Hi,
Like many of you and following the general consensus, I use moongel to isolate APM from my frame's vibrations. I have got quite good results and was at worst in a vibration range of plus or minus 0,2g (between 8 and 12 on the mission planner graph scale).
BUT but but, this was always measured in an ambient temperature in a range of 68-77° F (20-25°C).
However I'm now on holidays in a warm place of France where ambient temps are around 92°F (33°C and more). I fly there a lot and checked regularly my tlogs. Strangely enough, without modifying my craft I noticed a sudden increase of vibrations to plus or minus 0,5g (between 5 and 15 on the mission planner graph scale). I was wondering what the hell was happening.
Until I checked how was seating my APM board on its moongel pads : moongel had been totally melted and was "pouring" fro munder the APM on all sides !!!
Here is the pictures of the moongel pads I found (normally they are nice rectangular and flat):
The moongel pads had "melted" with the hot temperature and were becoming too thin to isolate vibrations effectively.
So I hope you can profit from my experience and adapt your copter accordingly to avoid this bad joke.
I'm still wondering how am I goign to coorect this to contain moongel and use it under hot temperature. Anyone ideas ?
Replies
I finally did the test of hard fixing the APM case to the frame, thus not having two separate masses with vibration dampening materials in between, as before (i.e. : frame/props on one side and APM on the other side).
I created for that a new post as it is outside this topic, click here :
http://www.diydrones.com/group/arducopterusergroup/forum/topics/opt...
Thx for your comments and ideas.
This afternoon I did the following tests :
-First experiment: I wrapped moongel in a plastic food wrap sheet. (You know the thing that drives you nuts in the kitchen because it sticks like hell and you can't cut it). Result is as terrible as before :+- 0,5g
-Second experiment: used four relatively soft silicon cubes underneath each corner of the APM case, then rubberbands pressing a moongel blob on top of the APM case. Result is better : back to +-0,2g
-Third experiment : tried to use a pastry roll to get my moongel bits back into shape. Just forget it. Even in France it does not work.
-Fourth experiment that will wait for tomorrow= what Frantz suggests = APM case tightly fixed on the frame with no isolation.
To be continued...
buy some more moon gel in local music shop...or buy elastic silicon gel for windows instead
Can you do the community a huge favor?
Under as controlled conditions as you can make two flights.
Report the two flight logs.
When I did controlled studies on my APM, the least vibration came when the APM was firmly locked onto the electronics board (and I tried every method discussed in this forum). With the APM securely tied down, the sensors are not as isolated from the motors and the signal to noise ratio was better.
I've heard lots of anecdotal evidence, but haven't seen any actual evidence that goo and gel does anything but decouple the APM from the environment it's trying to control. My experience, though, is only with custom made copters with low vibrations. Maybe goo and gel helps other types of ships.
You could answer a huge question for this forum.
Informative and funny! I'm glad it didn't end badly for your copter.
Interesting. In Texas, they would not have a chance then. I used a double thickness of gyro mounting foam on each corner of my APM. It seems to be working well.
Yeah....I live in the hot and humid Atlanta, GA area so I've already experienced this myself. My solution was to "encase" the moongel in the "Plasti-dip" product shown in this link...http://www.plastidip.com/. I've done this for the moongel underneath my APM as well as my GoPro camera. Seems to work pretty well and minimally impacts the dampening characteristics of the moongel. Over here, you can buy this stuff at any hardware store. Surely there's an equivalent option for you in France.
Good luck
Wayne