Dayton Murdock

Dayton Murdock

Well Known Member
Hi All

Over the weekend I was cruising along in my Lycodile powered RV4 @ 174kts 8500 msl and it occurred to me that some sound deadening would be a welcome addition to the environment. Not wanting to load my RV4 with pink household insulation I though I would ask the RV guys what they used for sound deadening and where they installed it.
 
I know they make an sound deadoning material for cars you can get it in sheets. I've seen in advertized in crutchfield but i'm sure any of the major brands would sell it. I've heard good things about the stuff it's thin too but don't know bout the weight
 
For effective sound deadening I use my Lightspeed 20-3g ANR headset installed on my head! (and one for the pax, too)
Seriously, though, I never experimented with sound deadening and don't think the benefits would outweigh the additional weight of materials needed to make a significant improvement. It is a metal airplane afterall.
I do fly behind a wood prop which I understand is quieter than metal and usually have the XM radio on. You can still hear the engine droning along (which is good) and my kids never have a problem falling asleep on long X/C's. So, the noise inside must be bearable and I must be a very boring pilot.:) (which is also good)
 
Dynamat

I'm using Dynamat Extreme in mine. I cut 3"x12" strips and put on in each side section. These will eventually be covered with an interior kit, so they won't be seen. One4 sq ft is about 2 pounds, and was enough to do from the rollbar forward. I found the best pricing on Amazon.




Do not use them on your floor, though; you'll want something removable so you can do your annuals (moisture gets trapped on the floor). For my floor, I used these pads from ACS.



I haven't decided which product to use on my firewall yet.
 
mass

I built a small project recording studio in my basement a couple of years ago, including a small sound-"proof" room for tracking vocals. I did a lot of research on acoustics and soundproofing. Some materials are definately better than others, especially in terms of *reflecting* sound... materials that can behave as springs to absorb acoustical energy (hence foam is used to deaden reflections in studios), but to really affect sound *transmission* there is no substitute for a lot of mass. Professional recording studios have massive concrete walls, even between parts of the studio. Gluing foam material to the insides of an RV may help reduce reflections, vibration and resonance, but it will do very little to actually reduce the SPL (sound pressure level). The only way to do this really effectively would be to use so much mass that the airplane would be too heavy to fly.
Reducing sound reflections by adding foam and stuff creates a more acoustically "dead" environment, and this can have the psychological effect of making it seem quieter, but the SPL won't be reduced much. ANR technology is a wonderful thing, and investing in a good ANR headset is the most effective soundproofing you can do.
Now on the other hand, adding foam for thermal insulation in your RV... that I have still yet to research... no idea whether it's practical or not.
 
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A non-RV data point

I had a 98 Tacoma that became too noisy for my taste. I pulled out the entire interior and covered the floor, roof, back wall and door skins with Dynamat. Reinstalled interior, fired it up and ... was darned dissapointed with the difference. No way I'm going through that with my plane.
 
depends on the vehicle, perhaps

szicree said:
I had a 98 Tacoma that became too noisy for my taste. I pulled out the entire interior and covered the floor, roof, back wall and door skins with Dynamat. Reinstalled interior, fired it up and ... was darned dissapointed with the difference. No way I'm going through that with my plane.
Click to expand...

I have an ancient Ford Bronco (1970) that I lined with a sticky-sided asphalt mastic product that I purchased from the "old truck" department of McMaster-Carr. Basically a low-budget version of Dynamat. The difference in interior noise was astounding. Literally a difference of needing earplugs on the freeway even with windows rolled up, to being able to have a quiet conversation. But what I did by using that stuff was to mass-load the affected surfaces, which is to say add a lot of weight. Maybe not such a good idea in an airplane, but it can be effective. The only problem with installing Dynamat before you fly is that it's harder to assess "before and after". I for one would be very interested in reading about any observations once you are flying.
 
I also had a vintage Bronco (71) and that thing was deafening at freeway speed. As I recall, there was no sound deadening of any kind and so I'm sure the Dynamat would help a lot.

