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Quietest GA plane I have ever heard

O

OBIO

Retired SOH Admin
Yesterday was my mother-in-law's 70th B-Day (she looks 50 at most). We had a surprise party for her on Sunday, and yesterday was a much quieter family only affair. I was sitting on the patio listening to and watching the planes fly over....when one flew over that made me think I had lost my hearing. It was one of the ultra-modern GA planes....very sleek, very stream lined. I couldn't tell you what it was....modern planes are not my thing, and like modern cars....they all look alike to me. But this plane was quiet. The prop chop was a fraction of what I normally hear on GA planes of this size (looked to be a 4 seater, single engine, low wing, fixed gear in some very snakish fairings). The plane was flying a lot lower than most of the planes....maybe 1500 feet AGL. Not sure what was different on this plane to make it so quiet....but it was cool hearing a plane that low being that quiet. Now, I would not trade the noisiest radial powered beast for a hundred of these quiet modern GA planes, but it was neat seeing modern technology and materials result in a GA plane quiet enough to stop people from complaining about airport noise.

OBIO
 
According to AOPA and Plane and Pilot the electric planes are being flown now as well...I think I would worry about that! You certainly would want to know what conditions cause the most battery drain.
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OBIO, you've brought up an interesting subject of mine.

Being a designer and toying with my own designs and things, I have been working on a plane that has sound dampening, with a two stage muffler/silencer system.

There was a VN era Recon plane back in the 70's that was made to be ultra quiet. It had many (many) silencers along the bottom side of the fuselage. It also had a bizzaro 4 bladed prop with giant paddles on it instead of thin blades. At night, with the lights off, you didnt/couldnt hear it. I forget the name of the thing.

Electrics are on their way. One is manufactured in China presently and is a nice little 2 place high wing GA Sport Aviation plane. ECO I think is the name of it. (My poor memory).

I think planes have been overly loud for too long. It will be great to see some break throughs in getting them quiet, as like they have with Helo's.


Bill
 
OBIO said:
Yesterday was my mother-in-law's 70th B-Day (she looks 50 at most). We had a surprise party for her on Sunday, and yesterday was a much quieter family only affair. I was sitting on the patio listening to and watching the planes fly over....when one flew over that made me think I had lost my hearing. It was one of the ultra-modern GA planes....very sleek, very stream lined. I couldn't tell you what it was....modern planes are not my thing, and like modern cars....they all look alike to me. But this plane was quiet. The prop chop was a fraction of what I normally hear on GA planes of this size (looked to be a 4 seater, single engine, low wing, fixed gear in some very snakish fairings). The plane was flying a lot lower than most of the planes....maybe 1500 feet AGL. Not sure what was different on this plane to make it so quiet....but it was cool hearing a plane that low being that quiet. Now, I would not trade the noisiest radial powered beast for a hundred of these quiet modern GA planes, but it was neat seeing modern technology and materials result in a GA plane quiet enough to stop people from complaining about airport noise.

OBIO
Click to expand...

My initial guess is you saw a complex airplane and the pilot had already retarded the prop RPM's. It is a very significant reduction in noise signature when you reduce the RPM's from max for takeoff power to around the standard 2,500 RPM's.

I am guessing that most aircraft flying over your house are fixed pitch props.

Cheers,

Ken
 
Lionheart said:
OBIO, you've brought up an interesting subject of mine.

Being a designer and toying with my own designs and things, I have been working on a plane that has sound dampening, with a two stage muffler/silencer system.

There was a VN era Recon plane back in the 70's that was made to be ultra quiet. It had many (many) silencers along the bottom side of the fuselage. It also had a bizzaro 4 bladed prop with giant paddles on it instead of thin blades. At night, with the lights off, you didnt/couldnt hear it. I forget the name of the thing.

Electrics are on their way. One is manufactured in China presently and is a nice little 2 place high wing GA Sport Aviation plane. ECO I think is the name of it. (My poor memory).

I think planes have been overly loud for too long. It will be great to see some break throughs in getting them quiet, as like they have with Helo's.


Bill
Click to expand...

There are prop blade designs (called Q-tips) that reduce the sound of the prop by reducing the chances of having localized sonic booms or vortices.

Ken
 
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