Piper Archer II Air Leak Problem by Back Seat.

Piper Archer II PA28-181
Help please !!
We have just replaced the cabin roof airduct in our 1977 Piper Archer II
PA28-181.
The duct feeds fresh air from the rear mounted blower to each of the 4
overhead air outlets.
The air is controlled by a push & pull cable mounted in the duct.
With the air duct closed, no air being fed to the overhead ducts, there is
howling cold airflow up through the right side of the rear seat floor duct.
The cold air flow with the overhead duct closed must be coming from central
air outlet under the belly of the bird ?
We never had this problem before the new air duct was fitted ?

Our maintenance crew have had both the overhead duct system apart and the
rear seat board out to inspect that area.
Everything looks normal and they are perplexed how to cure the problem.
I wonder how many other PA28 owners with overhead fresh air ducts have had
this issue ?

Thanks for all input.
--
Roy
Piper Archer N5804F

..

We have just replaced the cabin roof airduct in our 1977 Piper Archer II
PA28-181.
The duct feeds fresh air from the rear mounted blower to each of the 4
overhead air outlets.
The air is controlled by a push & pull cable mounted in the duct.
With the air duct closed, no air being fed to the overhead ducts, there is
howling cold airflow up through the right side of the rear seat floor duct.

Having spent a goodly amount of time working on (and replacing) that
very same fresh air flapper (the one that controls the ceiling ducts)
in my '74 Pathfinder, I can tell you without hesitation that it has
NOTHING to do with the air coming in the floor ducts.

If air is coming out of a floor duct, you've got a bad flapper valve in
that duct. Make sure to check that the cold air isn't actually coming
from under the back SEAT.

If you have the bench seat, this is an extremely common place for air
to leak into a Cherokee. Luckily, it can be easily remedied with a
strip of strategically-placed closed-pore foam insullation, laid down
where the bench seat meets the bottom of the airframe.

This 75-cent piece of foam can make all the difference in the world.

The cold air flow with the overhead duct closed must be coming from central
air outlet under the belly of the bird ?

Nope. However, there IS an inlet on the belly that could be the source
of air leaking under the seat. This inlet on the bottom of the plane
is simply an open hole -- there is no control.

Our maintenance crew have had both the overhead duct system apart and the
rear seat board out to inspect that area.
Everything looks normal and they are perplexed how to cure the problem.
I wonder how many other PA28 owners with overhead fresh air ducts have had
this issue ?

I spent a dozen or more hours weather-sealing my old '75 Warrior. It
was colder than hell in the winter, and my poor kids had to fly wrapped
in a sleeping bag in winter. After methodically sealing the door, and
each leak (Example: Stuff "Nerf" balls in the floor ducts to really
seal out any leaking air), we could fly that plane in shirtsleeves, no
matter what the weather.

Good luck!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Thanks Jay,

Unusually, I did not replace the upper air duct myself so I did not have the
chance to see the rear flapper valve.
I do know that the valve works effectively because when the operating knob
is pulled out to the off position all fresh air stops coming out of the 4
overhead ducts.

Now I am making an assumption that when the overhead duct is on, the cabin
is very slightly *pressurized* which stops the flow of up coming in from the
belly open duct.
The back seat set up in my Archer will be very similar to your Pathfinder, a
pair of seats which mount on the removable floor board which itself has a
vent each side.

I have been involved for several years assisting with annuals and fitting
new interiors to PA28-180/181 aircraft so I am very familiar with taking out
the floor boards etc.
I now do all of *preventative maintenance* that the rules allow on my own
Archer so frequently get to see the innards of the beast.
The centrally mounted belly vent, as you say has no valve, the external
shield should work a bit like automatic bailers fitted in racing sailing
dinghy's.
By hanging down in the breeze, it should create some "suck" and pull stale
cabin air through the rear board vents into the outside world.
But it does appear that when I close the overhead duct, I am getting a
reverse flow from under the rear seat board back through the board side
vents into the cabin.

At the time of fitting the new overhead plastic ducts [November] my shop did
several other jobs, namely I had them re-rig all the flight controls and
replace a couple of smoking rivets.
The issue with the draft appeared immediately after that spell in the shop.
The bird is booked into the paint shop in Feb and I am trying to make sure
that all is good before getting stripped and painted.
[In fact this week the shop is fitting gap shields and wing root fairings]

During December I had a new leather interior fitted, so the fit of the seat
board against the wall panels is now very snug.
But still the howling draft pours through the right side seat board vent.
I wonder why no draft out of the left seat board vent ?
That might be the key to solving the issue !

