Bilge Pump Thruster Kort Nozzle

[sthone]

BilgeKort004.jpg (118.89 KiB) Viewed 8597 times

The second one turned out a little better (still printed it fast but at 80% fill) and I fixed the shape of the nozzle a bit too. The first one had a hump on the down slope of the back and I didn't like that.

BilgeKort005.jpg (119.97 KiB) Viewed 8597 times

Had to mount it up on the Rov just to see how it looked.

BilgeKort006.jpg (118.86 KiB) Viewed 8597 times

I wasn't sure what to do for the prop clearance so the first one is about .05" I just need to get it in the thrust tank to see how it works.

These thrusters are hardwired into this Rov and I can't remember if I have any spares anywhere so I was just going to buy another one yesterday. I went to my local Cabelas and the replacement 750 GPH cartridges are selling for $34.95 now. I use to get these for 19 bucks (that's some B.S. ) I'm either going to have to cut one of these off or figure something else out.

-Steve

[bigbadbob]

Looking ace Steve!!!!
I can't remember the maths for thruster to nozzle clearance, think it's on here somwhere.
0.05" seems like a good realistic clearance though.
Using ABS as you mentioned before you could print one tight and machine it out to get the best clearance.
Keep us posted,

[sthone]

I did some testing on these today and I'm going to call them successful.

The results are....

Without the nozzle
Forward thrust was 2.2 Lbs @ 6.3 amps (12.38 volts)
Reverse Thrust was 1.5 Lbs @ 6.2 amps

With the Nozzle
Forward thrust was 3.0 Lbs @ 6.1 amps
Reverse Thrust was 1.5 Lbs @ 5.8 amps

I'd say that was a pretty favorable increase in Forward thrust with the New nozzle.

Overall I'm pretty happy with them considering I just traced the nozzle pattern from a picture.

-Steve

[sthone]

I still may refine the design but here's the original STL file if anyone is interested in printing this themselves in the future.

-Steve

BilgePumpKortV1.zip

(221.83 KiB) Downloaded 688 times

[mulze32]

Steve, just to give you a heads up. As I understand it, PLA is more "green" than ABS. While ABS is strong, I think for the purposes that you are using it for, PLA is just as suitable.

One question for you though. What kind of props are those?

Thank you.

[sthone]

Have to see what happens with them if left out in the sun for too long but other than that I think they will be fine for my needs.

The props are Robbe three blade 50mm, I get them at http://www.harbormodels.com

-Steve

[puzzler300]

That's a sweet print! I was doing some experimentation as well (viewtopic.php?f=3&t=1464) it seemed that, honestly, my arbitrary one had just about the same amount of thrust for prop speed. Have you tested any other airfoil's (Hydrofoils?) and compared? for my total of, like, two tests it made me feel like the specific airfoil wasn't nearly as important in this comparatively low thrust environment, as opposed to a large shipping vessel.

[sthone]

Posting these here too (from my other thread) just to have everything for the Mayfair 750 Kort design in one spot so it's easy to find.


This is the new design for the Nozzle which incorporates the mount for the thruster onto an all in one design.


The pump cartridges insert and lock into the housing much like the original bilge pumps they were designed for. They are designed to use Robbe three blade 50mm props available at http://www.harbormodels.com and the custom prop adapters the specs are Shown Here. (I'm not sure how different props or adapter lengths will vary the thrust results listed else where in this thread.)


The thruster housings are designed to mount to your Rov frame with a couple of 6/32" nuts and bolts. (Frame area around nozzle should be free of obstructions to allow proper flow.)


They were designed to be printing in this orientation to uses minimal supports. (supports shown as dark orange in the picture above)

I printed mine in ABS using Elmer's purple glue stick for bed adhesion with the following printer Settings

.20mm layer height
80% Infill
3 Top and Bottom Solid Layers
2 Outline/Perimeter Shells
(need to know anything else just ask)






The Finished Printed product.


.stl can be downloaded from the link below.

-Steve

[oceanrov31]

I am considering using these on an rov that would dive to 25ft to 50ft maybe even 100ft.

How deep can these 750 gph cartridge motors safely go without leaking in your experience?

also i read that the motor is rated for 3 amps max. but see that you have run it at up to approx 6 amps.
would this damage the motor due to overheating? can you comment on motor reliability at this current level?

thanks

[sthone]

I've tested these to a simulated depth of about 200' and while they didn't leak the pressure did cause added drag on the shaft seal which did in turn cause the amps to go up on the motor. My full test results on these pumps can be Seen Here. I'm not sure what the long term use of these pumps would be at the higher current levels but I've used the Rule brand pumps for awhile and never had any problems.

-Steve