Pneumatics Question

[jsbrake[_2_]]

Hi All,
Whenever I accelerate, my varios bump up and tell me I'm climbing,
then settle back to reality. Any idea of what I need to look for to
fix this?
My setup:
Kestrel 19, two static ports in the tail boom, pitot and TE in the
fin. The TE line is split under the seat using a Y connector and then
travels to two varios (a Winter mechanical and a 1990-era audio/final-
glide called a VariCalc). Pitot and static lines are split behind the
panel using T connectors.
I replaced all the non-permanent tubing last year and they all seemed
to be leak-free.
Thanks!
-John

[Tuno]

John,

I don't think you can have more than 1 pneumatic (mechanical) vario
connected to any TE pressure source. Did you have this vario
configuration before you replaced your tubing?

If it's not too much trouble I would try testing each vario
individually, pinching off (or replacing) the Y connector under the
seat so only one vario is connected to the TE at a time.

ted/2NO

[Darryl Ramm]

On May 24, 6:32*pm, jsbrake > wrote:
> Hi All,
> Whenever I accelerate, my varios bump up and tell me I'm climbing,
> then settle back to reality. *Any idea of what I need to look for to
> fix this?
> My setup:
> Kestrel 19, two static ports in the tail boom, pitot and TE in the
> fin. *The TE line is split under the seat using a Y connector and then
> travels to two varios (a Winter mechanical and a 1990-era audio/final-
> glide called a VariCalc). *Pitot and static lines are split behind the
> panel using T connectors.
> I replaced all the non-permanent tubing last year and they all seemed
> to be leak-free.
> Thanks!
> -John

Did it do this before you changed the non-permanent tubing?

Why was the tubing changed?

Did you do a real leak down test?

I would do the idiot test of confirming you have the vario connected
to the TE line (blow gently onto the the TE probe and confirm you hear
it affecting the electronic vario). But if you've got the static wired
to the TE you would expect the opposite of what you see. That makes me
suspect you have the TE line open to cockpit pressure somewhere. Other
options like a leak across the TE/static circuits with certain types
of TE probe/mount failure would also produce the opposite effect (i.e.
would show sink when you speed up). (And BTW thank you Mr. Greenwell I
was the idiot with the triple probe static port blocked with grease).

The variocalc has no capacity and the winter is connected to a
capacity flask. You rely on line impedance for this not to be a
problem, so good you have the TE line split far away, like under the
seat. The static and pitot lines are (obviously) irrelevant to the
vario.

It could be a TE line open to cockpit pressure. It could be a leak in
one of the varios themselves (less likely, but try taking one vario at
a time out of the pneumatic circuit). If things are leaking/open to
cockpit pressure it is hard to say for sure what they will do as you
speed up, depends on the cockpit venting. Does opening closing vents
do silly things?

I've found a nylon "T" piece once that was cracked wide open and
leaking so check things like that over carefully.

You can exclude the capacity leaking by taking the whole winter vario
out of the circuit, or you can block the capacity port on the winter
(which should then do nothing).

If all that passes, swap TE probes with another glider and test. What
type of TE probe is it?

Darryl

[sisu1a]

> Kestrel 19, two static ports in the tail boom, pitot and TE in the
> fin. *The TE line is split under the seat using a Y connector and then
> travels to two varios (a Winter mechanical and a 1990-era audio/final-
> glide called a VariCalc). *Pitot and static lines are split behind the
> panel using T connectors.
> I replaced all the non-permanent tubing last year and they all seemed
> to be leak-free.

Tailboom static. Prolly used to work OK till you fixed the leaks.
Simple test. Unplug the static tee from the tailboom source and let it
use cockpit air. Fly the ship and try to recreate the creeping
readings while using cockpit static. Lots of older ships had their
tailboom statics relocated due to errors induced at that location. At
least it's an easy test...

-Paul

[Darryl Ramm]

On May 24, 8:22*pm, sisu1a > wrote:
> > Kestrel 19, two static ports in the tail boom, pitot and TE in the
> > fin. *The TE line is split under the seat using a Y connector and then
> > travels to two varios (a Winter mechanical and a 1990-era audio/final-
> > glide called a VariCalc). *Pitot and static lines are split behind the
> > panel using T connectors.
> > I replaced all the non-permanent tubing last year and they all seemed
> > to be leak-free.
>
> Tailboom static. Prolly used to work OK till you fixed the leaks.
> Simple test. Unplug the static tee from the tailboom source and let it
> use cockpit air. Fly the ship and try to recreate the creeping
> readings while using cockpit static. Lots of older ships had their
> tailboom statics relocated due to errors induced at that location. At
> least it's an easy test...
>
> -Paul

He has a TE. Neither vario should be connected to a static source. The
old VariCalc I beleive have a single TE connection and is a direct
reading type electronic vario (no capacity flask).