Roy




"Jay Honeck" wrote in message
ps.com...
We have just replaced the cabin roof airduct in our 1977 Piper Archer II
PA28-181.
The duct feeds fresh air from the rear mounted blower to each of the 4
overhead air outlets.
The air is controlled by a push & pull cable mounted in the duct.
With the air duct closed, no air being fed to the overhead ducts, there
is
howling cold airflow up through the right side of the rear seat floor
duct.

Having spent a goodly amount of time working on (and replacing) that
very same fresh air flapper (the one that controls the ceiling ducts)
in my '74 Pathfinder, I can tell you without hesitation that it has
NOTHING to do with the air coming in the floor ducts.

If air is coming out of a floor duct, you've got a bad flapper valve in
that duct. Make sure to check that the cold air isn't actually coming
from under the back SEAT.

If you have the bench seat, this is an extremely common place for air
to leak into a Cherokee. Luckily, it can be easily remedied with a
strip of strategically-placed closed-pore foam insullation, laid down
where the bench seat meets the bottom of the airframe.

This 75-cent piece of foam can make all the difference in the world.

The cold air flow with the overhead duct closed must be coming from
central
air outlet under the belly of the bird ?

Nope. However, there IS an inlet on the belly that could be the source
of air leaking under the seat. This inlet on the bottom of the plane
is simply an open hole -- there is no control.

Our maintenance crew have had both the overhead duct system apart and the
rear seat board out to inspect that area.
Everything looks normal and they are perplexed how to cure the problem.
I wonder how many other PA28 owners with overhead fresh air ducts have
had
this issue ?

I spent a dozen or more hours weather-sealing my old '75 Warrior. It
was colder than hell in the winter, and my poor kids had to fly wrapped
in a sleeping bag in winter. After methodically sealing the door, and
each leak (Example: Stuff "Nerf" balls in the floor ducts to really
seal out any leaking air), we could fly that plane in shirtsleeves, no
matter what the weather.

Good luck!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

During December I had a new leather interior fitted, so the fit of the seat
board against the wall panels is now very snug.
But still the howling draft pours through the right side seat board vent.
I wonder why no draft out of the left seat board vent ?
That might be the key to solving the issue !

Wow, that's a weird one, Roy.

So the draft is coming through that fine mesh that buts up against the
sidewalls, right next to the rear bucket seats? But only on the
*co-pilots* side?

There is nothing underneath that plank that should be able to direct
the air in any one direction -- it's just an open cavity beneath that
big hunk of plywood. Why the air would only come out the RIGHT
mesh/vent/opening is truly a mystery.

I suppose you could try duct taping a piece of cardboard to the bottom
side of the mesh, and go fly it? If nothing else, you'd be able to
see if (a) the draft stops, and (b) if it now pours out the LEFT
mesh/duct.

You sure that the little shroud around the bottom vent hole isn't
installed backwards, turning it into ram-air instead of venturi?

You might post this on Cherokee Chat, the Cherokee Pilots Association's
website. If someone there doesn't know the answer, it's either
unanswerable, or you truly are a pioneer in this particular problem.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Hi Jay,
Yes you have a good understanding of the issue now. All the statements you
made are right on.
The air is pouring up though the fine mesh duct on the plank on the
co-pilots side of the bird.
As far as I can tell their is no draft coming out of the fine mesh plank
vent on the pilots side.

The external shroud is positioned as a venturi rather than a scoop !
The wings are in the normal place and no metal has gone missing on the
underside of the plane :-)
BTW this is the first time since owning the Archer that we have had an
overhead duct without holes in it !

Piper Chat ? Can you let me have a link?

Thanks

--
Roy
Piper Archer N5804F


"Jay Honeck" wrote in message
ps.com...
During December I had a new leather interior fitted, so the fit of the
seat
board against the wall panels is now very snug.
But still the howling draft pours through the right side seat board vent.
I wonder why no draft out of the left seat board vent ?
That might be the key to solving the issue !

Wow, that's a weird one, Roy.

So the draft is coming through that fine mesh that buts up against the
sidewalls, right next to the rear bucket seats? But only on the
*co-pilots* side?

There is nothing underneath that plank that should be able to direct
the air in any one direction -- it's just an open cavity beneath that
big hunk of plywood. Why the air would only come out the RIGHT
mesh/vent/opening is truly a mystery.

