Homebuilding a Scooter

[ben.mcgeever]

The motor in your picture looks physical big enough to give you reasonable performance. Its tough comparing motor specs, as just like scooters, as they are often over rated. Motor ratings also make assumptions about cooling, so if you have better cooling than the manufacturer assumed , like water, you can often significantly adjust performance.
My advice would be to test a lot, and iterate from there.
Make sure you have some sort of settable speed controller too, that way you can be less reliant on a single operating point. For example if your not getting the performance you want, but the motor is running cool, you can increase the battery voltage, lets say to 48v, but maybe at 48v the motor overheats immediately, so you can reduce the max allowable to where you get better performance, but don't overheat. I would switch to a brushless motor too, as you choice of options on both motors and speed controllers is going to be infinitely larger.

 

[tbone1004]

Motor ratings also make assumptions about cooling, so if you have better cooling than the manufacturer assumed , like water, you can often significantly adjust performance.
...
I would switch to a brushless motor too, as you choice of options on both motors and speed controllers is going to be infinitely larger.

Water cooling has got to be doing a mountain of benefit for the Blacktip. I know with the scooters that I've used and modified *silent submersions* that the water is really not doing anything. The motor is in an air space, which is then surrounded by an insulator with no fans other than the motor fins actually moving air around. I know the Genesis have the motors sunk into the tail which helps with cooling, the Blacktip is just straight up in the water itself, but with the "traditional" designs, I'd say they're actually providing a lot less cooling than the motor would normally experience.

Agreed on switching to brushless, the ESC options for brushed motors are not great. Extra advantage of going brushless is you can use your motor controller as a universal starting point while being able to use standard trigger options instead of sort out a variable speed controller.

 

[ben.mcgeever]

Yep, scooters with plastic tails are going to have next to no cooling. Also if you stick it up in mid air on a gearbox/ clutch etc, your going to have minimal cooling. You can make it work, but you have to have a larger motor than you might otherwise. That's fine for a lot of manufactures, but we probably cater to the travel market more than other manufacturers and so have always tried to push the limits of performance vs weight.

On the original Sierra we have an AL tail and mount the motor directly to it, The CUDA we sunk a bit deeper in the tail to make it better, The Piranha we have a big heat sink between the motor and the side wall to connect it thermally to the water (which works well) and Blacktip we just said Fu&^%% it and stuck it directly out there in the water, which obviously works the best

For a home builder this is going to be tough, but optimally you spec the motor to have your desired operating point be close to peak efficiency. You have less heat to deal with, and make the best use of your battery.
When your testing things, try to only change one variable, as it gets confusing fast, experimenting with props can drive you crazy, if you don't get a handle on all the key info. A new prop design may superficially use less power, but be worse, as it might have just changed your motor operating point to something that's more efficient.