Darryl

[sisu1a]

> > Tailboom static.
>
> > -Paul
>
> He has a TE. Neither vario should be connected to a static source.
>
> Darryl

POOF! (the sound of me vanishing in a puff of logic...)

[Mike the Strike]

What Tuno said......

Mike

[Peter Gray]

On 25 May, 02:32, jsbrake > wrote:
> Hi All,
> Whenever I accelerate, my varios bump up and tell me I'm climbing,
> then settle back to reality. *Any idea of what I need to look for to
> fix this?
> My setup:
> Kestrel 19, two static ports in the tail boom, pitot and TE in the
> fin. *The TE line is split under the seat using a Y connector and then
> travels to two varios (a Winter mechanical and a 1990-era audio/final-
> glide called a VariCalc). *Pitot and static lines are split behind the
> panel using T connectors.
> I replaced all the non-permanent tubing last year and they all seemed
> to be leak-free.
> Thanks!
> -John


A TE system in which the negative dynamic head compensation is exactly
'right' will do just this. It does not not necessarily indicate a
fault in installation. It is generally manifest during vigorous
changes in load factor. A TE vario reflects rate of change in energy
height not actual height so if you pull/push g the change in induced
drag as a result of load change represents a change in energy. e.g.
Pull up and increase load and therefore induced drag and your total
energy reduces which is manifest as sink on your total energy vario.
And vice versa.

Some commercial probes compensate for this by being deliberately not
quite exactly 'right'. Many probes are not spot on because the maker
can't manage it which is almost invariably true of any home made
device or one of poor design such as the Nicks and Braunschweig tubes.
Thus your observation is relatively uncommon.

If your system is truly reflecting your energy changes then try flying
a little more smoothly for you are throwing energy away.

There is no reason why you should not couple two varios to one TE
source but put the Y connector as far away from the panel as possible
to prevent one vario puffing into the other.

[jsbrake[_2_]]

To answer some of the questions posed regarding my setup:
- I replaced the non-permanent lines last year because they were quite
old and looking dry. I was also having TE troubles. The replacement
lines tested leak-free (I hooked up a hyperdermic and an ASI, the
speed held when I pushed the plunger). I left the hard plastic
original lines in place, figuring they weren't part of the problem.
- I split the TE line under the seat when I replaced the other
tubing. It was originally split with a "T" at the panel and I read
that this was a no-no (article by Mike Borgelt)
- I tested all the hard plastic lines with the hyperdermic an ASI,
they all held the pressure.
- then traced my original TE troubles to a leak in the 4-way connector
at the panel. Replaced the connector this year.
- I don't recall the varios doing a quick jump when I accelerate.
It's rather reminscent of a "stick thermal" on non-TE varios, lasts
only a couple of seconds
- I'm not doing hard accelerations, at least to my mind. Not feeling
much force on my body
- Winter mechanical has a capacity flask mounted under the instrument
hood. VariCalc has no flask.
- I'm not sure if there were vario changes when I opened or closed the
vents as I wasn't paying attention to that aspect.
- the VariCalc has connections for all three lines; the Winter
mechanical connects to TE and capacity. A problem in static shouldn't
affect both instruments.
- the TE probe is a simple straight out and then bend down, with 2
slots. No idea who made it, but I suspect it came standard from the
Slingsby factory in 1972.

According to Mike Borgelt's article, it's okay (but not best) to
connect two varios to TE, but they should be split as far away from
the instruments as possible. The farthest back I could get was under
the seat, since I'm too big to fit into the boom and all those pesky
control connections were in the way.

I'll try blocking off one vario at a time to see if that changes
things.

The VariCalc has an option for electronic compensation, but I read
somewhere that it's not as good as using a TE line.

