Problem Tail Wag

[blueskiesdz]

Hi guys,
I'm hoping you have a solution for a troublesome tail wag on my newly build 360. Kept it standard with an Ar7200bx, align servos but have had horrendous tail wag resulting in loss of control. I had my gain initially at 40 then wound it down to 30 then more wags and crash.

I've read many of the threads but just need clarification that the gain needs to be quite low and also the tail works best if the control horn is closer to the centre on the servo. It was at 12+ mm away from the centre but I've read 6mm is better.

Just like some advice after rebuilding the tail as I really don't want it happening again !!!

[Shogun71]

I have my tail servo ball 7-8 mm from center.

[Jeff_Barrett]

Try the ball at 8mm first ... do you visually see any tail vibes along the tail boom or tail fin?

[waxman]

Make sure you have set the travel up correctly if you just wound the slider untill it bound both sides then backed it off a bit you will have trouble lots of trouble. You should only have 9/10mm travel refer to manual.

[uiron]

debugging tail wag is a an art form few tricks from my camp:

1. measure pushrod resistance - with safety glasses and other precausions first: disconnect pushrod from servo, take off main blades, and power it on like this; run it at medum RPM, I'd say 2700-range for warp, try pushing/pulling servo pushrod (carefull, it will make tail want to move - hold things firmly). This will let you get an idea how much work tail servo has to do. multiple sources of resistance here, mainly bad bearings that only act up under load.

2. checking for vibrations - obvious one, of course. when all things fail, method "build from ground up" works best - disconnect everything in the drive train and spin it up - in Warp's case, just motor with belt disconnected. Then motor+ main shaft, no head or tail. Then motor+shaft+tail without tail hub. continue into motor+main shaft+tail shaft+ tail hub without blades. Last two phases with tail blades and with main head. Inspect how much vibrations increase with each next piece added, and act accordingly, e.g. "vibrations with tail blades increase a lot? balance tail blades or tail bearings show signs of wear/damage under pressure".

3. invest in good tail servo (I'd go for this step in any case). Align, especially in micro/mini category, is sub-par at most. if budget does not allow for DS95i, reviews were not bad for knockoffs (Servo king DS995i or KST). There's no more maddening thing in flying a heli than fighting a sub-par tail (looking at you, Blade micros!).

4. not an expert of beast, but maybe mounting pad could be inspected and replaced with softer/more layers? check other source of vibration to FBL unit, like wires firmly attached to the frame "on a short leash").

[blueskiesdz]

cheers guys much appreciated ! I'll follow your advice and post the result.