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What is the right choice for floor mats in an RV?

TCSMOORE

TCSMOORE

Member
I have an RV7A with an IO-360 engine. It currently has no floor mats.

With the exhaust outlets under the floor it is both very hot and quite loud.

A photo of the footwell can be seen here PHOTO

There seem to be many options. For example for USD438 (plus postage) I can get from www.quietride.com the following

VAN RV7-SFK Van?s Aircraft RV-7/7A Sub-Floor Acoustic Kit $169
VAN RV7-TFK Van?s Aircraft RV-7/7A Top Floor Acoustic Kit $229 (see Brochure RV7 page)

or for USD217 the floor mats from www.classicaerodesigns.com which can be seen at their page LINK

Any input based on other pilot's experience would be much appreciated. I am not obsessed with sound-deadening (thanks Bose A20) but it would be nice and not transfixed on a cheap solution just a neat one that is value for money.
 
In my RV-4, I fabricated footwell heat shields by cutting a thin (.020") stainless piece that matched the existing footwell profile, then bonded 1/4' thick high temperature silicone mat to the underside with high temp RTV. The heat shields are then bonded into place with the same RTV to the floor skin. Now I have scuff proof heat shields that also absorb the floor vibration. I am not a fan of carpet/rubber, as I like my heels to slide easily on the floor. Also, I have noting to fall loose or collect dust/dirt that comes out when doing acro,ect.
 
Buy some high end black or gray bath towels for $15 from the aircraft interior section of Bed, Bath and Beyond. I wanted the simple bare, no floor coverings for weight. (I spent months cleaning 70 years of dirt off the floorboards of my C140 and vowed to not do that on the RV) I put the towels in during phase 1 as temporary because I did not like the tinny sound of the bare floors. Towels have been there since. I put a sheet of that stuff you put down under a throw rug to keep it from sliding around. They are easily removed to put in the washing machine or get get new ones any time I want something different.
 
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here is what I did. I put sound absorbing material purchased a AS to line the floor and bring everything level. I did not bond that in place. Then, I cut 1/8" plywood boards to the shape of the floor (two pieces) and covered them with indoor/outdoor grey carpeting. I then velcroed two 032 pieces of aluminum about 8X12 where my heels need to slide. Works perfect. Easy to remove an looks great.
 
I used construction paper to create a template of the piece of carpet I wanted (in my case my 8), and once I had that cut, trimmed, and shaped how I like I went to home depot and got some outdoor carpet, for patios and such. Get a square, trace the template out on it, cut with scissors, and then liberally use Velcro pieces to secure it to the floor. You don't want it sliding around or under the rudder pedals.

I have a grey interior so the black carpet is a nice touch, plus it's super cheap and if it starts getting stained or worn out (or dirty) I throw it away and make another one in about 10 minutes.
 
Most RV engine compartment fires have melted the belly skin immediately aft of the cowl exit. In the event of fire, a flammable and/or smoke generating insulation placed against the aluminum belly skin will (1) significantly increase the likelihood of melt-through, and (2) make survival difficult at best.

I've not subjected Quiet Ride's Heat Shield material to a burn test, but a cursory review of their website leads me to think it is a plastic fiber insulator pad, and if so, it is among the worst possible choices for installation in the aircraft firewall region. Given that they seem to be marketing complete firewall and floor kits for RV's, perhaps it's time to take the burn rig down off the shelf.
 
High temp floor

DanH said:
Most RV engine compartment fires have melted the belly skin immediately aft of the cowl exit. In the event of fire, a flammable and/or smoke generating insulation placed against the aluminum belly skin will (1) significantly increase the likelihood of melt-through, and (2) make survival difficult at best.

I've not subjected Quiet Ride's Heat Shield material to a burn test, but a cursory review of their website leads me to think it is a plastic fiber insulator pad, and if so, it is among the worst possible choices for installation in the aircraft firewall region. Given that they seem to be marketing complete firewall and floor kits for RV's, perhaps it's time to take the burn rig down off the shelf.
Click to expand...

I would love to see your floor mat burn tests.
Bill has a good idea.
 
DanH said:
Most RV engine compartment fires have melted the belly skin immediately aft of the cowl exit. In the event of fire, a flammable and/or smoke generating insulation placed against the aluminum belly skin will (1) significantly increase the likelihood of melt-through, and (2) make survival difficult at best.

I've not subjected Quiet Ride's Heat Shield material to a burn test, but a cursory review of their website leads me to think it is a plastic fiber insulator pad, and if so, it is among the worst possible choices for installation in the aircraft firewall region. Given that they seem to be marketing complete firewall and floor kits for RV's, perhaps it's time to take the burn rig down off the shelf.
Click to expand...