[[email protected]]

On May 24, 9:32*pm, jsbrake > wrote:
> Hi All,
> Whenever I accelerate, my varios bump up and tell me I'm climbing,
> then settle back to reality. *Any idea of what I need to look for to
> fix this?
> My setup:
> Kestrel 19, two static ports in the tail boom, pitot and TE in the
> fin. *The TE line is split under the seat using a Y connector and then
> travels to two varios (a Winter mechanical and a 1990-era audio/final-
> glide called a VariCalc). *Pitot and static lines are split behind the
> panel using T connectors.
> I replaced all the non-permanent tubing last year and they all seemed
> to be leak-free.
> Thanks!
> -John

Next question is do they go down when you pull up. If both events
occur, you are somewhat over compensated.
Depending on the type of probe, this may be able to be tuned.
UH

[Peter Gray]

On 25 May, 15:13, wrote:
> On May 24, 9:32*pm, jsbrake > wrote:
>
> > Hi All,
> > Whenever I accelerate, my varios bump up and tell me I'm climbing,
> > then settle back to reality. *Any idea of what I need to look for to
> > fix this?
> > My setup:
> > Kestrel 19, two static ports in the tail boom, pitot and TE in the
> > fin. *The TE line is split under the seat using a Y connector and then
> > travels to two varios (a Winter mechanical and a 1990-era audio/final-
> > glide called a VariCalc). *Pitot and static lines are split behind the
> > panel using T connectors.
> > I replaced all the non-permanent tubing last year and they all seemed
> > to be leak-free.
> > Thanks!
> > -John
>
> Next question is do they go down when you pull up. If both events
> occur, you are somewhat over compensated.
> Depending on the type of probe, this may be able to be tuned.
> UH

To be pedantic what uncle Hank is saying is that in that case the
compensation is spot on and for comfort you need to be a tads under
compensated.
Your tube is a Braunschweig type commonly known amongst Anglo-Saxon
pilots as a Brunswick tube. They can be accurate but that is very
difficult to achieve by machining to a drawing. They usually need
calibrating by adjusting the length of tube distal to the lower slot.
The shape of the end is critical as it needs to be square and sharp
cornered. Not easy and devising the test bed be it bench or flight
test is pretty tedious.
The Brunswick is somewhat prone to yaw error. An Irving tube - the one
with two holes each facing 50 degrees away from the aft centre line is
less prone to yaw error and if accurately made to Frank Irving's
drawing will give the right amount of under-compensation without
calibration. If the degree of compensation proves to be your problem I
recommend you buy a commercially made Irving tube. You could spend all
summer messing around with a basically inferior tube. On no account
put in a Nick's tube with only one hole as they even more prone to yaw
error and poor compensation.

Slingsbys may have supplied commercially made Brunswick tubes so you
might have a good one if it is original.

Another source of confusing error is the use of long lengths of soft
silicon rubber tubing. (more than a few inches). Under varying 'G' it
deforms and causes air movement within the plumbing. PVC with a little
silicone grease and twist-wired at the joints is better if less sexy
and tedious to connect. A well made PVC joint left alone will last for
years.

If you want a bit of bed-time reading try "The influence of
acceleration on the sink rate of a sailplane and on the indication of
the variometer" by Frank Brozel; Technical Soaring; Vol X No1 p10.
Also anything you find by Frank Irving is always worth reading but I'd
have to do some deep research to give you any references so you are on
your own on that one.

[jsbrake[_2_]]

UH: When I pull up, the varios go up... both of 'em.

There's about 2' of silcon tubing in the circuit, all of it at the
panel end. The second line of TE is silicon from the Y splitter that
I installed, so call that about 4' long. The pvc lines end at the
central pedestal where the hood and panel are removable, so there's
silicon, then a 5-way quick-connector and then silicon to the
instruments. I could probably remove about 4-6" of extra silicon, but
it gives me some "play" for being able to get at the quick-connect
without needing extra joints in my arms.

I'm not doing heavy g manoevers, maybe 1.5 g on a pull-up, perhaps
0.75 g on a push-over. The most g I normally pull is during
thermalling turns.

I think I recall reading in the aircraft notes about a Brunswick
tube. It appears to be factory made and the slots are well-defined.

[sisu1a]

>. *Replaced the connector this year.
>
> - the VariCalc has connections for all three lines; the Winter
> mechanical connects to TE and capacity. *A problem in static shouldn't
> affect both instruments.

Faulty multi-connectors can also cause your described symptom as well.
Check the O-rings well, and silicone grease is your friend.

Hmmm, this puts possible tailboom static issues back on the map and
your VariCalc could be cross-talking that or an internal pitot leak
error to your Winter. Run it once with cockpit static before getting
too fancy with time consuming ground testing. It's real easy and you
get to fly... Your vario isolation test will also be useful here, I
suggest unhooking (plug loose lines!) the VariCalc first.

