Today's Message Index:
----------------------
1. 09:47 AM - Re: Exhaust Tailpipe Question (Mcculleyja@aol.com)
2. 02:18 PM - Re: Re: Exhaust Tailpipe Question (William Bernard)
3. 02:26 PM - Re: Re: Exhaust Tailpipe Question (George Turner)
4. 02:55 PM - Re: Re: Exhaust Tailpipe Question (Earl Luce)
5. 03:37 PM - Re: Re: Exhaust Tailpipe Question (William Bernard)
Message 1
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| Subject: | RE: Exhaust Tailpipe Question |
--> Tailwind-List message posted by: Mcculleyja@aol.com
Thanks, Bill and George for your responses. I have read Paser's book and it
is indeed very good. My plan is to angle the pipes ten degrees downward with
respect to the metal belly surface aft of the firewall and terminate the
pipes about 4 inches aft of the firewall, and with the exit about 2 inches
below the metal surface, but my concern is with what may be the temperature
seen by the fabric that begins approximately 15 inches beyond that point. I
suspect the aircraft angle of attack during climb will impose more hot flow
against the fabric than at any other flight condition.
Has anyone already acquired some measured data relative to this on a Tailwind?
Unfortunately, I don't have the lower cowl configuration that Jim Clement
uses.
Jim McCulley
>Jim Clement's pipes exit where the engine air exits so they are not in
>the slip stream and they point mostly back and down a little.
George....Phoenix
> William Bernard <billbernard@worldnet.att.net> wrote: --> Tailwind-List
message
>posted by: "William Bernard"
>Jim, A Mustang II builder named Kent Paser has done a lot of experimentation
>on going fast and has also written a book about it, "Speed With Ecomony"
>In his chapter on exhaust systems, he says the the exhaust pipes pointing
>parallel to the bottom of the fuselage give some 'jet thrust'. He also
>relates a story in which, during an experiment, the exhaust tips turned
>upward and melted the aluminum belly.
>Exhaust gasses are in the range of 1400-1600 degrees F and so you don't want
>them pointed at the airplane, unless perhaps it's made of titanium or
>inconel X. Maybe a good compromise might be to have the pipes exit at a
>slight angle away from the belly.
>BTW Kent's book offers a lot of tips applicable to any aircraft, to increase
>performance. I got my copy at buildersbookstore.com, if I remember
>correctly.
>Bill
----- Original Message -----
>From:
>Subject: Tailwind-List: Exhaust Tailpipe Question
> --> Tailwind-List message posted by: Mcculleyja@aol.com
> Does any measured temperature data or other information exist to identify
>how
> far below the ship's belly the end of the tailpipe must be and how far
>ahead
> of the start of the fabric it must terminate to avoid overheating the
>fabric?
> Has anyone successfully (i.e. safely) run their tailpipe(s) essentially
> parallel to the airflow below the belly to create less turbulence and to
>take
> advantage of the available jet thrust from the exhaust gases exiting
>parallel
> to the flight path? What are some typical measurements and angles at the
> exit end of the pipes that existing installations use?
>
> Jim McCulley
> (Seeing light ahead in the tunnel)
Message 2
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| Subject: | Re: RE: Exhaust Tailpipe Question |
--> Tailwind-List message posted by: "William Bernard" <billbernard@worldnet.att.net>
Jim, If my trigonometry is correct, the 'pulse' of exhaust gas should be
just over 4.5 inches below the belly when it gets to the fabric, using the
dimmensions you described. (10 degree angle, 15 inches back, two inches
below the belly)
This strikes me as a bit close and assumes that the gasses don't dispurse at
all in that distance. Maybe a bit more down angle 20 degrees??? might be
better.
Just a guess.
