Home Made Flume

We are still testing for another 2 weeks, if interested PM me please.

Hi @VeFoil. Thank you very much for info sharing! Awaiting for motors final testing! These are great news. We have 2 types of motors already customized for our projects the alien outrunner 100kv and yours. It is great step forward.

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Hi @Winging_it, where did you get the model for the boat propeller i been interested in trying out some.
image

morgansteven,

fancyfoam got it (possibly form this forum) fromw somewhere. He is doing the CAD work and the 3D printing for the test props. I’m sure he’ll be able to share what he has.

Why not make a 100kv motor?

Here is the link to the prop file that we had the most success with.

It was uploaded by Tunnelvision. Here is the link to his first discussion on this prop.

Mike

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Hey mate. I’ve modelled another prop based on a 4hp yamaha prop. It’s 177mm x 10mm. decent results. Happy to share the model (which is editable to suit your setup).

Aaron

That would be awesome. We are planing on doing a bunch of testing and would like with pitch, diameter and shape.
Can you provide a link to the file? Are you using fusion360?
Mike

Hi Mike,

Im not a fan of AutoCAD for 3D solid models. I use onshape (free 100% online-made by some ex soild works guys). Why don’t you give me three of 4 sizes you want and I’ll model them up for you. What file format do you want me to export them as (Exporting Files)?

I am trying different CAD programs to see what I want to use long term so I went ahead and downloaded Onshape. Can you share the file with me? mike@fancyfoam.com
Thanks.
Mike

Hi @tunnelvision. Actually I need help to design the motor mount for sss 360kv and the external Kort gotten from AliExpress of 80mm direct drive. I’m trying to do it with fusion but it is really complicated platform to quickly hands on. I can provide all the required info and dimensions if you can help with the modeling. Thanks a lot anyway to introducing this free tool for the design. Will try it.

Tunnelvision turned me onto Onshape. I like it better than fusion 360. It is free. Give it a try and if you get stuck I can help. Sharing designs is very easy with Onshape as when you share it with me I can modify your model.
Mike

Guys, do you know if its possible to import fusion 360 design into onshape so it can be modified in onshape later?

Not familiar with OnShape and Fusion but normal procedure is to export as a step file, which is normally importable by most CAD systems.

Hi @tunnelvision, can you please share your designs in onshape? Props and motor adaptors as you have posted early?

Here is the latest test data. Still have not found a better design than the original “boat” prop that we tested in the beginning. It is still better than the latest 2 blade design that i thought were quite close to the boat prop.
Mike

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Nice experiments, thank you for sharing!
I think, the main difference is the length of the profile near the hub and the area covered by blades near the hub. This could prevent a flow back of water near the hub. Also the thickness distribution is different, the commercial design looks more rugged and will deform less. Three blades instead of two also gives less load for the prop and also mechanical deformation.


Here you can see an example of commercial propeller 180mm cut down to 140mm diameter. There is a slight camber which becomes more distinct the more i cut away. (I turn this in the reverse direction to get less hard strokes when the tool hits the prop, so the gear is not worn too much. Therefore the tool is also mounted in reverse direction).

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The flume was rebuilt to allow the prop to unload some during testing rather than just testing static performance. It is working great.
We tested earlier this week but had an issue with the printed prop. I have reprinted them and we will test this weekend. I have made a 2 blade version of the 3 blade “boat” prop that has had the best results to compare. My parametric design has had some camber added. I hope it improves the performance.
Really looking forward to the weather warming up as we already have much better performance that the last test on the water.

FLUME 2.0

Mike and I have been testing with a new and improved flume for the last couple of months. This flume was built from an oval water tank. The motor was offset to one side to create a recirculating flow as Toto44 suggested earlier. This worked pretty well and created a recirculating flow of an estimated 8 to 10 mph. We could see the props unload as the water velocity increased, especially at higher power settings.

Here is how the flume morphed over time:

  1. Basic set up with only internals being the drive shaft; lots of splashing, vortexing etc.
  2. End plates added to reduce splashing and spillage.
  3. Clear center window added to further reduce vortexing.
  4. Center divider added to eliminate horizontal vortexing at high power
  5. Water level raised above the top plates to reduce turbulence.

The flume now operates very smoothly and give very repeatable results.

Modified animal watering tank

Thrust and torque measuring

showing center divider and propeller

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Shown below are all of the propellers that were tested. Most of the smaller props were tested with the Leopard 160 kV motor. The larger props were tested with the 50kV (65kV actual) Alien C80100 brushless motor.

The winning combination by a wide margin was the Alien motor with a 10" pitch RC aircraft propeller.

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