With ROG launches, it doesn't take munch of a "snag" from a blade of grass to cause the plane to cut across the circle. The other problem is running the engine so close to dirty ground. Hand launches don't need to be so....vigorous that the engine gets fuel starved. The problem a low time pilot has with hand launches, is typically jerking the handle to "full up" and stalling the model. It really does help if the pilot adjusts the control linkage so that "full up" with his handle only produces 15 degrees of elevator movement from neutral. I doubt a plane that is balanced at 15 to 20% of MAC could make use of much more than 15 degrees of throw before the elevator becomes a "drag brake".