19/02/2018. U39. 15" 220g. Twin Spring Motor/ Diving Tinplate Clockwork Submarine.
I developed the twin spring motor to have the same power output as a much larger motor but in a smaller unit, therefore the boat could be smaller. At only 15", U39 is a bit of a Minnow in comparison to my other stuff. The downside to this is duration, I think of it more as a rocket motor (horrendous power for a short time) the motor only runs for about 20 seconds, however the huge power drives it along like a torpedo for around twenty feet. I have to say its an hilarious beastie in the water and the reactive propeller torque causes the whole sub to twist starboard for the first ten feet of the run. All said and done a superb compact boat that looks really good on the surface and even better underwater.