On the other hand, my Tacoma had some sort of hard thick material on much of the interior floor and door skins. My guess is that this stuff was already doing all that could be done to quiet it down.
 
Dayton, if you click on Search under Forum Quick Links on the front page, then enter "Sound Deadening" in the search box and hit enter, it will display a list of several previous threads that will probably be of interest to you.

The one that is probably best is "Best "floor" covering material". In my previous investigation of this topic, it appears the best bang for the buck will be realized by installing sound deadening to the floor, due to it's proximity to the exhaust stacks.

Also, you may want to go to www.seatfoam.com, as they have FAA approved seat foam and sound deadening material. I have no personal experience with it, but maybe someone else has & will report their experiences.

Best regards, Joe Harwell
 
I can not remember where I read it but someone posted information recently about installing a 90 degree tail pipe exhaust deflector and there was a remarkable reduction in noise.
 
Lead Works

prkaye said:
there is no substitute for a lot of mass. Professional recording studios have massive concrete walls, even between parts of the studio. Gluing foam material to the insides of an RV may help reduce reflections, vibration and resonance, but it will do very little to actually reduce the SPL (sound pressure level). The only way to do this really effectively would be to use so much mass that the airplane would be too heavy to fly.
Click to expand...

The old recip airliners were insulated with rubberized lead blankets, (very similar to the lead apron you wear when having an x-ray. Heavy, but as stated above, it was the mass that deadened the sound.

I went with Bose. :)
 
Liquid Sound Proof

I planned on spraying the liquid sound proofing material on the inside of the Fuse, early on in that phase of things. A thin layer will add some weight but I can't wear ANR and want it quiet. Then plan on some lightwieght sound absorder as apposed to closed cell foam.

Anyone use the liquid soundproofing?
 
I don't think it is possible to make the RV's quiet if you want it to fly well. Most of the noise comes from the exhaust and also the prop thru the canopy. ANR or good passive headsets with ear plugs I believe are the only way to go.
 
Hi All
I tried earplugs with my David Clark 10-40s and it was great! But I could not turn the volume up enough to hear traffic commutations. So I was thinking that lowering the sound level in the cockpit would be the answer. I have installed some sound deadening material from Summit racing under my feet and up the firewall behind the rudder pedals. My son said there is a marked improvement. I am going to install more under the floor boards forward of the rear spar. Any suggestions from other builder/flyers will be appreciated.
 
sound deadening

I applied 3/4" sound deadning from ACS on the firwall and floor and cabin sides for two reasons, one for sound deadning the second for insulation from heat from the engine. I have no floor viberation and the firewall seem cool. While flying one day I lifted my headsets off my ears. The sound was deafening. I put let them back on my ears and all was quiet again. Had to try this again and again the sound was deafening. I would say that on a RV sound deadning is a wast of time money and wieght, execpt for making the fire wall cooler and maybe stop floor vibes. You can't stand the noise without good headsets.
 
Possible cheap & lightweight soundproofing

I'm just going to have to jump in here with my idea. Somebody is going to have to do the experiment themselves to verify my experience.

Let me just tell my story...I used to live in a house that was on a quiet street. Then one day the county rearranged the traffic pattern by reworking an intersection way down the street. Suddenly everybody seemed to be taking my street as a short cut. Now I lived on a noisy street. The crown of the roadway was just below the level of my windows. Most of the noise I had coming into the house was from the sound of the tires on the pavement. We decided we had to move. We decided I should paint the house before we sold it. I got out there and scraped and caulked and puttied. I got out my paper masking machine and masked off all the windows nice and tight. I didn't want my airless paint sprayer shooting paint through any pin hole or unsealed lap of masking paper onto my nice windows. I thought great I'm ready to shoot some primer. My wife and I stood in the front yard talking or rather shouting over the traffic noise. We were relishing the moment. Goodbye old ugly color. Here comes the new spiffy green. Well, let's go inside and have lunch before I fire up the airless. We go inside. And it is noticably quieter inside than before! The only explaination that I can have is that sound is a pressure wave and if you can stop it from traveling through free air passages, like the cracks all around my window frames, then it has to be powerfull enough to move whatever is blocking it's propagation. In my case that was fairly lightweight, yet sort of hard, brown masking paper and masking tape. I thought my ears were fooling myself so I went back outside and peeled back one corner of my 3' x 3' kitchen window and then went back inside. Sure enough I could clearly hear the sound bleeding in past the weatherstriping and various channels and corners that made up my kitchen window. Now again, I'm talking about the relatively high frequency noise that comes from car tires on pavement. Your mileage may vary. But I would like to try this on an airplane. I would just use regular masking paper and blue painters tape. I would mask off everything I could. I would try to mask off:
1.) The area under the intrument panel.
2.) The wing roots.
3.) The tailcone/baggage area.
4.) The side panels.
5.) The floor.
6.) Anything and everything that may have even a pin hole where sound pressure could find it's way through. I would even like to try making up some bellows/accordian type folded paper assemblies to accomodate the movement of control rods/cables.

