Today's Message Index:
----------------------
1. 03:39 AM - Re: Fuel leak (Linn Walters)
2. 06:09 AM - Re: Fuel leak (flyv35b)
3. 06:54 AM - Re: Fuel leak (flyv35b)
4. 06:54 AM - Re: Windshield (flyv35b)
5. 06:55 AM - Re: Fuel leak (FLYaDIVE)
6. 12:58 PM - Re: Fuel leak (Linn Walters)
7. 02:42 PM - Re: Fuel leak (Gary Vogt)
8. 02:54 PM - Re: Fuel leak (Gary Vogt)
9. 03:30 PM - Re: Tiger cowling for sale: $500 plus shipping. (Scott Trejo)
10. 03:53 PM - Re: Fuel leak (Linn Walters)
11. 06:31 PM - Fw: Wiring, was Windshield (Gary Vogt)
12. 06:48 PM - Windshield bonding details (Gary Vogt)
13. 06:48 PM - Re: Fuel leak (Gary Vogt)
Message 1
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Gary Vogt wrote:
> So, I got under the wing again, opened the inspection panels, and
> nothing. Still no stains anywhere. I pressurized the tank through
> the vent line. Since I had to hold pressure I couldn't actually feel
> around and look for a leak while the tank was pressurized. Nothing.
> No leaks.
>
> I removed the strap around the wing. Nothing. No stains at all.
> There was, however, fuel tank sealant applied to the outside. It
> looks post wing completion. I pressurized the tank again and after 30
> seconds or so, went to look for leaks. Nothing. What a pain in the
> ass. I needed to look for leaks with the tank pressurized.
>
> Then I thought, if I could plug the vent line, how could I pressurize
> the tank? Well, the solution was to pressurize through the sump fuel
> drain. I plugged the vent, then applied pressure at the drain, pushed
> it in as if to drain (but with air pressure on it) and I could hear
> bubbles going into the sump. Good first start. I waited about a 15
> seconds, then, removed pressure. No leaks. I went to the vent line
> and removed the plug. A small mount of air escaped. Good. It works.
> So, plug back in, I pressurized the tank and waited about 30-45
> seconds. Keep in mind I'm using 120 psi. I'll bet that got your
> attention. No, I'm using about 1 or 2 psi. Then I went looking for
> leaks.
>
> Guess what. On the very bottom of the spar, at the edge of the wing
> skin, where the sealant was applied, a very tiny wet spot. I got a
> paper towel and put it on it. It was that hard to see. There it was;
> the little bugger. Under pressure, at the rate it was leaking, it
> would take forever to drain the tank. If I had to estimate the hole
> size, I'd say about 100 microns.
>
> Is it worth trying to seal from the outside?
I'd say yes ..... the resulting stain would be aggravating. Get some
green Loctite, clean the hole: draw a vacuum on the tank and feed some
MEK through the hole ...... make take a lot of patience. Keeping the
vacuum on the tank, feed the hole some of the green Loctite. Remove the
vacuum once you feel the Loctite has gone through whole passage. Should
now stop the leak.
With the hole that small, getting fluid through the hole may be
problematic ..... the hole may seal under vacuum ..... use the MEK to
clean the external area real good and apply some proseal over the
exterior where the hole is.
Linn
PS .... the green Loctite trick came from the RV group.
>
> *
>
>
> *
Message 2
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Yes. What have you got to loose? I'd pick away any sealant that wasn't
attached well and maybe some of the externally applied sealant, add new
sealant and try and blow it inward with some air pressure to "fill" any
void then cover the whole area with sealant and see what happens. If
that doesn't work you will have to go inside again.
Cliff
----- Original Message -----
From: Gary Vogt
To: Teamgrumman List
Sent: Thursday, June 17, 2010 8:55 PM
Subject: TeamGrumman-List: Fuel leak
So, I got under the wing again, opened the inspection panels, and
nothing. Still no stains anywhere. I pressurized the tank through the
vent line. Since I had to hold pressure I couldn't actually feel around
and look for a leak while the tank was pressurized. Nothing. No leaks.
I removed the strap around the wing. Nothing. No stains at all.
There was, however, fuel tank sealant applied to the outside. It looks
post wing completion. I pressurized the tank again and after 30 seconds
or so, went to look for leaks. Nothing. What a pain in the ass. I
needed to look for leaks with the tank pressurized.
Then I thought, if I could plug the vent line, how could I pressurize
the tank? Well, the solution was to pressurize through the sump fuel
drain. I plugged the vent, then applied pressure at the drain, pushed
it in as if to drain (but with air pressure on it) and I could hear
bubbles going into the sump. Good first start. I waited about a 15
seconds, then, removed pressure. No leaks. I went to the vent line and
removed the plug. A small mount of air escaped. Good. It works. So,
plug back in, I pressurized the tank and waited about 30-45 seconds.
Keep in mind I'm using 120 psi. I'll bet that got your attention. No,
I'm using about 1 or 2 psi. Then I went looking for leaks.
