Cleaning a 3-way TE probe

"John Morgan" wrote...
If you regularly remove your probe, consider a plug for the hole on the
vertical fin to keep dirt out. I also use a tubular cover for the base end
of the probe to keep it clean too.

Make sure that plug isn't airtight (put in pinhole in it, or something), or
you'll probably be in the market for some new varios in the near future...

Marc

Dr. Jack,
Good stuff from Marc & John, also There ia a possibility that bugs have made a
home in the female hole (was that crude?) I have found an insect known as a
"Leaf-roller" in my probe holes (like that better?) Plug it when not in use,
with a small bleeder hole.

Now, if a leaf-roller has been at work in your hole, you may have shoved its
home way down inside your probe hole. Very bad news, you need to take your
probe hole to a hole checking (gynecologist) They masquerade as
glider-repairmen, but they are all just a bunch of hole checkers at heart. They
will flush out your hole by carefully applying pressure from the other end of
all the tubes that are attached to your hole. They know that ALL instruments
must be disconnected BEFORE giving your hole and associated tubing any
pressure. They also know that over-pressure can result in an aneurysm or even
worse, a blow-out deep inside your precious little darling.
JJ Sinclair

Thanks to Bumper (John), Marc, and JJ for passing on your knowledge. I
am going out to work on this today and test the pluming and see what I
find. Hopefully I'm get everything working early as it looks like an
excellent soaring day. I went flying yesterday but with, in retrospect,
the pitot and static TE ports blocked had no working vario or computer
so was not able to take much advantage of the conditions then - I was
wondering why my LNAV kept telling me I had a 50 kt tailwind! I might
have already damaged the mechanical vario per Marc's comment as I went
up to 8000 ft with the static port apparently blocked.

Regarding "leaf rollers", a few weeks ago I had to work on my
motorglider's (bear with me here JJ, stop gnashing your teeth) motor
retraction and the motor was extended for a long period. I happened to
notice an insect which seemed to be periodically flying in and out of
the motor, near the metal cooling fins on the cylinder. Finally when I
again saw it disappear in there I went and looked and found way back a
bug's eyes looking out at me! That thing did not want to budge, as I
tried poking in with a screwdriver (which could not fit all the way in
to the hole) and the bug stubbonly remained. Finally I found a long
very thin screwdriver and managed to kill it, but the fact that this bug
was seeming to want to make a hole in my engine certainly made an
impression! So perhaps this was one of those "leaf rollers". I had
been putting some white tape over the TE probe hole between uses, but
one time I noticed that the tape had not stayed attached so it is
certainly possilbe that something got in there, particularly since there
have been long periods when the plane has not been flown. Anyway, will
see what I find today.

I spent 4 hours today cleaning out junk from my TE tube "hole", didn't
get to fly. I had to use both mechanical and liquid means to get out
a lot of what must be insect byproduct - reminds me of yellow/orange
ear was. Final status is that the static port of the hole is no longer
blocked but the pitot port remains blocked. Using a bicycle pump I put
some pressure on that port and it help air nicely at 10 psi (mindful of
JJ's warning I didn't put any more pressure on it). Time now to find
a "hole" expert - I will first see if the mechanic at the local
gliderport has any "holy" experience. JJ, one thing that bothers me
is that it seems possible that _no_ amount of reasonable pressure
might not open the port - in which case I think I am in for a lot of
trouble. In the meantime I plan to get a T fitting and put the LNAV
on the airspeed pitot pressure as being better than nothing and
getting me back up in the air. And allowing me to test the LNAV since
I have never had it working correctly since I bought the plane and I
hope this might explain why. I had thought the problem lay in the
LNAV itself but perhaps it lay in the TE probe.

One thing I noticed while I was working was that there were a whole
lot of ants (about 30 at one time) crawling in a line up the front
of the vertical stabilizer to the top of the elevator (just above the TE
hole) where they milled around acting like they were looking for
something. They did this for about an hour, then disappeared for an
hour, then re-appeared for another hour. I couldn't see ants elsewhere
on the plane, which made me wonder whether they might be associated with
the insect "junk" in the TE hole - I had swabbed out the hole with
alcohol by that time and since ants rely on leaving chemical messenges
those would have been "erased" inside the hole itself. Likely there is
another explanation (possibly the ants are just like glider plots and
like to climb and stay high) but it did make me wonder if anyone else
had ever experienced problems caused by ants entering their glider.

"Jack Glendening" wrote in message
k.net...

In the meantime I plan to get a T fitting and put the LNAV
on the airspeed pitot pressure as being better than nothing and
getting me back up in the air.

Not quite sure what you meant by the above comment. The pitot for the L-Nav
should always be connected to the same pitot port as the airspeed indicator.
If you use the L-Nav for speed-to-fly info, it should come from the same
source as supplied to the airspeed indicator that you fly by. Of course
this is not necessary. You can have L-Nav info based on one pitot reading
and airspeed indicator based on another. But, it would be nice to have the
info correlated. Hopefully both pitot reading would be the same, but, that
is not always true.

