Finding a gear supplier for a contra rotating boat propellor.

[sweeveldt]

I’m the new propulsion engineer in a solar boat team (something like this

https://energyboatchallenge.com/en/home-english/,

solar class). This year I have to design and build a contra rotating propellor. It will exist of an inboard electric motor (approx. 8200 rpm at 11.5Nm) and a right angle transmission under water (something like this toy

https://www.thingiverse.com/thing:3873918

). The diameter of the driven gears (blue in picture of toy) are crucial for keeping the drag down, a maximum diameter of around 60mm would be preferred. For efficiency reasons a gear ratio of around 2:1 to 3:1 would be optimal.

Problem is that our previous gear supplier (assag) stopped doing small quantities. I’m having trouble finding a supplier that supplies small quantities and meets our requirements. I’ve so far been denied by Köbo, Elsto and Atlanta. I’m already in talks with a few others but any tips would be welcome.

 

[Artisi]

Run the motor in reverse direction....

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)