prop and motor setup

[rad35]

in a large boat 48 in. mono would it be better to use a tp 4060 1050 kv with a 69mm prop or a 1950 kv with a 47mm prop running on 6s. won't the bigger prop get the boat on plane better or will it be to much for that motor?

[ray schrauwen]

For a 48" mono you will need a motor that is larger unless you plan on buying a NEU or Lehner of approximately that size.

May I suggest a 1000kv SSS 56mm x 94mm on 8s2p with approximately 8000mah + min 40C rating.

These are very reasonable priced motors and run very nice. Sf240 minimum sf 300 is better.

You can also get a similar motor from Steve at OSE, a Leopard 56 x 84 or 56 x 94.



The large hull requires a larger motor to displace the geat

[rad35]

i am running a twin setup in this will that make a difference

[dasboata]

i am running a twin setup in this will that make a difference

You really need to give accurate descriptions of what your set up is,, so OP can access your set up for the proper advice I can't believe you failed to tell us it a twin

[rad35]

sorry guy's ya i should have added that my bad.

[rad35]

The way i understand this is the bigger props and lower kv gets the boat on plain with less amp draw i have 6's batterys so it may only do 40 or so but i can always go to 8-10's for more speed.
maybe im not understanding this right?

[martin]

1950kv is to high kv for 6s at over 43000rpm unloaded, 6s needs to be around a 1400kv motor.

[martin]

Your not going to be able to run a given motor & kv on 6s, 8s, & 10s, it dosnt work like that re kv x voltage. You will either be to low on rpm or way to high on rpm.

[martin]

Your not going to be able to run a given motor & kv on 6s, 8s, & 10s, it dosnt work like that re kv x voltage. You will either be to low on rpm or way to high on rpm ie 1400kv x 6s will give you 31000rpm unloaded which is ok , on 8s = 41000rpm is to high rpm. 10s will give nearly 52000 rpm way way to high.

[rad35]

martin i see what you are saying. If i use a tp 4260 it replaced the 4060 1050 kv on 6's whith a 69mmx1.4 pitch prop according to the speed calculator it will run loaded rpm 18648 speed 50 mph. 8s same prop loaded rpm 24864 speed 67. 10's loaded rpm 31080 speed 84. max amps for that motor is 137 max volts is 51 are these props (running twins R&L) going to be to much for the motors to get this 48 in. vx rocket up and going

[martin]

69mm is a massive size prop for those motors, you must also bear in mind that when you increase voltage from 6s to 8s & 10s you must reduce prop size accordingly. You cant just use the same size prop across the board.

[srislash]

martin i see what you are saying. If i use a tp 4260 it replaced the 4060 1050 kv on 6's whith a 69mmx1.4 pitch prop according to the speed calculator it will run loaded rpm 18648 speed 50 mph. 8s same prop loaded rpm 24864 speed 67. 10's loaded rpm 31080 speed 84. max amps for that motor is 137 max volts is 51 are these props (running twins R&L) going to be to much for the motors to get this 48 in. vx rocket up and going

Did I not just show you a vid of my 40" twin mono running only 42mm props ripping along nicely? 69 mm is way big.
Those big props are going to overwork an ESC immediately. There are two schools of thought on the lower RPM/big prop and small prop/higher RPM but 69mm is overboard.

And also remember when playing the numbers on motor specs that those are Max. Not the continuous rating. Continuous is the lower number.
Shawn

[martin]

Using speed calculators can be misleading, as you increase voltage & rpm on a given motor the motor efficiency normally drops off the higher you go, their for deducing the calculated speeds. You will also get more prop slip the higher the rpm goes slowing the calculated speed further. Theirs no way you will see 84mph with those motors in a 48" mono.

[Fluid]

How about a reality chech. A 48" mono is WAY bigger than a 40" hull. The OP clearly lacks the experience to build a twin boat which would challenge an experienced builder. If he wants to waste his time and money on failure good luck to him. He has a far better chance for success using a single Castle 2028 on 8S or 10S. This is a proven drive system for large boats, is less expensive than twins and will be far more reliable. Again, his choice.

[srislash]

How about a reality chech. A 48" mono is WAY bigger than a 40" hull. The OP clearly lacks the experience to build a twin boat which would challenge an experienced builder. If he wants to waste his time and money on failure good luck to him. He has a far better chance for success using a single Castle 2028 on 8S or 10S. This is a proven drive system for large boats, is less expensive than twins and will be far more reliable. Again, his choice.

And this was suggested in another thread, same OP.

I wasn't trying to say ' run 442's' just that it doesn't take a HUGE set of props to move a hull. I probably should have been more clear on that.