Remember all the sound that we hear made it's way into our inner ears through fairly small holes in our skulls. If we can keep it out of the cabin it won't reach our ears.

So you can take that for what it's worth. I just thought I would pass that along. Someday when I build my 9A that is just exactly what I am going to do. And if it doesn't seem to make any difference then I can just peel it all out and toss it in the recycle bin.
 
63scrounger said:
I would mask off everything I could. I would try to mask off:
1.) The area under the intrument panel.
2.) The wing roots.
3.) The tailcone/baggage area.
4.) The side panels.
5.) The floor.
6.) Anything and everything that may have even a pin hole where sound pressure could find it's way through. I would even like to try making up some bellows/accordian type folded paper assemblies to accomodate the movement of control rods/cables.
Click to expand...

I know what you are talking about when it comes to sealing out noise in our houses, I've had a similar experience with window sealing.

I certainly don't want to discourage you from trying whatever you wish to diminish noise in your -9A, but most of the objectionable noise in our planes is low frequency. That is why ANR headsets work primarily on low frequencies (prop, engine, and wind rumble) and allow the higher frequencies through.

A major problem is that we are riding around in a large drum with all the surfaces vibrating in concert with engine, exhaust and slipstream noise. What you have proposed may indeed have some benefit (even though making all the joints in an RV airtight would be a formidable task), but the low frequencies are what really make our planes noisy. That is why most of us have come to realize the most effective noise proofing is that which is purchased from folks like Lightspeed, Bose, David Clark, etc. :)
 
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EAR Specialties in Indiana, the ones who make those little foam ear plugs for high noise environments, has a line of sound reducing products just made for aircraft. I contacted them and got their booklet that shows each type and its use. Following the booklet's recommendations on type and placement, I ordered five types for the different regions of the cockpit. Two types are used on the firewall and the three other types are used in different fuselage areas. One of the major noise sources, which is really bad on aluminium planes, is the broad floor area and the bottom of the wings near the fuselage. This has the exhaust beating and drumming on it. That's why the 90 deg exhaust helps for sound reduction, even though it increases drag. I did my firewall, the floors, the forward fuselage behind the firewall, the bottom of the wing LE near the fuselage, the cabin sidewalls, and the bottom of the baggage compartment behind the seats. My friend Oscar has removed his headset when flying with me and has said the noise in my Lancair is definitely less than in his. I have less exhaust noise due to my augmenter which mixes the exhaust with the cooling air, and my three-blade prop which cuts down a little, but not much, on canopy noise. The speed-up of air coming from the prop has been highly exaggerated; its only about 5-8 fps on my plane at 200 mph. People seem to think tat the blast that they feel on the ground from the prop at high power is similar to what takes place in cruise; it isn't! There is one thing to keep in mind when flying with noise-reduction headsets. Because of the quieter environment they give to the ears, the ears relax their muscle which controls sound level. Have you noticed how much better you can hear when it has been very quiet? So even though the noise reduction of the headset is listed as so many dB, the actual perceived suppression is somewhat less due to the ear's action. That's why when you remove the headset in flight, the noise will overwhelm you at first; 'same thing when you take your fingers out of your ears at a rock concert!
 
