Actually, it sounds like it's suffering from something that happens a lot with tricycle geared model planes.

If the front gear is shorter than the mains, the plane will have a stance that places the wing nose down. If it's too much, when the plane starts to accelerate, the wing builds up lift...... toward the ground...... and builds it more the faster the plane moves. Depending on the CG and a couple other things, the horizontal tail just might not overcome the screwed up lift vector.

Look at the airplane from the side. You want the stance to position the wing's AOA near the zero lift AOA of that airfoil. Designers want that so the wing won't adversely affect acceleration on the takeoff roll until the pilot wants more lift. That also throws less downwash at the h.tail so there's less pitch up generated until the pilot wants it, and he pulls some elevator to get it.