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Is soundproofing worth it

BGordon

Well Known Member
Good evening everyone,
I am riveting the center skin to my cockpit skeleton and was wanting to inquire about soundproofing the cabin. Is it worth it? I know most noise will come from the cockpit and engine, but what about the bottom and sides. Will a layer of dynamat or lizard skin make a difference worth the time and weight due to its install?
Thanks,
Brandon
 
In my opinion, the short answer is no. The sure and economical way to fight noise is with a good headset.

John Clark ATP, CFI
FAAST Team Representative
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
 
In addition to the sound question, for us in the north, does the same insulation help to keep the cabin warm? Does an io-540 throw enough heat that this is a non-issue?
 
RV-10 has plenty of heat, but there can be a "hot feet, cold nose" problem if it is too drafty. Insulation (especially stopping leaks from the tailcone) can help.
I agree with the previous post about noise; even with insulation you need headphones, and with good headphones you don't need any more sound insulation.
 
I would like to see hard data. My anecdotal opinion is that soundproofing helps. No doubt that some material that helps deaden sound can also insulate.

I did the first flight of a 7A and during the first take-off roll the noise was so overwhelming that I aborted the take-off. While anecdoctal, I believe that it was far louder than my 6A which has sound deadening/thermal material on the floor and sides.
 
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I used "sound proofing" material on the floor of my 6 to reduce, or isolate, floor vibration. I also used it up the sidewalls forward of the center section. I have no idea if it helps in regard to cockpit noise or insulation but I would guess it helps some. Just a guess.
You do want something on the floor regardless in my opinion, at least for the side by sides and the dense foam products for sound control work well for vibration isolation. I have no experience with the 10 however.
 
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It goes without saying that soundproofing does something. The question is, is it worth the weight penalty? This is a subjective call.
 
I can't tell the difference

After I flew the -8 for a year, I took up the floor panels and side panels during condition inspection and put the 1/4" adhesive-backed sound treatment from ACS on the back side of the floor panels, plus the bottom skin. I made 0.016 aluminum panel inserts for all the bays in the sides (between the bulkheads and stiffeners) with the 1/4" sound proof padding, wrapped in upholstery fabric. I put the stuff on the underside of the fwd baggage compartment, on the inside of the rear side panels. Everywhere I could.

Between the sound padding and the upholstery fabric and the side panels, I added more than 10 lbs. to the airplane.

I can not tell the difference in sound level or chillyness in the cockpit.
Sorry no hard data, I don't have a sound level meter.
 
Not an ounce of sound deadener in the -8, but thanks to good headsets can listen to music and have a pleasant conversation in flight. The only way sound deadener is worth it is if you plan on flying without headsets, IMHO.
 
No. Save time, money and weight.

Unless you plan on double paned plexiglass and heated windshield like an airliner, your wasting your time on trying to heat a plane evenly like a house. As far as sound, our thin skinned planes are going to be noisy with or without soundproofing. Buy a good pair of American made Bose ANR's.
 
My vote is the combination heat shield - noise material they sell in sheets at ACS. Also without the carpet on the floor you feel the exhaust pulses.
 
Another Vote for a Top End Headset

No way for me to measure, but adding Classic Aero carpeting (it has insulation bonded to the bottom to fit between the stringers)seemed to be a big help in deadening the vibration and sound of the exhaust pulses. You can try non aviation solutions as well, just be aware of the potential of noxious fumes and flammability. Depends on what you use. Best bet is a Zulu or Bose. No more shouting, and the less noise, the less fatigue.
Terry, CFI
RV9A N323TP
 
I spent quite a bit of time insulating the -7A some 10 years ago. It was installed with 3M spray glue and layered with aluminum foil as per the kit instructions, 1/4" and 1/2" black foam as I recall.

The noise level was still very uncomfortable without a headset but ok with one. The most disappointing aspect of it was the glue let go at the firewall, due to heat I suppose, so I ended up removing most of it in time.

The -8 under construction will have zero insulating material but I do have a ZULU and know it works.

For sure insulating material works if properly designed and installed. I flew with a friend this week in his 50+ year old, beautifully maintain Comanche, and it was very comfortable with cabin heat and sound. But there is a penalty in weight, the quieter it is the more it weighs.
 
Disagree. The 10 I recently sold was insulated and upholstered six ways from Sunday. Had half a dozen very experienced pilots fly in it. Every one of them looked at me, pulled their headsets off and went "wow". It was every bit as quiet as a new Bonanza and just as quiet as a malibu or P-210 (before you hit the cabin with pressure).
 
