[PSUBS-MAILIST] Brushless Thrusters

Tue Sep 9 00:35:41 EDT 2014

Update,
Am still Googling away in pursuit of a home made brushless thruster.
I am set on using an in-runner motor as they have the coils on the outside & will be able
to transfer heat through the can.
The problem with in-runners is they have higher revs than out-runners, however either will 
require a planetary gearbox. I am looking at reducing the revs down to below 3000 rpm. 
This is based on other brushless thrusters I have looked at but might not be right ( any recommendations)?
Another problem is that most seem to draw huge amps.
Here is a 1200W motor for $30-. Of course there is the price of the controller & planetary gear that are needed.
http://www.hobbyking.co.uk/mobile/viewproduct.asp?idproduct=17720&type=&idparentcat=364
Most of the suitable motors seem to be found at places like Hobby King, and are used on RC trucks, or found on E bike sights. The aircraft motors aren't as robust.
These motors are tiny, but hugely powerful, so there is the potential to make a small streamlined
powerful unit.
I haven't had much luck with a matching gearbox. Some of the planetary gearboxes recommend
oiling (no good to me unless I oil compensate) while others don't. I am looking for a cylindrical unit to match my motor, preferably with thrust bearings.
If anyones got any advice or experience in this realm I'd be pleased to hear it.
Regards Alan

Sent from my iPad

> On 7/09/2014, at 8:43 pm, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi Hank,
> the kort nozzle on the Indonesian thruster looks a bit Naff. 
> ( I am designing an art work here.)
> I could get a price for the unit without kort nozzle, but
> I'm wondering if I could build something for 1/2 that price.
> There are some reasonably priced brushless motors about.
> I don't know that I could just retro fit a thrust bearing inside the can of the motor.
> I tried to put a thrust bearing for reverse inside my brushed thrusters, but
> couldn't find one with a thin enough section to fit.
> Also the motors are a bit expensive to just buy & hope you can fit one.
> How did you fit the thrust bearing on Gamma?  Did the propellor shaft extend out the back
> of the motor?
> Alan
> 
> 
> Sent from my iPad
> 
>> On 7/09/2014, at 7:22 pm, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> 
>> Allan
>> Dont worry about thrust bearings to much. They are aesy to get, I bought one for Gamma , real heavy duty for 80 dollars. Personally I would just use a good quality bearing and replace it once a year for 8 bucks, if it is a small thruster. Are you not happy with the Indonesia thrusters? Or to pricey?
>> Hank
>> 
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>; 
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>; 
>> Subject: [PSUBS-MAILIST] Brushless Thrusters 
>> Sent: Sun, Sep 7, 2014 11:58:56 AM 
>> 
>> Hi people,
>> I've spent several hours today looking at brushless thrusters & wonder if anyone else has looked at them or got any ideas. There is the Indonesian thruster I posted a few weeks back at US 2,200. There is also the Haswing Protruar 2hp that Emile has; however they state that it's for fresh water only, & I think Emile said it was a bit noisy.
>> The inrunner motors that have the winding on the outside, seem a good option as they cool through convection to the can. They also need higher revs for torque & require a planetary gear box or similar. ( which a lot have built in)
>>   I was looking at the option of making my own thruster, however the motor would require a thrust bearing & I don't
>> know of any that would have one other than maybe a high powered battery operated drill.
>> Any thoughts, suggestions thanks.
>> Alan
>> 
>> Sent from my iPad
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