noah_moore

There's about a million posts by people asking how to make their heli quieter. However i havent seen any real advice as to muffler design. Im interested in making my Z231 powered heli as quiet as possible. before anybody mentions it I UNDERSTAND i will most likely lose horsepower by doing this. so the question is, accepting the power loss, how would one make their heli queiter? What makes a muffler quieter? making it longer then stock? wider?

Looking forward to getting actionable advice. again taking into consideration this will have other negative results

Charlie

The baffle in a muffler is what makes it quit. Trying to come up with a baffle to make the motor quit and
have the right back pressure so the motor will run right would be a pretty tall order (especially trying to do it on a work bench at home).

I've played around with baffle in snowmobile exhaust before trying to squeeze a little more power out of them, it can get pretty tricky
trying to get it right, if you don't get it right, all you do is chase problems.

bikemad

yep charlie is right, I made an exhaust for a 125cc two stroke and it's a lot harder than you think, your better of buying one and add an extra baffle on the end if you need to make it quieter, thats easer to do than make one from scratch and you won't loss as much power,

noah_moore

Add-on huh? like another muffler? or another chamber with baffles in it? thanks for the advice

I also thought about enclosing an off the shelf muffler in another chamber, would that have any effect?

noah_moore

attached is a quick sketch i did. the open space between the stock muffler and homemade chamber could be taken up by some sound deadening material. think it would quiet things down any?

bikemad

It would be a bit on the end, you have to stop the pulse from the bang getting out so another chamber or baffle with two small holes off line with each other would work, what you have drawn would not make any difference[&o],