actually the LT 40 in our club (the club trainer) when at a normal throttle it will fly level and handle great but when just going forward without a turn if full throttle is given it will start climbing as if up is given but actually I believe it is the angle of attack on the main wing, Designed like that for the extra lift for the newbie learning to land, Wich I believe is the attitude xavier is refuring too. You could try putting a shim under the back of the wing but only put 1/16 of a inch at a time to see how it handles but it will start needing more length for takeoff and need more speed for landing, AND will stall at faster speeds so just do a little at a time until it handles more like your looking for.

xavier is the maiden name of my friends wife, Wonder is there is a relation.
Just my .02
Dauntae