Mechanical vario stuck on 5 kts up

[Movses Babayan]

Mech vario (PZL, I believe) got stuck on 5kts up. When lift exceeds that (e.g. on tow), needle moves up and then back down to 5. Never goes below 5.

Electric vario that is, to my best knowledge, connected to the same TE source behaves normally.

Questions:
- Can something like this be caused by an issue in the tubing, etc. or is it more likely an internal issue with the vario itself?

- Any particular way to tell?

Thanks,
-MB

[jfitch]

On Sunday, March 25, 2018 at 9:09:19 PM UTC-7, Movses Babayan wrote:
> Mech vario (PZL, I believe) got stuck on 5kts up. When lift exceeds that (e.g. on tow), needle moves up and then back down to 5. Never goes below 5.
>
> Electric vario that is, to my best knowledge, connected to the same TE source behaves normally.
>
> Questions:
> - Can something like this be caused by an issue in the tubing, etc. or is it more likely an internal issue with the vario itself?
>
> - Any particular way to tell?
>
> Thanks,
> -MB

I'd just pull the stick back and go with it......

[Senna Van den Bosch]

Op maandag 26 maart 2018 06:09:19 UTC+2 schreef Movses Babayan:
> Mech vario (PZL, I believe) got stuck on 5kts up. When lift exceeds that (e.g. on tow), needle moves up and then back down to 5. Never goes below 5.
>
> Electric vario that is, to my best knowledge, connected to the same TE source behaves normally.
>
> Questions:
> - Can something like this be caused by an issue in the tubing, etc. or is it more likely an internal issue with the vario itself?
>
> - Any particular way to tell?
>
> Thanks,
> -MB

Our club's Twin III vario behaves the same. When winch launching it will stick to 5 and on release stays there. We just tap the window very gently and it will come back down every time. Maybe the same problem?

[[email protected]]

Happened to my Winter 57mm vario.
Removed the vario with the intention to ship it for repair (opening it is best left to experts, the risk of total damage is relevant).

tapped the vario on the table, glass facing down. Gently. It now works perfectly. Maybe service can wait. Maybe I just didn't know what I was doing...

Aldo Cernezzi

[Chris Rowland[_2_]]

At 09:39 26 March 2018, wrote:
>Happened to my Winter 57mm vario.
>Removed the vario with the intention to ship it for repair (opening it is
>best left to experts, the risk of total damage is relevant).
>
>tapped the vario on the table, glass facing down. Gently. It now works
>perfectly. Maybe service can wait. Maybe I just didn't know what I was
>doing...
>
>Aldo Cernezzi
>
These varios depend on a vane moving in a chamber to measure the air flow.
The clearances are very tight so the slightest interference can cause it to
stick.

Maybe the tapping was enough to dislodge some tiny obstruction.

Maybe with the cheapness and simplicity of digital pressure sensors it is
time to consider going totally electronic, at least for varios.

Chris

[[email protected]]

On Monday, March 26, 2018 at 7:15:05 AM UTC-4, Chris Rowland wrote:
> Maybe with the cheapness and simplicity of digital pressure sensors it is
> time to consider going totally electronic, at least for varios.

I love having a backup that is independent of the battery system. Yes there are some electric varios with a built-in backup battery, not sure I'd be satisfied with that.

[Charlie M. (UH & 002 owner/pilot)]

Agreed.......2 separate systems (for the most part, may use the same pneumatics) is better.

Yes, I have flown with the pneumatics failed for both.
Then I rely on the "butt vario" and watching the altimeter.

Then go back to training......"does it look right, does it sound right, does it feel right"!?
Hopefully you were trained correctly.