aston70

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I have a Top Flight P-51B Mustang with a FA Saito .91S. I want to keep the muffler inside the cowl. To do this I will need to make my own or find something aftermarket. I would really like scale functioning exhaust, but if I can just shoot it down that's fine with me. I've seen aftermarket SuperTiger mufflers that do this, but none for the Saito.

Does anyone have any experience building exhaust systems like this?

What are the best materials to use and what tools will I need?

Here's my P51B Page:
My P-51B

Thanks,

v6goose

Hi Aston...

I built the D version of the same kit and have put a pitts style can muffler on the firewall below an ASP .75.
You will need (like me) to construct a custom header to get the exhaust from the engine to the can, which leaves a single exhaust hole out thru the bottom of the cowl at the firewall.

I have to do the same thing with my Kyosho F4U.
I have seen many types, all varying in complexity, but the best seems to be a SHS (square hollow section) capped at both ends, as long as you need. Then a hole is drilled or milled in the side, slightly smaller than the exhaust outlet on your motor, and holes for the bolts go right thru.

I can sketch it up for you if you wish, and cant make sense of my text )

Oh, and braize it, not solder obviously....

Good luck!!

aston70

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A sketch or some pics would be great. I have never done any braizing. I welded before using a mig, but I've never braized. Any tips as to what kind of materials to use and where is a good place to get them? The can idea sounds like a good plan.

Here are some pics of my predicament. It looks like I will need to make a manifold from some kind of pipe that will bend back almost immediatly 90*. I don't know if this will affect performance much. I don't know, but I don't see another way of to hide it.

Also, does aiming the exhaust downward get into your lower scoop? Is it a big deal or not?

aston70

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Here's another.
Thanks.

v6goose

Im quite the opposite, having never welded.
I wanted to do this without having to learn how to weld! :-)

Braizing is also called silver soldering (i think), i use a small acetelene torch and some local supplied solder.

I will sketch you something and put it here soon...

I suspect from your photo, it will suit it well...


later!

Goose

aston70

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That would be great.

One more question, should I use brass, copper, steel, tin, other?

Thanks, Goose

v6goose

Something like this... Its just a sketch, but you get the idea. :-)

Not sure how you could connect the manifold to the header, maybe silicone tube to the header, and the same from the header to the muffler (can).
Build your can so the exhaust exits the bottom of the cowl, that limits the mess on your plane as well as looking good.

Material? I have only made these from tin, and steel... you can weld aluminium too, but i hear its quite an art...

Good luch and let me know how you get on...

Goose

v6goose

The beauty of building your own, is you can make it fit, rather than fitting your plane to it... :-)

v6goose

I didnt make working exhausts on my 51-D, but i did drill the dummies out to let more air out.
You could apply this same method to your exhaust stacks, depending on how good your welding is.

Make an exhaust the same as your header, to the correct length, and weld scale stubbs along one length to exit the fuselage and be seen from the outside.
Weld an inlet stub to each scale manifold, and create a 'Y' connector (from silicone tube maybe?) to connect your header to each of the scale exhausts.

I have not done this, and im sure there are many ways to skin a cat, but this is how i would do it.

Cheap and relatively easy.

Good luck, and let me see how your cowl ends up.

Goose

aston70

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That's some sketch! Thanks.

I'll get with my brother. He has a body shop and might have some scrap metal around. Thanks again.

v6goose

If you care to sketch up the relevant dimensions for me, i can draught up a plan for you without much trouble.

As long as you dont need it yesterday, i dont have a lot of spare time, but I was a heavy mechanical engineering draughtsman (CAD) for lots of years...

Let me know..

Goose

aston70

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That's what I do as well. I work for a company called TVA. My brother-in-law does similar work for FLIR. I mostly work on electrical power drawings. I have done landscape dwgs as well, but there more asthetics than technical.

I was going to import the images into autocad and go from there. No, I am in no hurry. With my flying experience I really have no business flying this for at least another year. But, I've had it about 6 years now and I have the itch to finish it. I've moved a couple times so there are some important things I can't find like receiver and retract control valve. Expensive stuff to loose, but I'll get there sometime. Probably packed in a box somewhere. I do plan to fly it in my own lifetime though.