Guess what. On the very bottom of the spar, at the edge of the wing
skin, where the sealant was applied, a very tiny wet spot. I got a
paper towel and put it on it. It was that hard to see. There it was;
the little bugger. Under pressure, at the rate it was leaking, it would
take forever to drain the tank. If I had to estimate the hole size, I'd
say about 100 microns.
Is it worth trying to seal from the outside?
Message 3
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That might be a good idea, Linn. What is the number of the Loctite as
their are scores of different types. Is just "Green" that definitive?
Cliff
----- Original Message -----
From: Linn Walters
To: teamgrumman-list@matronics.com
Sent: Friday, June 18, 2010 3:18 AM
Subject: Re: TeamGrumman-List: Fuel leak
Gary Vogt wrote:
So, I got under the wing again, opened the inspection panels, and
nothing. Still no stains anywhere. I pressurized the tank through the
vent line. Since I had to hold pressure I couldn't actually feel around
and look for a leak while the tank was pressurized. Nothing. No leaks.
I removed the strap around the wing. Nothing. No stains at all.
There was, however, fuel tank sealant applied to the outside. It looks
post wing completion. I pressurized the tank again and after 30 seconds
or so, went to look for leaks. Nothing. What a pain in the ass. I
needed to look for leaks with the tank pressurized.
Then I thought, if I could plug the vent line, how could I
pressurize the tank? Well, the solution was to pressurize through the
sump fuel drain. I plugged the vent, then applied pressure at the
drain, pushed it in as if to drain (but with air pressure on it) and I
could hear bubbles going into the sump. Good first start. I waited
about a 15 seconds, then, removed pressure. No leaks. I went to the
vent line and removed the plug. A small mount of air escaped. Good.
It works. So, plug back in, I pressurized the tank and waited about
30-45 seconds. Keep in mind I'm using 120 psi. I'll bet that got your
attention. No, I'm using about 1 or 2 psi. Then I went looking for
leaks.
Guess what. On the very bottom of the spar, at the edge of the wing
skin, where the sealant was applied, a very tiny wet spot. I got a
paper towel and put it on it. It was that hard to see. There it was;
the little bugger. Under pressure, at the rate it was leaking, it would
take forever to drain the tank. If I had to estimate the hole size, I'd
say about 100 microns.
Is it worth trying to seal from the outside?
I'd say yes ..... the resulting stain would be aggravating. Get some
green Loctite, clean the hole: draw a vacuum on the tank and feed some
MEK through the hole ...... make take a lot of patience. Keeping the
vacuum on the tank, feed the hole some of the green Loctite. Remove the
vacuum once you feel the Loctite has gone through whole passage. Should
now stop the leak.
With the hole that small, getting fluid through the hole may be
problematic ..... the hole may seal under vacuum ..... use the MEK to
clean the external area real good and apply some proseal over the
exterior where the hole is.
Linn
PS .... the green Loctite trick came from the RV group.
href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.m
atronics.com/Navigator?TeamGrumman-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
ontribution
Message 4
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That's probably the worst wiring I have ever seen!
Cliff
----- Original Message -----
From: Gary Vogt
To: teamgrumman-list@matronics.com
Sent: Thursday, June 17, 2010 12:05 PM
Subject: Re: TeamGrumman-List: Windshield
It's been one of those weeks. Seems like everyone wants their plane
yesterday, the parts I get are either poorly manufactured, don't fit or
both, the workmanship of some mechanics is appalling, and I am
constantly amazed how plane owners accept 'good enough.'
In 1984, a few days after I bought my first Cheetah (which had been
sitting in the desert sun for 2 years), a 77 Cheetah with 714 TTSN, I
went to the local FBO to find someone to do an annual. I knew nothing
about planes. In the FBO, two A&Ps were installing an O360 into a
Cessna 172. I watched while preformed aluminum parts, included in the
STC, were being bent and deformed to force them to fit. Over the next
hour or so, I watched them forcing parts together that simply did not
fit. Their reasoning was, "the owner will never look under the
cowling." By 1984, I had built 2 hot rods and restored a 69 Corvette
and a 66 Chevy II Super Sport. It was then I decided that I would be
the only one working on my plane. I found a mentor I could trust and
began my tutelage.
I've turned away two potential customers in the last 2 months that
actually asked for me to do half-assed work and just get it signed off.
Their logic: my regular mechanic does it all the time but he's busy
right now. So can you do it?
Windshield: I've heard about installing windshields in the plane.
I've never seen how that could be done. Just getting the windshield
into the coving the windshield needs to be warped a bit. To keep the
bow square with the canopy, it would need to be clamped to the canopy
with 1/4 inch spacers to get the proper gap. That means there would be
no way to clamp the windshield in place. The windshield would need to
be held in place with the mounting screws. That being the case, how is
the proper gap held around the windshield bow? Where does the excess
adhesive go?
Rear windows: Getting the old sealant out sometimes requires sanding
it out. That means there is a whole lot of bare metal on the mounting
surface. Now, two things, either the old sealant is completely removed
by sanding and new strip caulk or RTV is applied on the bare metal, or
strip calk or RTV is applied over the old sealant. When I install rear
windows, I sand out all of the old sealant, alodine, prime, and paint
the mounting surface with Imrom. Then I let it sit for 7 days to
properly cross-link before installing windows.
