how much more weight can you add to a plane if she is very tail heavy, mind you the plane was built properly besides the balance situation. the plane weighs in at 5.8 pounds. its a 40 size from great planes.

How much weight does it take to make it balance? Have you tried shifting the battery and Rx forward?

yia everything i did is properly set up, this thing is just way to tail heavy. probably a tail of a great white!!!!

There are crankshaft weights available in up to 2 oz. They go in place of the prop washer. A 2 oz weight on the end of the crankshaft should be ABOUT the same as 3 - 4 oz on the firewall.

FWIW - 5.8 lbs is pushing it for a 40. A 46, or better yet a 53 2 stroke would be a lot better. You may also want to investigate a 70 - 80 4 stroke. In your case, a heavier engine would be better. If you have to add weight to balance it, make it useful weight. You might also try using an 1800 mah battery instead of the 600 mah battery (again, as far forward as possible).

Hope this helps.

You could also try moving the engine forward on the mount if there's room. That will shift the CG forward without adding weight.
Dennis-