I do not know what wheel size you are using going to a 3 or 3 1/2 inch may help ( sort of bush plane type) I do this with myVMAR apache 2s with a irvine 40 diesel flying off a rough grass field, and oher consideration putting a diesel head on the LA 40 i t turns into a bear when converted thse are excellant engines but to go from mild to great on diesel running a 12x5 or 12x6 will give you the thrust to get it uo martin