Canopy windows: I've seen it recommended to use the foam tape on the
canopy windows. There is just no way to install the canopy windows with
foam tape around the perimeter without tearing the foam tape to shreds.
There is a reason the factory used the felt tape: IT ALLOWS THE WINDOW
TO SLIDE INTO PLACE. The canopy windows are designed to leak. They are
designed to leak to the outside.
1348: cabin prepared for a new headliner
1334: typical avionics wiring. Nice huh. The glide slope receiver
was mounted on the bottom of the glare shield.
-------------------------------------------------------------------------
-----
From: FLYaDIVE <flyadive@gmail.com>
To: teamgrumman-list@matronics.com
Sent: Thu, June 17, 2010 5:20:20 AM
Subject: Re: TeamGrumman-List: Windshield
Gary:
What's the apology for? You did not hurt my feelings.
I was once condescended, but now I am convince.
I have not had the time to read and digest your posts, but I will.
After all I have only done 2 windows and I do respect my elders ;-)
I am impressed with your jig - Working out the size is quite an
accomplishment. I would have like to have been there as you designed
and manufactured it.
Anyway, whos feeling did you think you hurt? Hell, let them grow some
thicker skin.
Barry
"Chop'd Liver"
On Wed, Jun 16, 2010 at 2:28 PM, Gary Vogt <teamgrumman@yahoo.com>
wrote:
> Sorry I got so condescending about windshield. No excuse.
> By my count, I've installed 43 windshields since 1984. I've made a
lot of
> mistakes and learned a lot of 'tricks' to getting the windshield
square with
> the bow and getting the correct thickness of RTV.
> I built my jig in 1984 in an attempt to simulate the location and
shape of
> the windshield as installed. At the time, I was trying too imagine
how they
> were done at the factory. I figured they had some sort of jig to
put the
> windshield on the bow. The jig has gone through 2 revisions.
mostly to
> provide better access to the underside. The version I have now
guarantees
> an absolutely flat windshield bow to which the windshield is bonded.
I have
> a set of blocks of wood to put under the forward edge of the
windshield.
> These blocks locate and lock the forward edge such that when the
windshield
> is set into position, it always falls on the same position at the
windshield
> bow edge. The jig has dowels that locate the holes to be drilled at
the
> lower corners. Before the holes are drilled, I tape a strip of .020
> aluminum to the bow to simulate the thickness of the RTV when
installed.
> The holes in the lower corners are drilled with the windshield in
its final
> location. With those holes drilled, the windshield can be
positioned and
> the two holes on top drilled. It's at this point that I use a
feeler gauge
> the determine the gap between the windshield and bow. Where it's
too tight
> (meaning: places where the forward edge of the windshield bow would
project
> into the RTV making the RTV too thin, <.020, in that area), I mark
the
> windshield so that any clamps in that area are not over tightened.
I use
> two types of shims to space the windshield from the bow and maintain
the
> spacing during assembly.
> Shims I've tried:
> (1) self sticking foam that compresses to approx .025 inches. I
punched
> out dots using a hole punch. It worked, but left the dots showing.
I did
> one like this.
> (2) .020 safety wire clips at the forward edge of the bow. It
worked, but
> left little holes when I removed the clips. The holes couldn't be
filled
> with RV. I did two like this.
> (3) I made a spacer, .050 thick, the shape of the windshield bow,
attached
> to the bow through the holes used to hold the double bow seal on,
that stuck
> up .030 above the aft edge of the bow (same surface the seal uses).
> The idea here was to hold the windshield .030 away from the
bow
> uniformly from one corner to the other. At first, this sounded like
a great
> idea (it wouldn't work with an LP Aero windshield because
> there is no lip at the bow). The biggest problem was: the
bows are
> not all the same shape. I used this for 4 or 5 windshields before
it became
> obvious this was not practical. I kept filing and adjusting the
shape to
> get them to fit.
> (4) Then, I made little "L" shaped shims that can be placed under
the aft
> edge of the windshield between the bow and windshield. The long
side is
> flush with the windshield bow face.
> The long side is 1 inch long and is .063 inches thick. The
short side
> is .050 inches long and several thicknesses. I have 10 sets in
sizes
> from .025 to .040 inches.
> These work pretty well. At first, I clamped them into place.
Then,
> screws through the holes that hold the double bead seal to the
windshield
> bow. Then tape. All work pretty well.
> The gap can be filled with RTV after the shim is removed.
> (5) My favorite is just too simple to believe. Again, using the
holes that
> attach the double bead seal to the windshield bow, I use a #6 screw
onto
> which I put a wide area #10 washer plus a wide area 5/16 washer.
> I'd use just the wide area 5/16 washer but the hole is too
big; the
> #6 screw won't hold it by itself. With the windshield in place, I
can
> adjust the gap between the bow and windshield with the washers
tightened
> against the bow.
> When bonding, I tighten the clamps, located at the shims,
until the
> washer just shows through the RTV and just touches the windshield.
