A friend of mine at work uses the adage 'what is the stupidest thing it could possibly be, start there' when trouble shooting, I find I should use it more often than I do. I've not been too satisfied with my GeeBee QED; it has had a tendency to pitch down at frequent but irregular intervals. Not severely down but it happens often enough to make you feel like you are fighting to keep the plane in the air. Since this is an EPP plane I was thinking the issue was due to the wings flexing sometimes. For some reason today I decided to try moving the CG a bit farther forward. So I added two quarters and two nickels to the cowling. And voila the plane is now stable.
The little Miles M20 is now flying well. Something about this plane, probably it's size, makes it of interest to the local crows. Twice now they have flown over to harass it.