Bill
----- Original Message -----
From: <Mcculleyja@aol.com>
Subject: Tailwind-List: RE: Exhaust Tailpipe Question
> --> Tailwind-List message posted by: Mcculleyja@aol.com
>
> Thanks, Bill and George for your responses. I have read Paser's book and
it
> is indeed very good. My plan is to angle the pipes ten degrees downward
with
> respect to the metal belly surface aft of the firewall and terminate the
> pipes about 4 inches aft of the firewall, and with the exit about 2 inches
> below the metal surface, but my concern is with what may be the
temperature
> seen by the fabric that begins approximately 15 inches beyond that point.
I
> suspect the aircraft angle of attack during climb will impose more hot
flow
> against the fabric than at any other flight condition.
>
> Has anyone already acquired some measured data relative to this on a
Tailwind?
> Unfortunately, I don't have the lower cowl configuration that Jim Clement
> uses.
>
> Jim McCulley
>
>
> >Jim Clement's pipes exit where the engine air exits so they are not in
> >the slip stream and they point mostly back and down a little.
> George....Phoenix
>
> > William Bernard <billbernard@worldnet.att.net> wrote: --> Tailwind-List
> message
> >posted by: "William Bernard"
>
> >Jim, A Mustang II builder named Kent Paser has done a lot of
experimentation
> >on going fast and has also written a book about it, "Speed With Ecomony"
>
> >In his chapter on exhaust systems, he says the the exhaust pipes pointing
> >parallel to the bottom of the fuselage give some 'jet thrust'. He also
> >relates a story in which, during an experiment, the exhaust tips turned
> >upward and melted the aluminum belly.
>
> >Exhaust gasses are in the range of 1400-1600 degrees F and so you don't
want
> >them pointed at the airplane, unless perhaps it's made of titanium or
> >inconel X. Maybe a good compromise might be to have the pipes exit at a
> >slight angle away from the belly.
>
> >BTW Kent's book offers a lot of tips applicable to any aircraft, to
increase
> >performance. I got my copy at buildersbookstore.com, if I remember
> >correctly.
>
> >Bill
> ----- Original Message -----
> >From:
> >Subject: Tailwind-List: Exhaust Tailpipe Question
> > --> Tailwind-List message posted by: Mcculleyja@aol.com
> > Does any measured temperature data or other information exist to
identify
> >how
> > far below the ship's belly the end of the tailpipe must be and how far
> >ahead
> > of the start of the fabric it must terminate to avoid overheating the
> >fabric?
> > Has anyone successfully (i.e. safely) run their tailpipe(s) essentially
> > parallel to the airflow below the belly to create less turbulence and to
> >take
> > advantage of the available jet thrust from the exhaust gases exiting
> >parallel
> > to the flight path? What are some typical measurements and angles at the
> > exit end of the pipes that existing installations use?
> >
> > Jim McCulley
> > (Seeing light ahead in the tunnel)
>
>
Message 3
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| Subject: | Re: RE: Exhaust Tailpipe Question |
--> Tailwind-List message posted by: George Turner <tailwind222@yahoo.com>
If you tape a thermometer on your belly and ran the engine static at a high rpm
on the ground, I wonder if that would tell you much. George
William Bernard <billbernard@worldnet.att.net> wrote:--> Tailwind-List message
posted by: "William Bernard"
Jim, If my trigonometry is correct, the 'pulse' of exhaust gas should be
just over 4.5 inches below the belly when it gets to the fabric, using the
dimmensions you described. (10 degree angle, 15 inches back, two inches
below the belly)
This strikes me as a bit close and assumes that the gasses don't dispurse at
all in that distance. Maybe a bit more down angle 20 degrees??? might be
better.
Just a guess.
Bill
----- Original Message -----
From:
Subject: Tailwind-List: RE: Exhaust Tailpipe Question
> --> Tailwind-List message posted by: Mcculleyja@aol.com
>
> Thanks, Bill and George for your responses. I have read Paser's book and
it
> is indeed very good. My plan is to angle the pipes ten degrees downward
with
> respect to the metal belly surface aft of the firewall and terminate the
> pipes about 4 inches aft of the firewall, and with the exit about 2 inches
> below the metal surface, but my concern is with what may be the
temperature
> seen by the fabric that begins approximately 15 inches beyond that point.