(NA
> for LP Aero windshields)
> After the RTV is applied to the windshield bonding area, the
windshield can
> then be set into place and located over the dowels on the bottom
corners,
> the holes line up on top for the top two screws and special washers.
Clamps
> are applied until I get either the "L" shim showing on the edge of
the
> windshield or the washer showing through the windshield. At this
point, I
> know the gap at the forward edge of the bow is about .020 inches.
The gap
> is kept as uniform as possible. After it's all done being bonded, I
let the
> windshield sit for a week before moving it. The maintenance manual
says 3
> days but I've found the RTV to not be totally cured at 3 days.
> The windshield in the $80,000 Cheetah was done in 2003 when John
Rodgers
> owned the plane. It has always been parked outside. It's a
C.Bailey
> windshield. The bond is still like new.
> I've attached
Message 5
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Gary:
You got a conundrum...
You know where the leak is but you have to make the leak BIGGER.
The leak/hole is so small that there is no surface area for the
sealant to adhere to.
And it very well could be corrosion that caused the leak.
Sealant has a difficult time sticking to corrosion. Especially when
the hole is so small.
If it is accessible from the inside:
Drill out the hole - small - about 1/32" dia. - You have to give it
some area to adhere to.
Press & smear the sealant in and around the hole.
Verify that it comes through to the outside.
LET IT CURE - For at least 72 Hours.
Take a new razor blade and slice it off flush with the wing.
I do not know if PAINT will stick to the sealant?
If it is not accessible from the inside:
Drill out the hole as above - 1/32" dia.
Remove some paint around the hole. 1/4" Dia.
Chem-Film the bare aluminum.
Make a mask around the hole - masking tape.
Press & smear the sealant in and around the hole.
LET IT CURE - For at least 72 hours.
Use an X-Acto knife to make a nice clean circle around the hole
removing the excess sealant - 1/4" dia.
And in both cases - PRAY.
Of course there are the illegal chemicals...
Barry
Message 6
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flyv35b wrote:
> *That might be a good idea, Linn. What is the number of the Loctite
> as their are scores of different types. Is just "Green" that definitive?*
> **
> *Cliff*
' Green' would suffice .... all the different ones have different colors
..... green, blue, red ..... but the green is #290 ..... wicking
locktite
Linn
Message 7
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Well, now, there is something I hadn't thought of. I can draw a vacuum on the
tank and try the MEK to see if it pulls it through. Cool. Good place to start.
________________________________
From: Linn Walters <pitts_pilot@bellsouth.net>
Sent: Fri, June 18, 2010 3:18:58 AM
Subject: Re: TeamGrumman-List: Fuel leak
Gary Vogt wrote:
>
>So, I got under the wing again, opened the inspection panels,
>and nothing. Still no stains anywhere. I pressurized the tank through
>the vent line. Since I had to hold pressure I couldn't actually feel
>around and look for a leak while the tank was pressurized. Nothing.
> No leaks.
>
>
>I removed the strap around the wing. Nothing. No stains at
>all. There was, however, fuel tank sealant applied to the outside. It
>looks post wing completion. I pressurized the tank again and after 30
>seconds or so, went to look for leaks. Nothing. What a pain in the
>ass. I needed to look for leaks with the tank pressurized.
>
>
>Then I thought, if I could plug the vent line, how could I
>pressurize the tank? Well, the solution was to pressurize through the
>sump fuel drain. I plugged the vent, then applied pressure at the
>drain, pushed it in as if to drain (but with air pressure on it) and I
>could hear bubbles going into the sump. Good first start. I waited
>about a 15 seconds, then, removed pressure. No leaks. I went to the
>vent line and removed the plug. A small mount of air escaped. Good.
> It works. So, plug back in, I pressurized the tank and waited about
>30-45 seconds. Keep in mind I'm using 120 psi. I'll bet that got your
>attention. No, I'm using about 1 or 2 psi. Then I went looking for
>leaks.
>
>
>Guess what. On the very bottom of the spar, at the edge of the
>wing skin, where the sealant was applied, a very tiny wet spot. I got
>a paper towel and put it on it. It was that hard to see. There it
>was; the little bugger. Under pressure, at the rate it was leaking, it
>would take forever to drain the tank. If I had to estimate the hole
>size, I'd say about 100 microns.
>
>
>Is it worth trying to seal from the outside?
>
I'd say yes ..... the resulting stain would be aggravating. Get some
green Loctite, clean the hole: draw a vacuum on the tank and feed some
MEK through the hole ...... make take a lot of patience. Keeping the
vacuum on the tank, feed the hole some of the green Loctite. Remove
the vacuum once you feel the Loctite has gone through whole passage.
Should now stop the leak.
With the hole that small, getting fluid through the hole may be
problematic ..... the hole may seal under vacuum ..... use the MEK to
clean the external area real good and apply some proseal over the
exterior where the hole is.
Linn
PS .... the green Loctite trick came from the RV group.
>
>
> href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/contribution
>
Message 8
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The hole, where it's leaking, is at the very bottom of the spar in the middle.
It's leaking at the sealant on the bottom of the spar and not the wing skin.
