Hello All, I am designing a small Mil-spec power generation system and I wanted to ask opinions on which energy transfer drive I should use. I am currently calculating speed and torque reductions so I have not reached a final ratio yet. My design will most likely take low rpm and increase it to a higher rpm at the generator. Ive been looking at using two aluminum gears mounted on bearings in a housing (gearbox) or very small sprockets with a stainless steel roller chain. Which system is more efficient? If I were to use the chain drive would the losses due to friction and mass normally be much higher? If the generator is mounted below the power source vertically, will the normal force on the side of the chain moving in the direction of gravity, cause the climbing side of the chain to become more weightless as far as work required to pull it upward? Any opinions appreciated.