vbar failure with humidity and low temperature !

Hi
Me and my friend experienced vbar failure with low temperature and humidity last week_end !
The 2 helis could not even hoover without oscilating in both axles ( aileron and elevator ) as if there was
way too much gain !!
Back home after transport in warm car , it hoovered without a problem in the garden
Did someone experience that ?
Regards
Andre

Hi.

Without more specific information, I'd say it's a dampening issue. I've been using VBars well below zero deg Celsius for years.
Only issue imo, it can develop drift, but you can come around this by powering up, letting the electronics warm up, then cycle power again to get a new center reading.

Cheers

Eddi

Born to fly ...
forced to work.

Rather, check links!

I have winter loose links, meaning they bind BADLY if you do not have them really loose in room temp, have friends who locked up helis totally in the winter, crashing from it.

Put the heli out in the cold, unhook the links from the servo and try moving by hand.



Edited 1 time(s). Last edit at 02/03/2012 12:54PM by MrMel.

Hi
Mr Mel , this was my first thought because it behaved like a gyro for tail rotor having hard linkage and searching neutral .
We all experienced that once !
So I think the cold weather retracted the links on the balls .
Coming home I checked if the links were free , and I noticed all where not
I squeezed the links with pliers on the balls to get free operation
This must have helped
Will try tomorrow , as temperatures are again very low here !!
Another thing , last week-end , not only it was cold , but there was a lot , really alot of humidity in air : this is why I suspected electronics!
Thanks for your opinions
Andre

Hi
Just report here what I experienced this week_end : Both helis , my friend's and mine don't fly !!!
We checked every link , all loose : no issue !
I ordered new rubber dampers for the head , we will try .
It's a temperature problem as hovering the heli in my garden , after a while at home temperature , is OK !!!
Regards
Andre

Hi Andre,

what r/c equipment are you using on both helis?

Eddi

Born to fly ...
forced to work.

Hi Eddi,

For my part 617 Futaba reciever 3151 futaba servos , Hacker motor and Kontronik Jive
My friend has got different servos , align I think

Both helis ( logo 500 se ) flying "very well" since 2 years

My lockheed kavan flew well same weekend ! only difference : mini Vbar " inside the fuse " !

Regards
Andre



Edited 2 time(s). Last edit at 02/07/2012 07:51AM by andre.

Hi again,

well from the specs of the futaba servo imo it could be possible that they are struggling to overcome temperature influences.

Are you using the Jive's BEC?

In my career I once had a swash plate (an other brand ...) that was binding that much in the cold that it was hard to tilt it manually.
The ball links were well-worn but still going tight in the cold. I checked and found out since the heli was feeling sluggish and delayed to inputs.
I don't recall exactly if that was still with retro bar or already with VBar, though.

Eddi

Born to fly ...
forced to work.

Hi
Yes i use Jive's bec
I checked everything even the swashplate : loose
Another thing : As the Vbar is outside and recieves the airflow of the blades too , temperature being -5 outside , the Vbar must "feel " a temperature way below , something like - 10 or higher perhaps !!
I think electronics cannot work well in these conditions
Next step I will try to keep the Vbar more hot protecting it with some material above ; I hope this will help concerning the airflow of the blades
Regards
Andre

Well, theory has it that the windchill factor does not affect 'things' as much as 'life forms'.

Here's an old thread concerning temperature.

Maybe RV or ulrich can clarify on this one.

Eddi

Born to fly ...
forced to work.



Edited 1 time(s). Last edit at 02/07/2012 02:20PM by Eddi E. aus G..

Oszillating on the Swashplate is a typical effect in low temps. Its the head dampening which is stiffening up with cold temps.

The electronics can work with very low temps usually even if not specified that low. The Reason is, that the devices produce some internal heat, that keeps the temps on a good level inside the box. A plastic box does a good job here, much better than any metal cases.
VBars do have an internal heating system, that takes care of very low temps. On the separate sensor you can watch it lighting red if switched on in cold temp. After a few seconds it has heated up enough to match the minimum working temp. So the Sensors have more temp than the outside temp.

To help the electronics you can do 2 things:
- try to avoid quick temp changes on the sensors (i.e. cover the device with foam to avoid direct rotor wind).
- Switch on the Unit, let it run a few Minutes, then switch of/on again to get a fresh init.

Anyway, the oszillation is not an effect of cold electronics, so these actions are only applicable if you have even lower temps.

so long ... Uli
http://www.vstabi.de

Hi.

– 6 °C / 21 °F, 48 % humidity ... no problems but a tighter going tail slider (having some oscillations on full collective/full tail maneuvers that weren't there in the warm) and an occasionally ringing tail belt.

Logo 400 SE @ 2.250 and 1.800 1/min, Logo 400 dampening (soft).
Standard size VBar with sensor on the lower deck, Turnigy Plush 80A BEC as a power supply.

Cheers

Eddi

Born to fly ...
forced to work.

I fly much in cold winter days. -25 celcius and the helis fly nice. But the pilot freeze more so only 1-4 lipos and go home.