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Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by vlovich123 on Friday January 06, 2023 @03:51PM (#34280888)
Would that change when using an electric motor?
Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by rbanffy on Friday January 06, 2023 @05:47PM (#34282441)
I'd say the most favorable arrangement for noise would be a pusher configuration, with the engines close to the back of the plane instead of a tractor config on the front. This is done on the Piaggio Avanti. Not sure how well it works, but it looks like a spaceship.

Eviation electrical plane recently changed their pusher design to a tractor, but kept the engines on the back (IIRC, they started with a central big one and two auxiliary ones on the wingtips for use during takeoff).

Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by xplanephil on Friday January 06, 2023 @06:35PM (#34282929)
The problem with pusher configuration is that the prop operates in turbulent air, that has already ben disturbed by going around the rest of the airplane. Whereas in tractor configuration, the prop grabs "clean" air. This is traditionally cited as the reason why pusher prop planes are louder (from the outside). In fact, one of the noisiest GA planes is the Cessna 337, which is a pull-push twin configuration.

The advantage of the Piaggio Avanti is that you can do away with the prop heat completely, as the hot exhaust from the turboprop engine simply blows on the blades. Which makes for a very nice anti-ice system.

Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by rbanffy on Friday January 06, 2023 @07:32PM (#34283493)
> Which makes for a very nice anti-ice system.

Didn’t know about that. Sadly, there isn’t much hot exhaust from electric motors.

Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by AdrianB1 on Friday January 06, 2023 @08:35PM (#34284059)
This is for cabin noise, for overall noise tractor is still better. On some airports very close to the city the overall noise is the most concerning factor, in some places you cannot operate at night because of the noise, so in the end it depends what you are looking for.
Re:MT-Propeller 11 blade propeller delivers 15% increase in ... by AdrianB1 on Friday January 06, 2023 @08:34PM (#34284046)
To some extent, yes. Electric motors are not completely quiet, but there are some propellers that are relatively quiet, without hard numbers it is just informed guessing.