If a fire has burned through the lower skin of the airplane and into the cockpit, the flammability of the carpet is the least of my worries and I seriously doubt carries significant weight in the survivability. Altitude at that point is the biggest threat followed by a place to land.

Plus, how many fire resistant carpets out there have years of oil, brake fluid, avgas, etc tracked in or leaked on them? How many have firewall pass throughs of aluminum fuel lines right there above the exhaust?
 
Sig600 said:
If a fire has burned through the lower skin of the airplane and into the cockpit, the flammability of the carpet is the least of my worries and I seriously doubt carries significant weight in the survivability
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Dunno about carpet, but opinions tend to change rapidly after observing polyester fiber insulation in contact with a hot firewall.
 
Floor matts

I recommend nothing. Keep a shop towel handy and wipe your shoes when getting in. They serve no purpose other than to get in the way of things.
 
How I did it in Perth

Since you are from the same neighbourhood you might be interested in how I created a full custom carpet set. My 6A had 1/8 ply floor boards installed by the builder with what appears to be fire resistant soundproofing material underneath. I found the lacquered wood too slippery so decided to do a custom mat set including baggage area.

A commercial aircraft interior specialist advised me that pure wool house carpet is likely to be as fire resistant as treated polyester, so I shopped around for an offcut in the colour I wanted and eventually picked up a good sized piece from a carpet store at Vic Park for $100. My wife made cardboard templates then we took them with the carpet to Matcraft at Carlisle. For $150 they cut the three pieces to the complex templates, overlocked the edges and installed heel pads to match the rudder pedal positions.

I can't advise you on what to do for a base, but for $250 that's how I got a full carpet set that looks like a professionally made product. It looks really good but there is a bit of work in getting the template right.
 
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I would apply some E-A-R ADC-006 structural damping composite in this area to prevent "oil canning" and cracking of the floor skins. A similar structural dampening material is installed in certain areas of the inboard lower wing skins of Pipers and Cessnas. This product will also help prevent the belly skin cracking that is common in the -8. I have used ADC-006 mulitiple times to eliminate lower wing and fusealge skin oil canning during climb and steep AOA in several different piston singles. ADC-006 is approximately .045" thick so it fits nicely under carpet in floor board applications.


http://www.earsc.com/pdfs/engineering/literature/ProductBulletins/PB101ADCs.pdf
 
No carpet option - has some merit.

Guys - thanks for all the comments.

The 'no carpet' option reminds me of the old initial Datsuns. They were exporte with no carpets and when dealers pleaded with Datsun to put in carpets they were shocked as in Japan drivers would carefully use a dustpan and brush to carefully get every spec out of the car - hardly possible with carpet.

The carpet on fire scenario certainly has me very anxious - though I didn't think about it much prior to the original post.

It would be nice to think that one of the suppliers of carpet solutions had a well conceived fire-resistant option?

This may be an option? http://www.megasorber.com/soundproofing-products/sound-absorbers/fireproof-acoustic-material.html

Thanks for the comments

Tim
 
cork

I have Classic Aero carpet for my 9A. Under it, I will place 1/4" cork to help with heat transfer. I tested the cork with a torch and the aluminum melted before the cork got hot at all. Direct flame on the cork will cause it to burn - and smoke, but very little heat is transferred.

I hope that if I ever have a fire, it will give me a few more seconds to control the plane. I would like to use it on the firewall too, but I haven't figured a way to hold it on that doesn't create more fumes. I tried silicone and red RTV. Both failed within 30 seconds of heat from a torch on the aluminum side and the cork fell off.

I am amazed at how well the cork insulates for heat transfer. I could touch one side of the cork while I had a map gas torch burning the other.

I really appreciate Dan's testing and posting on this subject. Just reading manufactures descriptions and claims could easily cost your life.
 
I've experienced "hot feet" in my RV-4 and my Rocket. I added insulation as necessary to fix the problem.

I totally agree with Dan Horton that you need to give serious consideration to whatever you decide to add to either side of the firewall. But I also agree with others who say that a compromise is often required. So, use anything I say at your own risk!

I decided that the RV-6 that I'm building would be different from the start. My primary goal was to make sure that my feet would stay cool under normal ops. And if the feet are cool, the rest of the cockpit is easier to keep cool too.

I don't understand why Van's doesn't double layer the floor in his planes. It should be built in, IMHO.

So, after sitting in this RV-6, and other RV-6s for literally hundreds of flight hours, I decided that the addition of a floor doubler would have virtually no effect on foot room. Here's a photo:

front%20floor%20small.JPG


and one more:

front%20floor%20work%20small.JPG


The front side of the firewall is covered with HeatShield mat. There is more of the black foam insulation under the floorboards. Yes, it might produce nasty smoke if a fire occurred, but it is self-extinguishing and fire rated. I carry an aqueous foam extinguisher (because the foam tends to stay on whatever it's sprayed on), and I typically wear a chute.

