pitot and stall warning

bransom · Post by **bransom** » Sat Feb 18, 2012 10:47 am

Hi all,
I'm back to building after a few weeks of chaos getting things ready for my
daughter's wedding. Wow, what a ton of work!

Not real long before I will be doing final attach of LE skin on left wing and
I need to take care of pitot and possibly stall horn fittings. After
reviewing the archives, I think I will make my own pitot along the following
guidelines, but also with questions as shown:

** ~1/4 or 5/16" ID ram inlet. I'd like to go smaller to reduce rain input
but Bob, Wayne, and maybe others suggested large opening provided best
readings. Will put T with water trap on line inside. Other comments?

** will mount pitot near strut attach and run line down strut. I had not
planned on using the big doubler (W-601) that shows in the 1999 MAM (mine is
1994), but perhaps this would be best after all if I could kill 2 birds with
one stone by using it's forward inspection port as the base for pitot mount.
Thoughts on this? BTW, if someone could tell me the thickness of W-601.
_______________
WRT Stall warning -- any recommendations?

Thanks,
-Ben/ 496R

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Ken · Post by **Ken** » Sat Feb 18, 2012 10:47 am

Hi Ben
If you decide to put the pitot below the wing, I think Bingelis and his
article on the EAA site recommends 1/4" tube and I think they recommend
getting the probe about 5" below the wing and back about 1/3 chord from
the leading edge. I believe the the idea is that back that far insures
the flow is parallel to the wing and the probe. In theory then there may
be no need for a large diameter probe in that location. The heated
cessna probe just has a small hole in the bottom at the point where it
turns vertical to presumably drain water.
Ken

bransom@dcsol.com wrote:

Hi all,
I'm back to building after a few weeks of chaos getting things ready for my
daughter's wedding. Wow, what a ton of work!

Not real long before I will be doing final attach of LE skin on left wing and
I need to take care of pitot and possibly stall horn fittings. After
reviewing the archives, I think I will make my own pitot along the following
guidelines, but also with questions as shown:

** ~1/4 or 5/16" ID ram inlet. I'd like to go smaller to reduce rain input
but Bob, Wayne, and maybe others suggested large opening provided best
readings. Will put T with water trap on line inside. Other comments?

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bransom · Post by **bransom** » Sat Feb 18, 2012 10:47 am

Thanks Ken,
I'm still a little surprised at the 1/4" recommendations because IIRC,
looking around the airport I see Cessnas with smaller openings. But will go
1/4 here for the possibly wider AOA range. The 1/3 back (and 3" down) was
also in the archives here - a post from BobP. I'll go just in front of the
main spar so as to use easy tube routing to the lift strut.

Still no comments from anyone on stall horns. Assuming this means most feel
they are too annoying to put up with. ?
-Ben

Hi Ben
If you decide to put the pitot below the wing, I think Bingelis and his
article on the EAA site recommends 1/4" tube and I think they recommend
getting the probe about 5" below the wing and back about 1/3 chord from
the leading edge. I believe the the idea is that back that far insures
the flow is parallel to the wing and the probe. In theory then there may
be no need for a large diameter probe in that location. The heated
cessna probe just has a small hole in the bottom at the point where it
turns vertical to presumably drain water.
Ken

bransom@dcsol.com wrote:

Hi all,
I'm back to building after a few weeks of chaos getting things ready for

my

daughter's wedding. Wow, what a ton of work!

Not real long before I will be doing final attach of LE skin on left wing

and

I need to take care of pitot and possibly stall horn fittings. After
reviewing the archives, I think I will make my own pitot along the

following

guidelines, but also with questions as shown:

** ~1/4 or 5/16" ID ram inlet. I'd like to go smaller to reduce rain

input

but Bob, Wayne, and maybe others suggested large opening provided best
readings. Will put T with water trap on line inside. Other comments?

