Winter Vario Calibration and Sticking problem

[Chris Behm]

Hi all-

I have a Winter mechanical vario as backup in my glider. 

I have two issues with it:

1. It reads 1/2 to 3/4 kt positive at rest. 

2. When in a boomer, the needle gets stuck at 10kts up, and I have to tap the panel to get it to drop.

Neither of these "problems" are major, but they are a bit annoying, and I would like to fix them if able.

I read a couple things on the old RAS and then searched here. Not much here.

Old RAS had info for the calibration, two things to check-

1. Needle weight gets less with paint evaporation, throwing off calibration. 

Check this by removing and inverting the vario. If the needle reads exactly the opposite inverted, add weight to the need by a dab of epoxy, nail polish, paint, etc to get the balance back.

2. Spring adjustment behind hidden panel, if the needle holds its positive reading inverted.

For the sticking, someone suggested that the needle may be touching the glass at the extreme end of the range. 

This seems unlikely to me. To me it seems like an area of movement that doesn't get seen very often, and that maybe the movement at this extreme is gummed up? Thoughts?

Thanks!

Chris Behm

304DD

[Dan Daly]

Check for leaks as well; there is a winter tool to tighten (carefully) the ring that holds the glass to the o-ring, and the tubing of course

[Hank Nixon]

Offset van be fixed by balance.

Don't touch the springs
You almost certainly will break a pivot.

Been there done that.

I have one that sticks at 10 up.

The tapping solution beats the likely repair form trying to fix yourself.

UH 

On Monday, September 30, 2024 at 4:55:06 PM UTC-4 Chris Behm wrote:

[Moshe Braner]

I had a Winter mechanical vario that showed very asymmetric readings, small up and big down.  Thanks to tips from UH, figured that somebody has futzed with the spring.  Undid that and added weight to the needle instead.  The tips: You may need a special tool to remove the face bezel.   Turn the vario face-up.  That removes the gravity effect on the needle.  Adjust spring (gear-shaped wheel behind the middle cover) until it says zero.  Rotate back to normal orientation.  The needle will float up.  Add weight to needle until it shows zero again.  I used nail polish.  Add some, let dry, observe, repeat.

[John DeRosa]

I have seen this issue on old mechanical variometers.   I have used the dab of fingernail polish trick.  Worked a treat.  Add very small amounts one drop at a time and testing between drops.

About removing the glass face.  There is a thin (aluminum?) ring that holds the glass in place.   This ring needs to be unscrewed.  As Moshe mentioned you need a "special tool"  to remove that ring  There are two (or more) notches cut into the ring on opposite sides which the special tool will fit into.  By rotating the tool it unscrews the ring.  I made my own simple tool out of a strip of thin steel the correct length and thickness to fully engage the notches.  Then I used a pair of pliers to turn the tool. Note that sometimes both the ring and the glass can be difficult to remove due to the age of the vario.

Best of luck.

John (OHM)

[Charles Mampe]

A better DIY tool is a block of wood turned (on a lathe) so it fits against the glass and just fits inside the ring. Then, cut a slot across it exactly through the center and fit a part of a hacksaw blade in the slot. This supports the blade better while twisting.

[Michael Opitz]

I have always used Tim Mara's instructions from the old W&W web site.  I use an old hacksaw blade cut to the exact length, and

then clamp it in a vice (with rubber covers on the vice jaws) to keep it rigid.  Then I just turn the instrument upside down, position

the matching ring notches on the blade, and then grip the case of the instrument (for best leverage) to rotate it.

Mike Opitz

RO

[Sean Franke]

Winter makes a tool for removing the bezel.  The trimmed hacksaw blade works, but the winter tool is safer. I have used it. No vice clamping or rubber covers are required.

Sean Franke

[Nicholas Kennedy]

https://wingsandwheels.com/b400-borgelt-variometer.html

I've got a dead Sage mechanical in my ship now

After much research this is what I'm going to replace it with

Modern

Back up battery

Not very expensive for what it is.

I've had those winter mechanical varios in the past

For about the same price as a Winter, I think this would be MUCH better

If your power fails and your along way from home I think this  could really help to complete the flight.

That said I did do a OLC 1000 K out of Ely with just  Winter Mechanical after my battery came unplugged early on a good day.

Luckily I had a internal battery powered back up logger.

IMMV

Nick

A2

[John DeRosa]

Sean,

I see the tool now at https://wingsandwheels.com/tool-for-bezel-rings.html .  For rental, not purchase.

Thanks, John (OHM)

[chris behm]

Do you have them at WnW? If so, please provide a link. 

Thanks!

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[Charles Mampe]

Incorrect, you can buy for $49, or, buy for $49 and then ship it back for a $45 refund (not counting any shipping costs) when you're finished using it.

;-)

[Uli N]

I used a wide steel putty knife which I ground to the correct width on a belt-sander to fit into the bezel's slots. The advantage is that it comes with a nice wooden handle and no other tools are required to apply some torque.

Uli

'AS'

[Sean Franke]

It was intended to be a free rental when returned; just pay shipping. This has been corrected.

Best regards,

Sean

[Dave Nadler]

On Friday, October 4, 2024 at 11:19:30 AM UTC-4 Uli N wrote:

I used a wide steel putty knife which I ground to the correct width on a belt-sander to fit into the bezel's slots. The advantage is that it comes with a nice wooden handle and no other tools are required to apply some torque.

I did the same (well OK, I used a grinder). Add a layer or two of wing-tape to the steel blade to
make the tool fit snuggly in the slot and to avoid scratching anything...

[chris behm]

Thanks to all that responded.

I will work on this during the "SoCal 'off season(??)" upcoming. 

Unless I am going to order something else (and it IS likely!) from Sean, I will probably make my own tool to remove the bezel and glass to get at the needle.

I'll invert the ASI and see if the needle is light and if so, add some nail polish or epoxy (MGS? Nothing but the best!) to get it back on zero.

Thanks again.

Kind Regards,

Chris Behm

N304DD

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