On the 2005 AG5B, the gap at the bottom of the rib (normally just left open on
the AA5B and then filled with fuel tank sealant) is filled with an epoxy that
improves sealing. For all practical purposes, the wing is sealed without sealant.
I can't tell right now just exactly where the hole is. It's that small. I should
know more later today.
________________________________
From: FLYaDIVE <flyadive@gmail.com>
Sent: Fri, June 18, 2010 6:49:05 AM
Subject: Re: TeamGrumman-List: Fuel leak
Gary:
You got a conundrum...
You know where the leak is but you have to make the leak BIGGER.
The leak/hole is so small that there is no surface area for the
sealant to adhere to.
And it very well could be corrosion that caused the leak.
Sealant has a difficult time sticking to corrosion. Especially when
the hole is so small.
If it is accessible from the inside:
Drill out the hole - small - about 1/32" dia. - You have to give it
some area to adhere to.
Press & smear the sealant in and around the hole.
Verify that it comes through to the outside.
LET IT CURE - For at least 72 Hours.
Take a new razor blade and slice it off flush with the wing.
I do not know if PAINT will stick to the sealant?
If it is not accessible from the inside:
Drill out the hole as above - 1/32" dia.
Remove some paint around the hole. 1/4" Dia.
Chem-Film the bare aluminum.
Make a mask around the hole - masking tape.
Press & smear the sealant in and around the hole.
LET IT CURE - For at least 72 hours.
Use an X-Acto knife to make a nice clean circle around the hole
removing the excess sealant - 1/4" dia.
And in both cases - PRAY.
Of course there are the illegal chemicals...
Barry
Message 9
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| Subject: | Re: Tiger cowling for sale: $500 plus shipping. |
Anyone interested in this cowling please give me a call. I have it in
Texas at my hanger. I'll take $500.00 for the cowling and $140.00 for
the new exit ramps.
Scott Trejo
254-718-6655
On Jun 10, 2010, at 12:36 PM, Gary Vogt wrote:
> Scott is thinking about buying one of my new cowlings instead of the
cowling from Brian's plane. Scott purchased the cowling for $500. He
also wanted some of the larger fiberglass cooling exit ramps. Those
cost $140. I have it all in a box just slightly too big to ship UPS.
If I can get the box down to 41x37x24, if I recall correctly, the
shipping cost would be in the neighborhood of $120-$150 (to Houston).
>
> Garner, do you want this one?
>
>
>
>
>
Message 10
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Be careful. I use a shop-vac in the fuel filler and a rag to loosely
seal the opening. I've demonstrated PSI using a gallon can and a shop-vac.
MEK may not be the best .... hard to tell if it's evaporating or going
in the hole!!! You might use food coloring ..... after the vacuum's
been there for a while and you wipe the outside there may still be
enough color in the hole to be seen. Good luck!!!
Linn
Gary Vogt wrote:
> Well, now, there is something I hadn't thought of. I can draw a
> vacuum on the tank and try the MEK to see if it pulls it through.
> Cool. Good place to start.
>
> ------------------------------------------------------------------------
> *From:* Linn Walters <pitts_pilot@bellsouth.net>
> *To:* teamgrumman-list@matronics.com
> *Sent:* Fri, June 18, 2010 3:18:58 AM
> *Subject:* Re: TeamGrumman-List: Fuel leak
>
> Gary Vogt wrote:
>> So, I got under the wing again, opened the inspection panels, and
>> nothing. Still no stains anywhere. I pressurized the tank through
>> the vent line. Since I had to hold pressure I couldn't actually feel
>> around and look for a leak while the tank was pressurized. Nothing.
>> No leaks.
>>
>> I removed the strap around the wing. Nothing. No stains at all.
>> There was, however, fuel tank sealant applied to the outside. It
>> looks post wing completion. I pressurized the tank again and after
>> 30 seconds or so, went to look for leaks. Nothing. What a pain in
>> the ass. I needed to look for leaks with the tank pressurized.
>>
>> Then I thought, if I could plug the vent line, how could I pressurize
>> the tank? Well, the solution was to pressurize through the sump fuel
>> drain. I plugged the vent, then applied pressure at the drain,
>> pushed it in as if to drain (but with air pressure on it) and I could
>> hear bubbles going into the sump. Good first start. I waited about
>> a 15 seconds, then, removed pressure. No leaks. I went to the vent
>> line and removed the plug. A small mount of air escaped. Good. It
>> works. So, plug back in, I pressurized the tank and waited about
>> 30-45 seconds. Keep in mind I'm using 120 psi. I'll bet that got
>> your attention. No, I'm using about 1 or 2 psi. Then I went looking
>> for leaks.
>>
>> Guess what. On the very bottom of the spar, at the edge of the wing
>> skin, where the sealant was applied, a very tiny wet spot. I got a
>> paper towel and put it on it. It was that hard to see. There it
>> was; the little bugger. Under pressure, at the rate it was leaking,
>> it would take forever to drain the tank. If I had to estimate the
>> hole size, I'd say about 100 microns.
>>
>> Is it worth trying to seal from the outside?
