[PSUBS-MAILIST] Plastic Propeller

[Alan via Personal_Submersibles]

Thanks Ian, Greg & Hank.
Ian, I hadn't thought of that 2 propeller type bow thruster as a left hand
propeller source. I will track one down & test it. I can always trim the diameter
down a bit if it is in the ball park. The price isn't too bad either. If we could 
print our own propellers, that would be awsome.
   Greg, the motors I am using are rated for 50 Amps continuous & I am using
a direct drive. In my calculations, I would need to go to a really low pitch prop
if I went to a larger diameter, & I haven't seen anything that low. I was using
a 7&1/4" 2hp Yamaha prop for testing & it only drew 33 amps. It will be a matter of pool 
testing a few of these props & finding a good economy of Amp draw & thrust
but it is being dictated to a degree by what I can get in right & left hand.
   Hank, looking at these propellers again, it would be very difficult to cast them.
If I made a silicone mold I'd never get the part out. It would also be difficult to 
get resin in to the blade area & get air out. 
Found out that the new motors I ordered are being used commercially on
electric surf boards, so I can't be too far off track.
Cheers Alan

   


Sent from my iPad

> On 14/04/2017, at 12:32 PM, irox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hi Alan,
> 
> it might be a bit big for you, but the smallest cheap counter rotating prop set
> I've found is from "Quick", they do a 4 blade 185mm in RH and LH for $40-$80 (depending
> on where you order them).  Part numbers:
> BTQ185 LH (QI55507)
> BTQ185 RH (QI55508)
> 
> http://www.quickusastore.com/bow-thrusters/spare-parts/bow-thrusters-propellers.html
> 
> I got a pair and installed the on cheap ($45) trolling motors.  They made a big difference over the stock props, but of would probably burn out the cheap trolling motors quickly.  I didn't get around to look into reducing the diameter to better match the motors (plus I want to use better motors anyway).
> 
> An SLA 3D Printer may be able to print something which could be used (after UV curing).
> 
> Cheers,
>  Ian.
> 
> -----Original Message-----
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
>> Sent: Apr 13, 2017 4:52 PM
>> To: personal_submersibles at psubs.org
>> Subject: [PSUBS-MAILIST] Plastic Propeller
>> 
>> Greg, (or anyone else as knowledgeable)
>> I am going to test a Vetus 146mm propeller soon. On paper it
>> seems a good match to my motor. I have not seen a left hand prop (which I
>> need) & the right hands go between $56- & $100-. Also I may need a slightly
>> smaller diameter. They are made of delrin. 
>> Is there an easy / inexpensive way of replicating 
>> something similar? I was thinking they could be printed & the print used
>> as a lost wax type aluminium casting.
>> I could make a silicon mold from a print & cast a fiber reinforced propeller, 
>> but aren't sure about the strength & quality I could get.
>> Any thoughts on the best way of doing this?
>> Thanks, Alan
>> 
>> 
>> Sent from my iPad
>> 
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