TP 4050 1950kv on 6s

[danzuby]

Greeting everyone I'm thinking of a new motor setup for my cat hull, I have a seaking 180v3 and using max amps 6s batts 8000 mah 150c, was looking at TP 4050 1950kv turning an x642, I have seen some of you warn against anything more than 1700kv when using 6s. Can anybody give me some insight on this subject? Please help.

[R2315]

What hull? this thread may also be helpful: https://forums.offshoreelectrics.com...58811-Motor-kv

[danzuby]

What hull? this thread may also be helpful: https://forums.offshoreelectrics.com...58811-Motor-kv

Cat hull 39"

[danzuby]

Ok thanks for the link to the chart guess that answers my question. I didn't know if anyone was pushing the envelope or not. It looks like my choice will end up being the TP 4050 1700kv. Thanks for your time.

[danzuby]

The one thing I still wonder about in the chart is are the rpm rating are they load or no load?

[R2315]

No load, Fluid mentioned to Multiply by .85 to obtain closer to "real world" rpm.

[R2315]

You can even get a lot out of 1500kv on 6s, depends what your goals are really

[danzuby]

No load, Fluid mentioned to Multiply by .85 to obtain closer to "real world" rpm.

I found boat calculator at radiocontrolinfo.com that allowed me to enter motor kv, cell count, hull type, and specific prop size pitch and manufacturer
which gave me the speed, load rpm which came out to 32,000 rpm roughly. Really nice calculator, I know it probably not dead on but I'm sure it's pretty close, hopefully someone else can get some use of it as well. Thanks again.

[danzuby]

According to that calculator 1700kv on 6s will give me 56mph with a x642 and if I go to an x645 I can be around 60mph, I think I will be happy with that it puts me in the high performance range and with a 39" Cat hull I think that will good balance of speed and run times.

[Peter A]

X642 is a small prop for a 39" hull, not very efficient. You may be better off with 1250 kv and a bigger prop 47-50mm.

[MarkF]

That's a small motor for a big cat. I run the 4070 1570kv in my 38" rigger and get 80 mph with an ABC 2215 prop. You can run a 2116 in your cat and probably get close to that and not burn stuff up. I would use the swordfish 220X esc as it is a very good controller for 6s. A 1250 kv motor with a 52 to 55mm prop would be an even better choice if your not looking to go 80 and will be happy with 65 to 70 mph. If all your looking for is 55 to 60 mph you can do that safely with a 4s set up.

Mark

[Mxkid261]

I agree with Mark I think I would run a larger can than the 4050. I have the 4060 in a 32" cat. I would go with the 4070, they stock a 1220kv which would probably be a good option.

[danzuby]

I get 56 mph and 25 minute run times with this setup, how much more efficient should I be? My plan a this point is to upgrade to the TP 4050 1700kv and spin an X645 which will put me at 60mph and I'm guessing will cut me back to 18 minutes run time. I'm trying to stay out of the SAW range.

[Fluid]

I get 56 mph and 25 minute run times with this setup....

This is of course a big can of applesauce. The average amp draw would be just 17 amps, which would bearly get the boat moving. Obviously if the time is accurate (very doubtful) then a lot of time is spent dead in the water (or the prop is badly cavitating and not reaching 56 mph most of the time). Too, 56 mph is not at all fast for a 6S cat, the OP could go faster with a much lower Kv motor and a 50 mm or larger prop. A 45 mm prop is too small and inefficient for a cat that size.

But the OP knows best, good luck to him.


.

[T.S.Davis]

Wow. 25 minutes! The gas guys can't even run that long.

Dan, why's ya ask if you already have the answers?

Maybe it's a spring thing. Every spring we hear about high kV setups with tiny props and how great they are.