Vibration- What Do You Do To Secure The Airframe And Electronics?

[DizzyDiggins]

Hi,


Long time reader first time poster with the exception of my post introducing myself. I am getting ready to start my build, but concern with vibration and electronics. I understand to use quality motors and propellers, but there has to be some vibration,

Question: With all the screws, nuts, standoffs, etc. do you use Loctie? If you do what level of Loctite and what components are getting Loctite on them?

Question: What are you using to insulate the electronics from vibration? and how are you securing the electronics to the airframe? I have a roll of open cell 1/8" foam that could be used to insulate the electro is, would this work?

 

[Old Man]

Any metal fastener that has threads requires thread lock compound. Any good medium grade, typically but not always blue on color, works for the application. There are some stronger versions that can be wicked onto a fastener after it has been assembled but usually those applications are fine threaded and small diameter. Learn how to use the stuff. Gooping it on does you no favors. Only an amount necessary to wet the threads roughly equal to the thread height for the length it engages the nut is necessary. More than that makes life tough taking it apart later.

As for vibration, balancing the propellers is a great start. I use Align anti vibe jell for sensitive electronics. Foam pad works well too if you have the room for Velcro or similar to strap equipment onto the foam. Secure the wires, especially near where they connect with something. Constant bending at a connector is a sure way for a wire to break at the worst possible time. Don't permit GPS cables to hang free from beginning to end. Essentially, treat a multirotor like it's a real airplane. Just because it's small doesn't mean all the lessons learned in man aviation don't apply. They do.

 

[DizzyDiggins]

Any metal fastener that has threads requires thread lock compound. Any good medium grade, typically but not always blue on color, works for the application. There are some stronger versions that can be wicked onto a fastener after it has been assembled but usually those applications are fine threaded and small diameter. Learn how to use the stuff. Gooping it on does you no favors. Only an amount necessary to wet the threads roughly equal to the thread height for the length it engages the nut is necessary. More than that makes life tough taking it apart later.

As for vibration, balancing the propellers is a great start. I use Align anti vibe jell for sensitive electronics. Foam pad works well too if you have the room for Velcro or similar to strap equipment onto the foam. Secure the wires, especially near where they connect with something. Constant bending at a connector is a sure way for a wire to break at the worst possible time. Don't permit GPS cables to hang free from beginning to end. Essentially, treat a multirotor like it's a real airplane. Just because it's small doesn't mean all the lessons learned in man aviation don't apply. They do.

Thanks for the reply. I have an entire second center section of a Tarot 650. The plan is to have the ESC's on the first section and the electronics on the second center section. A third layer is possible to mount the GPS antenna and the other antenna's if needed. Batteries will mount on the lower rails and balance out the gimbal/camera.

 

[R_Lefebvre]

Multirotors are fairly easy in this regard. As OM stated, just secure the wires, and try not to run them over the *edge* of any plates. If you do, you can stick a little heat shrink tube where the contact is, that provides a minimum of extra protection. No matter how much balancing you do, a multirotor will vibrate anyway, since the rotors are rigid. Soon as the air starts moving around the blades, they vibrate.

I just spent 10 hours rewiring my gas helicopter to try and prevent problems. I had an electronics failure after only 1 hour due to the vibes on that thing. Now all wires are covered in anti-abrasion woven sleeve, strain relief loops where needed, heat-shrink strain-relieving boots on all connectors, etc.

 

[Cbergen]

Yikes Rob! I have some experience with gassers and how to mitigate the vibes you speak of. Give me a holler if you'd like to discuss.

While prepping your electronics is certainly a good idea, be sure to eliminate the root cause of the vibration problem.

 

[caferacer]

Has anybody used a Tarot Anti-shock Motor Mount?

I'm wondering how effective this is.

 

[R_Lefebvre]

Yikes Rob! I have some experience with gassers and how to mitigate the vibes you speak of. Give me a holler if you'd like to discuss.

While prepping your electronics is certainly a good idea, be sure to eliminate the root cause of the vibration problem.

The root cause of the vibration is an unbalanced standard Zenoah G29RC. I purposefully chose the worst-case condition since this is a test-bed. Also, the Helix Heli kit is made from a very poor grade of G10, I've never seen anything like it, it's about as stiff as acrylic sheet. That doesn't help. I had to make significant modifications to the frame to stiffen it up just so the throttle servo didn't get killed.

A balanced engine would obviously help a lot. As would a stiffer frame and engine anti-vibe mounting.

Do you use vibration damping mounts on your engines? I haven't seen anybody else doing it.

I have this thing flying again, but only about 30 minutes on it. I'm not expecting a problem. What I did before was an obvious oversight. The only thing that is not damped now is the radio Rx. I'll probably do that one too, just in case.

 

[Cbergen]

I see. Send the engine to BH Hanson for smoothing out, but it can help to tune it "in a certain way".... It's one of the things I argued about constantly on the forums, oil type, mixture, etc.

I do not use any dampening on my engine mounting, and I use G10, but probably a better grade. I prefer G10 over carbon as it does have some dampening qualitites vs carbon, but if it's too thin or low grade, then yea...

I mount my gyros using Zeal Tape, and simply velcro the Rx, battery, etc in place, with a safety strap made of velcro around them also.

Good luck, it's hard to test electronics when the aircraft is giving you fits...