Another option

I have a sample kit of a 3m sound damping product that may have some merit. I am a long way from flying so I cannot comment on its efficacy, however, 3m does advertise it for aviation use. This product is very light weight and does not require full coverage to work. The samples I have are very impressive. Please view the following links for information. The second one is very informative about sound damping techniques.

http://solutions.3m.com/wps/portal/3M/en_US/3M-SpecialtyTapes/SpcltyTape/ProdInfo/Spec6/Damping2552/

http://www.appliancedesign.com/CDA/Archives/41a3a3405ca38010VgnVCM100000f932a8c0____
 
There was a fairly detailed article in Sport Aviation on this subject a while ago. I'm sorry I don't have the particular issue date, but I'm sure somebody will.
 
What about enclosing the 90 degree exhaust deflector described by David-Aviator within a streamlined airfoil type body to reduce/remove any additional drag? Directing the exhaust below and away from the fuselage seems to make intuitive sense as the best bet for noise reduction.
 
rodeomanny said:
What about enclosing the 90 degree exhaust deflector described by David-Aviator within a streamlined airfoil type body to reduce/remove any additional drag? Directing the exhaust below and away from the fuselage seems to make intuitive sense as the best bet for noise reduction.
Click to expand...

Before doing that, I'd check out everything in regards to scavenging the exhaust and back pressures changes due to pushing the exhaust at a 90 degree angle to the slip stream (is that the proper term?).

L.Adamson
 
Flammability

I continue to see builders filling up their cabins with highly flammable (and smoke producing) trims ....seats, side trims, carpets, tonneau covers...and of course sound insulation. Automotive products complying with nothing more than FMVSS-302 (auto fire standard) can be virtually guaranteed to have a rapid spread of flame and to produce copious quantities of smoke. Many polymers will also melt and drip onto your skin when they ignite, causing horrific burns.

Personally I wont put any trims in my aircraft that wont meet or exceed FAR 25.853 (FAA flammability requirment). And that includes heat and sound insulation.

Put in sound insulation by all means...but don't use flammable materials.

I mean, the noise might be inconvenient, but a fire in the cabin is certain to be a lot more unpleasant.

If you are in any doubt as to the flammability of a product, just put a cigarette lighter to it for 10 to 15 seconds. If it continues to burn after you have removed the lighter (the source of ignition) then it should not go in your aircraft. If it continues to burn at an accelerating rate then it DEFINITELY shouldn't go in your aircraft.
 
http://silentcoating.com/how.html

Here's an interesting product. At eight ounces/sq ft when applied in the recommended 50 mil thickness it's not light, but I don't think it needs to be applied everywhere.

The article referenced above noted the best results (for a Lancair Legacy anyway) were had by adding soundproofing to the underside of the glare shield and the cabin floor -- both vibrate like drums I suppose.

According to the site, the product may be applied to any properly prepared surface including aluminum and fiberglass. The product is water-based and cleans up with soap and water.

It's also advertised as having US Coast Guard approval for flammability and toxicity as well as European Union approval and Lloyd's Registry approval.

Click on the video for a short demo of the product's effectiveness.

Regards,

Mark Sletten
 
What I did...

I followed Noel Simmons's practice for sound deadening" Completely envelope the firewall with the stuff, and then use little pieces for the panels that receive the most prop blast. (basically the first two sets behind the cowl) The little pieces change re resonance from twaang to "thunk". My plane is getting an interior, so that will help as well.

DSCF57821.jpg


DSCF57781.jpg
 
Standards - auto vs. FAA

Captain Avgas said:
....... Automotive products complying with nothing more than FMVSS-302 (auto fire standard) can be virtually guaranteed to have a rapid spread of flame and to produce copious quantities of smoke. Many polymers will also melt and drip onto your skin when they ignite, causing horrific burns.

Personally I wont put any trims in my aircraft that wont meet or exceed FAR 25.853 (FAA flammability requirment). And that includes heat and sound insulation.
.......
Click to expand...

