Arrggghh... Bl**dy Gyro's

[Blahblahman]

Hi Guys, after getting my CSM420 to work pretty well and then deciding that its a bit old hat and a newer shiny 720 is the way forward, I've just been over the field only to find the 720 not working at all well.

It takes off ok, but within seconds its doing a wag that can only be described as self destruction, swinging 45 deg left and right. It calms down a bit in rate but its clear that something is very wrong. The mechnical setup should be fine as its not changed since the 420 was on and that worked ok.

I think its only settings so any ideas ?

I've tried gain values for both rate and HH of 50 to 130 but its clear that it just gets worse the higher the gain.

The only other thing is mounting. Vibration filter is off, and its mounted on a single CSM pad, metal plate and then hard mounted to that with very thin double sided tape. If there were problems in this area i would have expected drift rather then a violent wag.

Any help would be much appreciated. Failing advice here its gonna be a call into Dr TrevB and a cheeky trip to the Hayling field.

[colin n]

what aux channel have u got it plugged in to ?

or even a gear channel.

when u say u adjusted the rate did u actually mean that u adjusted rudder dual rate or the value for the gain on the aux/ remote gain channel ??

[heliward0]

daft question i know but have you checked the teeth on your tailbelt and gears??

[Blahblahman]

Mechanically, its all ship shape, like i said, all i've done is replaced the 420 with the 720. I got it second hand so i've email the guy to see if he changed any settings via the PC interface.

Rgearding the gain settings, i tried both... using Gyro for Gear (which never worked with the 420) and 100% rate and then adjusted the Gain on the Gear travel adjust and also with the same setup as the 420 with Gear set to Gear and the gain adjusted just on the Gear travel adjust.

[3dbasher]

something is very wrong... could be many things

[SRH990]

Try removing the thick squidgy CSM mounting pad and replace with a Futaba 401 pad or similar, the CSM pads allow too much movement as I've seen with my Fury Extreme.

[Blahblahman]

I thought about that, the 420 worked best with a thin bit of double sided (actually number plate mounting tape) but everywhere its says to use the CSM mounting pads etc etc so i started with that.

[SRH990]

I had huge problems when my 720 was mounted with the pads at each corner recommended mounting, the heli shook something fierce during flips and the tail always seemed vauge. Since swapping to a single 401 pad it's been much more locked in and since it's been swapped over to my 700N it's now running over 80% gain and is locked in very nicely.

When I came across this on the Fury I suspected the tail servo, a 9254, as I've had a couple go bad on me so I replaced it with a BLS251 - and found it was exactly the same Changing the mount made a dramatic difference, it's got to be worth a try for the cost of a mounting pad. I've been told that the Quick UK mounting tape is very good too.

[Blahblahman]

ok, mounting pad changed... fingers crossed for no rain after work tomorrow for a second attempt.

[Blahblahman]

Thank God for this forum and the willing help of other members.

Firstly lets thanks TrevB for his help today and to Hayling Heli's for their patience in putting up with the non-member who just won't go away .

The problem was with the mechanical setup... not the servo, arm, spacing etc but with the classic noob mistake of having the twist in the tail belt round the wrong way so that the tail blades were acting with the wash from the main blades, not against.

Pulled it apart, twisted it over, back together, Trev helped with the end point setup (99% / 101%) and put the Gyro back to factory settings and were all sorted.

Tails absolutely nailed considering the low head speed and perfect for a beginner like me to get on with the minor matter of learning to fly instead of spending all my time trying to figure out whats wrong !

Thanks Guys. I owe you BIG one.

[trvo]

No probs, always happy to help.

Trev