I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
acceptable. I want to use it for a model of the headers of a tuned exhaust
for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
The idea is to have 4 equal length pieces attached to exhaust flanges bolted
to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
coat the tubing with epoxy resin so that the shape is maintained and then
present these pieces to be copied by the exhaust bender.

Stu

Stuart & Kathryn Fields wrote:

> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
> acceptable. I want to use it for a model of the headers of a tuned exhaust
> for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
> The idea is to have 4 equal length pieces attached to exhaust flanges bolted
> to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
> coat the tubing with epoxy resin so that the shape is maintained and then
> present these pieces to be copied by the exhaust bender.
>
> Stu
>
>

I did one a long time ago using elbows and pieces.
(Couldn't spend money on it, so)

To "measure" the pipes, I filled the sample pipe with water
and measured the volumn of water for each pipe.

Lengthen the short ones, shorten the long ones.

It was a bit of a hassle, but it did work ok.

For what it's worth...

Richard

On Tue, 8 Jul 2008 18:21:43 -0700, "Stuart & Kathryn Fields"
> wrote:

>I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
>acceptable. I want to use it for a model of the headers of a tuned exhaust
>for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
>The idea is to have 4 equal length pieces attached to exhaust flanges bolted
>to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
>coat the tubing with epoxy resin so that the shape is maintained and then
>present these pieces to be copied by the exhaust bender.
>
>Stu
>

hey stewie go down to the local electrical place and buy yourself 4
vacuum cleaners, or find a 'vacuums are us' and buy 4 replacement
flexible wands. they are plastic, are flexible and are the diameter
you need.

good luck on the chopper.

btw I have seen an RV6 that used 4 pipes into one with no muffler at
all. it was the quietest aeroplane engine I've ever heard. I dont know
what the trick was in the geometry but it used the same engine as you
are using. some amazing stuff is possible there.

Stealth Pilot

Stuart & Kathryn Fields wrote:
> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
> acceptable. I want to use it for a model of the headers of a tuned exhaust
> for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
> The idea is to have 4 equal length pieces attached to exhaust flanges bolted
> to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
> coat the tubing with epoxy resin so that the shape is maintained and then
> present these pieces to be copied by the exhaust bender.
>
> Stu
>
>

Nylon hose is cheaper. Shape it to where you want it, drill a 1/4" hole every few inches and pump it full of
Great-Stuff spray foam.

PVC tubing will also form fairly well if you warm it up good with a heat gun.

Clothes dryer ducting.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"Stuart & Kathryn Fields" > wrote in message
...
> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
> acceptable. I want to use it for a model of the headers of a tuned
> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
> helicopter. The idea is to have 4 equal length pieces attached to exhaust
> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
> maintained and then present these pieces to be copied by the exhaust
> bender.
>
> Stu
>

"RST Engineering" > wrote in message
m...
> Clothes dryer ducting.
>
> Jim
>
> --
> "It is the mark of an educated mind to be able to entertain a thought
> without accepting it."
> --Aristotle
>
>
> "Stuart & Kathryn Fields" > wrote in message
> ...
>> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel
>> is acceptable. I want to use it for a model of the headers of a tuned
>> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
>> helicopter. The idea is to have 4 equal length pieces attached to exhaust
>> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
>> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
>> maintained and then present these pieces to be copied by the exhaust
>> bender.
>>
>> Stu

To date I've tried flex conduit, both steel and aluminum and both sag like
crazy and change lengths easily and don't hold their shape. Heating and
bending PVC pipe is such a cut-and-try process which also produces some
fumes off the PVC that is not supposed to be nice and the use of elbows and
saw cuts is kind of workable and I have a set of 4 equal length pieces that
have been shaped to do the job but the thing looks like crap and the exhaust
is really open for view on this helicopter. Hopefully the flex exhaust
tubing will hold its shape when bent by hand long enough for me to coat it
with epoxy to lock in the shape and hold it for a trip to the exhaust tube
bender guy.
The trick that I'm counting on, and it looked possible when I was using
conduit, is to connect the tubing to exhaust flanges bolted to the cylinders
and position all 4 pieces to intercept the 4-into-1 collector at
approximately the same time and counting on the flex tubing to hold its
shape and length, long enough for some epoxy to sieze the flexables even
further. The idea then is to remove each piece and have it matched.
I've tried AutoZone, Pep Boys, Napa, and JC Whitney. McMaster-Carr, Toys 4
Trucks, Whitney does have some SS flex but at $30 each 5' piece. This would
run the cost up a bit. I hope to finde some galvanized steel flex somewhere
at a lower price.
Stu

