There are always some adverse effects when combining several instruments on
the same pneumatic source, there are greater degrees of these errors when
combining transducer types (as almost all electronic types are today) with
vane or calibrated leak type and thermister types...these errors can be
reduced some with more "creative" plumbing, but honestly.the errors are
generally small......and in most club type gliders in the hands of many club
type pilots, generally what they look at is the ups and downs indications
more than the ups .010 knots as opposed to .015 knots indications....even in
most "so called" sophisticated competitions sailplanes, I seriously doubt
their pilots really know just how accurate or inaccurate their indications
are, though they may have done a little more to tune their TE systems, few
ever get the indicated average on their flight computers to match their
altimeters....try it sometime...read the averager, set a stop watch, try to
maintain the average (even in smooth air in glide) and compare....you might
be surprised..but up is still up and down still down......a needle-width
will not make any of us great champions or losers...
The vario will report what it sees......meaning if you have good pneumatics
the instruments should indicate correctly....as for response rates and
dampening, that is generally in the variometer design quality. Most today
are usually good.....
features you can compare that are selectable by the model and choice you
make are quality of construction....display quality, visually and
durability..audio sound and quality through the ranges...ad finally things
like RF shielding...
I've flown with nearly all types you might mention....I tend to prefer the
"feel" for lack of a better description, of a needle movement (no....I'm not
a junkie) as opposed to the LCD types...it just looks or appears more like
the sensations in flight....I think this is a little easier on club type
flyers also since it's more natural along other mechanical instrument
movements....Since I do sell instruments I have both LCD types and normal
needle types.....I have no special bias to either...
tim

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"Bruce" wrote in message
...
Time to start a new debate.

How do pressure transducer varios compare to traditional mechanical varios
in club use?
Can you mix and match a capacity vario and a pressure transducer vario on
a single TE probe?
Do students - please note NOT experienced pilots - find the lcd display
units easy to use, or are moving needle varios better (I know we should be
using the audio - but for the times when we want to see the climb
performance the question is still valid)

We are looking at replacing some vintage mechanical varios, and have some
debate about the advisability of needing electrical power for the vario
and the relative benefits of the Borgelt B40 and the Tasman V1000, and of
course another set of Winter mechanicals...

Being a computer type, I am biased towards the "no moving parts" V1000.
So - any views?

Bruce