Hi Everyone,
I just finished a NitroPlanes Tiger Moth120and want to maiden it this weekend. I have a problem. The little instruction book that was in the box says the CG is 4-4.5 in. from the leading edge of the top wing. The manual that you can download from NitroPlanes says 5.5 in. Which is right? If it is 4-4.5 in I will have to add lots of weight. If it is 5.5 in. I will only add a few onces.

This plane went together veryeasy looks greatand is well made but the hardware sucks.

Thanks,
Truman

It should fly within those two ranges.

However always err on the side of safety, so move the C.G. forward as much as possible.

An easy way to do it, which is easily reversible, is to affix the battery pack directly to the engine mount, with servo tape and strong wire ties.

Fly the plane this way and see how you like it, then slowly move things back.

You could move the pack to the firewall next, or behind it, then close to the center of the top wing in the fuse, etc.

Thanks for the info. I set it at 5in. for now. I found another doc. that said 2.9 in back from the leading edge of the top wing with the plane upside down. I don't have a cg device so that may be interesting tomeasure without one.
Thanks again,
Truman

Do you mean 2.9" from the leading edge of the "lower" wing? That is, the wing closest to the landing gear?

As measured when the plane is upside down?

Yes, your right. It is the wing closest to the landing gear.

Ok, that would make more sense.

Normally biplanes have their C.G. measure with them upright, and the C.G. obtained from the center chord of the top most wing.

Hi opjose,
I maidened the Tiger Moth this afternoon and it flew great. The only problem I had, it was 100deg. outside today. Everyone in our club loved the plane. It flys so slow and looks good in the air.
Thank again for your help,
Truman