muffler silencers

Jedijody

Proud father of Soldiers
"Silencer" is a bit of a stretch but they do work, not a dramatic reduction in db at WOT but it changes the tone so your ears don't bleed as much. The other thing they do is rob power, 300-500 rpm, depending on which engine model.
 

yakken

Well-Known Member
"Silencer" is a bit of a stretch but they do work, not a dramatic reduction in db at WOT but it changes the tone so your ears don't bleed as much. The other thing they do is rob power, 300-500 rpm, depending on which engine model.
I am running a 111 at 106dbs at wot. Do u think if I use these silencers and a 28x10 I can get to 98 dbs? I am running a 27x10 and I tached it on the ground at over 6800 rpms.
 

Jedijody

Proud father of Soldiers
That sounds like you're running a Xoar CF prop? If so the noise is the prop not the engine. My 55M has stock exhaust and a laminated Xoar 27x10, very quiet, definitely under 98 db over grass. Oh, I can rip it in the air if I want to but it's not 1/2 as loud as the CF prop. Don't use the Xoar CF 28x10, you'll get the same RPM as the 27" prop, more prop torque, and it'll be even louder, ear, eyes, nose, and mouth bleeding loud. I'd do canisters before I would put plug in my exhaust pipe.
 

Jedijody

Proud father of Soldiers
Ah, they're very similar loading as a Xoar CF, the Mejzlik 28x10th will be about the same. With the 27" prop your tip speed is .72 mach at 6800 RPM, well into the "loud zone", unloaded in the air your WOT RPM is near 8000. You need to load the engine more, get it down to 6300-6400 static, going bigger diameter isn't always the best option. Bigger diameter means more tip speed, at 6400 RPM a 28" prop is hitting .7 mach. I would try a heavier loading prop like Fuchs, Biela, or laminated Xoar, thrust will be as good or better and much quieter..
 

yakken

Well-Known Member
Ah, they're very similar loading as a Xoar CF, the Mejzlik 28x10th will be about the same. With the 27" prop your tip speed is .72 mach at 6800 RPM, well into the "loud zone", unloaded in the air your WOT RPM is near 8000. You need to load the engine more, get it down to 6300-6400 static, going bigger diameter isn't always the best option. Bigger diameter means more tip speed, at 6400 RPM a 28" prop is hitting .7 mach. I would try a heavier loading prop like Fuchs, Biela, or laminated Xoar, thrust will be as good or better and much quieter..
I have been using the muffler silencers at the local club. Today it was around 80 degrees. My engine seemed to be lacking a lot more power than when it was cooler out. Also after a flight I would let it set while my buddy flew and was very hard to start like it was getting hot and vaporising the fuel in the carb. Will the silencers make your engine run hot? Also what pitch prop would you recommend for running stock mufflers w/o silencers that is quite and good for 3d. thanks
 

BryceSteenburg

"Where would we be withou
Do they have the winter grade gas and summer grade gas there? Alcohol content in winter gas will cause this.
 

yakken

Well-Known Member
i see in your previuos post that you said you were running a 27x10 lam. zoar. i will give it a try.
 

yakken

Well-Known Member
I'm not sure about the gas. But I am trying to reduce the noise w/o the weight penalty of cans.
 

BryceSteenburg

"Where would we be withou
I have been using the muffler silencers at the local club. Today it was around 80 degrees. My engine seemed to be lacking a lot more power than when it was cooler out. Also after a flight I would let it set while my buddy flew and was very hard to start like it was getting hot and vaporising the fuel in the carb. Will the silencers make your engine run hot? Also what pitch prop would you recommend for running stock mufflers w/o silencers that is quite and good for 3d. thanks
I was going for the lack of power and hard starting issue. Silencers make your engine run hot? That all depends BUT normally....no
 

Buttface

You want me to do what...?
Limit the throw on your throttle arm in half...gaurenteed to cut the noise down! :biggrin:
 

pereivers

Well-Known Member
Canister mufflers do about provide the same horses ore more like open exhaust running, whilst providing better muffling and fuel economy per delivered horse. Next step upward are tuned pipes, best for muffling and power. if set up well, instant throttle response.
 
Top