In the spirit of "while we're talking about this..."

http://www.vansairforce.com/community/showthread.php?t=47587&highlight=insulation+tests

This research that Dan did is potentially life saving. I wish that I had read it before I did sound/heat insulation on the cabin side of my plane. My installation required a big amount of work to redo it to my safety comfort level after reading Dan's research. I took a look at how the big Lancairs are done and they use a foil encased insulation in the firewall side. I think this is a much better solution than anything on the cabin side but requires doing it before engine installation for greatest ease.

A repeat offender suggested that I take some thin angle and use some 3M UHB tape to affix it between some of the areas that are prone to oil canning to help deaden any resonance. I also used some of the foil backed self adhesive backed thin EAR type foam between panels for the same purposes. On top of that, I use Bose X headsets. My hearing is kinda important to me:eek:
 
I insulated our rv10 everywhere I could. In some cases I used a very lightweight product. On the firewall I used two layers of fiberfrax with a layer of fireproof foam on top of the fiberfrax. Yes, I did a 1500 deg. burn test using a simulated firewall prior to the installation.
The results after 75 hours? You still have to almost yell at each other at full cruise. At slower speeds, it is very quiet. The majority of the noise is wind noise and it comes through the glass and the cabin cover structure, which is fiberglass. I was hoping for the same level of noise as my well insulated piper archer, which I flew for years ( in the old days) without headsets. It doesn't even come close.
With regard to the heating, it is very comfortable and requires very little heating. My floor and tunnel are cool to the touch.
The weight penalty had to have been at least 15-20lbs. If I did it again, I would use thinner insulation in the sides and rear areas.
Bose headsets are the answer for the noise.
 
Good evening everyone,
I am riveting the center skin to my cockpit skeleton and was wanting to inquire about soundproofing the cabin. Is it worth it? I know most noise will come from the cockpit and engine, but what about the bottom and sides. Will a layer of dynamat or lizard skin make a difference worth the time and weight due to its install?
Thanks,
Brandon
I highly recommend insulation of some type in the bottom of the fuse near the exhaust outlet (noise and dampening), and on the back of the firewall (temp and noise). Can't speak to the other models, but my 1500+ hr -8 has, and continues to, experience minor damage due to resonation (sp?) of the skins at the exhaust outlet ramp area. Feet used to get hot before insulation on the back of the firewall.

And Gig 'em Aggies!
 
Bill, that's kind of interesting. Your top is hard painted inside? Overhead console? Painted doors? My last had unpadded fabric on doors, unpadded fabric on front half of cabin top and 1/8" cc foam & fabric aft of doors. I'm wondering how much of the noise radiates through the roof. Your Piper certainly had a headliner. Have you guys ever moved your hand or a chart or something around while flying and zeroed in on particular noises? Sometimes you can literally put your finger on noises.
 
The doors are painted and are insulated inside, at least in the cavity areas. Aerosport console with insulation inside the overhead. Headliner from the rear of the door openings. I've ridden in several others and they were just as noisy
 
I insulated all sheet metal from the firewall back to, and including the baggage bulkhead. Cost 15 pounds, but we fly mostly as a 2 seater, so I don't mind the weight. It is definitely quieter than the factory -10, and it is possible to carry on a conversation without headsets. I already have enough hearing loss that I don't do that, but it is possible. The tunnel is cool, and I am not aware of any drumming. I would do it again.

For you Lightspeed users, the Zulu 2 is noticeably quieter than the original Zulu. Love it.

Jim Berry
RV-10
 
I am opting for no insulation as I had read mostly negative about how it would help. I have read in the past about the exhaust turn downs helping with the floor vibration and noise.
Any comments from any that have tried this?
 
None for me

I didn't put any insulation or sound-deadening in my -10 and almost every person who has flown with me has commented on how quiet it is. I have good headsets, but even without them it isn't objectionable to me or passengers - especially experienced pilots (maybe we're all deaf?). My research on sound deadening indicated there is only one way to deaden sound energy reliably - mass - and that seemed antithetical to an efficient airplane. AND, it has to be in the right spot(s). As someone said, a lot of our airplanes are single layer - aluminum, fiberglass, plexiglass - so there's no way to insulate them or deaden them effectively (except for thermal insulation as interior panels/headliners). Seemed like a lost cause to try to chase it, and I might end up with heavy deadening material in places I couldn't remove it. I could always (and may) add interior panels or headliner if I want it down the road.

I currently have no head liner (painted cabin top interior), no interior upholstered panels, and nothing in the floors. I insulated the bottom and forward walls of the tunnel to reduce heat in the tunnel. Works pretty well.