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Walter Klatt · Post by **Walter Klatt** » Sat Feb 18, 2012 10:47 am

FWIW, I use the standard MAM pitot tube with static port on the
side, mounted on the left leading edge near where the strut
attaches. The lines run down inside the strut and through the
fuselage at the bottom. Always worked fine for me. I know the
speed calibration can be adjusted with an O-ring near the static
opening, but mine is pretty well bang on as is. Also, I should
mention that it is bent down slightly to compensate for the
positive angle of attack of the wing in level flight and also
gives me good readings right down to the stall. If you don't do
that, you will likely get too low readings at stall speed. Under
the wing should be OK, though, as the airflow should still be
parallel to the wing.

I have never found the need or desire to have a stall horn. The
Rebel gives you plenty of warning before it stalls. Also, it gets
a very high rate of descent long before the stall. I rarely slip
mine. If I need to lose altitude, I just slow it down, and at 60
mph, it's starts acting like a brick.

Walter

-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of
bransom@dcsol.com
Sent: Wednesday, July 27, 2005 9:00 AM
To: rebel-builders@dcsol.com
Subject: Re: pitot and stall warning

Thanks Ken,
I'm still a little surprised at the 1/4"
recommendations because IIRC,
looking around the airport I see Cessnas with smaller
openings. But will go
1/4 here for the possibly wider AOA range. The 1/3
back (and 3" down) was
also in the archives here - a post from BobP. I'll go
just in front of the
main spar so as to use easy tube routing to the lift strut.

Still no comments from anyone on stall horns. Assuming
this means most feel
they are too annoying to put up with. ?
-Ben

Hi Ben
If you decide to put the pitot below the wing, I
think Bingelis and his
article on the EAA site recommends 1/4" tube and I
think they recommend
getting the probe about 5" below the wing and back
about 1/3 chord from
the leading edge. I believe the the idea is that
back that far insures
the flow is parallel to the wing and the probe. In
theory then there may
be no need for a large diameter probe in that
location. The heated
cessna probe just has a small hole in the bottom at
the point where it
turns vertical to presumably drain water.
Ken

bransom@dcsol.com wrote:

Hi all,
I'm back to building after a few weeks of chaos
getting things ready for
my
daughter's wedding. Wow, what a ton of work!

Not real long before I will be doing final attach
of LE skin on left wing
and
I need to take care of pitot and possibly stall
horn fittings. After
reviewing the archives, I think I will make my own
pitot along the
following
guidelines, but also with questions as shown:

** ~1/4 or 5/16" ID ram inlet. I'd like to go
smaller to reduce rain
input
but Bob, Wayne, and maybe others suggested large
opening provided best
readings. Will put T with water trap on line
inside. Other comments?

-------------------------------------------------------
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bransom · Post by **bransom** » Sat Feb 18, 2012 10:47 am

Is the standard MAM pitot a straight tube into the front of the Leading Edge
skin, or is it an L shaped (Cessna look) that mounts to the underside of the
wing (LE or main)?
Thanks,
-Ben

FWIW, I use the standard MAM pitot tube with static port on the
side, mounted on the left leading edge near where the strut
attaches. The lines run down inside the strut and through the
fuselage at the bottom. Always worked fine for me. I know the
speed calibration can be adjusted with an O-ring near the static
opening, but mine is pretty well bang on as is. Also, I should
mention that it is bent down slightly to compensate for the
positive angle of attack of the wing in level flight and also
gives me good readings right down to the stall. If you don't do
that, you will likely get too low readings at stall speed. Under
the wing should be OK, though, as the airflow should still be
parallel to the wing.

I have never found the need or desire to have a stall horn. The
Rebel gives you plenty of warning before it stalls. Also, it gets
a very high rate of descent long before the stall. I rarely slip
mine. If I need to lose altitude, I just slow it down, and at 60
mph, it's starts acting like a brick.