Duane

Welcome to the insect world, Dr. Jack. I once had the little buggers fill my
hole in one afternoon, as I attended to some routine items on the ship. I
religiously keep the hole covered, now.

You can apply reverse pressure to your pitot, static and TE lines from the
instrument panel. be sure to remove ALL connections to your instruments first.
Then I give each line, short bursts, of compressed air, as I watch the hole for
debris exiting.

Your L-Nav should be on the ships pitot & static system, also check the ASI
calibration page for correct numbers (see manual) the constant tail-wind sounds
like a pitot problem, L-Nav not generating a good TAS, so it must drive in a
big tail wind to make things equal out with the GS its getting fron thr GPS.

Its only October, you got all winter to work on this. Don't you just love a
challenge? :)
JJ Sinclair

Today while working on my glider I watched a line of ants continually
going to and fro, from the tiedown rope along the front of the
vertical stabilizer and into the glider, the second day in a row that
this has happened. I finally took off the elevator and found them
entering/exiting a hole into the rudder compartment, where I can't
see. What are those buggers doing there?? Paranoia is kicking in.
Next time I go out I'm taking a can of ant killer and spraying it
inside that hole.

Dr. Jack,
Did you solve your plugged up *hole*, problem?

Just a bit of information for all the *rule-followers*, out there. Your ships
manufacturer specifies the pitot and static sources that must be used in order
to make the airspeed read the same as it did when the design was certified. The
computer manufacturers tell us to use the same pitot and static that our
airspeed indicator uses. SO, we should use the same one that is specified by
the sailplane manufacturer. This applies to type certificated ships as well as
those licenced in the experimental category. Because, your experimental
airworthiness certificate says something like, This ship will be operated in
accordance with its flight and maintenance manuals, and that specifies the
source of pitot and static.
:)
JJ Sinclair

"JJ Sinclair" wrote in message
...
Just a bit of information for all the *rule-followers*, out there. Your
ships
manufacturer specifies the pitot and static sources that must be used in
order
to make the airspeed read the same as it did when the design was
certified. The
computer manufacturers tell us to use the same pitot and static that our
airspeed indicator uses. SO, we should use the same one that is specified
by
the sailplane manufacturer. This applies to type certificated ships as
well as
those licenced in the experimental category. Because, your experimental
airworthiness certificate says something like, This ship will be operated
in
accordance with its flight and maintenance manuals, and that specifies the
source of pitot and static.
:)
JJ Sinclair

Pardon me for changing the subject of this thread, but, I have to ask a
question of your above statement.
The Limitations of the Experimental Certificate on my current sailplane
(Ventus 2 Bx) does not state anything about operating in accordance with
flight/maintenance manuals. Also, I do not remember any such wording in any
of the other "Experimental" sailplanes that I have had in the last 30 years.
Do your Experimental Limitations really have such a requirement? Just
curious.

As an aside to which static ports to use, I agree that normally the ports
prescribed in the Flight Manual should be used. However, due to a very
early placement of an order, I received the first Discus to come to the U.S.
This aircraft had static ports both under the wing and in the tailboom.
Later models had only the tailboom static ports and that is what the ship
was eventually certified with. Klaus Holighaus, however, advised me to use
the under wing static ports because they "worked better for thermalling"
even though they were not as accurate. How is that for decision making;
follow the manual or follow an expert who designed the sailplane.

Duane

JJ Sinclair wrote:
Just a bit of information for all the *rule-followers*, out there. Your ships
manufacturer specifies the pitot and static sources that must be used in order
to make the airspeed read the same as it did when the design was certified. The
computer manufacturers tell us to use the same pitot and static that our
airspeed indicator uses. SO, we should use the same one that is specified by
the sailplane manufacturer. This applies to type certificated ships as well as
those licenced in the experimental category. Because, your experimental
airworthiness certificate says something like, This ship will be operated in
accordance with its flight and maintenance manuals, and that specifies the
source of pitot and static.

JJ,

not sure how to interpret what you wrote but suspect you may have been
thinking that my ASI/altimeter were connected to the triple (TE) probe
coming out of the stabilizer, which was not the case. My ship was set
up (as it came to me, not from any change by me) with the ASI/altimeter
connected to the forward pitot/static ports (which I believe are the
"correct" ones) and the Cambridge computer being connected to the triple
probe and the only connection to it. (The mechanical vario was connected
to the altimeter static port, not to the TE probe)

Having the computer on its own probe set into the free-stream flow
seemed like a good idea to me offhand (assuming the air speed adjustment
was done correctly), but I now gather there are differences of opinion
as to what the "best" setup is. My response whenever I see something
like "the computer manufacturers tell us to use the same pitot and
static that our airspeed indicator uses" is to ask why, to make sure the
reasons are those which apply in my case, but in this case I don't know
enough to answer that question.

Will write a separate post regarding present status, as am presently in
triage status.

Jack