Scale 50% Dalotel 165

[49dimes]

That should give a nice exhaust note and keep performance up .

 

[stangflyer]

Here is an update on the muffler design

Are you calculating any degree of pressure from the exhaust port to get the correct size exit for best performance, tuning and overall dependability? If so, how are you going about the calculations? Reason I ask, I've been very interested in "matching" exhaust systems to some of my engines. Yes, I know many of tried different setups with different engines. And for the most part... some are coming up with some really good numbers. It would be nice to know if there is a formula to use to really get the exact setup.

 

[Forgues-Research]

Are you calculating any degree of pressure from the exhaust port to get the correct size exit for best performance, tuning and overall dependability? If so, how are you going about the calculations? Reason I ask, I've been very interested in "matching" exhaust systems to some of my engines. Yes, I know many of tried different setups with different engines. And for the most part... some are coming up with some really good numbers. It would be nice to know if there is a formula to use to really get the exact setup.

Unfortunately I am simply making the expansion chamber as big as I can get it inside the cowling, so no magic numbers there, then the two pipes coming out into a single unit, are simply the size that will fit inside the Y adapter with a bunch of holes in them , basically as many holes as I can not to create too much back pressure. but these small holes will also help to kill the high pitch 2 cycle sound to a lower octave
You might remember with glow engines, with straight expansion chamber mufflers, they still had the high pitch annoying sound, and what many of us use to do, was to drill two small holes at the back and insert a two small bolt in a 90 degree pattern , this would deflect the exhaust and in return kill some of that annoying high pitch sound.
So for me right now , I'm winging it and simply hope for the best LOL

 

[stangflyer]

Unfortunately I am simply making the expansion chamber as big as I can get it inside the cowling, so no magic numbers there, then the two pipes coming out into a single unit, are simply the size that will fit inside the Y adapter with a bunch of holes in them , basically as many holes as I can not to create too much back pressure. but these small holes will also help to kill the high pitch 2 cycle sound to a lower octave
You might remember with glow engines, with straight expansion chamber mufflers, they still had the high pitch annoying sound, and what many of us use to do, was to drill two small holes at the back and insert a two small bolt in a 90 degree pattern , this would deflect the exhaust and in return kill some of that annoying high pitch sound.
So for me right now , I'm winging it and simply hope for the best LOL

Man, do I remember those days! Thing I've found is the only real way to cut down on the annoying pitch of a two stroke is to choke the crap put of it with a restrictor. But than performance suffers. That's why I like the Greeves pipes and MTW tuned pipes. Only problem is, few at best... very few airframes are accommodating to such long pipes. Next best thing is a good quality canister that is tuned to the exhaust expansion of individual engines. I am sure you will get what you're hoping for. Still so excited to hear and see that bird run/fly.

 

[Forgues-Research]

the mufflers are taking shape, have to redo one of the rectangles, no big deal, and still have to make the two tubes that goes inside, with all the holes in it but so far its working

 

[49dimes]

Can't hit the "Love it" button cuz there aint one .

 

[Forgues-Research]

Can't hit the "Love it" button cuz there aint one .

The fact that no one has told me to get loss is love enough LOL

 

[Bartman]

You're a force of nature Roger......this is going to be the completion of an epic achievement the day it flies.

 

[Forgues-Research]

You're a force of nature Roger......this is going to be the completion of an epic achievement the day it flies.

Thanks, your way too kind, but first flight should be end of July to early august. ,

 

[Bartman]

Where are you located?