KitBuilder

I have seen in use a flexible metal tubing.. similar looking to the small bendable conduit used in electrical wiring for muffler extensions. This has been used to route exhaust over short distances say through a fuse out the bottom. Does anyone know where this can be found or suitable substitute. I don't beleive the electrical conduit is gap free and would leak exhaust.

gene6029

I use the flexable bend tubeing on my larger gas motors. Yes they will leak, but a common practice we do is wrap the flex with plumbers teflon tape. Looks good & i have never had any problems in the last 10 or so years that i have been useing it. Its cheap enough to try and only needs to be wrapped over the flex 2-3 passes......Gene

KitBuilder

Thanks.

jay2000dakota

Ive tried them all and for the most part they didnt work for very long. I came across a company called Macs Products and there flex pipe is by far the best ive ever used. Ive flown 2 seasons with their pipe and no leaks, breaks or cracks. check them out on the web http://www.macspro.com/

KitBuilder

Great.. thanks.

da Rock

There is a large silicone hose sold in most LHSs. It's sold as a tuned pipe connector or somesuch. It happens to be translucent blue. It works perfectly for relatively short, straight exhaust extensions.

It's basically just HUGE fuel line. It is thick walled and would provide a bit of insulation that metal tube would not.

Unfortunately, for awhile now, it's been out of stock just about everywhere. That caused me to do some searching and I found a source of similar tubing. What I found is sold by hobby beer brewing equipment suppliers. There is a translucent white silicone hose with only about half the wall thickness. It works as well to route exhaust cleanly, but is not as rigid.

The silicone tubing would seal perfectly and bend to suit your routing problems with no effort at all. It grips exhaust pipes to form that seal perfectly. It is NOT going to leak. It could be locked into a permanent path by coiling malleable wire around it in a straight coil, then bending the "spring wound tube" to match the path. You would probably still need to brace toward the end to insure it staying where you want it. The brace wouldn't need to be attached to it as long as it securely trapped it.

da Rock

I just noticed the Mac's Muffler products.

They have silicone tubing listed. It's probably the same stuff sold in LHSs under another name. But it has pretty much the same price structure. It's something like $26 for a foot to $55 for a yard, depending on size. The brand the LHSs used to carry was priced less, but still not what you'd call affordable. I bought something like 15 feet of it for something like $3/ft. Sorry, but I don't have the name or address and don't remember the price exactly, but the brewing supply company was in Minneapolis-St.Paul and should show up on a Google (which is how I found it).

BTW, 3-4 years ago a buddy was buying corrugated metal flex hoses for one of his planes. They leaked and couldn't take the vibration of his engine/setup. Hose would have easily solved the problem. The corrugations were apparently causing backpressure within the pipe as the engine really didn't run well. Every time the suckers cracked, he could tell by the increased airspeed. This silicone tube isn't going to give that problem. However, any length tubing, just by it's length, can have an effect on the engine's power.

Here is a pix of the LHS purchased stuff being used as extensions to replace the length that was removed from a Pitts muffler.
And a pix of the stuff used when the stock muffler was enclosed by the lower cowl and underbelly of the P47 and the tubing was needed to get the exhaust out of the plane. You gotta look hard. It's in the shadowns.

Sorry, I don't have any better pictures or pictures of the brewing hose, but I don't usually take pictures of that stuff.

SoCalSal

My Feedback: (16)

Try this site. http://www.seetemp.com/products.htm this is what you want.

Rodney

The blue silicon tubes will not stand up to a 4 strokes exhaust temperatures.

BalsaBob

My Feedback: (24)

I have also seen people use automotive heater hose for short distances. It is available in different diameters ... and best of all ... you can get it at many many places locally.

Bob

KitBuilder

That's it.. Thanks !


Rodney.... I assumed a 4 stroke exhaust would not be as hot as a 2S b/c it's burning every other stroke.

da Rock

4 strokes are quite a bit hotter because they burn the fuel more completely. 2 strokes pass a significant quantity of fuel through unburned. Less fuel burned, less heat. Even with the "wasted" strokes, the heat difference is considerable. Fours exhaust gasses are much hotter.

KitBuilder

I like when people make sense... rare these days!! Thanks.

So is it safe to assume my plane will be less slimy... or I guess the lubricant does not actually get burned or that would defeat the purpose?