Bob,

I was under the impression that the auto standard has been updated (perhaps in the 80's/90's) and that the FAA standard dates back to before the middle of the previous century....:)

Is the auto standard really weaker now than the FAA standard?

Does anyone have access to the details of the specifications?

When I worked on my Tiger interior, I did perform the flame test you mention on some Airtex FAA foam and some similar looking upholstery foam... the results were very obvious... Don't use upholstery stuff, even though it looks identical.

gil A
 
Does it really matter if the seat cushions are fire proof or not? I mean if the seat material or side panels gets up to the temperature of burning wouldn't you already be dead?
 
Whats the "Stuff"

Nucleus, What the "stuff" you used on the firewall. Looks like the 3M coated aluminum foil product?
 
I'm using SoundEx Products solution. This is FAA certified (not that it matters for us) and seems well thought out. The kits for RV (especially the -10 @ $1025) are pricey but I think you would make out better if you "roll your own" kit using their bulk material panels.

So far, to do all the bottom closeout areas in the RV-10 I've used 1 - 7/8 X 36 X 48 panel and 1 - 1 1/4 X 36 X 48 panel. Not flying yet so I'll have to compare to an un-insulated 10 after flying.
 
az_gila said:
Bob,
Is the auto standard really weaker now than the FAA standard?

gil A
Click to expand...

Gil, the auto standards on trim flammability are almost meaningless. If you get a piece of typical synthetic fabric from car seats and put an ignition source to it you will soon see what I mean. Invariably the fabric exhibits a very rapid spread of flame (the flame front grows exponentially) and a huge quantity of thick black smoke is generated. When the source of initial combustion is removed the fire continues to accelerate. The product also typically emits flaming molten drips.

Basically what it all really gets down to is the Oxygen Index of the material. The Oxygen Index is that level of oxygen as a percentage of the total gas environment required for the material to continue to burn in the absence of a seperate combustion source.

Air is approximately 21% oxygen. Therefore materials with an Oxygen Index of less than 21 will readily burn in air. Those with an index over 21 will self extinguish in air if the seperate combustion source is removed.

So this is a simple matter for RV builders to come to grips with. Before putting any trim of any type in the cabin get a sample and put an ignition source to it. Once it starts to burn remove the ignition source. If it does not eventually self extinguish with time then do not use the product.
 
Norman CYYJ said:
Does it really matter if the seat cushions are fire proof or not? I mean if the seat material or side panels gets up to the temperature of burning wouldn't you already be dead?
Click to expand...

All things being equal I suspect you'll be better off with low flammability materials anywhere in your cabin in the event of a fire.

However in the final analysis using low flammability products is not about fire proofing yourself...it's about buying a small amount of precious time. That is, time to get on the ground or time to exit the aircraft. For the same reason I would always advocate wearing clothes when flying made of natural fibres rather than highly combustible synthetics. In a fire just small things may mean the difference between say 10% burns and 70% burns.

RVs are very short coupled and have a propensity to tip over in off-field forced landings. And getting out of an RV canopy when inverted can also be problematic. In an accident wiring can be damaged along with fuel lines. Why surround yourself unnecessarily with highly flammable cabin materials and make the situation worse.
 
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Any newer real world PIREPS on this stuff.

Just been reviewing this stuff and it seems the old rubber type mats etc are getting poor reports, add weight and may be somewhat dangerous in some situations.
The most promising way i can see so far to keep weight down, but help with vibration and noise...is as follows.
Tape off joints and front area with 3m damping foil 2552. Good enough for f-15's works for me. (or is that marketing bs? dont know)
Floor and side panels forward of elbows, coat in Silent Running sr1000.
Then, install a decent interior kit as light as you can, but that suits your taste for luxury. I know rv's are noisy, and weight is an issue, but....my mission is about comfort too, not just fast. Trying to find the balance.

I am in no hurry, just doing some research here, but this solution seems pretty high tech, pretty safe (fire/smoke wise) and weight wise, within limits.

