I want to build a drivetrain for a pedal boat. The turning action of the pedals is to be transferred by a 90 degree turn to a driveshaft with a propeller.
Now I’m weighing the pros and cons of using two steel gears against putting a rubber wheel at the end of the driveshaft and let it rest against a revolving, wooden disk, driven by the pedals.
Which of the two systems, do you reckon, would result in better efficiency?
I need this thing to turn nice and willingly.
The boat is a canoe, and I hope to commute with it over a stretch of water 8 miles long each way.
forget friction think traction. . . you need steel gears
The steel gears have less friction, though you would need friction to get the rubber wheel to work. Favios has got it right. . . there are so many more problems that can arise with the rubber wheel and the wood, though it is a good idea. For reliability and durability, stick with the steel.
I would say the steel gears have less friction because the force they “feel” is just plain force and little friction. On other hand the mechanism of movement between the rubber wheel and the wood relies very much more on friction.
I think you can make the revolving speed of the propeller more controllable with steel gears.