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