Make a quieter RAF?

dunc

Active Member
Joined
Aug 1, 2016
Messages
255
Location
Crawford, CO
Aircraft
AR-1C 915is, RAF/SH/SC
Total Flight Time
5000
Has anybody done a sound spectrum analysis to determine if the engine noise or the prop noise is the biggest culprit?

That said, any experience with quieter mufflers or props?
 
Good evening Duncan.

I know enough about making something quieter to have a sense of the magnitude of the challenge to making something quieter.

Noise is cumulative.

If you quiet either the engine or the prop it will make the aircraft quieter.

A turbocharger is a great muffler and often only an after muffler is required to make the exhaust fairly quiet.

There is a lot of intake noise too and anything you do there will make her quieter.

How the prop interacts with the things around it also makes a big difference in the total decibels produced.
 
Go on YouTube and listen to a Cessna 185. Then listen to a Cessna 185 set up for floats. The float plane that has exactly the same equipment except for the prop will be enormously louder than the non float plane. The prop makes that much difference. The bigger the prop and the slower you can turn it, the quieter the plane.
 
The same propeller installed in front of a tractor is much less noisy than when it turns behind a pusher
 
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