SharpProp

Hello All. I'm currently in the middle of building my first Gas plane (30cc Sbach) and I have a question about routing the exhaust.
I have the engine inverted so I had to cut a hole in the cowl so that the head of the DLE can poke out of the bottom of the cowl. At first I cringed at the idea of cutting that beautiful cowl but now that the engine peeks out a pit I think it looks pretty good and will allow the engine to cool down easier.
So now I have to figure out what to do with the exhaust. The easy thing to do would be to point the stock "muffler" down and let the exhaust come out right next to the head of the engine. But I just don't want to hack up that cowl anymore. I don't want to get involved with a canister and tuned pipe just yet, but I might in the future. So I was wondering... What if I just install a header and attached some 3/4" heater hose and route the exhaust out towards the back / center of the cowl? Would that mess with how the engine will run? Technically, the header is not a muffler, but then again I don't believe the Stock muffler is anything more than an exhaust deflector.
This is all for aesthetic reasons, so if it will negatively affect the performance of my engine I will just install it the "ugly" way...ha!
Thanks!

MetallicaJunkie

you are better off with using the stock muffler vs just a header with no canister or tuned pipe...

captinjohn

There is going to be a very neat header & exhaust parts availible here in USA...same as one ones on The Toni Clark web-site. I will try to find my link & post it. Capt,n

SharpProp

Thank you, that would be appreciated.

SharpProp

Well I found an awesome black Pitts muffler on valleyview rc that will be perfect on my sbach. Looks like I'll be going this route.

Tired Old Man

My Feedback: (1)

Something pretty common for people doing their first gas engine is the discovery the engine will likely end up sticking out of the cowl. Glad you found a pitts muff to avoid opening up the side even more.

Unlike glow engines a gasser will have a hard time fully enclosed. They run a lot hotter so that first time gas engine hanging out of the cowl helps the newbie out quite a bit where engine cooling is concerned. If the engine was fully enclosed it would burn itself up in short order unless a lot of attention was dedicated to directing the available airflow into, through, and out of the engine. So the exposed engine can be a bit of a dissapointment, but the upside is you should not have many cooling issues, which gives the gas beginner a good head start in gasser experience to carry forward into other projects.

SharpProp

The funny thing is, I wasn't as disappointed as I though I would be with the engine sticking out a bit. It sticks out right at the bottom center of the cowl and it really makes this plane look sweet......like the engine is too big to be contained..haha. But I think this pitts muffler I ordered will tuck beautifully behind the head of the engine, and look pretty sweet doing it. Plus if I ever do move to a tuned pipe, there won't be a gaping hole where the muffler once exited.
Thanks for the assistance.

Tired Old Man

My Feedback: (1)

Bear in mind that air has to get out, and hottor air requires more exit area than cooler air. This is another place gas initiates run into problems. The "rule of thumb" is exit area equalling triple the inlet area. That can be modified but you need to play with baffles and exit ducting and ducting shapes.

So you still end up with a hole in the cowl to exhaust the hot air or the engine encounters thermal difficulties that interfere with performance, tuning, and longevity.

captinjohn

I found the website. There is a place to email also a phone number to call. I would call....but wife is attached to the phone this afternoon!

http://www.vogelsang-aeroscale.com/

VF84sluggo

My Feedback: (55)

Yes indeed. I've seen guys who are having engines running hot keep enlarging the inlet area - thinking that this will allow more cooling air in and solve their problems - when the true problem is that the volume of air entering the cowling was already sufficient, it just had no where to go. Until they open up the exit area and let that air flow on through, they never cure the hot-running engine.

captinjohn

This was supposed to be in stock in november in USA.......I guess more guys need to call....maybe then something will happen. Capt,n

Phone 919-533-6275 ....also there is a website ....look on previous post