Center of Gravity

[FredStork 453]

The recommended CG for the Avid flyer model C is, if I'm not mistaken, forward limit 11.185 inches and aft limit 16.5 inches from the leading edge. (I have a hand written note on the cope on the manual I have saying "19.0'' STOL wing Dean Wilson". Not sure what that is worth..).

Being nose heavy is a common problem for the Avid Flyer and I assume many of us are flying close to the forward limit. While that is not a problem I was just wondering how efficient this is. We compensate a forward balanced plane with engine and/or elevator or trim.

Would we gain noticeable performance/fuel reduction with a better initial balance (say in the middle of the advised CG range)?

Any thoughts, experience, expertise on this?

I have a Model C HH, and unless I go on a long comping trip with a  lot of luggage I will always fly close to the forward limit. And I do have a permanent trim force on the stick...

Regards
Fred 

[BryceKat 125]

Hi Fred,

My MKIV flies MUCH better the further back the cg goes. The cg on mine originally started off at something like 8.45" and the forward limit is 8". The airplane flew ok with anything above 80% power, but reduce the power and it glided like a brick, it was scary!  Dean Wilson told me to move cg back .5" at a time until There was no improvement in flight \gliding performance by adding weight to the handles on the tail. He said he tested the cg to 21" and the airplane was controllable. On mine, it's about 14.5" now.  My battery and elt are mounted in the tail and I also add 10 lbs back there.  The Avid glides much better and flies a lot better! Good luck, Bryce

[Knuckledragger 135]

How, with regard to the fabric, do you move the battery into the tail end of the fuse?  I think I'd like to try this as well.  I can relate to your description: "The airplane flew ok with anything above 80% power"  I also find that I have to add a lot of down elevator trim to fly level at higher power settings.

is it major surgery to open up and move the battery back?