Bit late on the drift now so may as well finish off. The J3 Cub 'as was' with its A65 hp cont was in fact perfect for Army use and the equivalent of an airborne jeep. In fact I am a big fan of the A65 as a no nonsense unit. Like the Merlin the reduction box on a Pobjoy is the final piece of the power train even though the Pobjoy version is probably rather over engineered (good job to).