Winter mechanical vario reading high

Pneumatic total energy relies on applying a partial
vacuum (proportional to airspeed) on the static side
of the vario. If you have a leak on the flask side,
then the partial vacuum results in a flow through the
vario and apparent climb. A leak on the total energy
side would just result in poor compensation.

You also mention long plumbing to the flask, this adds
to the total volume on the flask side and can make
the vario over read both lift and sink.

At 03:18 10 April 2006, Alan Meyer wrote:
Hartley,

Could you elaborate a bit on this explanation?

I would think that a leak would lead to a reduced response
in all
modes - showing a reading closer to zero than should
be, whether
going up or going down. I wouldn't expect a consistent
up
indication - but maybe I'm not thinking about it correctly.

Thanks.

Incidentally, regarding the alternative explanations,
my plane is
a 1966 era Libelle H301. The loss of flourescent paint
seems
possible on a 40 year old plane, but I'm surprised
to find the
effect so marked in just one year out of 40.

Alan

'HL Falbaum' wrote in message
news
Mine--(57mm) reads zero on the ground, but about 2
kt high in the air, compared to a
S-Nav. Yes I understand the 'relative netto' thing,
but this occurs while thermaling at
48-52 kt in a DG800B, with the pneumatic switch on
'TE probe'.
In addition, the Winter is faster in response than
the S-Nav with the Cambridge set on
'fast' (1 sec). The DG factory installation has very
short leads off a 'Y' to the S-Nav
and Winter, but they are on separate flasks--both
0.45l, with fairly long leads.

I'm guessing a very small leak in the Winter. I have
just removed it and will test
tomorrow.

I thought it was just me!

--
Hartley Falbaum
'Alan Meyer' wrote in message
...
Last year my Winter mechanical variometer may have
read a bit
high, but not very much. Today however, on my first
flight of
the year, the vario appeared to read 400 feet high
in the air and
about 75 feet high on the ground. With the vario
reading 400
feet per minute up, the altimiter wasn't doing anything
and the
Cambridge electric vario was reading zero sink.

I've searched the r.a.s. archives and found the advice
about
zeroing the needle using the adjustment under the
faceplate and
putting a trace of nail polish on the needle to weigh
it down.

Do these seem like appropriate repairs for this problem?

Can anyone speculate on why the vario might read so
much higher
in the air than on the ground? Is there a plumbing
problem I
should look for to explain this?

Thanks for any ideas.

Alan