbs whereas mine is at 6lbs.

I do have dual rates on my radio so I can make sure that they are toned down on the maiden flight.

Thoughts anyone? I would love to know what you would do. I could definitely move the C.G even further forward by adding weight to the front, but there is no easy way to bolt weights on to the front. I can definitely epoxy them in, but I have a minor fear of the weight(s) breaking loose, if not bolted, especially now that the engine compartment has been painted (fuel-proof).

Thanks...

for me I'd set the batt and rx so that my CG came in at 3.5 with is mid way of the range for the test flight. From there you can decide which if any direction you wanna go

Doug

I would be content with 3.5", but I don't think that even with the battery and rcvr as far forward as I can put them (leading edge of wing), that I can get there.

I guess part of me is also asking because so many really say to not add weight if at all possible. Once I get the rcvr and battery in foam, I will check it again and post where I am at.

If your plane is balancing at the rearmost advised CG location without the battery, and of course with an empty fuel tank, I would think you'll be ok if you put the battery as far forward as possible. Get as close as you can to the recommended control throws for the maiden flight, and adjust from there to suit your flying style and preferences. Just make sure the CG isn't behind the rearmost recommended location, else as I'm sure you know, your first flight could be a handful. Good luck and enjoy!

Well, I never set it back up to measure it. I knew it would in the range, so I just left it where it was and took it up today... It flew great!