Anyone actually done this type of thing and have any feedback. Lots of things look good on paper, but just "dont fly"
 
Oshkosh Presentation

We find that vibration is a significant contributor to pilot fatigue, even tho we can control for noise, vibration reduction is beneficial for X-country flights. The Air Force now plans and flys 36 hour unaugmented flight operations and we look to control vibration in addition to noise.

This is a phenominal presentation given at Oshkosh reference the kitplane noise abatement article looking at a Lancair case study. LIGHT AIRCRAFT INSULATION: THERMAL AND NOISE CONTROL IN YOUR AIRCRAFT

www.orcon-aerospace.com/datasheets/2005%20Oshkosh%20presentation.ppt#256


Is it worth the weight, depends how much weight right. I think I can effect 80% of the problem by targeting 20% of the cause. I'll spray liquid damper and use lightweight open cell absorber under the fabric. I think I'll stay away from the closed cell foam. Good cranium sets will take care of the rest.
 
Great Article Paul

Thanks Paul, that was worth reading over. Appreciate the link.
Do you have certain products/brands that you feel are better than others for your plans?
 
My plan...tell me if I'm stupid

I trust the smart people on this site...tell me if I'm off the mark. wont start the fuse until July so have some time.

I attached a guess at the weight I budgeted
KOOLMAT INSULATION HEAT BARRIER or similar for firewall forward 3lbs

2 coats liquid soundproof on firewall and floor 5 lbs

3M barrier tape on firewall and floor 2 lbs

FAR close cell foam on inside of firewall

1 coat liquid soundproof on back of instrument panel and sidewalls 3 lbs

1 inch lightweight sound absorber - Soundex is the brand that has the qualities I want for an absorber.

Felt, thick carpet over foam or something else on

Interior - fabric over 1/8 inch lightweight foam. Fabric seat covers. No
leather. The weight I'll save not using leather or vinyl will compensate
for some of the added weight from noise barriers. Also plan to have only 2" of confor foam in seats

Best canopy seal I can find.
 
Bugsy said:
I trust the smart people on this site...tell me if I'm off the mark. wont start the fuse until July so have some time.
(clipped)
Interior - fabric over 1/8 inch lightweight foam. Fabric seat covers. No
leather. The weight I'll save not using leather or vinyl will compensate
for some of the added weight from noise barriers. Also plan to have only 2" of confor foam in seats

Best canopy seal I can find.
Click to expand...

Don't know if I fit the "smart" category, but you won't save all that much weight by skipping the leather. Check with someone like Classic Aero to see the difference. I would guess only maybe 3 pounds for a complete interior if you are comparing to a good quality upholstery cloth. I went with Classic's carpet and could tell a difference in the sound level. Sounds like a good plan for some peace and quiet. Build away!

Bob Kelly
 
Thanks Mark for the info.

For anyone interested I talked with them and they have another product, not listed, SR700 which is 25% lighter.



Msletten said:
http://silentcoating.com/how.html

Here's an interesting product. At eight ounces/sq ft when applied in the recommended 50 mil thickness it's not light, but I don't think it needs to be applied everywhere.

The article referenced above noted the best results (for a Lancair Legacy anyway) were had by adding soundproofing to the underside of the glare shield and the cabin floor -- both vibrate like drums I suppose.

According to the site, the product may be applied to any properly prepared surface including aluminum and fiberglass. The product is water-based and cleans up with soap and water.

It's also advertised as having US Coast Guard approval for flammability and toxicity as well as European Union approval and Lloyd's Registry approval.

Click on the video for a short demo of the product's effectiveness.

Regards,

Mark Sletten
Click to expand...
 
Wade? Where did that come from.

I liked their little video and was interested in the sr1000. My chemist buddy told me it was a big waste of money and couldnt work as advertised. What does he know...no idea, i just asked his opinion. Anyway, where did you get info the on the sr700? I cant find it on any of there info or press news? Anyone actually use any of this liquid or another brand in and a/c?
 
How do you apply it?