I suppose you could try duct taping a piece of cardboard to the bottom
side of the mesh, and go fly it? If nothing else, you'd be able to
see if (a) the draft stops, and (b) if it now pours out the LEFT
mesh/duct.

You sure that the little shroud around the bottom vent hole isn't
installed backwards, turning it into ram-air instead of venturi?

You might post this on Cherokee Chat, the Cherokee Pilots Association's
website. If someone there doesn't know the answer, it's either
unanswerable, or you truly are a pioneer in this particular problem.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

As far as I can tell their is no draft coming out of the fine mesh plank
vent on the pilots side.

That is so weird. Is there something blocking *that* opening? I just
can't imagine what's causing that kind of strong air-flow.

The Cherokee Chat is the Cherokee Pilot's Association on-line chat
room. You've got to be a member, but it's worth every penny to join,
and then some. See them he http://www.piperowner.com/

With over 4000 Cherokee owners in the organization, you can always
count on getting an answer on ANY Cherokee question you might have.
And they have the BEST fly-in of the year. See info on that he
http://cherokeeflyin.com/

We've attended the last four, and intend to go again this year.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Looking at my ARCHER II manual...

The outboard floor vents are connected to the wing root openings.

The heater vents run along the center tunnel between the seats.

The overhead vents connect to the vertical stabilizer opening with the
blower in between.

The outboard floor vents are connected to the wing root openings.

The heater vents run along the center tunnel between the seats.

The overhead vents connect to the vertical stabilizer opening with the
blower in between.

Yep, but he's not talking about ANY of those vents.

There is a fine grating piece that fits alongside the rear seats,
between the seat and the outer wall of this model of Cherokee. This
grating allows air to flow freely the cabin and the under-seat
compartment (where the battery is on some Cherokees), and then out a
hole in the bottom of the plane.

Think "flow-through ventilation", circa Pontiac 1968.

That hole has a shroud around it that makes it act like a venturi in
flight, actually SUCKING the air through those mesh grates, and out the
bottom of the plane. For some reason, the OP is getting air coming OUT
of that grating -- only on the right side -- which is seemingly
impossible.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Does anybody know the shape of the connection where the left and right sides
join before exiting the outlet? "T"? "Y"?
Could it be shaped so that the rushing air escaping from the left side is
creating a low pressure area inside the tube on the right side causing air
to enter the exit port and flow into the right side? Like a shallow well
pump forces some water down the well through a venturi to force more water
up the well. What happens if you put some duct tape over the outlet opening
on the bottom of the plane?
Jim

"Jay Honeck" wrote in message
oups.com...
The outboard floor vents are connected to the wing root openings.

The heater vents run along the center tunnel between the seats.

The overhead vents connect to the vertical stabilizer opening with the
blower in between.

Yep, but he's not talking about ANY of those vents.

There is a fine grating piece that fits alongside the rear seats,
between the seat and the outer wall of this model of Cherokee. This
grating allows air to flow freely the cabin and the under-seat
compartment (where the battery is on some Cherokees), and then out a
hole in the bottom of the plane.

Think "flow-through ventilation", circa Pontiac 1968.

That hole has a shroud around it that makes it act like a venturi in
flight, actually SUCKING the air through those mesh grates, and out the
bottom of the plane. For some reason, the OP is getting air coming OUT
of that grating -- only on the right side -- which is seemingly
impossible.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message
oups.com...
The outboard floor vents are connected to the wing root openings.

The heater vents run along the center tunnel between the seats.

The overhead vents connect to the vertical stabilizer opening with the
blower in between.

Yep, but he's not talking about ANY of those vents.

There is a fine grating piece that fits alongside the rear seats,
between the seat and the outer wall of this model of Cherokee. This
grating allows air to flow freely the cabin and the under-seat
compartment (where the battery is on some Cherokees), and then out a
hole in the bottom of the plane.

Think "flow-through ventilation", circa Pontiac 1968.

That hole has a shroud around it that makes it act like a venturi in
flight, actually SUCKING the air through those mesh grates, and out the
bottom of the plane. For some reason, the OP is getting air coming OUT
of that grating -- only on the right side -- which is seemingly
impossible.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"



Jay has it correct.
I happen to be a pretty capable mechanical engineer and this issue has me
totally foxed.
The airplane is in the shop right now and I have asked them to pull the rear
seat plank out again.
As soon as they do that I am going to have another look and also check why
air is not coming out of the mesh grill on the other side of the seat plank.
Thinking about it, they also fitted new seals to the other 4 floor ducts,
which also now shut off very nicely.
Perhaps she is just too tight :-)

Roy