unstable when using anti vibration mount

[Nick Mumby]

I have a SP Racing S4 Evo mounted on an anti vibration mount, with 980Kv motors, S500 frame.

Its very difficult to fly and seems quite erratic.
When I mount it on rigid standoffs its much more stable, and seems to fly correctly.

What could be causing this?
the only thigs I can think of are;

prop wash causing the FC to move on the soft rubber?
mounted too high? (its about 10mm higher on the ant vibration mount than it is on the standoffs).


Thanks!

[shawdreamer]

too much anti vibe dampening can be just as detrimental as to little, ideally you want your FC to be as solidly mounted as possible while accounting for any vibes that might be effecting it.

I generally never use rubber anti vibes and always mount my fc';s on high density foam which absorbs any stray vibes while keeping the fc rigid enough that the jiggling about doesnt effect gyros and other sensors which is what too much vibe dampening does.

either up spec your rubber to harder versions or switch out to foam mounting.

[Nick Mumby]

Thanks, that makes sense.

I think my problem is more serious than I thought..

Originally I built a quad with;

• S500 frame
• Naze32 Acro
• Propdrive 3536 910kv
• Flycolor Raptor 30A opto ESC';s
• 10x4.5 gemfan plastic props
• Turnigy SBEC
• 8000mAH battery

first time I';d built a quad.. and it flew great straight away in acro/horizon.

I decided I wanted to do some other stuff, so added 12v LED';s, bluetooth, go pro gimbal.
all still working well.

Moved from cleanflight to INav, had a play around with some PID settings and at some point around this time it started to have problems.

Went back to cleanflight with stock settings.. still have issues

Most of the time it just flips on takeoff. Sometimes I can get it in the air but very unstable.

I';ve been though all the standard stuff (more than I did when I got it flying well initially).

Accelerator calibrated
ESC';s are calibrated
ESC using latest BLHELI
subtrim on TX all at 1500

set to quadx
motors in correct order
props turning correct direction
board alignment correct

modes correct aux 1 - arm aux 2 switches between Angle Horizon and Air


I';m stumped... what else could it be?

[Fletch]

Don';t soft mount it unless you really need to

Try reflashing and doing a full erase
Try Running Betaflight
Try the Naze again
Do all the motors/ESCs work from the cleanflight motor test
All Props and motor directions right?

Its not the first time things have been checked, double checked and props still missed as being on the wrong rotation

[Cheredanine]

What are you using to soft mount it?
If motors or props were wrong you wouldn';t get off the ground appart from in some sort of terminally accelerating spiral.

Whilst I disagree with fletch about soft mounting, it needs to be done properly hence the question

[Nick Mumby]

Thanks for the replies.

Prop and motor direction is definitely correct - I';ve spun each prop slowly in cleanflight and compared it to the diagram.



I';ve tried a couple of methods..

1. with one of these


and

2. right now its mounted with some short standoffs on a piece of acrylic with some neoprene foam underneath (which is a bit firmer http://www.ebay.co.uk/itm/351276352073

[Nick Mumby]

brand new Naze. connected it up and one of the motors/esc';s seemed to have  a mind of its own.
It started spinning erratically as soon as the lipo is connected, forwards and backwards.

After calibrating the esc';s it seems to have stopped.

It still wont fly with the new naze flashed with the latest cleanflight/full erase.


Here are a couple of videos...

https://www.dropbox.com/s/kqxx1rfsaicl71f/20170618_180624_1.mp4?dl=0

https://www.dropbox.com/s/j4uvpfquinjn3sr/BLACKBOX_LOG_20170618_181813.webm?dl=0

[shawdreamer]

as annoying as it might sound to be asked this repeatedly but are you ABSOLUTELY sure of your motor spin direction and correct prop rotation?

I only ask because the first video you posted there just looks like the nearest side is down thrusting while the furthest is lift thrusting, theres literally no sign whatsoever of one side lifting atall, exactly like it being anchored down by wrong rotation props or motors.