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Originally posted by scallybert
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Update and good news - its sorted!!!!!!!!!!!!!!!!!!!!
I changed EVERYTHING on this heli chasing the problem. In the end I was pointing the finger at the motor/clutch/fan assembly so out it came. I'm running the CNC bearing block and found the bearings where pretty shot so I replaced those. I then took a trip down to Probuild in the hope that the YS experts would be able to help with the vibration problem. (btw, the guys down there are fantastic). So, we concluded the engine is fine but the clutch was running high in the clutch bell causing it to rub on the top of the bell. This was basically caused by bolting the engine into the frame with the heli upside-down. The couple of mm drop into the bell caused the clutch to hit the top of the bell resulting in vibration. I should have spotted this but the lesson here is to flip the heli back onto the skids THEN tighten up the mount bolts. Engine running great after this with a lovely calm tank and just a ripple from the pressure waves. The gov sensor was also toast so this was also replaced.
Ok, after all this the vibs have all but gone but the tail is still terrible. Now, I think it was Barney and Raptorheli2 who suggested changing the boom supports. I checked my originals and found a bit of play at the pin joint but a bit of epoxy cured that (or so I thought as it didnt improve things).
Today I was in the area of QuickUK and thought I would buy a new set of boom supports - just incase. I also picked up a set of CNC blade grips and Radix tails. Fitted, test flown and it rocks!! I increased the gain by a huge 12% and it still didn't wag in funnels/backwards.
Now, I'm pretty sure we are saying the boom supports were the issue. Back in January when the Align step down failed causing a crash I didnt replace the boom supports as they looked fine. Or, it could be the QUK tail. I will put the original tail grips/blades back on and test this.
This has been a real PITA the past few weeks guys. My conclusion is that the cause was a number of things included a slightly bent boom (I know, I know!), engine fitted incorrectly and the boom supports being fatigued. I've learned alot from this, mainly to go back to basics and check the basic things before blaming electronics/motor etc.
I'd just like to thank everyone for all your suggestions. In particular I'd like to thank Busterboy and Mattie-Lodge for offering to loan me an engine to rule out the possibility of engine troubles. Thank you guys, I seriously appreciate the offer. Also, to Probuild (Phil and Steve) for allowing me to spend a fantastic afternoon in their workshop. Thanks to Aidi for giving me a gov and sensor to try. Also, thanks to Richie Clark, Mattie and Aidi for listening to me whining about my 700!!!
Thanks guys. Its been an interesting thread this one!!!!!
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