-Paul

[Peter Gray]

On 25 May, 17:29, jsbrake > wrote:
> UH: When I pull up, the varios go up... both of 'em.
>
> There's about 2' of silcon tubing in the circuit, all of it at the
> panel end. *The second line of TE is silicon from the Y splitter that
> I installed, so call that about 4' long. *The pvc lines end at the
> central pedestal where the hood and panel are removable, so there's
> silicon, then a 5-way quick-connector and then silicon to the
> instruments. *I could probably remove about 4-6" of extra silicon, but
> it gives me some "play" for being able to get at the quick-connect
> without needing extra joints in my arms.
>
> I'm not doing heavy g manoevers, maybe 1.5 g on a pull-up, perhaps
> 0.75 g on a push-over. *The most g I normally pull is during
> thermalling turns.
>
> I think I recall reading in the aircraft notes about a Brunswick
> tube. *It appears to be factory made and the slots are well-defined.

An up indication no matter which way you push or pull isn't a matter
of degree of compensation. A few inches of squashy tube won't make a
difference and it sounds like you have relatively modest quantities.

I am puzzled why different manoeuvres have the same effect. It
somewhat suggests multiple pathology.

Two questions ref egg sucking. Pneumatic netto was common in the
seventies, presumably there is no cruise/climb switch in the plumbing
to the Winter?
When you did your leak test did you connect to the Brunswick tube? If
so did you remember to put a piece of wire (about .020") up the slots
and into the plastic test pipe to stop the pipe sealing around the end
of the probe?

Make an exact diagram of all the plumbing. It helps enormously in
keeping track and thinking about what effect a leak at any position
will have.

[jsbrake[_2_]]

On May 25, 1:23*pm, Peter Gray > wrote:
> On 25 May, 17:29, jsbrake > wrote:
>
>
>
>
>
> > UH: When I pull up, the varios go up... both of 'em.
>
> > There's about 2' of silcon tubing in the circuit, all of it at the
> > panel end. *The second line of TE is silicon from the Y splitter that
> > I installed, so call that about 4' long. *The pvc lines end at the
> > central pedestal where the hood and panel are removable, so there's
> > silicon, then a 5-way quick-connector and then silicon to the
> > instruments. *I could probably remove about 4-6" of extra silicon, but
> > it gives me some "play" for being able to get at the quick-connect
> > without needing extra joints in my arms.
>
> > I'm not doing heavy g manoevers, maybe 1.5 g on a pull-up, perhaps
> > 0.75 g on a push-over. *The most g I normally pull is during
> > thermalling turns.
>
> > I think I recall reading in the aircraft notes about a Brunswick
> > tube. *It appears to be factory made and the slots are well-defined.
>
> An up indication no matter which way you push or pull isn't a matter
> of degree of compensation. A few inches of squashy tube won't make a
> difference and it sounds like you have relatively modest quantities.
>
> I am puzzled why different manoeuvres have the same effect. It
> somewhat suggests multiple pathology.
>
> Two questions ref egg sucking. Pneumatic netto was common in the
> seventies, presumably there is no cruise/climb switch in the plumbing
> to the Winter?

It did have pneumatic netto, but the plumbing was removed before I got
the ship. I still have the brass fitting.

> When you did your leak test did you connect to the Brunswick tube? If
> so did you remember to put a piece of wire (about .020") up the slots
> and into the plastic test pipe to stop the pipe sealing around the end
> of the probe?

I removed the Brunswick and connected directly to the stub sticking
out of the fin. Air flows easily through the Brunswick.
>
> Make an exact diagram of all the plumbing. It helps enormously in
> keeping track and thinking about what effect a leak at any position
> will have.

Straight runs from point of opening (fin for TE/pitot, 2 in boom for
static) to the pedestal. From there, it's silicon to the quick-
connect and then to the instruments. Pitot and Static are both T-
split in the panel, the TE is Y-split under the seat. Nothing else in
the circuit. Pitot goes to ASI and VariCalc; Static goes to ASI and
Alt; TE to the varios; Capacity to the mech vario. Basic setup,
matches what I found on W&W and Winter websites about connecting
plumbing to instruments.

