motors for 1:72 typhoon - which is best

[gof]

Being new to rc submarines and scratch building a 1]http://www.subcommittee.com/forum/icon_smile.gif[/img]
So a couple of questions and no dout that i will have more questions as i progress along with this progect and from what i have read on the forums so far. Is that if no one has done what you are asking that they will give there opinion on what u have asked which is much appresiated.
and as for stupid or silly question as one of my sargents use to say "is that the only stupid or silly question is the ONE that you dont ASK."

first after reading some of the older posts i came accross one that talked about using the 900BB Grauper motor for the typhoon as they RPM are lower so i would not have to use a gear box. So i went searching for the motor and found a site that had a fair number of Grauper motors with the spec's. Here are the spec's for the two motors that looking suitable for the typhoon.
Motor Nominal Voltage Voltage
Speed 720 BB TORQUE 12v 6-13v
Speed 900 BB TORQUE 12v 6-40v
RangeNo-Load RPM NO-Load Current Current @ Max Effic.
4,100 0.75A 3.0A
6,500 1.1A 8A

Stalled Current Max Efficiency Case Length Case Diam
13.5A 75% 72mm 44.5mm
54A 71% 95mm 51.5mm
Free Shaft Length Shaft Diam Weight
6.5mm 5mm 380g
15mm 6mm 645g

from you experenced boat builders which one of these motors would suit the typhoon the best ?
am leaning towards the 720 BB motor

the second question from what i have read is that the WTC can get hot inside while the submarine is working, I was thinking of placing the motors in thier own WTC then soldering a wire to each motor then attaching it to a piece aluminum that i will be using as the keel. Am also trying to figure out how to use the aluminum as a heat sink for the rest of the electrical stuff in the boat as the aluminum will be sitting on the outside of the submarine. any advice on both question will be very helpfull.

thanks in advance

regards
Lee

(ps please forgive the spelling as i failed sellnipg at school lol)



Edited By gof on 1125151876

[wayne frey]

An opinion, as I do

An opinion, as I do not yet have true practical experiance.
Your question has good merit. For the "known hull designs", the choices are easy, as there is history from others efforts.
I have the 1/72 Akula to figure out the same problem. Since they are both the same scale (I call "brusier class"), they are somewhat similar.
I bought a 700BB, but have changed my mind. Direct drive is the coolest,for sure. But after wearing myself out debating 700 vs 900, direct drive,gear drive, and belt drive, I decided to simplify things.
The motors are surrounded by water.Use it. If your draw is not too high, there should not be much heat generated. But if you are still worried, there is a setup I have seen with a coil wrapped around the motor that has water running through it.
You may want to wait for this, and run the boat first. It may not be an issue.
Jealously, I see the electric plane boys have fin kits for their motors. I would throw down for fins because they look sexy on the motor. But, they do not make them for the 700-900 motors YET that I have found.
A 900 with a 3-1 will dang sure work. I figure install it, run the boat! After that, I will figure out later if something needs to be changed because of reduced run time or lack of power.
I doubt lack of power will be a problem.
I want to try a belt drive. Graphner makes a 2-1. Nobody makes a nice, wide, belt though in the 3-1 size.
I will solve that when I get there.
Right now, I am just getting ready to start on it.
Any way I can help on your project, let me know.

[gof]

Hi Wayne
yer i know

Hi Wayne
yer i know what u mean lol u read a post and they come up with an idea and u think cool then some one else comes up with another idea so u spend a lot of time debating ur self as to which one to use. well for me it is going to be a very steep learning curve but its worth it in the end. have a mate that lives in the same set of flats and hes just a interested as i am to get this boat into the water lol the only problem with him is that he only builds target models have tryed to talk him into building a real model lol

regards
Lee

[Guest]

Couple of car heater blower

Couple of car heater blower motors out of the breakers yard will sort you out nicely.

12 volt low current draw, more torque than you can shake a stick at (so no need for gearboxes) and excellent low speed running.

Probably set you back a few dollars for a pair (match them from the same make and model).

Andy

[wayne frey]

I have read a few

I have read a few times where people have tried this with some success.
I wonder if a particular blower motor is sized about right for our purposes and does well for draw and torque. Any experiance out there willing to step forward. I mean, when we talk a D&E 3.5 with a 500 motor, everybody knows roughly what that will work with. But a blower motor out of a 2001 Grand Cherokee? Who knows?
As a side note, I may have tripped across a source for a sturdy gear drive that is pretty variable. I emailed the owner of the website. He said the gearbox will fit a motor with two bolts on a one inch center. He said he thinks a 600 will work.
Check out the ratios avalible! If a 600 works, a 500 probably will.
I was wondering if someone had a 700 or 900 they could measure off of. I think it will be a little bigger. Maybe adapt it somehow.
The link is ]http://www.modelelectronicscorp.com[/url]
Check it out. Very interesting.