On Thu, 04 Feb 2021 13:12:03 -0800, Tom BravoMike wrote:

On Thursday, February 4, 2021 at 8:07:31 AM UTC-6,
wrote:
I’ve seen these described as an option where you don‘t want to share
the TE probe between two varios. However, I can’t find details on them.
I’m just curious about how they work (the theory) and how they are
plumbed? I know most would use TE probe for one vario and electronic
compensation for the other but that’s not an option when using a SN10b.
I’m thinking it might be better to use the probe for the 10b alone and
the KWEC for the mechanical vario rather than splitting the probe
between the two or leaving the mechanical uncompensated.

You can check for the "Wariometr energii całkowitej" paragraph on this
website (in Polish - go down slightly beyond the middle of the long
page) with an image and explanation:

http://www.plar.pl/szyb/instrum/instrum.htm

A similar explanation found elsewhere on the web and translated by
Google says:

"The prototype of KWEC was the Isler compensation box. Schuemann's KWEC
(Polish: Kompensator Wariometru Energii Całkowitej - total energy
variometer compensator) is a flat, tight box; the two equalizing
chambers to which the pressure feeders are connected are separated by a
rubber (latex) diaphragm mounted on a spring. As the speed of flight
increases, the total pressure increases, and thus the diaphragm bulges,
increasing the pressure in the thermos. When the speed drops, the
opposite occurs and the pressure in the thermos drops. This way the
speed changes in the variometer readings are compensated.
KWEC should be located vertically (diaphragm vertical), and also
sideways to the direction of flight (diaphragm parallel to the direction
of flight). This eliminates the influence of weight and acceleration.
The disadvantage of this compensation system is the wear of the KWEC
rubber diaphragm, which should be replaced after approx. 10,000 cycles.
Accurate compensation is difficult to obtain. Additionally, one KWEC
must be used for each variometer."

I may well be wrong, but to me the KWEC sounds more like a TE probe
replacement rather than a device for preventing a flow-based vario from
interfering with a pressure-sensing one.



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Martin | martin at
Gregorie | gregorie dot org