LARCO said:
This what we have used on several RV's and it helps. We installed it on the floor and firewall. Larry

http://www.aircraftspruce.com/catalog/appages/dampingpanels.php
Click to expand...

Larry... the AC Spruce page was rather deviod of details....:)

The 3M data sheet is also sparse, but does say it's 1/4 inch thick and weighs about 1/4 lb per sq. ft.

http://multimedia.mmm.com/mws/mediawebserver.dyn?6666660Zjcf6lVs6EVs666AFUCOrrrrQ-

Could you tell us how you apply it to a typical Vans two seater? Do you apply it to tightly fit the spaces, or just as a dampener in the center of the panels?

thanks gil A
 
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Straight from the source

Rick

It came directly from Silent running, I emailed then called to talk with them. While they recommend 50 mils, Marc said given the thickness of our skins I could get away with cutting down to 40 mils, so that should shave a bit of weight as well. I bought a 1 gal kit which they say covers 40 sq ft at 50 mils. I plan on coating the top front skin (glareshield to firewall), firewall, and floor. Although, I do not think fire is a problem with it, given the published flame propagation data, I will enough extra to do my own fire tests to be 100% sure. Hopefully some time this year we'll see how well it works.:)

Here is a copy of the email text I received.

"In the interest of weight we came up with the SR 700, which is about 25%
lighter than the SR 500 or SR 1000.

While not yet on the website, it is available.

Sound damping properties are essentially the same as the others, while
saving weight.

Flame and smoke tests differ only slightly, the SR 1000 has to pass much
more rigorous test to meet the US Coast Guard approvals, the SR 500 has
passed the CA state building code section 8.1 approval as well as the
Federal Railroad Assoc. test for flammability and smoke density.

Basic bottom line is, if any of our products are on fire, you have much
bigger problems!

If you would like to see copies of any of the above please let me know.

Thanks for your interest in Silent Running.

Marc Doheny
Silent Running"


RickWoodall said:
I liked their little video and was interested in the sr1000. My chemist buddy told me it was a big waste of money and couldnt work as advertised. What does he know...no idea, i just asked his opinion. Anyway, where did you get info the on the sr700? I cant find it on any of there info or press news? Anyone actually use any of this liquid or another brand in and a/c?
Click to expand...
 
Hi Gil, They fit real nice between the floor stiffners and we just cut the stuff to fit the areas of the firewall. I have used it since 1995 when I built my 6 and it really helped on the floor. It also helped adding the turn downs on the exhaust, at that time the exhaust pipes came straight out. It seems that everyone who has used this since has been happy with the results. Of course the Bose helps with the general noise also. :) Larry
 
# of layers?

LARCO said:
Hi Gil, They fit real nice between the floor stiffners and we just cut the stuff to fit the areas of the firewall. I have used it since 1995 when I built my 6 and it really helped on the floor. It also helped adding the turn downs on the exhaust, at that time the exhaust pipes came straight out. It seems that everyone who has used this since has been happy with the results. Of course the Bose helps with the general noise also. :) Larry
Click to expand...

thanks Larry,

Do you just use one layer on the floor, or build it up with three layers to make it flush with the top of the stiffener angles?

gil A
 
I just used one layer. The carpet looks ok but you can see the stiffners. I am using the same thing on the 7 now in progress, and will add another 1/4 in perhaps but want my feet as low as possible. Some have complained about their feet being to high if to much stuff is put on the floor. Larry
 
sound

Did the floor with 3/4 super sound foam from spruce (plus 1/4 plywood & carpet), front side walls with 1/8 and the firewall with 3/8. Showed a 2 to 3 db difference depending on where you measured, which was noticeable and I am glad I did it. Unfortunately I used 3M spray adhesive which was not a good solution long term as foam (especially firewall) has become unglued in places.

Bryan
 
When to apply insulation?

I am currently working on the firewall forward area of the fuselage and ready to attach the aft fuselage to the center and forward sections. I am not sure what type of insulation I will use yet, so I am following this thread. Question. When should insulating/soundproofing materials be applied? Or does it matter.
 
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