"cavelamb himself" > wrote in message
...
> Stuart & Kathryn Fields wrote:
>
>> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel
>> is acceptable. I want to use it for a model of the headers of a tuned
>> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
>> helicopter. The idea is to have 4 equal length pieces attached to exhaust
>> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
>> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
>> maintained and then present these pieces to be copied by the exhaust
>> bender.
>>
>> Stu
>
> I did one a long time ago using elbows and pieces.
> (Couldn't spend money on it, so)
>
> To "measure" the pipes, I filled the sample pipe with water
> and measured the volumn of water for each pipe.
>
> Lengthen the short ones, shorten the long ones.
>
> It was a bit of a hassle, but it did work ok.
>
> For what it's worth...
>
> Richard

Thanks for the tip on measuring the pipe length using water. Neat.

Stu

"Stealth Pilot" > wrote in message
...
> On Tue, 8 Jul 2008 18:21:43 -0700, "Stuart & Kathryn Fields"
> > wrote:
>
>>I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
>>acceptable. I want to use it for a model of the headers of a tuned
>>exhaust
>>for my 0320 Lycoming engine that I have mounted in my Baby Belle
>>helicopter.
>>The idea is to have 4 equal length pieces attached to exhaust flanges
>>bolted
>>to the cylinders, arrange the 4 pieces to intercept the 4-into-1
>>collector,
>>coat the tubing with epoxy resin so that the shape is maintained and then
>>present these pieces to be copied by the exhaust bender.
>>
>>Stu
>>
>
> hey stewie go down to the local electrical place and buy yourself 4
> vacuum cleaners, or find a 'vacuums are us' and buy 4 replacement
> flexible wands. they are plastic, are flexible and are the diameter
> you need.
>
> good luck on the chopper.
>
> btw I have seen an RV6 that used 4 pipes into one with no muffler at
> all. it was the quietest aeroplane engine I've ever heard. I dont know
> what the trick was in the geometry but it used the same engine as you
> are using. some amazing stuff is possible there.
>
> Stealth Pilot

Interesting idea If the flexible wands hold their shape to a reasonable
degree we may have a solution.

Stu

On Jul 8, 6:21*pm, "Stuart & Kathryn Fields" > wrote:
> I'm looking for a source of 1 1/2" flexible exhaust tubing. *Mild steel is
> acceptable. *I want to use it for a model of the headers of a tuned exhaust
> for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
> The idea is to have 4 equal length pieces attached to exhaust flanges bolted
> to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
> coat the tubing with epoxy resin so that the shape is maintained and then
> present these pieces to be copied by the exhaust bender.
>
> Stu

http://www2.cip1.com/ProductDetails.asp?ProductCode=C13%2D3499

Aluminum "wrinkle belly" tubing should hold it's shape nicely. This
stuff is a little oversize. Great Plains Aircraft Supply carries this
stuff too, if you want to support an aviation vendor.

flybynightkarmarepair wrote:
> On Jul 8, 6:21 pm, "Stuart & Kathryn Fields" > wrote:
>> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
>> acceptable. I want to use it for a model of the headers of a tuned exhaust
>> for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
>> The idea is to have 4 equal length pieces attached to exhaust flanges bolted
>> to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
>> coat the tubing with epoxy resin so that the shape is maintained and then
>> present these pieces to be copied by the exhaust bender.
>>
>> Stu
>
> http://www2.cip1.com/ProductDetails.asp?ProductCode=C13%2D3499
>
> Aluminum "wrinkle belly" tubing should hold it's shape nicely. This
> stuff is a little oversize. Great Plains Aircraft Supply carries this
> stuff too, if you want to support an aviation vendor.


I have seen such ducting in paper also which would make epoxying it
into shape easier. Try J.C. Whitney, they used to carry it.

Dan, U.S. Air Force, retired

RST Engineering wrote:

> Clothes dryer ducting.
>
> Jim
>


To model the exhaust pipes for a 985 or 1340?

Think about the hot-air connections on old VW (bug) defrosters off the
exhaust shroud.