> I'd say yes ..... the resulting stain would be aggravating. Get some
> green Loctite, clean the hole: draw a vacuum on the tank and feed some
> MEK through the hole ...... make take a lot of patience. Keeping the
> vacuum on the tank, feed the hole some of the green Loctite. Remove
> the vacuum once you feel the Loctite has gone through whole passage.
> Should now stop the leak.
>
> With the hole that small, getting fluid through the hole may be
> problematic ..... the hole may seal under vacuum ..... use the MEK to
> clean the external area real good and apply some proseal over the
> exterior where the hole is.
> Linn
> PS .... the green Loctite trick came from the RV group.
>>
>> *
>>
>> href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List <http://www.matronics.com/Navigator?TeamGrumman-List%22%3Ehttp://www.matronics.com/Navigator?TeamGrumman-List>
>> href="http://forums.matronics.com">http://forums.matronics.com <http://forums.matronics.com%22%3Ehttp://forums.matronics.com>
>> href="http://www.matronics.com/contribution">http://www.matronics.com/contribution <http://www.matronics.com/contribution%22%3Ehttp://www.matronics.com/contribution>
>>
>> *
>
> *
>
>
> *
>
> *
>
>
> *
Message 11
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| Subject: | Wiring, was Windshield |
----- Forwarded Message ----
From: Gary Vogt <teamgrumman@yahoo.com>
Sent: Fri, June 18, 2010 9:55:12 AM
Subject: Re: TeamGrumman-List: Wiring, was Windshield
This is the worst I've seen. None of the circuit breakers in the front were being
used. There were, however, a dozen in-line fuses behind the panel. This
is in a Cheetah that got a Garmin stack worth $20,000. It got all new CBs and
wiring.
________________________________
From: flyv35b <flyv35b@minetfiber.com>
Sent: Fri, June 18, 2010 6:13:34 AM
Subject: Re: TeamGrumman-List: Windshield
That's probably
the worst wiring I have ever seen!
Cliff
----- Original Message -----
>From: Gary
> Vogt
>To: teamgrumman-list@matronics.com
>Sent: Thursday, June 17, 2010 12:05
> PM
>Subject: Re: TeamGrumman-List:
> Windshield
>
>
>It's been one of those weeks. Seems like everyone wants their plane
> yesterday, the parts I get are either poorly manufactured, don't fit or both,
> the workmanship of some mechanics is appalling, and I am constantly amazed how
> plane owners accept 'good enough.'
>
>
>In 1984, a few days after I bought my first Cheetah (which had been
> sitting in the desert sun for 2 years), a 77 Cheetah with 714 TTSN, I went to
> the local FBO to find someone to do an annual. I knew nothing about
> planes. In the FBO, two A&Ps were installing an O360 into a Cessna
> 172. I watched while preformed aluminum parts, included in the STC, were
> being bent and deformed to force them to fit. Over the next hour or so,
> I watched them forcing parts together that simply did not fit. Their
> reasoning was, "the owner will never look under the cowling." By 1984, I
> had built 2 hot rods and restored a 69 Corvette and a 66 Chevy II Super Sport.
> It was then I decided that I would be the only one working on my plane.
> I found a mentor I could trust and began my tutelage.
>
>
>I've turned away two potential customers in the last 2 months that
> actually asked for me to do half-assed work and just get it signed off.
> Their logic: my regular mechanic does it all the time but he's
> busy right now. So can you do it?
>
>
>Windshield:
> I've heard about installing windshields in the plane. I've never
> seen how that could be done. Just getting the windshield into the coving
> the windshield needs to be warped a bit. To keep the bow square with the
> canopy, it would need to be clamped to the canopy with 1/4 inch spacers to get
> the proper gap. That means there would be no way to clamp the windshield
> in place. The windshield would need to be held in place with the
> mounting screws. That being the case, how is the proper gap held around
> the windshield bow? Where does the excess adhesive go?
>
>
>Rear
> windows: Getting the old sealant out sometimes requires sanding it out.
> That means there is a whole lot of bare metal on the mounting surface.
> Now, two things, either the old sealant is completely removed by sanding
> and new strip caulk or RTV is applied on the bare metal, or strip calk or RTV
> is applied over the old sealant. When I install rear windows, I sand out
> all of the old sealant, alodine, prime, and paint the mounting surface with
> Imrom. Then I let it sit for 7 days to properly cross-link before
> installing windows.
>
>
>Canopy
> windows: I've seen it recommended to use the foam tape on the canopy
> windows. There is just no way to install the canopy windows with foam
> tape around the perimeter without tearing the foam tape to shreds. There
> is a reason the factory used the felt tape: IT ALLOWS THE WINDOW TO SLIDE INTO
> PLACE. The canopy windows are designed to leak. They are designed
> to leak to the outside.
>
>
>1348: cabin prepared for a new
> headliner
>1334:
> typical avionics wiring. Nice huh. The glide slope receiver was
> mounted on the bottom of the glare shield.
