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:
- Check Gyro gain - Done (In my case 35% Rate mode - 75% Head Holding Mode) - Used a HK 401b which I think survived the crash
- Reset rudder sub trimming to 0 – Done
- Double check tail rotation direction - Done, tail turning anti-clockwise with the leading edge.
- Check control arm to make sure I have a 90 degree angle with the tail boom – Done
- Check throws on the rudder, and make sure the servo doesn't bind – Done
- Switch the gyro to Rate Mode and start trimming the tail until there is no drifting.
- 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 :
- Never throw away old parts, always safe what you can.
- Never blame the gyro, always check your hardware first.
- Trust your instinct as I had a feeling from the beginning that the tail would be the cause of my problems.
- New equipment isn't always the answer, use what you have if you can.
Happy flying :)
That'll bite you in 30 years. ;)
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I am using a Corona MG939 digital servo, works since day one. Not the fastest servo out there, but works great.
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