Or maybe the flex-line that conducts hot air from exhaust manifold shroud to
the automatic choke on older (carbureted) auto engines?

Flash





"Stuart & Kathryn Fields" > wrote in message
...
> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
> acceptable. I want to use it for a model of the headers of a tuned
> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
> helicopter. The idea is to have 4 equal length pieces attached to exhaust
> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
> maintained and then present these pieces to be copied by the exhaust
> bender.
>
> Stu
>

"RST Engineering" > wrote in message
m...
> Clothes dryer ducting.
>
> Jim

That is 3 inch.
--
Jim in NC

Stuart & Kathryn Fields wrote:

>> hey stewie go down to the local electrical place and buy yourself 4
>> vacuum cleaners, or find a 'vacuums are us' and buy 4 replacement
>> flexible wands. they are plastic, are flexible and are the diameter
>> you need.
>>
>> good luck on the chopper.
>>
>> btw I have seen an RV6 that used 4 pipes into one with no muffler at
>> all. it was the quietest aeroplane engine I've ever heard. I dont know
>> what the trick was in the geometry but it used the same engine as you
>> are using. some amazing stuff is possible there.
>>
>> Stealth Pilot
>
> Interesting idea If the flexible wands hold their shape to a reasonable
> degree we may have a solution.
>
> Stu
>
>

Stiffen the hose with a piece of 14-3 house wiring running through the center. Or encapsulate the shaped tube in about
3 layers of cheap duct tape.

On Tue, 8 Jul 2008 18:21:43 -0700, "Stuart & Kathryn Fields"
> wrote:

>I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
>acceptable. I want to use it for a model of the headers of a tuned exhaust
>for my 0320 Lycoming engine that I have mounted in my Baby Belle helicopter.
>The idea is to have 4 equal length pieces attached to exhaust flanges bolted
>to the cylinders, arrange the 4 pieces to intercept the 4-into-1 collector,
>coat the tubing with epoxy resin so that the shape is maintained and then
>present these pieces to be copied by the exhaust bender.
>
>Stu
>

http://www.flexatube.com/flex.htm has it for $1.84/ft.

--Andy Asberry--
------Texas-----

"Stuart & Kathryn Fields" > wrote in message
...
> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel is
> acceptable. I want to use it for a model of the headers of a tuned
> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
> helicopter. The idea is to have 4 equal length pieces attached to exhaust
> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
> maintained and then present these pieces to be copied by the exhaust
> bender.
>
> Stu
>

Stu,

Why can't you model your headers with equal lengths of 1/4" steel brake line
tubing? It's easy to bend without kinking, and could be bent around simple
plywood templets to maintain the minimum radii of the larger tube. Just
route it to represent the center line of the 1 1/2" tubing, and maintain at
least 1 1/2" between tubes.

"Maxwell" <luv2^fly99@cox.^net> wrote in message
...
>
> "Stuart & Kathryn Fields" > wrote in message
> ...
>> I'm looking for a source of 1 1/2" flexible exhaust tubing. Mild steel
>> is acceptable. I want to use it for a model of the headers of a tuned
>> exhaust for my 0320 Lycoming engine that I have mounted in my Baby Belle
>> helicopter. The idea is to have 4 equal length pieces attached to exhaust
>> flanges bolted to the cylinders, arrange the 4 pieces to intercept the
>> 4-into-1 collector, coat the tubing with epoxy resin so that the shape is
>> maintained and then present these pieces to be copied by the exhaust
>> bender.
>>
>> Stu
>>
>
> Stu,
>
> Why can't you model your headers with equal lengths of 1/4" steel brake
> line tubing? It's easy to bend without kinking, and could be bent around
> simple plywood templets to maintain the minimum radii of the larger tube.
> Just route it to represent the center line of the 1 1/2" tubing, and
> maintain at least 1 1/2" between tubes.

A trick I found while trying conduit was that if I had all 4 pieces cut to
the same length and had them connected to the cylinders thru a flange, then
I could kind of bend them all at the same time keeping their other ends
together and have them all come to the collector at the same time. Doing
one cylinder at a time presents a bunch of trial and error, re-bend and try
again. I think that having the flex exhaust pipe might just save some time
and using up all of my cuss words. (I've only got about 15 minutes worth
before I start repeating myself) I found some galvanized flex exhaust on
Amazon.com

Stu