Quadcopter anti-vibration tube mounts.

Having seen a vast improvement in the Arducopter handling when vibration was reduced I decided to experiment further. I thought it was worth trying to soft mount the tubes so cobbled together a test frame on a bit of 4x2. The 12mm tube mounts are held in place with ‘o’ rings. The video is with standard 75 shore rings 17mm ID. This was just the first test so was quite pleased but will experiment with other types/sizes.

This method will probably only work on a ‘H’ frame where the motor lift balances out.

 

 

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Comment by OlivierD. on January 19, 2013 at 5:02pm

Cool stuff! What is the name of the App you are using on the galaxy to measure vibrations?

Comment by Vince Hogg on January 19, 2013 at 5:08pm
Comment by Vince Hogg on January 19, 2013 at 5:19pm

If all goes well, hope to end up with something like this.

Comment by OlivierD. on January 19, 2013 at 6:10pm

Very slick. I imagine H quad tuning is the same as that of an X quad? Pardon the noob question, never flown and H but the more I look at them, the more I like the idea. Thanks for the App!

Comment by Joshua Ott on January 19, 2013 at 7:34pm

Good looking project Vince. I've said before, multirotors are ultimately just a packaging exercise and the traditional hub and spoke frames are a bit tight, especially when one is trying to separate video Tx, RC Rx, data TRx, GPS Rx, power supplies, ESCs, batteries, etc. It's amazing any of these things work at all!

Have you considered making the motor boom quick release or rotate to facilitate ground handling and transport? I have vowed to only make folding frames in some type of H config for all my future projects. 

Comment by Vince Hogg on January 20, 2013 at 3:21am

I found that my traditional open ‘X’ frame was getting splattered with mud and debris and is very difficult to clean. I thought it was just a cosmetic problem until one ESC failed. On examination it was very wet inside the plastic wrap. It started working again after being dried out.

I expect tuning will be like a normal ‘X’ except it may need slightly higher gains in pitch due to the increased inertia around that axis.

The shell will be of Kevlar/carbon around a ‘lost foam’ mould. It doesn’t produce a nice surface (without a lot of finishing) but Im not bothered. Hope to start that today. The ‘airplane’ shape fuselage is just to help with visual orientation. Some people think the 5.8G FPV interferes with GPS so they will be at different ends. I do intend to put legs on it when I attach the camera gimbal.

It probably would be easy to make the booms quick release but Im not bothering this time.

Am in a hurry to finish so I can try 2.9!

Comment by Vince Hogg on January 25, 2013 at 2:26am

Hi Thomas.

All good info thanks.

I did put a post somewhere (Mission Planner forum?) asking if we could highlight parts of a graph and get statistical data.

My test was not that scientific but I was just proving to myself that the o-ring mounts were worth taking further. I will use the APM to get good data when its flying. It would be nice to have a league table of 'good' and 'bad' vibration measurements. The phone program I was using gave a vector total vibration but Im not sure the APM will go that, just separate axis.

I think almost everyone misses the trick of using the battery mass to dampen vibration by just hanging the battery loosely below.

I will clamp it tightly just above the APM and will try some 5mm 'special' foam to mount the APM on but have seen it cause more problems in the past.

There have been comments that my 4008 type motors have weak shafts and that any prop ground contact will cause a bend. I think some of mine may be slightly off so will replace with hardened ground shafts.

Expect to be flying in the next day or two.

Comment by Vince Hogg on January 25, 2013 at 8:38am

Im in UK so prob not much help.

http://www.easycomposites.co.uk/

I wont be buying Kevlar anymore. Its such a pain to work with.

 

Comment by Joshua Ott on January 26, 2013 at 6:27pm

Vince, I bought some carbon/kevlar weave to remake the front of a Raven for a camera gimbal quite a while back, and pretty much just shelved it after trying to cut that fabric : /

I would like to get back on it soon, however. What method did you use to cut the cloth, rotary cutter, scissors? My sharpest TiN scissors just squished it around leaving a very ugly frayed edges, very frustrating.

You make good progress friend, I hope you get that adverse yaw figured out. I'm intrigued by your idea of changing the rotor directions.

Comment by OlivierD. on January 26, 2013 at 6:41pm

Joshua, there are special scissors for cutting Kevlar, the blades have a specific angle and when you use those, you will be amazed, it`s like cutting regular cloth. For even better results, sandwich the area you want to cut between two boards, this will prevent the fabric from moving around as you try to achieve a straight cut.

Do a google search for kevlar cutting scissors

Another thing to keep in mind with carbon kevlar fabric is that the kevlar is reluctant to absorb the epoxy or polyester that you will be using. You need to make sure your resin penetrates properly to soak the fabric. You can always wipe out the excess before it sets. Apply resin prior to applying the fabric, apply resin on the fabric then add another coat and force it in there with a roller. It`s tricky stuff but it`s well worth it. This stuff is indestructible.

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