I
> suspect the aircraft angle of attack during climb will impose more hot
flow
> against the fabric than at any other flight condition.
>
> Has anyone already acquired some measured data relative to this on a
Tailwind?
> Unfortunately, I don't have the lower cowl configuration that Jim Clement
> uses.
>
> Jim McCulley
>
>
> >Jim Clement's pipes exit where the engine air exits so they are not in
> >the slip stream and they point mostly back and down a little.
> George....Phoenix
>
> > William Bernard wrote: --> Tailwind-List
> message
> >posted by: "William Bernard"
>
> >Jim, A Mustang II builder named Kent Paser has done a lot of
experimentation
> >on going fast and has also written a book about it, "Speed With Ecomony"
>
> >In his chapter on exhaust systems, he says the the exhaust pipes pointing
> >parallel to the bottom of the fuselage give some 'jet thrust'. He also
> >relates a story in which, during an experiment, the exhaust tips turned
> >upward and melted the aluminum belly.
>
> >Exhaust gasses are in the range of 1400-1600 degrees F and so you don't
want
> >them pointed at the airplane, unless perhaps it's made of titanium or
> >inconel X. Maybe a good compromise might be to have the pipes exit at a
> >slight angle away from the belly.
>
> >BTW Kent's book offers a lot of tips applicable to any aircraft, to
increase
> >performance. I got my copy at buildersbookstore.com, if I remember
> >correctly.
>
> >Bill
> ----- Original Message -----
> >From:
> >Subject: Tailwind-List: Exhaust Tailpipe Question
> > --> Tailwind-List message posted by: Mcculleyja@aol.com
> > Does any measured temperature data or other information exist to
identify
> >how
> > far below the ship's belly the end of the tailpipe must be and how far
> >ahead
> > of the start of the fabric it must terminate to avoid overheating the
> >fabric?
> > Has anyone successfully (i.e. safely) run their tailpipe(s) essentially
> > parallel to the airflow below the belly to create less turbulence and to
> >take
> > advantage of the available jet thrust from the exhaust gases exiting
> >parallel
> > to the flight path? What are some typical measurements and angles at the
> > exit end of the pipes that existing installations use?
> >
> > Jim McCulley
> > (Seeing light ahead in the tunnel)
>
>
---------------------------------
Message 4
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| Subject: | Re: RE: Exhaust Tailpipe Question |
--> Tailwind-List message posted by: "Earl Luce" <luceair@worldnet.att.net>
Hey guys;
I think your thinking tooooooooooooo much !!!! The object is to keep it
simple and safe , go with what works and get it in the air sometime in your
lifetime.
Earl Luce
----- Original Message -----
From: "William Bernard" <billbernard@worldnet.att.net>
Subject: Re: Tailwind-List: RE: Exhaust Tailpipe Question
> --> Tailwind-List message posted by: "William Bernard"
<billbernard@worldnet.att.net>
>
> Jim, If my trigonometry is correct, the 'pulse' of exhaust gas should be
> just over 4.5 inches below the belly when it gets to the fabric, using the
> dimmensions you described. (10 degree angle, 15 inches back, two inches
> below the belly)
>
> This strikes me as a bit close and assumes that the gasses don't dispurse
at
> all in that distance. Maybe a bit more down angle 20 degrees??? might be
> better.
>
> Just a guess.
>
> Bill
> ----- Original Message -----
> From: <Mcculleyja@aol.com>
> To: <Tailwind-list@matronics.com>
> Subject: Tailwind-List: RE: Exhaust Tailpipe Question
>
>
> > --> Tailwind-List message posted by: Mcculleyja@aol.com
> >
> > Thanks, Bill and George for your responses. I have read Paser's book and
> it
> > is indeed very good. My plan is to angle the pipes ten degrees downward
> with
> > respect to the metal belly surface aft of the firewall and terminate the
> > pipes about 4 inches aft of the firewall, and with the exit about 2
inches
> > below the metal surface, but my concern is with what may be the
> temperature
> > seen by the fabric that begins approximately 15 inches beyond that
point.
