I'm using a Slimline muffler on a DA-50, in a confined area under a cowl. Do you know of a quieter muffler that I might use, or a way to make the combination quieter ? Is the Slimline considered a quiet muffler, or are there better ?


Thank you.

Ed

Ed, it would be best if you posted some specifics like what prop you are running, what type of airplane and what rpm figures are you getting at full throttle? The Slimline is a fairly good muffler, better then the stock muffler but a canister setup would be the quietest option if you have room for it. That being said, you can use prop selection to load the engine enough to keep it below 6,500 rpm. This would reduce both prop and exhaust noise.

I'm using a 22x8 Zinger on a heavy 28 lb warbird, as I felt I needed good acceleration on takeoff. Last time that I tacked it, it was 6700 - 6800, so you make a very valid point. I've got some Zinger 22x10's that I could try, doya think that might help to quiet things down ? Got no room for canisters.

Ed

Do you have enough room in the cowl to run a length of ribbed stainless flex tube then into the muffler?

Zingers are about the loudest props out there. They tend to flatten out at the tips and unload a lot more while in the air. You may want to try a PT 23X8 or a Falcon 23X9, they are going to be much quieter.

I think you would have to go with a prop like Speedracerntrnxie stated, Lower the RPMS and use a more quiet propeller.

Otherwise, you have to go with a canister muffler which probably won't work for you. The other thing is to use a vibration damper system on the engine to airframe connection to help reduce vibrations going to the airframe. The airframe can make a lot of noise too.

Some guys have routed the exhaust inside the cowl into a auxiliary box inside too. They make a wood or aluminum box and route the exhaust gasses into it and the box serves as a second muffler chamber then. It doesn't need complicated sealing or anything. But if you have the room inside that might work for you too.