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Old Dec 19, 2011, 05:02 AM
r0sewhite is offline
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It wasn't me
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Augsburg, Germany
Joined Mar 2010
437 Posts
It is most likely that either your PID settings are too high or that you have too much vibration. The best way to start is to work on the cause and not on the symptom.

So we start at the props: Put the 3-bladed prop on a balancer. We assume that each blade has a different weight. The lightest one will face most upwards, the heaviest one most downwards. You have to decide wether to add or reduce weight.

When you want to add weight, you take the lightest blade first which shows most upwards. Add weight until one of the other two blades shows exactly 90 upwards. The two lower blades now are in balance. Then you take the blade which shows upwards and add weight until the prop will stop turning at no special point anymore.

After your props are balanced you should take a look at the construction. Hold the copter tight in your hand and give throttle to check wether the frame is stiff enough or if there is a range where the frame starts to vibrate badly. Check the whole throttle range. If you can't improve by balancing, you must get your frame stiffer. Paul added some cf rods to the frame kit which should be glued on the lower side of the frame. Did you do this?

If the frame is stiff enough, check the pad which dampens the sensors. The lighter the sensor BOB is, the stiffer the pad must be. Sounds strange but is right. Try a stronger pad.

If you have followed all 3 steps above, all what's left to do is PID tuning. Though there are no real rules in PID settings, I found out that the lighter and smaller a copter is, the lower the proportional (P) value for pitch and roll can be. A good value to start with is 1/10 spread -1. That means if your copter has 40cm spread, divide the 40cm through 10 which is 4 and count off 1, which is 3. With the flydumini you can start with a P value of 2.
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