>
>
________________________________
From: FLYaDIVE
> <flyadive@gmail.com>
>To: > teamgrumman-list@matronics.com
>Sent: Thu, June 17, 2010 5:20:20
> AM
>Subject: Re:
> TeamGrumman-List: Windshield
>
>--> TeamGrumman-List message
> posted by: FLYaDIVE <flyadive@gmail.com>
>
>Gary:
>
>What's
> the apology for? You did not hurt my feelings.
>
>I was once
> condescended, but now I am convince.
>
>I have not had the time to read
> and digest your posts, but I will.
>After all I have only done 2 windows and
> I do respect my elders ;-)
>
>I am impressed with your jig - Working out
> the size is quite an
>accomplishment. I would have like to have been
> there as you designed
>and manufactured it.
>
>Anyway, whos feeling did
> you think you hurt? Hell, let them grow some
>thicker
> skin.
>
>Barry
>"Chop'd Liver"
>
>
>On Wed, Jun 16,
> 2010 at 2:28 PM, Gary Vogt <teamgrumman@yahoo.com>
> wrote:
>> Sorry I got so condescending about windshield. No
> excuse.
>> By my count, I've installed 43 windshields since 1984.
> I've made a lot of
>> mistakes and learned a lot of 'tricks' to
> getting the windshield square with
>> the bow and getting the correct
> thickness of RTV.
>> I built my jig in 1984 in an attempt to simulate the
> location and shape of
>> the windshield as installed. At the time,
> I was trying too imagine how they
>> were done at the factory. I
> figured they had some sort of jig to put the
>> windshield on the bow.
> The jig has gone through 2 revisions. mostly to
>> provide
> better access to the underside. The version I have now
> guarantees
>> an absolutely flat windshield bow to which the windshield
> is bonded. I have
>> a set of blocks of wood to put under the
> forward edge of the windshield.
>> These blocks locate and lock the
> forward edge such that when the windshield
>> is set into position, it
> always falls on the same position at the windshield
>> bow edge.
> The jig has dowels that locate the holes to be drilled at the
>>
> lower corners. Before the holes are drilled, I tape a strip of
> .020
>> aluminum to the bow to simulate the thickness of the RTV when
> installed.
>> The holes in the lower corners are drilled with the
> windshield in its final
>> location. With those holes drilled, the
> windshield can be positioned and
>> the two holes on top drilled.
> It's at this point that I use a feeler gauge
>> the determine the
> gap between the windshield and bow. Where it's too tight
>>
> (meaning: places where the forward edge of the windshield bow would
> project
>> into the RTV making the RTV too thin, <.020, in that area),
> I mark the
>> windshield so that any clamps in that area are not over
> tightened. I use
>> two types of shims to space the windshield from
> the bow and maintain the
>> spacing during assembly.
>> Shims I've
> tried:
>> (1) self sticking foam that compresses to approx .025
> inches. I punched
>> out dots using a hole punch. It worked,
> but left the dots showing. I did
>> one like this.
>>
> (2) .020 safety wire clips at the forward edge of the bow. It
> worked, but
>> left little holes when I removed the clips. The
> holes couldn't be filled
>> with RV. I did two like this.
>>
> (3) I made a spacer, .050 thick, the shape of the windshield bow,
> attached
>> to the bow through the holes used to hold the double bow seal
> on, that stuck
>> up .030 above the aft edge of the bow (same surface the
> seal uses).
>> The idea here was to hold the
> windshield .030 away from the bow
>> uniformly from one corner to the
> other. At first, this sounded like a great
>> idea (it wouldn't
> work with an LP Aero windshield because
>>
> there is no lip at the bow). The biggest problem was: the bows
> are
>> not all the same shape. I used this for 4 or 5 windshields
> before it became
>> obvious this was not practical. I kept filing
> and adjusting the shape to
>> get them to fit.
>> (4) Then, I
> made little "L" shaped shims that can be placed under the aft
>> edge of
> the windshield between the bow and windshield. The long side is
>>
> flush with the windshield bow face.
>> The long
> side is 1 inch long and is .063 inches thick. The short side
>> is
> .050 inches long and several thicknesses. I have 10 sets in
> sizes
>> from .025 to .040 inches.
>>
> These work pretty well. At first, I clamped them into place.
> Then,
>> screws through the holes that hold the double bead seal to
> the windshield
>> bow. Then tape. All work pretty
> well.
>> The gap can be filled with RTV after
> the shim is removed.
>> (5) My favorite is just too simple to
> believe. Again, using the holes that
>> attach the double bead seal
> to the windshield bow, I use a #6 screw onto
>> which I put a wide area
> #10 washer plus a wide area 5/16 washer.
>>
> I'd use just the wide area 5/16 washer but the hole is too big;
> the
>> #6 screw won't hold it by itself. With the windshield in
> place, I can
>> adjust the gap between the bow and windshield with the
> washers tightened
>> against the bow.
>>
> When bonding, I tighten the clamps, located at the shims, until the
>>
> washer just shows through the RTV and just touches the windshield.
> (NA
>> for LP Aero windshields)
>> After the RTV
> is applied to the windshield bonding area, the windshield can
>> then be
> set into place and located over the dowels on the bottom corners,
>> the
> holes line up on top for the top two screws and special washers.
