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SOUND PROOFING A MOONEY BRAVO

beausking

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LOOKING FOR OTHER OWNERS EXPERIENCE IN ADDING SOUND PROOFING TO A MOONEY. ANY RECOMMENDATIONS ON SOUND PROOFING UPHOLSTRY SHOPS PREFERABLY IN TEXAS? DOES ANY ONE HAVE EXPERIENCE WITH SPECIAL PROPELLERS THAT QUIET THE PLANE? WHAT ABOUT FIRE WALL AND FLOOR INSULATION? ANY EXPERIENCE WITH ADDING THICKER GLASS LIKE 1/4 INCH OR 3/8 INCH? I HAVE NOT FOUND THAT ANY OF THE NOISE CANCELLING HEADSETS ARE THE LONG TERM SOLUTION TO HIGH NOISE LEVELS PRESENT IN THE MOONEY COCKPITS. USEFUL THOUGHTS OR COMMENTS ARE APPRECIATED.




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If you think a Bravo is noisy wait till you fly a husky/pitts/super cub/Maule /aero commander/islander/mu 2...

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I find the Bose A20 is the most cost effective solution.  The plane is noisy internally because it does not have a structural element to its fueslage skin, ie it is loose and thus vibrates like a drum.  You will NEVER overcome this.  I have flown Mooneys on 5 hour trips regularly and the Bose quietens everything to almost a whisper to the point that ATC often ask me to talk louder as i subconciously lower my voice because the noise in my ears is non existant.  

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A lot of the wind noise  comes from the cabin door seal. In flight run a rag around the door perimeter for noise change. To seal the door I use weather strip (see bag). Last five years with no air or water leaks. The problem with inflatable seals is water leaks when on the ramp and raining.

While in flight press your open hand over the glare shield and listen for noise changes. Noise from the glare shield is due to the shield vibrating against its holding perimeter frame. Press your hand around the perimeter to locate the loose area. I use the same weather strip on the glare shield to tighten the fit on it. Works really well.

Vibrating side panel noise can also be attenuated by placing the same weather strip between the panel and the tubular structure.

For ultimate noise reduction I use these rubber ear plugs together with my headsets

http://www.aircraftspruce.com/catalog/pspages/earplugs1.php?clickkey=3008573

10 times better than Bose ANR and you can hear the radio.

José

 

Seal Bag.JPG

Cabin Door Seal.JPG

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6 hours ago, Piloto said:

A lot of the wind noise  comes from the cabin door seal. In flight run a rag around the door perimeter for noise change. To seal the door I use weather strip (see bag). Last five years with no air or water leaks. The problem with inflatable seals is water leaks when on the ramp and raining.

While in flight press your open hand over the glare shield and listen for noise changes. Noise from the glare shield is due to the shield vibrating against its holding perimeter frame. Press your hand around the perimeter to locate the loose area. I use the same weather strip on the glare shield to tighten the fit on it. Works really well.

Vibrating side panel noise can also be attenuated by placing the same weather strip between the panel and the tubular structure.

For ultimate noise reduction I use these rubber ear plugs together with my headsets

http://www.aircraftspruce.com/catalog/pspages/earplugs1.php?clickkey=3008573

10 times better than Bose ANR and you can hear the radio.

José

 

 

+1   I use the same stuff as Jose.  Keep in mind that it is not likely that you will ever get the sound level of cruise flight to get much less than 85 dB, which is the base level for being deemed a noise hazard.  That is why good headsets are very important.  Most of us today, whether or not we have measured it, are probably flying with around 90+ dB in the cockpit.  That is what mine is.  Why?  Because of wind noise, engine noise, prop noise are all bouncing sound waves off the skin (not stressed and not structural) and the plexiglas.  If you manage to drop it by 3 dB or more it would be quite an accomplishment.

As Jose has mentioned, finding the places that are actually vibrating in flight will help.  

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On 5/31/2016 at 8:59 PM, Piloto said:

A lot of the wind noise  comes from the cabin door seal. In flight run a rag around the door perimeter for noise change. To seal the door I use weather strip (see bag). Last five years with no air or water leaks. The problem with inflatable seals is water leaks when on the ramp and raining.

While in flight press your open hand over the glare shield and listen for noise changes. Noise from the glare shield is due to the shield vibrating against its holding perimeter frame. Press your hand around the perimeter to locate the loose area. I use the same weather strip on the glare shield to tighten the fit on it. Works really well.

Vibrating side panel noise can also be attenuated by placing the same weather strip between the panel and the tubular structure.

For ultimate noise reduction I use these rubber ear plugs together with my headsets

http://www.aircraftspruce.com/catalog/pspages/earplugs1.php?clickkey=3008573

10 times better than Bose ANR and you can hear the radio.

José

 

Seal Bag.JPG

Cabin Door Seal.JPG

Jose,

Do you put the weatherstrip on top of the rubber door seal that's already there?

Also, do you use this on the baggage door also?

Thanks,

Lance

 

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1 hour ago, LANCECASPER said:

Jose,

Do you put the weatherstrip on top of the rubber door seal that's already there?

Also, do you use this on the baggage door also?

Thanks,

Lance

 

I remove the old seal, clean the surface and stick the weatherstrip. I use the same for baggage and cabin door. At first you may need to press on the door to close it. Leave the door closed to allow the seal to mold. After that is easier to close the door.

José

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I have lots of experience with this, as I have been trying to make my Bravo not only quieter for me, but to some of my furry passengers on my P&P flights who can't have headsets. The following are the things I've found in order of best cost effectiveness in terms of noise reduction amount and approximate cost. (cost data may be inaccurate as I got these quite a long time ago)

1) Bose A20 ANR headsets, Huge noise reduction, $1,000 (a great ANR a must with a our engine) If you don't have a good ANR, doing the rest of these will be completely cost ineffective.

2) Inflatable door seal, Moderate noise reduction, ~$3,000 for automatic electric pump, less for manual pump. this also made a very big difference at altitudes above 12k

3) Interior soundproofing (replacement of insulation, insulating floorboards etc) ~$5,000, mild noise reduction, not very cost effective, but does reduce a little bit.

 

 

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