Three of these 40mm jetdrives with 56104 790kv 12s6p for a total thrust of 465N I calculate a target 60kmh at 35k nominal RPM, total watts 7700/motor for total 31.28 HP, and 4.81lb/ft torque
I figure I could save on the jets at $33 each, the 56104s are around $100 each, the ESC would be the most expensive.
Beats dual drive with 50mm $136/jet with 56123 motors at $200 each.
or 3 50mm jets https://www.aliexpress.com/item/4000643150931.html
with thrust of 17kg each, that is 500N force. So should be able to reach almost 40mph or 64kph speed. kv500 or 790 not sure at 12s
marginal cost increases by $180
You won’t need 56xxx series motors for the 40mm jet pump, you can go with 40xx 42xx series motors, from my experience you can go up to 1000kv, it’s a RC boat toy grade jet pumps. Forget about 60kph speed you need around 20kw to get there, that’s a lot of work, if you go for a triple-jet setup you gonna spend a whole year to finish your project.