AND, the heater seems to work pretty good, even in these northern climes. I was up yesterday with and OAT of 2 deg F and was comfy, although I think there are a few drafts I need to chase down that I didn't notice until it got cold. I used the Flightline aileron boots and don't notice any drafts from down there.
YMMV
 
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Thanks Bill. I'd like to identify the sources of the major noises, so all you guys keep it coming. You musicians out there certainly know the difference between a hard room and a soft room. I'm wondering how much hard interior surfaces have to do with perceived noise. Can't do anything with all the windows, but everything else can be softened up somehow. If there's a clear choice between quiet and wood chipper loud I'd spend 20 pounds in a heartbeat. There's so much ooomph in the 10 and other places to save weight that I think it's worth it.
 
Thanks Bill. I'd like to identify the sources of the major noises, so all you guys keep it coming. You musicians out there certainly know the difference between a hard room and a soft room. I'm wondering how much hard interior surfaces have to do with perceived noise. Can't do anything with all the windows, but everything else can be softened up somehow. If there's a clear choice between quiet and wood chipper loud I'd spend 20 pounds in a heartbeat. There's so much ooomph in the 10 and other places to save weight that I think it's worth it.

Dave,

I was an audio engineer and an early adopter of TEF and LE/DE recording studio design in Nashville early in my career.

While it would be nice to carry those principals to our RV interiors, the physics just aren't there. An acoustic low frequency trap would be much too large for aircraft.

The insulating foam is great for insluation, but for sound, it's only going to attenuate higher frequencies. As a side consequence, most of the insulating products that look like black foam will generate some pretty nasty gases if heated up. (See Dan H's threads for more details).

Over the last five years, I've had the opportunity to ride in many RV-10s. I don't want to put any of the owners on the spot, so I'm not going to mention any names. Some of the RV-10s were built to plans with no insulation to the other extreme with every nook and cranny stuff with insulation.

The bottom line is that, at least for the RV-10, insulation does make a difference for both acoustics and thermal protection. I haven't taken my test gear up to make any measurements, but the differences are quite apparent. None are perfectly quiet, since there really is no effect method to attentuate those lower frequencies produce by the fan up front.

The RV-10s that seem to be quieter all have had some common denominators. All have had interior panels, like those from Aerosport Products, with insulation between the side walls and the interior panel, as well as underneath the floor and in the tunnel.

Yes, these aircraft probably did gain 20lbs or so with their interiors. While they aren't perfectly quiet, you can carry a normal convesation in them. Naturally, with a decent headset, noise is almost completely eliminated.

As with anything with RVs, YMMV depending on the materials used. Please ensure that you understand what are the traits of the materials that you used, should they be exposed to flames or excessive heat.

bob
 
Could you all type louder I can hardly hear you!

Not one pound for insulation in my RV nor do I have any interior side or floor panels. I use the QT Halo headsets. Would not change anything as I feel it is very quiet. Sometimes I take the ear piece out to hear if the engine is still running.
 
Hey Steve, You mentioned a sound meter. Found a free DB sound app for my Android phone. Works pretty good a night club suppose it would work in a Vans RV. I'll check in my 172 next time i fly.

Ron in Oregon
 
Go try one with and without insulation

Like Bob, I flew in each before finishing my -10. I noticed a difference in sound level, mainly on takeoff, less so in cruise. Nothing I could not deal with.

I then looked at others empty weights. If I wanted an ifr, single alternator, dual battery 925L/680, 2700 lb gross weight airframe to haul my family of four, then I had to keep it light. Cost, less to burn, ease of maintenance and cleaning were also considerations. I used fiberfrax on inside of firewall and tunnel bottom. The entire interior is painted, including floor pans. We had cloth seats covers made locally for $650. Our empty weight came out to 1,626 before paint, not much more than the quieter 172S that I did my training in. Paint added 30 lbs and moved EWCG back 3/4". Glad I went with Hartzell prop even though I noticed less noise with a three blade I flew behind.

Now after a year of flying with the family and maintenance, I am happy with our decision. We are able to load 4- 15 lb nylon bags, cover, tools, oil, tow bar and fist aid/emergency kit which totals 75 lbs in the baggage area and stay just under 2700 lbs. We fly within 3/4" of aft limit. By the time everyone else has their wool blanket(we fly high and I like it cool), ANR's and cruise power is back at 55-60% one really won't notice. Flying solo(rare), the things I notice are the short takeoff roll, high climb rate, slight noise increase, greater nose down trim for takeoff and nose up trim for landing. If you are building for you and one or two passengers then it probably won't matter.
 
