hey everyone i have a 38cc mac chainsaw engine im converting and i want to build a muffler for it out of alimumin, i have no idea about sizing or anything so any help will help me out heaps.

thanks

brad burling
new zealand

Check out this website. Ive built a few mufflers (Ryobi 31cc's) this way and they worked great.
http://www.rcfaq.com/ANSWERS/ENGINES/mufflerplans.htm

Burling, Brad, Do you have machine tools or are you converting with "hobby" tools? I build some of mine from aluminum plate and seamless cans that are very light and the steel cans can be brazed, however machine tools make it happen. The beauty of the "can " muffler is that you can adjust for volume and cowl area, make a mystake, toss the old can and make what you want. Prof G

Go to this website. If he doesn't have it in stock, I'm sure he can make it. http://www.lambertsrc.com/

i'm just posting to get you guys to correct my possibly wrong theroys

first....to get maximum performance you will need a tuned pipe mached t oyour top rpm for maximum power.
but tuned pipes are unfortunatly louder than some, but sound awfully cool

with a pitts style muffler the amount of "stacks" can affect performance and noise levels.
but my understanding was that the pitts will perform better with the stacks pointing up, this works like so...the exhaust port has a large box to dump all of its fumes easily and the stacks act like a chimny on a furnace drawing out the fumes (hot gas rises) so therefore the stacks should be pointing up for max performance.

i dunno if i am wrong or right but i hope you guys can tell me


i have had some success with using a paint can, i made a exhaust manufold and header pipe out of a bicycle handel bars and bashed the paint an's mouth where the spreyer goes in smaller to fit it. then i drilled 3 equal sized holes (around 10mm) starting at the bottom and rizing in 15mm incraments.
i then painted it with standard acrilic paint adn hey presto!!!

the results were....
1. reasonably quiet
2. upped the RPM only very slightly (500 maby)
3. cheap and easy to make

and contradictory to other peoples beliefs the paint did NOT burn off[X(] it hardly got a burn mark at all exept for a light brown around the outlet holes.

so i am a beliver in the pitts and the paint can muffler.
i plan to use both next time, a pitts style but when noise is a problem and power isnt i'll add 2 plug in versions of the paint can mufflers.

shaun

the direction it points won't affect power unless you pointed it into the prop thrust, which should decrease power, the engine is pushing the gases out with more power than gravity. if you're wanting to remove the gases fastest, just have them cut perpendicular to the airstream and it'll be a vacuum and suck it out, but I don't know if that would hinder or help performance...

http://www.modelbouw.gompy.net/uitla...alculator2.zip
http://www.modelbouw.gompy.net/uitlaat/cone13.zip

hey thanks every one. im to bum to work out the exhaust calculator thing but i did look at some of the web pages you guys sujested. do the bolts the hold the muffler to the engine have to be enclosed in a sealed area away from the direct heat, gases, flames or will they be sweet going through th emiddle of the muffler?