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Motor recommendations please

R/C Submarine modelers

Motor recommendations please

Postby roedj » Sun Oct 12, 2008 4:55 am


Another fellow and I are gathering up ideas on how to build a sub with the following proposed specs:

1) Mid 20th century type - typical surface type with ability to dive quickly
2) About 43.3" (1.1m) inch long in 1:30 scale
3) Twin screws - each screw driven by its own motor
4) Dry hull with an expected displacement of about 20 to 25 pounds (10 kgs. +/-)
5) Must be able to move with a good turn of speed

Please allow me to be vague at this point in time as to the actual sub type - Top Secret and all that.
We're looking for recommendations as to type and size of motors. We're thinking brush less at this point for small size with high torque but what are your ideas? Direct drive or geared? One ESC or two? That sort of thing.

Thanks for your time,

Dan :?:
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your Desired Boat

Postby GreyAkula52 » Sun Oct 12, 2008 12:13 pm

A Type XXI.........
Fits the Description You Mentioned
Andre S. Burgess, P.E.
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Postby gantu » Sun Oct 12, 2008 1:51 pm

No that´s not the one sir.

Postby roedj » Sun Oct 12, 2008 3:26 pm


The guess of a XXI is off by at least a factor of 2.4:1.

I apologize for the vagueness but at this time please allow me to be so.

However, to help your helping us, I have revised the specs a bit:

Weight: Nearer to 5 kgs than 10 kgs.

Screws: Each screw at 1:30 will be about 3 cm DIA.

Motor: Brushed motors are OK

Hull form: Think Holland sub from the side and late WWII German sub (like a XXI) from the top

Hints: No more hints, but clarifications are possible

It goes without saying, but I'll say it anyway, I would not even be attempting this build if I didn't believe I could always obtain help from my fellow SC members

Again, as always, thanks for your help and time,

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Postby fgroza » Sun Oct 12, 2008 8:16 pm

You could go speed 400 with 3-1 gears. Both motors run from one esc. Brushless outrunners would go great and are very torque minded. I would use two escs for them .You can get reversing brushless escs from
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Postby Mike Dory » Mon Nov 17, 2008 12:58 pm

Howdy - If your looking at Speed 400's Take a close look at Graupner's #1719 Speed 400, it comes with a 4 to one gear box and is the only Speed 400 rated for 12 volts of continures service. It has run my Type 23 U-Boat in 1/32 scale for 15 years and it does it well. Best Wishes on your project.....Mike Dory
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