[Dan[_4_]]

In the case of using a mechanical and an electronic vario - capacity
and no capacity respectively - and a glider in which the tubing aft of
the panel is not that accessible, I wonder whether just teeing and
having a 7 foot length of tubing to the vario would isolate the TE
line enough to minimize mutual interference. I accept that this would
add volume to the system, which may be a problem, and that the handful
of tubing might be a problem for space behind the panel.

Would this be a workable solution?

[sisu1a]

>*Pitot and Static are both T-
> split in the panel, the TE is Y-split under the seat. *Nothing else in
> the circuit. *Pitot goes to ASI and VariCalc; Static goes to ASI and
> Alt; TE to the varios;

OK not static. Sounds like cross talk between your pitot and TE
through that VariCalc's internals. Still an easy test- unhook it and
fly.

-Paul

[Bob Salvo[_2_]]

Get rid of the 4-way connector. They are unreliable, sometimes
causing cross-talk between paths. For peace of mind, use separate
connectors.

Bob


> - then traced my original TE troubles to a leak in the 4-way connector
> at the panel. *Replaced the connector this year.

[Peter Gray]

On 25 May, 19:39, jsbrake > wrote:
> On May 25, 1:23*pm, Peter Gray > wrote:
>
>
>
> > On 25 May, 17:29, jsbrake > wrote:
>
> > > UH: When I pull up, the varios go up... both of 'em.
>
> > > There's about 2' of silcon tubing in the circuit, all of it at the
> > > panel end. *The second line of TE is silicon from the Y splitter that
> > > I installed, so call that about 4' long. *The pvc lines end at the
> > > central pedestal where the hood and panel are removable, so there's
> > > silicon, then a 5-way quick-connector and then silicon to the
> > > instruments. *I could probably remove about 4-6" of extra silicon, but
> > > it gives me some "play" for being able to get at the quick-connect
> > > without needing extra joints in my arms.
>
> > > I'm not doing heavy g manoevers, maybe 1.5 g on a pull-up, perhaps
> > > 0.75 g on a push-over. *The most g I normally pull is during
> > > thermalling turns.
>
> > > I think I recall reading in the aircraft notes about a Brunswick
> > > tube. *It appears to be factory made and the slots are well-defined..
>
> > An up indication no matter which way you push or pull isn't a matter
> > of degree of compensation. A few inches of squashy tube won't make a
> > difference and it sounds like you have relatively modest quantities.
>
> > I am puzzled why different manoeuvres have the same effect. It
> > somewhat suggests multiple pathology.
>
> > Two questions ref egg sucking. Pneumatic netto was common in the
> > seventies, presumably there is no cruise/climb switch in the plumbing
> > to the Winter?
>
> It did have pneumatic netto, but the plumbing was removed before I got
> the ship. *I still have the brass fitting.
>
> > When you did your leak test did you connect to the Brunswick tube? If
> > so did you remember to put a piece of wire (about .020") up the slots
> > and into the plastic test pipe to stop the pipe sealing around the end
> > of the probe?
>
> I removed the Brunswick and connected directly to the stub sticking
> out of the fin. *Air flows easily through the Brunswick.

What that doesn't do is test the integrity of the joint between probe
and socket in the fin.

[Ventus_a]

;730074']Hi All,
Whenever I accelerate, my varios bump up and tell me I'm climbing,
then settle back to reality. Any idea of what I need to look for to
fix this?
My setup:
Kestrel 19, two static ports in the tail boom, pitot and TE in the
fin. The TE line is split under the seat using a Y connector and then
travels to two varios (a Winter mechanical and a 1990-era audio/final-
glide called a VariCalc). Pitot and static lines are split behind the
panel using T connectors.
I replaced all the non-permanent tubing last year and they all seemed
to be leak-free.
Thanks!
-John


Hi John

Have a read of this article by Rudi Brozel of Ilec re compensation

http://www.nadler.com/sn10/Brozel_TE_Compensation_20020510.pdf


ps is it Kilo Yankee

Cheers

[sisu1a]

> Get rid of the 4-way connector. *They are unreliable, sometimes
> causing cross-talk between paths. *For peace of mind, use separate
> connectors.


