sideoftheroad

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I am currently building a Hangar 9 P40. The instructions show a picture of the bottom front part of the cowl has been cutout to make room for the Pitts muffler. I want to see if there is a way to not cut that part of the cowl. I thought of just shortening the motor mount but then I don't think the prop will rest up against the drive hub.

KazeRacing

i put a ys 115 in mine u have to cut off 1 1/2" off the firewall then your good

opjose

sideoftheroad

What engine are you going to use?

If you could put a header on the engine, you may be able to use a Top-Flite In Cowl Muffler...

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHY77&P=7]Click me![/link]

sideoftheroad

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Funny enough that is the exact engine I am going to put on it. An OS Max FX 61

opjose

If the header and the intake side of the can muffler does not line up, you can always use other tubing too.

I've used this muffler for cowled .91 OS and Magnum four stroke engines, using automotive tubing and clamps.

sideoftheroad

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Would you mind posting a pic of it installed? Thanks

opjose

Sorry I will not have access to those planes for a few weeks ( storage ).

The "can" mounts on the firewall or where-ever you can affix it.

I used small clamps to affix auto tubing between the four strokes normal header without the muffler.

Your only big concern is that the exhaust tubing must be able to sustain higher temps. That is why silicon is normally used.

By the time the exhaust passes the header, it is not still being burned, so it does not tend to scar the silicon tubing.

Automotive tubing used around exhaust manifolds also have to take high heat so it works well.

Check into things used for tuned mufflers too, as they have the same routing problems with their tubing.

sideoftheroad

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I found this but 3 times the cost of what you posted. Also thought about straight pipes but not sure if they are made for my engine.

sideoftheroad

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With the Top Flite In Cowl muffler you posted, I found on eBay you can buy the header by itself. Part # TOPQ7920.  Probably could drill/tap the nipple for vent but for the cost of the header by itself you might as well buy the whole thing.

opjose

That Tower Hobbies in-cowl muffler has the right header for your engine so you're way ahead of the game already.

That header could be used for a straight pipe or the CAN muffler Tower provides in the link above

The concern is that once you obtain it, you may find you cannot fit the CAN in such a position that there is a straight shot back from the header.


Here is a better picture of the Jtec muffler [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVNG5&P=7]Tower Jtec Link - Click me![/link]

As you can see the muffler affixes directly to the engine and the engine must be mounted inverted, then you have to cut holes for the exhaust.

You may end up having to cut a whole side of the cowl to get that Jtec muffler to fit.

With the Top Flite stuff you could always hook things up with something like this...

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXACCG&P=7]Coupling[/link]

Or this...

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZ670&P=7]Click me too![/link]

Cut to size and tied down with wire ties.

opjose

Yup and even if you don't use the CAN, you could always use it in a future project.

Yup I've seen it used for that very purpose. It's loud though, but not quite as loud as no muffler or header.

You can also hacksaw that down to any size you want.

I would pull my P40 out and check the fit of the TopFlite Can for you, but I cannot do that for another week or two.

sideoftheroad

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I think I got the top flite figured out. You have to buy both topq7915 & topq7920 for around $45 total if you want the muffler and header.

sideoftheroad

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KazeRacing & opjose   How far do you have the end of the cowl to the leading edge of the wing?  The manual says the distance should be 4 15/16" from the firewall to the end where the prop would rest on and with the cowl on the spinner back plate should have 3/16" space.  Last night I mounted the engine and measured just over 4.5" from firewall and measured 3/8" from backplate.  I moved the engine to the next hole up and got to like 4 13/16" from firewall which is closer.  I figured I could move the cowl forward or backward to make up the 3/16 space from the backplate if needed to but I am taking a chance when I cut the cowl that the muffler hole is not cut in the correct spot.

sideoftheroad

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Anyone have thoughts on how I can do the cowl?

sideoftheroad

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Opjose by chance are you able to take pics yet?