Make a quieter RAF?

dunc

RAF/Sparrowhawk/SC 2.5 FI
Joined
Aug 1, 2016
Messages
167
Location
Crawford, CO
Aircraft
1967 Turbo/RSTOL/VG Cessna 185 Skywagon, 1946 Grumman TBM Avenger
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?
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,519
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
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.
 

j4flyer

Member
Joined
Apr 7, 2004
Messages
249
Location
Woodland, Ca
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.
 

Jean Claude

Junior Member
Joined
Jan 2, 2009
Messages
2,185
Location
Centre FRANCE
Aircraft
I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
Total Flight Time
About 500 h (FW + ultra light)
The same propeller installed in front of a tractor is much less noisy than when it turns behind a pusher
 
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