i'm a novice pilot who has hovered my cp2 in out of the box form. wanting to see how smooth i could get it to fly, i set out fine tuning it yesterday. it appears esky has added a ton of positive pitch at the factory (factory settings are roughly +5 to +25 in FM0 & -5 to +20 in FM1). so i adjusted for -10 to 10 degrees in idle up (FM1), which gives 0 to +10 in normal mode. after this fix, my cp2 started to have the notorious sudden blast off problem. you may have read about this elsewhere, but some ppl have taken their cp2s out, started to spin up, reaching nearly full throttle with no lift, then randomly the heli jumps up 10' high. i never had this problem until i corrected my pitch curve, so i decided to investigate closer to find out why. from my bench testing i observed these symptoms:

1) from spinup, near full power is reached and the collective doesn't respond. suddenly the collective kicks in, RPMs drop, and the heli rockets skyward (LED goes green to red the instant this happens)
2) vibration is noticed when cyclic is added at any speed in any mode
3) one blade was non-responsive to cyclic and collective, particularly at higher headspeeds
4) the non-responsive blade can be "brought temprarily back into track" with the application of cyclic. example: as collective is increased to some point, only one blade responds. the other blade is now out of track, but will go in track if the cyclic is tapped a bit. subsequent changes in collective result in the same behavior, requiring cyclic input to bring the "bad blade" in track.

by fixing the pitch curve to go -10 to +10 in FM1, the headspeed is greatly increased, but so is the centrifugal force acting on the bell hiller arm and its' linkages (hmm, maybe esky had a reason for the high pitch angle: it is one easy way to fix binding, nyuk nyuk nyuk. not laughing). it was apparent to me that binding caused this problem, so i went about trying to smoothen things out. all my ball links had up to 1.5mm of flashing from the mold that i had to remove and the some of the balls were molded out of alignment (i sanded these down a little). i also found that one of my bell hiller arms was binding on its pivot. the binding arm is not obvious on the bench, but if you mimick centrifugal force by slightly pushing the arm away from the hub, it binds a bit.

the only thing i could do to smoothen it out besides removing the mold flashing, is to lube the swashplate bushing with oil, and the bell hiller arms with silicone lube. it's a little more predictable now, but still vibrates on the cyclic. since my blades were only balanced statically, the next thing i'm going to do to smoothen things out is balance my blades the right way (right way=matching blade CGs, not just tape on the tip). i'll let you know how it goes.

my point is not to trash talk here. the cp2 is what it is: an inexpensive heli, and i love the way it flies when it's setup right. i just had some issues setting it up right and wanted to share them here. if anyone has tips to help with binding on plastic heads or any generally helpful advice with cp2/blade binding like better lubes, inexpensive mods..., please report them here.

thanks in advance!