What are safe motor rpm?

[JCAustralia]

Hi guys

Can you please tell me what are the safe rpm for sport boating?

A friend of mine told me up to 40,000 rpm should be fine. Could push it to 45,000 but no more than that......

Anything below 40,000 rpm should safe to the motor

I do mainly sport boating and longevity and durability of my motor is more important that going faster.

Also would a low rpm like 15,000 damaged the motor, esc or battery?

What are your opinions on that?





Thanks a lot.

JC

[siberianhusky]

30,000 rpm aprox.
45,000 is out to lunch! Does he actually run a boat?

[photohoward1]

Depends on the Motor and how well it's made. Most High end Motors are good to 60k. Also the speed controller is only good to a certain RPM. A controller might be able to switch a 2 pole motor up to 100k, but a 4 pole motor to 50K and so forth down the line.
remember also the faster the shaft spins it creates more friction. I try to set up my race boats for about 25-30k. sport running a bit less.

Good luck don't push it to far.

[Fluid]

A friend of mine told me up to 40,000 rpm should be fine. Could push it to 45,000 but no more than that......

Your friend obviously has little FE boating experience. While most quality motors can spin 40,000 rpm given enough voltage, it is a poor idea to do so for any length of time. Straightline racers will run their motors to 40,000 rpm, but only for a few seconds at a time. Unless the boat is moving very fast, that rpm is very inefficient for the props normally used for sport boating. Motors will heat up rapidly at that speed if run like an oval or sport boat. Motors set up to run at that speed are usually very sensitive to prop loading and boat setup - a small change can drop rpm into dangerous amperage draw levels.

A good guideline for beginning FE boaters is below. You can venture outside those ranges, but I'd not stray far without being very careful.

Sport Boating - 20,000 - 25,000 rpm
Oval Racing - 25,000 - 30,000 rpm
SAW Running - 35,000 - 40,000 rpm

.

[JCAustralia]

Thanks all for the expert opinions Always a pleasure to hear from experienced boaters here.


I've got a Hobbyking 2700 kv motor that I was running on 4s. ESC is Turniguys 180. Boat (Aeromarine Challenger) was flying but motor got hot. I stopped before things got too hot

http://www.hobbyking.com/hobbyking/s...idProduct=5146


I used to run on 2 6cell packs NIMH batteries but since switching to Lipos the difference has been huge But also my stress level that there might be component failure I'm 100% sportboater and speed is not my main aim...... The feeling and fun of running a boat I built is just so fantastic......

I'm now considering running on 2S instead with that motor. Max RPM would then be 19980. Not contemplating 3S at the moment as all the Lipo packs I have are 2S.....

Is that a good idea? Thanks

[blackcat26]

Jerome that motor in that big of a boat on 4s is too much boat for the motor size. I would recommend at least a "xl" length 36mm motor. Castle has some great deals on some closeouts that would be better suited for your application. Like the 1520. Plenty of power and better efficiency to keep the heat monsters at bay. You could run it on 4s 5s or 6s depending on how much you wanna haul.