Quick Tips: Good-bye to Bad Vibes
Vibration on your airframe can be a pesky problem and not just because it causes distorted video – the dreaded rolling-shutter or ‘jello’ effect. Bad vibes caused by unbalanced motors and propellers, dirty or damaged bearings, can trick the flight controller into a cascade of over-corrections that end up in a wobbly flight or even loss of control. If you experience unusually wobbly flight you can de-tune the flight controller to be less sensitive to vibration or to respond less aggressively, but maybe just isolating the physical problem is an easier answer.
Unbalanced props and motors are a pretty common problem, but ordinarily the vibes they cause shouldn’t be too severe by the time they travel through the frame to where your flight controller sits.
If your aircraft design has a clean/dirty section it is really important to minimize accidental contact between the two. This morning my hexacopter flipped itself in reaction to vibes transferred from the dirty plate by the head of a zip-tie. The fix? I just moved the tie to a spot with a bit more clearance.
Clean/dirty designs just try to keep inevitable vibrations isolated where they won’t bother anything sensitive.
Some kind of flexible material, like foam padding or rubber damping bobbins keep the two sections separate. The idea is nothing new; it’s the same as shock-absorbers and soft tires on a car. The ‘clean’ section usually includes the mount for the onboard flight camera (GoPro or Mobius) and perhaps the FPV camera. In some cases the flight controller mount is in this ‘clean’ area, too. If your airframe flies a little twitchy and your flight controller is in the ‘dirty’ section, consider using some foam padding or other flexible material between it and the frame.
When Shock Absorbers Fail
Wait! I added some foam under my camera and flight controller and I still have problems!
Shock absorbers can be anything from a bit of memory foam or velcro to adhesive rubber products like Moongel, but what’s effective for one application may just make things worse in other cases. Generally, the less mass you want to isolate, the more give the material must have. That’s why what works for a GoPro Hero that weighs 70-100 grams might not be effective for a little Mobius that weighs 38 grams. You may just need a little trial-and-error to get rid of the problem entirely without resorting to tweaking settings on your flight controller.
If you have any effective vibe-dampening solutions or materials, leave a comment. Part of the fun with RC flight is the DIY troubleshooting, but we can always learn from one another!