Motors surging & Yaw odd interaction

[steve fh]

Hi.

Ok so having found a work around to the arming problem (see other thread) I finally had the new quad ready for pre flight set up and a test hop this evening. Or so I thought.

So props on arm the quad and keeping it held down bring the throttle up until the motors start (together)

feed in some pitch and roll and i can feel the machine responding as expected and when rocked you can feel the quad compensate.

Then try some yaw and things get odd. The motors surge randomly and quite violently after which revs are higher even though throttle is the same. If i yaw by hand you can feel it try to control it so it';s trying to stabilise.

Back indoors with the props off you can hear the motors change pitch when yaw is fed in but they do not settle back to where they were when yaw is centred ??

So where to look first ? is this an ESC calibration issue ? radio issue ? vibration issue ? PID issue ?

Help.

Spec as bellow.

Spider 635 frame
Sanwa 35mhz 6 chanel radio (to be upgraded once the rest of the kit works)
Cirus AIO Pro V2 (no extension boards or GPS at this time) powered via ESC BEC
MegapirateNG V2.8 R3
TBS 750kv Motors
TBS 30a ESC';s (simonk)
10x4.5 props
4S 4000mha Lipo

[Jumpy07]

Think need video to understand...

Take it you have done all the basic';s.. ie: calibrate level, EC';s etc etc ?

[Gaza07]

Yea a video might help to see whats wrong 

[steve fh]

Right i noticed running through the setting in the mission planner that the default P values in the stabilise set up were way above those mentioned in the Arducopter PID set up guide.

Dropped them down and the whole thing calmed down enough for a few test hops.

Still something odd going on but i';ve an idea it';s being caused by ageing 35mhz TX. Time to get the Credit card out i think for some 2.4ghz kit. I';ve spent too much time and money on the rest of the kit to trust it to the old gear.

Question is do i go for the supposed better quality spectrum 6i or have the expandability of one of the x9 systems ?

[Gaza07]

If you PIDs are wrong you might want to drop in to the CLI and run a erase and reset to make sure there are no parameters mixed in from another firmware, doing the erase and reset will wipe all the parameters and then put them all back as default for the firmware your running 

[steve fh]

I did an erase the other day to resolve a few other issues so there should be no old firmware settings.

I';m thinking the issue is possibly now a TX or RX hardware issue as they are getting old.

The brief hops i did this evening were enough to suggest the aio board and esc';s are set up ok and it';s like it';s getting erratic throttle value from the TX or RX

Just about to order some 2.4ghz kit to be sure.

Thanks for the input

[steve fh]

Ok so this evening i';ve reduced all the P settings and the whole quad has calmed down a lot.

Held in my hand the whole machine seems to behave, responds as expected to stick inputs and does nothing odd and self levels after stick inputs

However every time i try to fly the motors start to surge and the quad flips left very quickly.