Walter

-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of
bransom@dcsol.com
Sent: Wednesday, July 27, 2005 9:00 AM
To: rebel-builders@dcsol.com
Subject: Re: pitot and stall warning

Thanks Ken,
I'm still a little surprised at the 1/4"
recommendations because IIRC,
looking around the airport I see Cessnas with smaller
openings. But will go
1/4 here for the possibly wider AOA range. The 1/3
back (and 3" down) was
also in the archives here - a post from BobP. I'll go
just in front of the
main spar so as to use easy tube routing to the lift strut.

Still no comments from anyone on stall horns. Assuming
this means most feel
they are too annoying to put up with. ?
-Ben

Hi Ben
If you decide to put the pitot below the wing, I
think Bingelis and his
article on the EAA site recommends 1/4" tube and I
think they recommend
getting the probe about 5" below the wing and back
about 1/3 chord from
the leading edge. I believe the the idea is that
back that far insures
the flow is parallel to the wing and the probe. In
theory then there may
be no need for a large diameter probe in that
location. The heated
cessna probe just has a small hole in the bottom at
the point where it
turns vertical to presumably drain water.
Ken

bransom@dcsol.com wrote:

getting things ready for
my
of LE skin on left wing
and
horn fittings. After
pitot along the
following
smaller to reduce rain
input
opening provided best
inside. Other comments?

-------------------------------------------------------
----------
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username "rebel" password "builder"
Subscription services located at:
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List administrator: mike.davis@dcsol.com
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WALTER KLATT · Post by **WALTER KLATT** » Sat Feb 18, 2012 10:47 am

Straight in.

Walter

----- Original Message -----
From: bransom@dcsol.com
Date: Thursday, July 28, 2005 8:30 am
Subject: RE: pitot and stall warning

Is the standard MAM pitot a straight tube into the front of the
Leading Edge
skin, or is it an L shaped (Cessna look) that mounts to the
underside of the
wing (LE or main)?
Thanks,
-Ben

FWIW, I use the standard MAM pitot tube with static port on the
side, mounted on the left leading edge near where the strut
attaches. The lines run down inside the strut and through the
fuselage at the bottom. Always worked fine for me. I know the
speed calibration can be adjusted with an O-ring near the static
opening, but mine is pretty well bang on as is. Also, I should
mention that it is bent down slightly to compensate for the
positive angle of attack of the wing in level flight and also
gives me good readings right down to the stall. If you don't do
that, you will likely get too low readings at stall speed. Under
the wing should be OK, though, as the airflow should still be
parallel to the wing.

I have never found the need or desire to have a stall horn. The
Rebel gives you plenty of warning before it stalls. Also, it gets
a very high rate of descent long before the stall. I rarely slip
mine. If I need to lose altitude, I just slow it down, and at 60
mph, it's starts acting like a brick.

Walter

-----Original Message-----
From: mike.davis@dcsol.com
[mike.davis@dcsol.com]On Behalf Of
bransom@dcsol.com
Sent: Wednesday, July 27, 2005 9:00 AM
To: rebel-builders@dcsol.com
Subject: Re: pitot and stall warning

Thanks Ken,
I'm still a little surprised at the 1/4"
recommendations because IIRC,
looking around the airport I see Cessnas with smaller
openings. But will go
1/4 here for the possibly wider AOA range. The 1/3
back (and 3" down) was
also in the archives here - a post from BobP. I'll go
just in front of the
main spar so as to use easy tube routing to the lift strut.

Still no comments from anyone on stall horns. Assuming
this means most feel
they are too annoying to put up with. ?
-Ben
think Bingelis and his think they recommend about 1/3 chord from back that far insures theory then there may location. The heated the point where it getting things ready for
my of LE skin on left wing
and horn fittings. After pitot along the
following smaller to reduce rain
input opening provided best inside. Other comments?

-------------------------------------------------------
----------
List archives located at: https://www.dcsol.com/login
username "rebel" password "builder"
Subscription services located at:
https://www.dcsol.com/public/code/html-subscribe.htm
List administrator: mike.davis@dcsol.com
-------------------------------------------------------
----------

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