> Clamps
>> are applied until I get either the "L" shim showing on
> the edge of the
>> windshield or the washer showing through the
> windshield. At this point, I
>> know the gap at the forward edge of
> the bow is about .020 inches. The gap
>> is kept as uniform as
> possible. After it's all done being bonded, I let the
>> windshield
> sit for a week before moving it. The maintenance manual says 3
>>
> days but I've found the RTV to not be totally cured at 3 days.
>> The
> windshield in the $80,000 Cheetah was done in 2003 when John Rodgers
>>
> owned the plane. It has always been parked outside. It's a
> C.Bailey
>> windshield. The bond is still like new.
>> I've
> attached
Message 12
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| Subject: | Windshield bonding details |
1350: Washer shims
1351: Top of windshield, "L" spacers
1353: Gap growing from .020 to .25 inches.
Message 13
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After I cleaned out all of the sealant on the OUTSIDE of the tank, I pressurized
and squirted on soapy water. You can see it in pic 1359. The other side of
the leak looks like this: 1258. About the only ay I can see that it would still
be leaking is if it is coming in at the top and running down the inside between
the rib and any doublers. What a pain.
________________________________
From: Linn Walters <pitts_pilot@bellsouth.net>
Sent: Fri, June 18, 2010 3:53:07 PM
Subject: Re: TeamGrumman-List: Fuel leak
Be careful. I use a shop-vac in the fuel filler and a rag to loosely
seal the opening. I've demonstrated PSI using a gallon can and a
shop-vac.
MEK may not be the best .... hard to tell if it's evaporating or going
in the hole!!! You might use food coloring ..... after the vacuum's
been there for a while and you wipe the outside there may still be
enough color in the hole to be seen. Good luck!!!
Linn
Gary Vogt wrote:
>
>Well, now, there is something I hadn't thought of. I can draw a
>vacuum on the tank and try the MEK to see if it pulls it through.
> Cool. Good place to start.
>
>
________________________________
From: >Linn Walters <pitts_pilot@bellsouth.net>
>To: teamgrumman-list@matronics.com
>Sent: Fri, June 18,
>2010 3:18:58 AM
>Subject: Re:
>TeamGrumman-List: Fuel leak
>
>>Gary Vogt wrote:
>
>So, I got under the wing again, opened the inspection panels,
>>and nothing. Still no stains anywhere. I pressurized the tank through
>>the vent line. Since I had to hold pressure I couldn't actually feel
>>around and look for a leak while the tank was pressurized. Nothing.
>> No leaks.
>>
>>
>>I removed the strap around the wing. Nothing. No stains at
>>all. There was, however, fuel tank sealant applied to the outside. It
>>looks post wing completion. I pressurized the tank again and after 30
>>seconds or so, went to look for leaks. Nothing. What a pain in the
>>ass. I needed to look for leaks with the tank pressurized.
>>
>>
>>Then I thought, if I could plug the vent line, how could I
>>pressurize the tank? Well, the solution was to pressurize through the
>>sump fuel drain. I plugged the vent, then applied pressure at the
>>drain, pushed it in as if to drain (but with air pressure on it) and I
>>could hear bubbles going into the sump. Good first start. I waited
>>about a 15 seconds, then, removed pressure. No leaks. I went to the
>>vent line and removed the plug. A small mount of air escaped. Good.
>> It works. So, plug back in, I pressurized the tank and waited about
>>30-45 seconds. Keep in mind I'm using 120 psi. I'll bet that got your
>>attention. No, I'm using about 1 or 2 psi. Then I went looking for
>>leaks.
>>
>>
>>Guess what. On the very bottom of the spar, at the edge of
>>the
>>wing skin, where the sealant was applied, a very tiny wet spot. I got
>>a paper towel and put it on it. It was that hard to see. There it
>>was; the little bugger. Under pressure, at the rate it was leaking, it
>>would take forever to drain the tank. If I had to estimate the hole
>>size, I'd say about 100 microns.
>>
>>
>>Is it worth trying to seal from the outside?
>>
>I'd say yes ..... the resulting stain would be aggravating. Get some
>green Loctite, clean the hole: draw a vacuum on the tank and feed some
>MEK through the hole ...... make take a lot of patience. Keeping the
>vacuum on the tank, feed the hole some of the green Loctite. Remove
>the vacuum once you feel the Loctite has gone through whole passage.
>Should now stop the leak.
>
>>With the hole that small, getting fluid through the hole may be
>problematic ..... the hole may seal under vacuum ..... use the MEK to
>clean the external area real good and apply some proseal over the
>exterior where the hole is.
>>Linn
>>PS .... the green Loctite trick came from the RV group.
>
>
>>
>>
>>
>> href="http://www.matronics.com/Navigator?TeamGrumman-List%22%3Ehttp://www.matronics.com/Navigator?TeamGrumman-List
>> href="http://forums.matronics.com%22%3Ehttp://forums.matronics.com
>> href="http://www.matronics.com/contribution%22%3Ehttp://www.matronics.com/contribution
>>
>
>
>
>
> href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/contribution
>
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