Hi Pe,

Just wondering if you could give me some tips on reducing the noise output of my MVVS 58?

I'm trying to achieve 96dB(A) at 3 meters with the noise meter 30cm off the ground. This is to the F3A standard and testing is being done over short grass.

My current set-up results in 102dB(A) @ 3 meters.

The current set-up is:
Airframe: Extreme Flight Yak 54 88" span.
Engine: MVVS 58 Std.
Muffler: KS 1060 Tuned Pipe. Soft mounted KS kit.
Flex Header: Home made with KS parts 440mm long. Soft mounted near teflon joiner.
Prop: Mejzlik 24 x 10TH.
Spinner: 4" Carbon by Precision Aerobatics.
Engine mount: MVVS standoff.

The engine is currently doing around 6300 RPM.
I have tried a Mejzlik 24 x 12 prop but the result was still 102dB(A). RPM dropped to about 6150 with this prop.

I've been told that a 3 blade prop would reduce the noise and was thinking of a 24 x 10 (3 blade). I also have the soft mount for the motor and could re-install that. My only concern with this prop would be the load on the engine. MVVS has it as a recommended size though so it should be ok.

I see that you are meeting your 80dB(A) limit at 7 meters so achieving 96dB(A) at 3 should be achievable. I hope...

Many thanks.
Jason.