T E Compensation

All

Last May '02 I flew Estrella, Az and had a great experience.

I was particularly pleased with the state of the SGS 2-33's.

Bruce had TE compensated the seemingly common vario's.

The TE probe that ran down the aft side of the pitot static tube with the venture hole on the aft side penetrated a hole that was drilled in the pitot static probe base plate and the TE probe passing to the back side of the instrument panel.

They were a great aid to the experience.

The Illini Glider Club has two 2-33 with uncompensated vario's.

My question: Can A PZL and Winter 39362 vario be compensated.

As best I can tell there appears to be no data requiring a flak size.

TIA

Thanks Tim Is there a certain flask size? Your web pages indicate a .45 liter flask would work.

Thanks Rod

Mike Where can diaphragm compensators be purchased?

Try the Bielsko 1 guys in Poland or maybe someone here has one or more in the back of a cupboard that they would be willing to give you.

These things aren't popular anymore as they are difficult to set up properly and only provide correct compensation at one altitude. They also depend on a vario with a separate flask which is getting rare(read obsolete) apart from mechanical varios(I haven't had one of those for the last 24 years either.)

It is just my personal opinion but I think the diaphragm compensator was one of the giant setbacks to glider instrumentation beating even the Macready ring.

I must get around to writing the 'history of varios' article for the website.

Mike Borgelt

Mike Let me summarize what it is I think I know: 1. The PZL mechanical (diaphragm, vane,tautband?) vario in our 2-33 can be TE compensated- 2. Compensation requires a TE probe AND? a capacity bottle- 3. Guessing now-the vario now has Pstatic only- so I need to attached a TE probe to the Ppitot side and Pstatic PLUS a capacity bottle to the static side

All subject to what the glider actually has -I'll find out tomorrow.

Thanks Rod

Let me summarize what it is I think I know: 1. The PZL mechanical (diaphragm, vane,tautband?) vario in our 2-33 can be TE compensated- 2. Compensation requires a TE probe AND? a capacity bottle- 3. Guessing now-the vario now has Pstatic only- so I need to attached a TE probe to the Ppitot side and Pstatic PLUS a capacity bottle to the static side All subject to what the glider actually has -I'll find out tomorrow.

I think you are a little confused. Mechanical varios ALL have a capacity bottle, as it is this which provides the constantly updated reference pressure used by the vario to measure whether the outside pressure (whether from static port or TE probe) is rising or falling. To achieve a Total Energy compensated vario, use a TE probe attached to the 'Static' input of the vario, and the capacity bottle attached to the 'Capacity' input of the vario. The TE probe provides a pressure at the vario input which is the outside static pressure MINUS the dynamic pressure due to speed of the glider. If you do the maths, you will see that the difference between this pressure and the immediately previous stored value in the capacity bottle gives a measure of the rate of change in total energy of the glider. Reichmann has a good explanation of this in his book on cross country flying. Cheers, John G.

Tim answered your question in 3 Sentences! Then came the other guys and sidetracked this Subject with netto, which comes later maybe! I will have to read Mikes site, but did not have the time. Also, if you would have looked at the 2-33 at Estrella, you would have found that the TE Tube/Hose went to the static port of the vario. It is that simple. Leave the rest alone and have someone help you find a little tube like you saw on that AZ 2-33. There is some experimenting to be done with the location and configuration of that TE Tube. Get together with the local instructor, and the two of you....read up on it! BTW The other tube on the 2-33 is pitot (pressure) only. I forget where the static holes/tubing come from , it may not need any. But look for them on the preflight!

Think Up!

Rod,

Simply take the present connection of the vario to static and connect that line to a TE probe. Simple!

Mike Borgelt

Correction! I had forgotten, sold my 2-33 six years ago. Remember vagely now! The ship does have the static and the pitot tubes right next to each other, right in front of the windsield , so to speak. I think I installed a third tube right behind the other two, going streight up with the small cuts in the back.

Sorta off-topic: If you're handy with a soldering iron and a drill, you can easily make your own Nicks style TE compensation wand. Here's a link to a Les Sebald article in Soaring about making your own combination TE probe and radio antenna:
http://www.soaridaho.com/Schreder/Construction/ T_E_PROBE_ANTENNA.html

I've made almost twenty of these things, and they seem to work fine in both regards. It's not the greatest show on earth, but for a couple-three dollars in parts you can't beat the bang for the buck. The one on my HP-11 is just a fabulous radio antenna.

You can also just use the dimensions in that article to make just the TE wand part, and forget about the stuff for the antenna. That works OK if you locate it carefully. The extra height required to make it work as an antenna makes it a bit less sensitive to location.

Thanks, and best regards to all

Bob K.

Mike and Jonh

Now that I understand.

Thanks all for the help

Regards