stunthanger.com
Engine basics => Engine set up tips => Topic started by: Motorman on May 20, 2017, 01:48:59 PM
-
blank
-
It might be convenient to make the through bolt to use a comparable OS or other bolt. Threaded rod is usually cheap steel and will probably fatigue. Most of the muffler through bolts, if not hardened are made with an expanded thread for the nut, which is lighter and hard to do manually.
Try to make the parts at least a light press fit.
-
Post pictures! How do you plan to hold the muffler body to the header? I keep drooling over TIG welders, but somehow Santa hasn't given me one yet.
-
I make very light and quiet mufflers, chamber volumes (2 expansion and 1 side resonance chamber) optimized to my engine spectrum.
-
Lauri
have youever made any to fit an OS LA46?
Thanks
-
I make very light and quiet mufflers, chamber volumes (2 expansion and 1 side resonance chamber) optimized to my engine spectrum.
I know you've told me before -- how do you stick 'em together?
-
I'm attempting to make a few DIY Dinger style mufflers. So far the materials list is as follows:
- 1" x 36" .035" wall 6061 tube cut into 3.5" lengths( http://r.ebay.com/bNiIV1 (http://r.ebay.com/bNiIV1))
- 7/16 x 12" .035" wall 6061 aluminum tube - K&S 83034 (this super close to the size of the exhaust on a real dinger st46 muffler)
- 3/8" x 12" .035" wall 6061 aluminum tube - K&S 83033 (experimenting with exhaust outlet size)
- 1" round x .032" thick - Aluminum Circle Stamping Blanks used for the end caps. https://www.michaels.com/impressart-aluminum-stamping-blanks-circle-1in/10441834.html (https://www.michaels.com/impressart-aluminum-stamping-blanks-circle-1in/10441834.html)
- Header section cut off of an OS 3030 muffler.
- My first *attempt* came out to 1.2oz.
*Attempt is the key word...I applied too much heat and ended up melting the aluminum instead of joining the aluminum.
-
I know you've told me before -- how do you stick 'em together?
-Brazing (Castolin #190) for front manifold and rear stinger.
-Interference fit for body/side resonance thing.
-JB-Weld for gluing the end caps to body (also light interference fit)
The pictures are of older versions with some screw joints. That was necessary before I got good, hard dural tubing for the body.
No Carl, sorry. My engine is bigger, .77.
Lauri
-
I'm attempting to make a few DIY Dinger style mufflers. So far the materials list is as follows:
- 1" x 36" .035" wall 6061 tube cut into 3.5" lengths( http://r.ebay.com/bNiIV1 (http://r.ebay.com/bNiIV1))
- 7/16 x 12" .035" wall 6061 aluminum tube - K&S 83034 (this super close to the size of the exhaust on a real dinger st46 muffler)
- 3/8" x 12" .035" wall 6061 aluminum tube - K&S 83033 (experimenting with exhaust outlet size)
- 1" round x .032" thick - Aluminum Circle Stamping Blanks used for the end caps. https://www.michaels.com/impressart-aluminum-stamping-blanks-circle-1in/10441834.html (https://www.michaels.com/impressart-aluminum-stamping-blanks-circle-1in/10441834.html)
- Header section cut off of an OS 3030 muffler.
- My first *attempt* came out to 1.2oz.
*Attempt is the key word...I applied too much heat and ended up melting the aluminum instead of joining the aluminum.
might want to look at this. https://www.alumiweld.com/
There's a youtube tutorial https://www.youtube.com/watch?v=jtvOkI_pvMI
George Albo
-
Motorman
Here's my seat-of-my-pants attempt at a homemade muffler for a Fox 35. I don't have Db numbers but it was very effective.
It was my understanding (I may have imagined it) that one source of engine noise is the energy of the hot air coming out the exhaust. The cooler the exhaust, the less agitated the molelules of air are and the quieter the noise. So I thought the longer the gasses are in the muffler, the more time they'll have to cool. The exhaust goes into the Fox end, through the brass tube to the back chamber, back into the middle chamber through the middle baffle perforations, into the exhaust pipe perforations in the middle chamber and out.
The front end is the front half of a stock Fox muffler and the assembly is held together by a 2-56 rod threaded on one end. The rod is held in place in the rear by a collar and with a lock nut in front drawing the assembly together. I drilled all the baffle holes in a piece of bar stock first and then separated them so the holes line up perfectly.
The K&B Sportster mufflers were, I thought, the most effective non-tongue mufflers. They also had a double (triple?) baffle system that were light and effective. I adapted one to my Fox 19/Acromaster that worked well. They were the inspiration for mine.
I've retired it to my Fox 25 plain bearing for flying RC and use either no muffler, and when I have to, a tongue muffler.
Ara
-
For my HP 40 ( RPR ) I used 1 1/4 Dia. Alumn. , about 2 in. long .
Put 10 ? 2 mm holes in it outboard aft . X pattern Square .
Fairly Quite and mellow . Equiviant area to one bigHole .
bin Racking the brain for which muffler I used in the Spit for the worlds best engine run , on the G-51 . !
Thinking it was the ST Sausage thing , with the outlet bunged . And 10 holes outboard aft , as above .
Like toungue muffler holes .
Theory on the big muffler is theyre differant ( not ONE ) distance from the ' source ' of the ' pulse ';
Thus not one shock wave , acoustically . And also a broadening of the powerband , de sensitising
of the needle . Thats my theory & Im sticking to it . 8)
Will drag it out for next weekend .P -51 may need the nose weight .
below a pic. of That Type of MUFFLER , un modded . ( Bung outlet & drill Sq Pattern ( 4 x 3 ? ) x 2 m.m.
(http://i20.photobucket.com/albums/b210/ProETNova/JARED-PC/Airplanes%2080_s/SCAN0032.jpg)