Mufflers on Aircraft engines

A discussion on ways to reduce it.
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blackpowderscout
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Mufflers on Aircraft engines

Post by blackpowderscout »

I figured I'd start a new thread for this topic and maybe some people with car motors can do the same.

I just installed a set of inexpensive mufflers on my boat. I have an angle valve 0470 with a 74x32 wood prop. At idle it is like night and day. Before, it was the typical aircraft engine sound with just flex pipe. Loud but it still sounded good. NOW, it is much quieter!! I can actually carry on a conversation with someone standing right next to the motor without raising my voice whereas before I just about had to holler.

As far as how it performs at WOT, I don't know yet. I am going to test that out at the Melbourne ride(hopefully). I don't really think it will make much difference but we'll see.

Anyone have any experience with mufflers on aircraft setups?

Adam
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rick
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Post by rick »

I have small stainless bullet mufflers on my O320 Adam. I wouldn't recommend the ones I have because they cost over $100 and I would imagine your budget mufflers will do a better job.

You're right though, at low rpm's there's a big difference. Good for froggin if your slow like me.

I'd like to know how your setup does when you get to run it under normal conditions. I also want to try aiming my exhaust into the prop wash area. I heard that here, in the forum, and it sounds like that might help also.

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blackpowderscout
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Post by blackpowderscout »

I'd like to try that exhaust aiming thing also.

Rick, how does your's sound under normal conditions? Did it help any or only at low RPM's?
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rick
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Post by rick »

Prop noise takes over when you shower down on it, but they may be helping at minimal plane. I just bought a digital db meter from Radio Shack to try to get an idea of the rpm's my boat takes to break the 90 dba @ 50'.

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blackpowderscout
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Post by blackpowderscout »

I was able put my mufflers to the test at Melbourne. I am much quieter at idle, very pleasant. Of course on plane I'm still loud but might be a little quieter. Perfomance has not diminished and might have even improved. Before the muffler installation, I could turn my 74x32 FAP prop right at 3000RPM in skinny water. At Melbourne on the return to the ramp when running over the hydrilla on Sawgrass I was able to turn it up to almost 3100RPM and she was still increasing. I was afraid of blowing the prop so I stopped. Take it for what it's worth but my motor has definitely not been hurt by the mufflers.

Adam
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cntry141iq
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Post by cntry141iq »

Darn Adam now you have done it. you went and spent 40 bucks on mufflers and now you need to buy a new adjustable prop. Your wife is gonna kick our butts.
Don't waste your time ... it is the only thing you can't get more of
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rick
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Post by rick »

I can vouch for the that. Adam, when you came by me & twirled your hand up into the air, I knew you were gonna open it up. You had that boat cranking across the hydrilla.

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Post by rjonesboy »

I used the 120 degree heat shields on my Supertrapp mufflers and they direct the exhaust toward the prop wash. I don't know how much of a difference it makes though. I do know it is much quieter at idle which is great around houses and boat ramps.

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blackpowderscout
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Post by blackpowderscout »

Now that I have installed these mufflers, I'm curious as to how long I can expect them to last. Does anyone know how long the fiberglass lasts (approximately) before it all burns away? I'm not real familiar with muffler topics so I'm learning as I go here.
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