Discussion in 'Propulsion' started by OverThinker, Jun 16, 2020.
so what is a good reliable.... and fairly inexpensive 6v motor to run? I need 3 for my Bismarck
Johnson 550 cans. What rule set are you building this Bismarck for? Most people don't power all three shafts. Will seriously negatively affect the boat's ability to turn.
Easiest setup would be similar to what I have in my Scharnhorst. Two 550 cans geared to a single shaft. Use drag disks on the outer shafts.
Battlers connection has the gearboxes, motors, speed control, and shafts all for this ship. They call it a drive system.
What is a drag disk?
a solid disc that is the same diameter as you prop, that is on the outer shaft and doesn't spin
I think the idea with drag discs is that it allows you to maximize propulsion from the prop(s) that flow best over your rudder. Since the motors are typically vastly overpowered relative to scale you can have an inefficient hull drag-wise and overcome this will some extra power from the motors. Small price of using a bit more power, but the payback in terms of improved steering is well worth it.
what do you guys recommend that I use for my cruiser with four props and a top speed of 40 knots.
You will only need 2 motors and Jeff has a link to a motor that works for smaller boats.
hmmmmmmm but my boat has four prop shafts don't I have to have four motors?
It would be a lot easier to power two screws. Probably the inboard ones.
For optimal turning, you want to put your forward thrust out of the props closest to your rudder
ok and the front ones are just dummies right
What format are you building for?
400 size family motor on gearboxes or 550 direct drive. With big gun there are many options because you just need the rpm to make the relatively slower speed.
will this work without a gearbox?
No, to small. Look for RS-550 or RS-555 motors.
Garrett I run those G9332 motors (actually marked Johnson 30011 373002) in all of my ships. They work great direct drive, and tend to have loads more power than is useable for a 1:144 scale ship with a standard hull and no drag disks. I use a simple piece of polyurethane tube between the prop shaft and the motor to serve as a flex adapter. My Alabama is running the two inboard screws only and I have to limit my max speed in the radio to keep her legal. I have a Roma that has 4 powered screws and its the same issue... I have to limit throttle in the radio to not exceed her top speed.