Dual Speed Controls - What are the Pros and Cons?

[mermaid]

??? I'm in the early stages in building a 1/48 scale Gato. I plan to power it with two motors. Some people insist that there is no advantage to being able to control each motor independently because the shaft spacing is only about 3". Others maintain that there is an advantage, particularly in low speed maneuvering as in docking. Should I invest in a second speed conrol or not?



Edited By Mermaid on 1142045627

[horribleharry]

You should have no problems

[color=#000000]You should have no problems using 1 speed control. I am using a Mtroniks SUPERMARINE 3 in my 1/22 Type VIIC. It has ample power and a VERY good frequency rate allowing me to get roughly 60 rpm or less with a 3]

[Guest]

Diane,
Why not set it up

Diane,
Why not set it up with one speed control for both motors, then, while adjusting and trimming your model, disconnect one of the motors and see how it changes steering at high and low speed. If there is a significant favorable change, and you want to power the motors independently, you still may be able to do it by using a double pole double throw switch, and one speed control.

[the black knight]

diane has a good point.

diane has a good point. try one, then two. ive personaly been told that for american and japanese subs, you want to controll the motors seperatly. remeber that you only have one rudder with two props. this was a weakness of jap and american boats creating a larger turing circle. the type VII's and other german subs have 2 rudders(one behind each prop) which allows them to turn much tighter than other subs at the time. so in a u-boat, there is no advatage but in american or jap boats this could help tremendously. so definatly try it

[mermaid]

Thanks for the feedback. My

Thanks for the feedback. My gut reaction is to go with two ESCs. I can always use the second one on another sub if it turns out that two are not really necessary!



Edited By Mermaid on 1142089910

[wingtip]

or if one burns out

or if one burns out you still have another to limp back to drydock too

[subdude]

Do some math. The props

Do some math. The props are 3" apart. The boat is 78" long. Calculate how much force you'll need to generate with the reversed prop to make any difference on that much mass protruding that far away from the moment of inertia.

Nobody could convince me that I didn't need 2 controllers when I built Batfish.

Used the second speed control in another boat.

BTW, the rudder on a fleet boat when put hard over places the front part of it behind one prop, and the after part behind the other prop.

Jim

[mermaid]

Good point about the rudder

Good point about the rudder Jim. I hadn't even thought of that! I'll buy two ESCs and experiment. I plan to buy an F-14 radio so I'll have twin throttles on the Tx anyway. If the second ESC seems redundant, I'll just use it in another boat.

[wolfsong]

i don't have the experience

i don't have the experience yet with the VII-C, but ill set my typhoon up with 2 esc..
as for the remote i bought the tracker from polks...much much cheaper than the robbe (8channel for $200.-) and no chrystals.
i got both esc mixed with the rudder.. so i don't need the twin-sticks. i got it mixed , so in low throttle the inside engine will even go in reverse...
havent gotten it in the water yet.. but i think the twin esc will realy help on that boat...

stefan

[prototype3a]

I have a french destroyer

I have a french destroyer FS Mogador with 2x 30mm props about 2.5" apart and am using a Robot Power Scorpion HX to control a pair of Maxon motors driving them. This boat is about 3' long. The first time I tried using the prop reversal trick I was very surprised by the results. It provides pretty good maneuverability at slow speeds and minimal at flank. I'm using a Futaba 9cs to control it and have it setup for triple rates with the rudder signal mixed into a third channel for sending to the scorpion. The lowest rate has the full rudder signal going to the scorpion and throttle limited to 20% for max maneuverability. The next rate is about 40%/50% then the third is 0%/100%. The 9CS is one trick radio. I'd like to try out one of those polk recievers though.

[wolfsong]

i think, you can do

i think, you can do just about the same with the polks receiver. all kind of mixing-setup / rates.. any channel with any channel... and $200.- surely was a sellingpoint for me

[spongjim]

The dual speed controllers do

The dual speed controllers do make a difference in the turning radius on the Vll c .I have tried it both ways. But thats a u boat not a gato which what you where asking about.


Jim

.

[mermaid]

Thanks for the feedback folks.

Thanks for the feedback folks. My primary reason for wanting to use two ESCs is for maneuverability at ultra low speeds. It should even work at a standstill to twist ship while docking. I don't expect the twin throttles to make much of a difference in the turning radius at anything above very moderate speeds.



Edited By Mermaid on 1142563481

[jaschwink]

I have the Engel fleet

[color=#000000]I have the Engel fleet boat (1]

[mermaid]

Thanks for the comment jaschwink.

Thanks for the comment jaschwink. My gut has been telling me that the Dual ESCs should help reduce turning radius even at higher speeds yet some people with a lot of experience have told me that they are a waste of money! Who to believe? In a situation like this, I think I'll go with my "woman's instinct". (Helps that engineering has been an avocation of mine for years!) So, I've made up my mind about the dual controls. Now the question becomes which controls to use? Is it worthwhile to go to the Vantec RFDR21 which is a single unit incorporating two speed controls which features a logic to mix in rudder? Or, should I just get two seperate quality speed controls and let the radio do the mixing? By the way, which motors are you using? I've posted on this topic but never had a reply. I'm thinking of using Graupner 12V 600s



Edited By Mermaid on 1142978822