The Dodgy Tail

I recently had a bad crash with my 450 class heli, and I had to purchase a new frame.

I decided to buy a new frame and start from scratch. The build went well and after a few hours I was done. Next followed the fine tuning.

Once I started up the heli I saw trouble on the horizon, the tail was wagging from side to side, very slowly, and rudder input would just cause the tail to move in the opposite direction, and I could not get the tail steady.

Then I had to turn to my recipe on how to sort out your heli tail. (If you want to
add more ingredients, feel free to do so in the comments )

My Recipe is as follows:

1. Check Gyro gain - Done (In my case 35% Rate mode - 75% Head Holding Mode) - Used a HK 401b which I think survived the crash
2. Reset rudder sub trimming to 0 – Done
3. Double check tail rotation direction - Done, tail turning anti-clockwise with the leading edge.
   
4. Check control arm to make sure I have a 90 degree angle with the tail boom – Done
   
5. Check throws on the rudder, and make sure the servo doesn't bind – Done
6. Switch the gyro to Rate Mode and start trimming the tail until there is no drifting.
7. Once the drifting in Rate mode is gone, switch to Head Holding mode, and adjust gyro gain to eliminate tail wagging.

I never even got to step number 8 as the same problem kept kreeping in, the tail would just not stop swaying from side to side...and above all this recipe never failed me before, but I could not get the tail to remain steady without drifting from one side to the other, it was almost as if it was like a swing in the park, swinging from side to side, out of control.

I then turned to the Gyro and replaced it with a ASSN 250 gyro.
Full of hope, I started the whole process again from scratch. Same problem, no solution yet.

I then replaced the Assan with a GY-520 Gyro....same problem. I t was obvious the Gyro was not causing the problem.

I turned to YouTube for advise and spent allot of time on the internet to find a case similar  to mine. NOTHING!

My last option was to replace the whole tail assembly. Seeing that the crashed heli still had a good tail I swopped it with the current one, and as I removed the "New" tail I saw that the bearings was not as effective as the older tail. The "New" tail would stop turning due to drag caused by faulty bearings.

I smiled, installed the old tail which worked perfectly compared to the "New" tail, started the recipe all over again, and then I smiled again, my 450 heli was back, even better than before.

Lessons learnt :

1. Never throw away old parts, always safe what you can.
2. Never blame the gyro, always check your hardware first.
3. Trust your instinct as I had a feeling from the beginning that the tail would be the cause of my problems.
4. New equipment isn't always the answer, use what you have if you can.

Happy flying :)