Which sound proofing material?

[Lood]

I want to do a thorough sound proofing job on my Mooney during its next annual. I've had a look on Spruce, but like always, there are too many to choose from. Then, to complicate matters, most sound proofing materials come in different thickness.

I would appreciate any advice on which would be the best material to use as well as other general soud proofing tips. I flew with a friend in his C170 a while back and it was so quiet inside that I only realized my headset was still on my lap when didn't respond to my questions. I've had a look behindsome of the interior panels in my Mooney and all the original sound proofing material seems to have been removed. It is very loud inside it during flight - even with a headset.

[clh]

I used two layers of the foil backed bubble wrap.  It is the stuff with two layers of bubbles in each ply.  My cabin runs 85-87 dB during climb.  It looked like a good compromise in weight and sound deading ability.    I didn't think to measure the noise before, but it sounds substatially less.  You can carry on a conversation without really raising  your voice. The package solutions in ACspruce were quite a bit higher priced.  Don't know how well they will work.

 

[Mooney65E]

I had my plane soundproofed ten years ago while redoing the interior. I used approx. 5/8" thick black foam material on the advise of my mechanic. He showed me a simple burn test of several samples using a lighter. Some of the materials actually caught fire and billowed black smoke while others would not even ignite. I don't have any way to check dB levels, but I did notice the cabin is just a little less noisy  and is warmer in the winter. I didn't soundproof the most important place (firewall) and I suspect that is where the majority of my noise is coming from. I may redo the firewall in the future when I get spare time to tackle the tedious task.

[KSMooniac]

A top-shelf ANR headset will do more for reducing dB than any heavy, expensive, and tedious soundproofing material.  Unless you expect to ditch headsets completely, my opinion is to just enjoy the higher useful load and a better headset.

[jlunseth]

Be really careful with this.  Look at SB208MB, which is the corrosion service bulletin.  There are a number of types of insulation that retain moisture, the one I had in my plane was a foil backed felt.  Great for noise attenuation, but the edges of the insulation pads are against the steel tube frame, and they cause corrosion.  No corrosion and better headphones, is a better way to go than great noise attenuation and corrosion in the frame.

[jetdriven]

What about the double foil mylar faced bubble wrap?

[rogerl]

Lood,

Check out thread:

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=3&threadid=418

[jlunseth]

Well, am not a mechanic, but the SB and the Mooney Maintenance Manual need to be complied with.  The SB is here:  http://www.mooney.com/servicepdf/1967.html

I think the maintenance manual needs to be purchased. 

All I am saying is that Mooneys have a known issue with moisture retaining and non-specified insulations being used next to the frame members.  Don't get yourself in the corrosion trap.

[Lood]

Thanks for all the replies, so far. Just to clarify, I intent to have my AME do the job during the next annual, or at least assist me and I am only looking at FFA certified and approved materials. I see Super Soundproofing claims that their product won't absorb moisture or odor. Have anybody used it?

http://www.aircraftspruce.com/catalog/appages/soundproofinstall.php

[Ned Gravel]

Lood:

I have recently used it in replacing the old fiberglass and aluminum foil combo that was in my '65 E model.  It really absorbs the sound well and provides a much better thermal insulation than the old stuff as well.  Easy to cut and install.  My wife and I did the entire interior in less than one day.  We bought 5 linear feet off the roll and we had about 4 square feet left over, if I recall.

[Lood]

Edgargravel, thanks a lot for that pirep. Can you recall what thickness you used?

[Ned Gravel]

Quote: Lood

Edgargravel, thanks a lot for that pirep. Can you recall what thickness you used?