> I
> > suspect the aircraft angle of attack during climb will impose more hot
> flow
> > against the fabric than at any other flight condition.
> >
> > Has anyone already acquired some measured data relative to this on a
> Tailwind?
> > Unfortunately, I don't have the lower cowl configuration that Jim
Clement
> > uses.
> >
> > Jim McCulley
> >
> >
> > >Jim Clement's pipes exit where the engine air exits so they are not in
> > >the slip stream and they point mostly back and down a little.
> > George....Phoenix
> >
> > > William Bernard <billbernard@worldnet.att.net> wrote: -->
Tailwind-List
> > message
> > >posted by: "William Bernard"
> >
> > >Jim, A Mustang II builder named Kent Paser has done a lot of
> experimentation
> > >on going fast and has also written a book about it, "Speed With
Ecomony"
> >
> > >In his chapter on exhaust systems, he says the the exhaust pipes
pointing
> > >parallel to the bottom of the fuselage give some 'jet thrust'. He also
> > >relates a story in which, during an experiment, the exhaust tips turned
> > >upward and melted the aluminum belly.
> >
> > >Exhaust gasses are in the range of 1400-1600 degrees F and so you don't
> want
> > >them pointed at the airplane, unless perhaps it's made of titanium or
> > >inconel X. Maybe a good compromise might be to have the pipes exit at a
> > >slight angle away from the belly.
> >
> > >BTW Kent's book offers a lot of tips applicable to any aircraft, to
> increase
> > >performance. I got my copy at buildersbookstore.com, if I remember
> > >correctly.
> >
> > >Bill
> > ----- Original Message -----
> > >From:
> > >Subject: Tailwind-List: Exhaust Tailpipe Question
> > > --> Tailwind-List message posted by: Mcculleyja@aol.com
> > > Does any measured temperature data or other information exist to
> identify
> > >how
> > > far below the ship's belly the end of the tailpipe must be and how far
> > >ahead
> > > of the start of the fabric it must terminate to avoid overheating the
> > >fabric?
> > > Has anyone successfully (i.e. safely) run their tailpipe(s)
essentially
> > > parallel to the airflow below the belly to create less turbulence and
to
> > >take
> > > advantage of the available jet thrust from the exhaust gases exiting
> > >parallel
> > > to the flight path? What are some typical measurements and angles at
the
> > > exit end of the pipes that existing installations use?
> > >
> > > Jim McCulley
> > > (Seeing light ahead in the tunnel)
> >
> >
>
>
Message 5
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| Subject: | Re: RE: Exhaust Tailpipe Question |
--> Tailwind-List message posted by: "William Bernard" <billbernard@worldnet.att.net>
Earl, you probably don't want to hear about the computer controled variable
geometry outlet nozzles for the exhaust pipes, do you? <Grin>
Bill
----- Original Message -----
From: "Earl Luce" <luceair@worldnet.att.net>
Subject: Re: Tailwind-List: RE: Exhaust Tailpipe Question
> --> Tailwind-List message posted by: "Earl Luce"
<luceair@worldnet.att.net>
>
> Hey guys;
> I think your thinking tooooooooooooo much !!!! The object is to keep it
> simple and safe , go with what works and get it in the air sometime in
your
> lifetime.