When I helped my friend finish his RV-8, we put a lot of insulation under the floor panels, and it has upholstered interior panels too. It's still about as noisy as riding around inside a flying jackhammer :eek: , and on cold winter days the guy in the back seat still freezes. I don't think the insulation helped much at all. My RV-6 has no insulation under the floors or behind the interior panels... only carpet on the front floor. Investing in good ANR headsets is money better spent. I have a couple sets of (original) Zulus and they work great in the RVs.
 
Sound transfer reduction (as opposed to sound proofing) is difficult and I suspect not widely understood. More like a black art than science. I am no expert by any means but have done some research about what's involved (to reduce sound transfer)and am not flying yet. So I cannot say how successful my attempts have added up to be.

I wonder if there may be more to sound than what you actually hear. Sound is vibrational energy. Your ears may still be subject to the frequencies that you do not hear and are therefore not targeted by the headphone manufactures. And even if you sufficiently block it from your ears using headphones, the rest of your body is still subject to it.

Therefore I feel it may still be a worthwhile goal to keep extreme sound at bay, especially in areas such as floorboards where exhaust noise is the strongest.

Maybe there is an audiologist that can chime in here.

Bevan
RV7A with mufflers and some reasonable sound transfer efforts in place. (headsets too) :)
 
Good evening everyone,
I am riveting the center skin to my cockpit skeleton and was wanting to inquire about soundproofing the cabin. Is it worth it? I know most noise will come from the cockpit and engine, but what about the bottom and sides. Will a layer of dynamat or lizard skin make a difference worth the time and weight due to its install?
Thanks,
Brandon

Van has said many times, over the years, to build the RV's basic and light.
I have flown bare interior RV's as well as insulated and upholstered RV's.
My vote is with the others here, to invest in good headsets and minimal insulation and upholstery. Clarity Aloft head sets for me and I love it.
Remember that dead air space is what makes up insulation properties.
There are many options. I would wait and see if you feel the need after flying in other RV's. Any RV gets loud when flown fast. Good head sets.
 
I see some people saying they have no insulation, from all the past posts on preventing a hot tunnel, isn't insulation needed to prevent that issue?Specfiically, insulating the floor of the tunnel, and the front firewall area inside the tunnel, in addition to changing the heat control valves.
 
I did insulate the floor of the tunnel with two layers of fiberfrax and also the entire floor of the aircraft. I do not have any hot tunnel issues, its cool to the touch. I also used the replacement stainless heat valves.
 
I only insulated firewall inside and tunnel bottom with 1/8" fiberfrax. I also used ss heater box. No tunnel heat issues with the long exhaust pipes.
 
Sound Proof

Buy the forward carpet from Classic Aero - They make an awesome carpet kit that has padding / soundproofing under the carpet. It is laser cut to fit over the floorboard stringers for a perfect fit. About 1 inch of padding helps with the noise.
 
I vote for soundproofing

I believe the best solution is both good soundproofing and good head sets. The combo makes for a really quiet comfortable flying experience. I have nice headsets but they are not ANR nor $1000.00 a pop. I do not need them.

I 'sound proofed' my RV8. Those who have been in a bare bones RV can tell the difference. 'Wow, it is quiet' is the usual response. True to the 'Sound Proofing Manual' from ACS, the canopy places a limit on the total noise reduction so headsets are still needed. But I also noticed a more solid feel to the airplane, a subjective quality to be sure, but it is there.

Another benefit is the heater doesn't have to work so hard. Result, in winter (Eastern Washington) I am throttling the heater down and fresh air up. My back seat passenger (the Mrs.) says she is fine whenever I ask about the heat. I might add that I used Airtex materials and carpet in addition to the 'official' black sound proofing foam from ACS.

I also followed the guidelines in the "Sound Proofing Manual". This last part is important as it details how an airplane should be sound proofed and what material to use. I suggest you at least get this manual as I think it is still free from ACS and decide for yourself.

As for Weight penalty? That's what I see on the scale every morning. :rolleyes:

It is a personal choice, that's why most of us are building (in my case built) custom airplanes, but I place a premium on creature comfort, that creature being me. I would sound proof as much if not more should I decide to build another RV.

Vince Himsl
RV8 N8432 Flying
 
In my opinion, the short answer is no. The sure and economical way to fight noise is with a good headset.

John Clark ATP, CFI
FAAST Team Representative
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA

I agree with this. I don't have any sound proofing, saves weight. I have a Bose and a Clarity Aloft headset. Haven't thought about it since I got those.
 
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