Good morning and thank you all once again...sure because , after joining in to MBMH, i could learn ample of things from many authorised persons...once a three screw craft was my nightmare because of ignorance in maritime technology. my research subject is aeronautics. now i am too proud and happy, because i have some good friends and guidance from MBMH.and in to subject... all propellers are hand made..i purchased 1 square feet of zink sheet from a bus body building material supplier shop, and drawn three circles by a compass.then divided it in to 120 degree each, with a protactor,from an school geometry box, then cuts in to shape with meat slicing scissors.two of them are angled with a rounded nose plier towrds out, and centre one spins with the adjoining one. i do not have any outlet for motors here, so i searched in a scrapyard and found some toy motors, and rewinded its armature for a 7.5 volt. i replaced its back plastic cover with brass bushes, taken from old walkman capstan assy. all three motors drawn only 800 Ma, so with a 3.2 ah battery, in to 7.5 volt, nimh, telephone battery, it runs more than an hour...without heating up motors...i used a toy rc for it, from an rc helicopter, and works nice...speed controller made from a toy gear box,one spins a volume controller , one controls the base bias of power transistor.i will post all my prooven circuits here...motor speed controller, rudder, thrust pump controller..all...