Shape of the craft has little or nothing to do with stealth, in terms of drones. UAV's emit very little heat signatures, so the aerodynamics really do not matter much anyways. It'd be better if you researched stealth in detail; may be then you would understand the purpose of special aerodynamics.
And yes, propellers produce less heat than jet-engines, which definitely makes the drone more stealthy. American Reaper and Predator UAV's, along with most others in the world, also use propellers. I don't know what you are trying to get at, but it sounds pretty stupid.
heat signature and stealth? wow! you think stealth is by low heat signature? my GOD! awright man....tell me when you've read something about stealth and we'll engage.