He mentioned it's a 5 way (although only 4 ports are currently being
used) in another post, which I mean to take is a Winter unit. I've
personally had good luck with those but I still prefer the positive
locking threaded compression connection of my 4 way PZL version. I've
had no leaks with either though, nor any crosstalk (ahem- well just be
sure you didn't x-thread the PZL unit back together on after you show
it off just before takeoff... heh.) Only problems I've heard of with
the quick connects are leaks when the stock O-rings are old/crusty,
which is an easy inspection/replacement (spend the extra $.12 on
Viton!). While crosstalk is possible on the PZL 4-way with it's
compression loaded seals, on the Winter 5-way there is no *real chance
of it as the o-rings form a male seal at least 1/4" into the female
sockets, effectively isolating the individual lines from each other in
case of seal failure, even with dual seal failure. Rubber is not
ageless... and again, silicone (spray, applied via cotton swab) is
your friend, same for the probe/socket...

It's also unlikely a probe connection problem since it is not a double-
probe and I feel safe to assume the probe gets taped at each assembly
of course. Borrowing a probe from another ship will help isolate any
problems with the probe itself it It winds up being suspect.

I may just have tunnelvision but really I think an old vario (with
aged internal seals...) that has pitot and TE seems more suspect of
crosstalk issues than a new Winter quick connect or probe performance
issues...

Slightly OT, I like to use these to seal pneumatic instrument hoses on
barbs:
http://www.jollygerman.com/products/goats/rings.shtml cheap, last
bout 5yrs and gives a uniform 360deg seal (UNlike zipties...) that is
easily future-accessed with no damage to hose/barb. Got idea from
Borgelt but it took me a while to figure out what these little green
rubber Cheerio things were *really* used for... OUCHY!!!

-Paul

[Peter Gray]

> It's also unlikely a probe connection problem since it is not a double-
> probe and I feel safe to assume the probe gets taped at each assembly
> of course. Borrowing a probe from another ship will help isolate any
> problems with the probe itself it It winds up being suspect.

The Brunswick socket won't have any internal seals. Just one tube
inside another. Tape is unreliable. A short length of silicon tube
tightly fitted over the joint is better. If the tube can stay in situ
in the trailer then wire it or castrate it with a couple of Cheerios
and leave it well alone.

> I may just have tunnelvision but really I think an old vario (with
> aged internal seals...) that has pitot and TE seems more suspect of
> crosstalk issues than a new Winter quick connect or probe performance
> issues...

Seems the first port of call for an elimination exercise. I await some
more real data with fascination.

[jsbrake[_2_]]

Whee ! Looks like I'm in for some fun this coming weekend, trying to
figure out what's leaking. I'll probably fly it in the daytime and
try to test it during the evening, or bring the panel home to test the
varios.

I think I was happier before I asked the question... oh well, test it
out and get it working nicely.

Thanks to all for the information and advice; I'll report back when I
figure it out.

-John

[ZZ]

On 5/25/2010 7:13 AM, wrote:
> On May 24, 9:32 pm, > wrote:
>> Hi All,
>> Whenever I accelerate, my varios bump up and tell me I'm climbing,
>> then settle back to reality. Any idea of what I need to look for to
>> fix this?
>> My setup:
>> Kestrel 19, two static ports in the tail boom, pitot and TE in the
>> fin. The TE line is split under the seat using a Y connector and then
>> travels to two varios (a Winter mechanical and a 1990-era audio/final-
>> glide called a VariCalc). Pitot and static lines are split behind the
>> panel using T connectors.
>> I replaced all the non-permanent tubing last year and they all seemed
>> to be leak-free.
>> Thanks!
>> -John
>
> Next question is do they go down when you pull up. If both events
> occur, you are somewhat over compensated.
> Depending on the type of probe, this may be able to be tuned.
> UH


I agree with UH. If you accelerate AND descend the energy added to the
glider is virtually zero and the vario should read zero IF it is
correctly compensated. What you are describing in your original post is
classic TE overcompensation. If this is so, a pull up should produce a
negative vario reading, momentarily.

I realize this is theory and does not "find the leak" if there is one
but perhaps UH's comments will get you going in the right direction.

Good luck,

Paul
ZZ

[jsbrake[_2_]]

I've gone over the tubing looking for leaks and it all seems patent.
I pulled everything apart, lubed and reconnected and it's looking good
(including the much-maligned quick-connector). Unfortunately, I
haven't had a chance to fly it to find out if the tubing was my
problem or if it's the instruments (but BOTH varios behaving badly the
same way seems to indicate that it's not the instruments).

On the plus side, one off my club's members is a licenced instrument
mechanic and he's said he'll take a look at my setup when we can get
together. Hopefully that'll get it fixed.

Now, is there some way that I can use this as an excuse to convince my
wife that the "mistress" needs a panel upgrade?