Replies to This Discussion

Permalink Reply by eric on May 28, 2012 at 8:38am

Guess not all that new, found another similar model: http://j.mp/KKcAw1

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Permalink Reply by Crispin on May 28, 2012 at 8:43am

I used the silicone PC fan mounts. They work perfectly. The thin side fits snugly through the APM holes and the fat side fits snugly through 3.5mm holes drilled into the quad's top board.

They a dirty cheap as well (if you don't have them in your parts bin anyway...)

For the motor mounts (3DR quad) I used silicone washers under the motor (between motor and arm) and used the same same silicone washers to insulate the quad's carrier board from the main frame.

Again, for about 50p I got 20 of them :D

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DeveloperPermalink Reply by R_Lefebvre on May 28, 2012 at 8:46am

Yeah, not new.  I've got some just like that I used to mount an APM2, but I'm not that impressed.  Probably better than nothing, but not great by any means.

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Permalink Reply by Crispin on May 28, 2012 at 8:49am

probably granny and eggs here but, How tight did you make them? If they're compressed then anything will transmit the vibration.

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Permalink Reply by eric on May 28, 2012 at 12:58pm

Ok, not new. But I was thinking of doubling them like this: 

If I use it like this, and then for the board itself, I just cant imagine this having absolutely no optimizing effect at all. Any thoughts?

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Permalink Reply by Crispin on May 28, 2012 at 1:07pm

Eric,

I'm no expert on this but my take is that, it would be better than nothing but if you tighten it up, even slightly, then the silicone would be compressed and transmit most of the vibration. If your nut was a nylock type of nut, this could be mitigated.

Seeing as your top plate is nothing other than holding the electronics, why not look at the fan mounts. For example: http://images.highspeedbackbone.net/skuimages/large/S23-1084_main_i.... 

I've mounted them standing up. So the fat, blind end, is pulled through the quad's frame and then through the APM. The APM then is basically resting on it. Because of the various lips, it cannot move.

It would be interesting to set up a vibration sketch with using something like a piezo as a sensor and measure different methods. I'm going to guess that various methods will dampen various frequencies and pass others through.

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Permalink Reply by eric on May 28, 2012 at 1:30pm

Oooooh FAN MOUNTS!!! I see :-P I thought you ment something like this: http://j.mp/LCsaGL. You may be right. I think its worth a test..

BTW, If you have an iDevice, you can strap it to your construction and test these methods using the "Accelerometer Data" app. Many people use the app to test vibrations in a variety of constructions. Theres even an app for macbook, and maybe for android I'm not sure...

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Permalink Reply by Crispin on May 28, 2012 at 1:36pm

Thanks for the tip. I'm an iDont though :)

I'll see if I can play with the code or write another sketch to measure the data.

My current setup includes props which have not been balanced (but my home made balancer says they're ok :p) and two motors with slightly bent shafts. I can throw the quad around and it's quite happy. it'll also sit and hover dead still.

When about 1/2 throttle there is washing machine type vibration which can be heard a long way off. It does not seem to affect it and I chalk that up to the silicone washers under the motors and fan mounts for the APM and carrier board -> frame mount.

One day I'll change the motors ;)

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Permalink Reply by eric on May 28, 2012 at 1:43pm

LOL, I'm an iDid ... iT broke but iWont because i'D rather built a quad than be an iDid it again...
Sound fan mounts have proven themselves. I may do this for the carbon plates, but I' sold on the boards. Thanks for your input!

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Permalink Reply by Crispin on May 28, 2012 at 1:47pm

just a thought, I got some CF plates from a friend (off-cuts from a Boeing's wing! How cool is that) which I will be using for a quad. he warned my that the edges are stupidly sharp. Unless the drilled holes are very smooth (polished?) could they not rather quickly cut the silicone?

Might be worth buffing the inside of the holes? Like I said, first time novice with CF so don't know much (other than it's impossible to bend!)

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Permalink Reply by eric on May 28, 2012 at 3:32pm

I imagine thats gotta be some hi-grade material! Any cutting or drilling should be done with special diamond treated CF tools. You don't want to damage or pull the fibers. They can run like a stocking and ruin the goods. Then you should seal the cuts with epoxy.

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