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Old June 18th 13, 10:34 PM posted to rec.aviation.soaring
Peter von Tresckow
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Default Compensated Capacity Flask

Steve Leonard wrote:
On Tuesday, June 18, 2013 1:36:28 PM UTC-5, vontresc wrote:
At the recent VSA meet in Lawrenceville I picked up an old capacity
flask with a built in compensator. This is an old 1 pint vacuum bottle
with a compensation bellows attached to the stopper. This gismo has a
rubber bellows sandwiched between two metal plates. The bellows are
attached to a second input for the pitot pressure. The labeling of the
compensator bits is in German. Can anyone identify the contraption?
Personally I think it is a neat design, and I'd love to learn more about this thing. Peter


Hopefully, the compensator is tee'd on to the line coming out of the
flask. Here is how it works:

Pitot pressure is applied to one side of the diaphram, the other side of
the diaphram is tee'd onto the line between the bottle and the variometer.

You are flying fast, and pull up. Air wants to go out of the flask,
which makes the variometer show a big climb. As speed reduces due to the
zoom, the pitot pressure is reduced on the diaphram, so it flexes away
from the tee and takes some of the volume from the bottle without it
going through the variometer, thus providing total energy compensation.
Or, you are flying slow and push over. You are coming down fast, and air
is trying to go into the bottle. Pitot pressure pushes the diaphram
towards the bottle, adding air to the bottle without it having to go
through the variometer, so it provides total energy compensation.

No total energy probe required. Just need good pitot and good static.
Should work with any flow sensing vario that uses that size of flask.

You may find it is a PZL compensator. Feel free to send me a picture of it, Pete.

Steve


Actually it is not one of the Diaphragm Compensators. This is actually in
the vario flask. I'll take a picture tonight and post a link to it in the
thread.

Peter