A quick question about Brushless Motors, Feat. Spinner Design.

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patlinnett
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Re: A quick question about Brushless Motors

Post by patlinnett »

After careful consideration, I went for the Redcon 2204s as recommended by Shakey. I'm in CAD as we speak, designing a blade. However, I have no way of precisely taking the measurements for the mounting onto the motor - does anyone have any advice on how to handle this problem? I can't find the dimensions of the mounts on the motor anywhere online, either. I'm designing a single-toothed blade, and I'm very conscious of the balance - the mounting has to be just right, or all the work I'm doing balancing the thing will be for nothing.

Thanks in advance again, guys!

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Shakey
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Re: A quick question about Brushless Motors

Post by Shakey »

https://www.aliexpress.com/store/produc ... 79679.html

The aliexpress listing has some more information.
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patlinnett
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Re: A quick question about Brushless Motors

Post by patlinnett »

You, sir, are a scholar and a gentleman. Thank you!

patlinnett
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Joined: Tue Mar 21, 2017 1:53 am

Re: A quick question about Brushless Motors, Feat. Spinner Design.

Post by patlinnett »

Right, so I'm at the point of designing the actual blade, and after slaving away at AutoCAD I have come up with something that looks reasonable.

It's based on a spiral and the dimensions are in mm. Does this seem reasonable? If I've not overlooked anything I'll order some! The only issue I can think of with it really is the fact that it's a spiral - could that affect engagement? Should I make the spiral more aggressive?

Image

Thanks in advance again guys!

Andrew_Hibberd
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Re: A quick question about Brushless Motors, Feat. Spinner Design.

Post by Andrew_Hibberd »

From my experience when the disc is up to speed it's less than 2mm of the tooth that engages. So your tooth needs to stick out at least that from the rest. If you are getting it made by someone else it's worth getting a couple of different designs made and try them out.

Also it doesn't look like the cog is centred. Normally the counter weight is opposite to the tooth. Pulsar the heavy weight is a good example of the counterweight direction from the tooth.
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Shakey
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Re: A quick question about Brushless Motors, Feat. Spinner Design.

Post by Shakey »

With that style of disc you do end up rotating the centre bit. Not sure how to put it but once you make the outer ring you line up the central 'bar' along the current COM and the true centre, than you can use the counter weighting to shift it along that line without worrying about pulling it off to the sides. That one does seem rotated a bit far though.

You can see it on my discs as well though far less pronounced.
Image

My advice is to CAD the outer edge of the disc without any middle part, mark the centre of rotation though. Once you have that mark the centre of mass as it is currently. Then draw a line between the COM and rotational centre, all the middle bar and counterweight line up along that line.
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patlinnett
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Re: A quick question about Brushless Motors, Feat. Spinner Design.

Post by patlinnett »

That's really good advice, as always. I'll draw one up tomorrow using that plan!

With the disc you pictured, did you start with a spiral or with a circle? I feel like the spiral shape is more 'elegant' but I can foresee possible problems with engagement. What are your thoughts?

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