Hush kit insulation, is it worth it ?

[Houman]

Hi,

As for of my interior redo project, I'm seriously considering PlanePlastic's Hush Kit insulation, and was wondering if anyone has installed it in the M20.

PlanePlastic dos'nt have a template for Mooney but can sell by square foot and I would have to do the cutting and fitting.

Wondering if the benefit in claimed noise and vibration reduction, plus the added thermal comfort is worth the cost and added weight to the plane ?

[Cris]

ANR headset's are the better bang for the buck! You'll get nothing on the resale and you need headsets anyway. So if you don't have them this is the excuse to purchase.

[LANCECASPER]

Here's another option:

 

The patterns can be ordered from: http://planepatterns.com/products/

 

The material can be ordered from: http://www.soundexproducts.com/order.html

 

I did this on a 1989 TLS Bravo that I had and it made a difference.

[cujet]

As an A+P, DOM of a corporate flight department and operator of multiple aircraft, aircraft owner and all around "interior guy" I can state, clearly, a well designed insulation package works wonderfully. With subsequent reduction in noise levels and vibrations. 

 

However, the added weight of a properly engineered, and effective package will shock you. For example, we added well over 1000 pounds on our Gulfstream GV when we chose to insulate the aft section of the cabin against engine noise and vibration. Damping material was applied to every available fuselage skin. But, that simply reduced the vibrations transmitted. Then multiple weighted layers were required. It's a nomex/weighted layer sandwich that has varying densities. 

 

Our helicopter is very weight sensitive. So we did something similar. Without the weighted layers (nomex and fiberglass). It's a lightweight package and noise is not significantly reduced. Headsets are a must. 

 

On light aircraft, one can target certain noise sources with weighted layers or damping material. Such as the belly skin near the exhaust system. But, don't kid yourself, without properly weighted layers, (such as nomex or fiberglass alone) noise is not reduced to the point where headsets are unnecessary. In fact, I'd say noise is not significantly reduced at all. 

 

SD40 ALPSA (an EAR product designed for damping) weighs 0.44 pounds per square foot! 

MDL 125 and other similar weighted layer products are even heavier. 

 

http://www.earsc.com/HOME/products/DampingandIsolation/DampingMaterials/SD/index.asp?SID=153

 

http://www.earsc.com/HOME/products/BarriersandAbsorbers/Barriers/index.asp?SID=186

 

So, when it came to my personal aircraft, I removed all insulation. Do I notice a difference? Not at all. 

[M20F-1968]

I can share some experience here.  I started off using Scandia's sticky backed white foam insulation (some with aluminum cap and some with a blue dense foam cap supposedly with better vibration protection). 

In the end, It took it out (which was a pain) due to weight and used the soundex stuff below the windows and bagged fiberglass insulation in the ceiling.  That worked well.  I did not glue the insulation to the skins so it can be taken out for inspection.   Sound level, vibration and heat retention are all improved.  I have not done any objective testing.

 

John Breda

[Houman]

Yeah, I have ANR headsets for me and my son, additional and occasional passengers, well normal headset but that is not my problem.

 

As for insulation, with the tubular structure and from what I remember in my pre-purchase inspection, I don't if it is really worth it, but was asking the question here anyway to benefit from the collective wisdom...

 

John, where did you buy thje sounex stuff and what was the costs ?, as for the fiberglass as well, I guess both products must be aviation grade and have fireproofing papers, right ?

[ryoder]

I tried to soundproof my Corvette and it made almost no difference and caused issues with carpet fitment. The Mooney has some soundproofing in it and it's ok but not perfect. I really wish there was a Corvette quiet exhaust for this Lycoming.

[Piloto]

A lot of the noise comes thru the firewall and the dashboard plastic panel. Make sure the dashboard is not reverberating. I put Velcro strips (soft side) on the dashboard edge so the windshield will make pressure down. It made a significant difference. You can try covering the underside of the dashboard with thin carpet type material to further attenuate the acoustic reverberations. You can do the same for the side panels. The plastic panels reverberates like speaker cones. I noticed a very significant noise reduction in planes that have cloth/leather side panels instead of plastic. You can hear a pen tapping on a plastic panel but not on a leather panel. Also check for door air leaks passing a rag around the door perimeter while in flight.

You may notice a noise reduction when you have four onboard. Fat absorbs noise. When I have my wife, her sister and niece onboard they don't bother to use headsets. They just gossip and then fall asleep.

José

[Rustler]

"Fat absorbs noise. When I have my wife, her sister and niece onboard they don't bother to use headsets. They just gossip and then fall asleep."

 

Oh, José, I wouldn't touch that line with somebody else's ten-foot pole!

[N201MKTurbo]

When I redid the interior of my old M20F, I removed all the fiberglass and covered the inside of all the sheet metal with EAR soundproofing material.,it was about 3/8 inch thick with heavy aluminum foil on one side. I don't remember it weighing all that much. The plane was noticeably quieter and warmer in the winter. I think it was worth it.

[helitim]

The plane was noticeably quieter and warmer in the winter. I think it was worth it.

[ArtVandelay]

There is a free app for iPhone call decibel, you can use to give you quantitative measurements, my J runs 90-95dB, that's a level that can cause hearing loss with extended exposure.

[N201MKTurbo]

The plane was noticeably quieter and warmer in the winter. I think it was worth it.

And this coming from a brutal winter temp of 80 F in Arizona ....Edit- smiley face is not working here

[ryoder]

Good point about plastic. Fabrics are great for soaking up noise. I once had a comforter in the back of my Camaro and the thing was whisper quiet. It soaked up all the noise being balled up in the back. We had work done at the office and the atrium is so noisy now thst they removed some strategically placed fabric covered panels. You can hear conversations clear across the room on the third floor.

I hate noise and am going to get carpet with sound proofing on the underside and may consider having plastic panels covered in wool or leather.

[Marauder]

A lot of the noise comes thru the firewall and the dashboard plastic panel. Make sure the dashboard is not reverberating. I put Velcro strips (soft side) on the dashboard edge so the windshield will make pressure down. It made a significant difference. You can try covering the underside of the dashboard with thin carpet type material to further attenuate the acoustic reverberations. You can do the same for the side panels. The plastic panels reverberates like speaker cones. I noticed a very significant noise reduction in planes that have cloth/leather side panels instead of plastic. You can hear a pen tapping on a plastic panel but not on a leather panel. Also check for door air leaks passing a rag around the door perimeter while in flight.

You may notice a noise reduction when you have four onboard. Fat absorbs noise. When I have my wife, her sister and niece onboard they don't bother to use headsets. They just gossip and then fall asleep.

José

"Fat absorbs noise. When I have my wife, her sister and niece onboard they don't bother to use headsets. They just gossip and then fall asleep."

Oh, José, I wouldn't touch that line with somebody else's ten-foot pole!

And you guys were always giving me a hard time about my women...

You could hear a mouse fart with them onboard.

[Andy95W]

And you guys were always giving me a hard time about my women...

You could hear a mouse fart with them onboard.

Maybe it wasn't the mouse that was farting...

...maybe they just blamed it on the mouse.

[Andy95W]

The greatest noise reduction I have always found comes from reducing wind noise, usually coming from the door seal. Best door seal I've ever had was a Bob Fields inflateable. In my old Aztec with the seal inflated it was the difference between the back seat passengers needing headsets or not.