> Earl Luce
> ----- Original Message -----
> From: "William Bernard" <billbernard@worldnet.att.net>
> To: <tailwind-list@matronics.com>
> Subject: Re: Tailwind-List: RE: Exhaust Tailpipe Question
>
>
> > --> Tailwind-List message posted by: "William Bernard"
> <billbernard@worldnet.att.net>
> >
> > Jim, If my trigonometry is correct, the 'pulse' of exhaust gas should be
> > just over 4.5 inches below the belly when it gets to the fabric, using
the
> > dimmensions you described. (10 degree angle, 15 inches back, two inches
> > below the belly)
> >
> > This strikes me as a bit close and assumes that the gasses don't
dispurse
> at
> > all in that distance. Maybe a bit more down angle 20 degrees??? might be
> > better.
> >
> > Just a guess.
> >
> > Bill
> > ----- Original Message -----
> > From: <Mcculleyja@aol.com>
> > To: <Tailwind-list@matronics.com>
> > Subject: Tailwind-List: RE: Exhaust Tailpipe Question
> >
> >
> > > --> Tailwind-List message posted by: Mcculleyja@aol.com
> > >
> > > Thanks, Bill and George for your responses. I have read Paser's book
and
> > it
> > > is indeed very good. My plan is to angle the pipes ten degrees
downward
> > with
> > > respect to the metal belly surface aft of the firewall and terminate
the
> > > pipes about 4 inches aft of the firewall, and with the exit about 2
> inches
> > > below the metal surface, but my concern is with what may be the
> > temperature
> > > seen by the fabric that begins approximately 15 inches beyond that
> point.
> > I
> > > suspect the aircraft angle of attack during climb will impose more hot
> > flow
> > > against the fabric than at any other flight condition.
> > >
> > > Has anyone already acquired some measured data relative to this on a
> > Tailwind?
> > > Unfortunately, I don't have the lower cowl configuration that Jim
> Clement
> > > uses.
> > >
> > > Jim McCulley
> > >
> > >
> > > >Jim Clement's pipes exit where the engine air exits so they are not
in
> > > >the slip stream and they point mostly back and down a little.
> > > George....Phoenix
> > >
> > > > William Bernard <billbernard@worldnet.att.net> wrote: -->
> Tailwind-List
> > > message
> > > >posted by: "William Bernard"
> > >
> > > >Jim, A Mustang II builder named Kent Paser has done a lot of
> > experimentation
> > > >on going fast and has also written a book about it, "Speed With
> Ecomony"
> > >
> > > >In his chapter on exhaust systems, he says the the exhaust pipes
> pointing
> > > >parallel to the bottom of the fuselage give some 'jet thrust'. He
also
> > > >relates a story in which, during an experiment, the exhaust tips
turned
> > > >upward and melted the aluminum belly.
> > >
> > > >Exhaust gasses are in the range of 1400-1600 degrees F and so you
don't
> > want
> > > >them pointed at the airplane, unless perhaps it's made of titanium or
> > > >inconel X. Maybe a good compromise might be to have the pipes exit at
a
> > > >slight angle away from the belly.
> > >
> > > >BTW Kent's book offers a lot of tips applicable to any aircraft, to
> > increase
> > > >performance. I got my copy at buildersbookstore.com, if I remember
> > > >correctly.
> > >
> > > >Bill
> > > ----- Original Message -----
> > > >From:
> > > >Subject: Tailwind-List: Exhaust Tailpipe Question
> > > > --> Tailwind-List message posted by: Mcculleyja@aol.com
> > > > Does any measured temperature data or other information exist to
> > identify
> > > >how
> > > > far below the ship's belly the end of the tailpipe must be and how
far
> > > >ahead
> > > > of the start of the fabric it must terminate to avoid overheating
the
> > > >fabric?
> > > > Has anyone successfully (i.e. safely) run their tailpipe(s)
> essentially
> > > > parallel to the airflow below the belly to create less turbulence
and
> to
> > > >take
> > > > advantage of the available jet thrust from the exhaust gases exiting
> > > >parallel
> > > > to the flight path? What are some typical measurements and angles at
> the
> > > > exit end of the pipes that existing installations use?
> > > >
> > > > Jim McCulley
> > > > (Seeing light ahead in the tunnel)
> > >
> > >
> >
> >
>
>
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