Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Sportsman Twin Motor Set Up  (Read 2209 times)

IanLloyd

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 51
  • Model Boat Mayhem Forum is Great!
  • Location: Hampshire
Sportsman Twin Motor Set Up
« on: January 30, 2017, 08:31:25 AM »

Some advice please.

I am currently rebuilding a Lesro Sportsman 2. It is fitted with twin 540 sport motors and twin rudders. I am converting to brushless which is fine but I notice the original props and motors run in the same direction. So teo questions.

Is there an advantage to running contra rotating props and motors?

I understand there is an electronic gizmo that slows one motor in turns, is this an advantage or not worth the bother?

While I quite like a bit of speed I am NOT a speed freak,
Logged

jarvo

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 679
  • Etherow model boat club
  • Location: Bredbury Stockport Cheshire
Re: Sportsman Twin Motor Set Up
« Reply #1 on: January 30, 2017, 12:08:04 PM »

Hi Ian, definitely, contra props, make the model handle much better, also you wont get Torque roll as you open the power up. You would need to swap 1 prop though, either way round, some swear   by inward turning others outward, try them both!!!  as to the mixer you spoke about, on a fast hull i don't see the point, you don't need the maneuvering ability.


As to a speed freak, on a 34" hull with twin brushless i will go like stink!!!! 


Regards


Mark
Logged
Tugs are for pulling

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,506
  • Location: Blackpool
Re: Sportsman Twin Motor Set Up
« Reply #2 on: January 30, 2017, 10:04:02 PM »

Def go with cr props you will need two esc for brushless and to get one spinning opposite you just swap any two wires on the motor. Outwards rotation tends to be the way to go on a mono hull, it gives better smoother performance, if you spin inwards on a mono the prop wash from one prop to the other causes issues .
You wont need large motors for that boat ,how many cells are you planning on using for each motor ?.
Logged

IanLloyd

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 51
  • Model Boat Mayhem Forum is Great!
  • Location: Hampshire
Re: Sportsman Twin Motor Set Up
« Reply #3 on: January 31, 2017, 08:33:37 AM »

Will be running 11.1v 3 cell Lipo. Have twin Mtroniks 30amp combos. They seem very small but have been told they will be fine. Time will tell.

Am I being stupid here as I would have thought the prop wash was just transferred from the top to underneath if you run props one way then the other?
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,506
  • Location: Blackpool
Re: Sportsman Twin Motor Set Up
« Reply #4 on: January 31, 2017, 09:03:35 AM »

Try it and see i mainly run surface prop setups and  it makes a massive difference to how the boat handles as props are closer together than on a cat. Customers who have ran my Apache with cr setups have all ended up going with outward rotation but like i say those are surface drives . Submerged drive in a slower boat it may not be as big an issue but i still think outwards will work better but no harm in trying both ways .
Logged

IanLloyd

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 51
  • Model Boat Mayhem Forum is Great!
  • Location: Hampshire
Re: Sportsman Twin Motor Set Up
« Reply #5 on: January 31, 2017, 09:10:44 AM »

Thank you. Will try and see.
Logged

canabus

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 763
  • Boats a hole in the water you pour money into!!!
  • Location: Tasmania,Australia
Re: Sportsman Twin Motor Set Up
« Reply #6 on: January 31, 2017, 10:24:35 AM »

Hi Ian

Replacing 540 motors (about 90 watts) with the same size brushless motors(35mm) is a straight bolt in.

The problem is the great increase in power and with two motors it's going to be a beast.
I have a 34" Sea Commander with one 3639-1100kv 800watts, 12,210 rpm on 3S with a 2 blade 40mm prop.
This boat runs about 35 kph.

What size props has your boat have??
Logged

IanLloyd

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 51
  • Model Boat Mayhem Forum is Great!
  • Location: Hampshire
Re: Sportsman Twin Motor Set Up
« Reply #7 on: January 31, 2017, 10:48:46 AM »

Have not purchased props yet. Was thinking of 30mm two bladed plastic to start with. What do you think?
Logged

jarvo

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 679
  • Etherow model boat club
  • Location: Bredbury Stockport Cheshire
Re: Sportsman Twin Motor Set Up
« Reply #8 on: January 31, 2017, 11:31:41 AM »

Hi Ian, if you run racing type 2 blade props i would think about 40 - 45mm but if you run 3 bladers try 45 - 50mm


Mark
Logged
Tugs are for pulling

canabus

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 763
  • Boats a hole in the water you pour money into!!!
  • Location: Tasmania,Australia
Re: Sportsman Twin Motor Set Up
« Reply #9 on: January 31, 2017, 11:37:21 AM »

Hi Ian
I have a 2 blade 30mm prop on my 25 and 1/4" Sea Hornet with a smaller 28 mm brushless motor (B28-57-15L, 750 watts, 1900kv, 21090 rpm on 3S 2650mah Lipo).

It's a rocket, runs about 45kph!!!
OK in flat water, I am not testing it in waves.

Another boat I have is a 24" deep vee with a Hobbyking Sprint F3 outboard on the back.

28mm motor 3000kv in small waves stands on the prop from wave to wave.

I tested a 37mm alloy 3 blade prop on the Sea Commander, it was a bit slower and used more power.
Logged

IanLloyd

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 51
  • Model Boat Mayhem Forum is Great!
  • Location: Hampshire
Re: Sportsman Twin Motor Set Up
« Reply #10 on: January 31, 2017, 11:39:34 AM »

OH OK will try various and see what happens. Not done this before so a will need to experiment a bit I think.  It was running 35mm 2 bladed with the brushed set up so assumed smaller would be better with the brushless set up.

Think I will need several types to test and see what is best. More expense!
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,506
  • Location: Blackpool
Re: Sportsman Twin Motor Set Up
« Reply #11 on: January 31, 2017, 12:24:49 PM »

Go with smaller brushless motors and the small props.
Logged

jarvo

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 679
  • Etherow model boat club
  • Location: Bredbury Stockport Cheshire
Re: Sportsman Twin Motor Set Up
« Reply #12 on: January 31, 2017, 07:02:34 PM »

Ian, start with plastic props, cheap to buy and also get you in the ballpark for the size of the expensive brass props


Mark
Logged
Tugs are for pulling
Pages: [1]   Go Up