Originally Posted by
wikitjuggla
the center gravity is just barely tail heavy (prolly cause of the smaller engine) which my instructor said helps with take offs and I never have used the trainer flaps or air foils. Bought it used from another club member. Heaviest things i got in it are a 5s nimh battery stuffed behind/under the fuel tank and 1 metal gear servo for steer and rudder. Prolly don't need metal gear but its what I had lying around. The bottom of the wing is bubbling a little bit with the foil cover. Don't know if that creates excess drag or not.
Tail heavy is not good, while it makes the elevator very responsive, as Chuck points out it is an issue. Move the motor forward a bit until you get it to balance properly, spacers off of the firewall, or drill new mounting holes on the mount and move the motor forward. It wont take much to get the COG set properly.
The bubbles are not a big issue for a trainer unless the covering is getting very saggy then it be a good idea to hit it with a heat gun to get it tight.