Quiet Park Flier?
04-07-2003, 11:39 PM
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Quiet Park Flier?
Hi folks, I am building a Lazy Bee for flying in a residential park close to my house. I am planning on using an OS.15 but need it to be super quiet. Any tips or tricks to really quiet this little engine down? Loss of power does not really concern me as long as it still runs good. I plan to use the extended exhaust pipe and maybe a cowl? Or will an intake filter help? Maybe a different engine would be better?
Thanks,
Bill Cripe
Thanks,
Bill Cripe
04-08-2003, 12:03 AM
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Quiet Park Flier?
I've not quieted the OS .15s, but on two different OS.10 I did quiet them down.
The first one I just put an 36" aluminum tube coupled to the stock muffler, flew a powered sailplane with it. It cut the noise in 1/2. The prop noise and carb bark where as loud as the exhaust note.
I don't know how much power was lost, never flew it without the setup, but the .10 powered the 75" Grob motor-glider very well.
The second I machined two muffler extensions, each as big as the original muffler with baffles on their ends, so I had three chambers. This was very quite 1/3 as loud as stock, the prop noise and carb bark where louder than the exhaust. maybe 20% lose of power.
You might want to try a moose can after-muffler, they're cheap, easy to add, just some silicone, and light. If you can, enclose the carb in the cowl to muffle the carb bark. Play with the prop also, try a bigger one than you normally would use, maybe a 9x4, to slow the engine down. Also the ACPs seem quieter to me.
The first one I just put an 36" aluminum tube coupled to the stock muffler, flew a powered sailplane with it. It cut the noise in 1/2. The prop noise and carb bark where as loud as the exhaust note.
I don't know how much power was lost, never flew it without the setup, but the .10 powered the 75" Grob motor-glider very well.
The second I machined two muffler extensions, each as big as the original muffler with baffles on their ends, so I had three chambers. This was very quite 1/3 as loud as stock, the prop noise and carb bark where louder than the exhaust. maybe 20% lose of power.
You might want to try a moose can after-muffler, they're cheap, easy to add, just some silicone, and light. If you can, enclose the carb in the cowl to muffle the carb bark. Play with the prop also, try a bigger one than you normally would use, maybe a 9x4, to slow the engine down. Also the ACPs seem quieter to me.
04-08-2003, 12:36 AM
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Quiet Park Flier?
You might want to try www.flyquiet.com for some silencers. I had their quiet pipe on my .061 and it reduced the noise considerably without a performance loss.
04-08-2003, 01:01 AM
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Quiet Park Flier?
Along with the secondary muffler added to the stocker may I suggest a larger than regular prop? This will greatly cut down the prop noise and with something like a 15 on a Lazy Bee you've got lots of excess power so the loss wouldn't be any problem.
If it calls for a 8x4 I'd run a 10x4 or 10x3 if you can find such an animal.
This is sort of like the use of the large props for the 1/2A Texaco event. Those engines are quiet and inoffensive even with no muffler.
If it calls for a 8x4 I'd run a 10x4 or 10x3 if you can find such an animal.
This is sort of like the use of the large props for the 1/2A Texaco event. Those engines are quiet and inoffensive even with no muffler.