Unrelated to the original topic, but also shown in the photos, is the tunnel that I added for electrical and fuel lines. I also lowered the fuel valve so it won't stick me in the back while working under the panel. It is still easily seen and reached.

YMMV!
 
vfrazier said:
The front side of the firewall is covered with HeatShield mat. There is more of the black foam insulation under the floorboards. Yes, it might produce nasty smoke if a fire occurred, but it is self-extinguishing and fire rated. I carry an aqueous foam extinguisher (because the foam tends to stay on whatever it's sprayed on), and I typically wear a chute.
Click to expand...

Heat Shield mat on the front side and black foam rubber on the cabin side. Yeah, let's put that combo on the test rig. How about it Vince? Need 2'x2' of each material.

BTW, "self extinguishing" is only after the heat source is removed. The heat source for the airliner upholstery material flammability tests so often quoted by vendors ("Passes FAR 25.853!") is a burner with a little blue flame cone 3/4" long. The material can catch fire and still pass the test, as long as the burning material doesn't continue to burn more than 15 seconds after the flame is removed. It's a "Little Johnny with a Zippo" test.

A firewall insulation test is somewhat more difficult. The material may not ignite while the firewall is subjected to a flame temperature of not less than 2,000 degrees F for 15 minutes, and the prescribed method heats 25 sq inches, meaning a far, far higher heat flux.

Heat Shield on the engine side of the stainless may not be an optimum choice, but it is far better than no insulator, and has no downside. Is it good enough to prevent ignition of foam rubber on the cabin side?

This is Soundex black rubber insulation against hot stainless:

 
Classic Aero Designs

I have been flying with a Classic Aero Designs carpet in my RV-7A for over 4 years. No issues. The carpet has sound deading foam glued to the underside of the carpet that fits perfectly with the floor stiffiners. So the carpet deadens sound and floor vibration.

Additionally according to CAD the carpet is chemically treated to reduce it's flammability.

I would definately recommend the product.

TCSMOORE said:
I have an RV7A with an IO-360 engine. It currently has no floor mats.

With the exhaust outlets under the floor it is both very hot and quite loud.

A photo of the footwell can be seen here PHOTO

There seem to be many options. For example for USD438 (plus postage) I can get from www.quietride.com the following

VAN RV7-SFK Van?s Aircraft RV-7/7A Sub-Floor Acoustic Kit $169
VAN RV7-TFK Van?s Aircraft RV-7/7A Top Floor Acoustic Kit $229 (see Brochure RV7 page)

or for USD217 the floor mats from www.classicaerodesigns.com which can be seen at their page LINK

Any input based on other pilot's experience would be much appreciated. I am not obsessed with sound-deadening (thanks Bose A20) but it would be nice and not transfixed on a cheap solution just a neat one that is value for money.
Click to expand...
 
DanH said:
Most RV engine compartment fires have melted the belly skin immediately aft of the cowl exit.
Click to expand...

I saw that in an RV-6 some years ago. I should have put some stainless on the belly but I was not thinking about it as a solution when I built my chariot. I chose to make 3/4" thick aluminum foil encased "pillows" of McMaster Carr ceramic batting to nest in-between the floor stiffeners and turn a few inches up the firewall. I covered the pillows with a couple of floorboards I made out of some Kevlar I had from years gone by. Made a nice flat floor.
 
TCSMOORE said:
This may be an option? http://www.megasorber.com/soundproofing-products/sound-absorbers/fireproof-acoustic-material.html
Click to expand...

Appears to be a fine product for its intended purpose, architectural sound damping. The test parameters I was able to find are pretty loose (AS/NZS 3837:1998, see below) and the heat flux (0 to 100 kW/m2) is zip to quite small. The "fireproof" and "fire resistant" claims may not hold up in a firewall application, as none of it is rated anything like 2000F. They'll probably pass the "Little Johnny with a Zippo" test, and as such might make a good cabin wall insulator.

1.1.3 Test parameters Specimens may be exposed to heating fluxes ranging from 0 to 100 kW/m2. External ignition, when used, is by electric spark. The value of the heating flux and the use of external ignition are to be as specified in the relevant material or performance standard. The normal specimen testing orientation is horizontal, independent of whether the end-use application involves a horizontal or a vertical orientation. Provisions are also made for vertical orientation testing; this is intended for exploratory or diagnostic studies only. NOTES:
1 The test method does not prescribe the irradiance levels nor whether external ignition is to be used. For an insight into the development of the test method, the features of the apparatus and the use of the data, see Appendix A. 2 See Appendix B for a list of papers that provide additional technical background.
 
Floor insulation and fire resistance

I have been looking through old threads that gave me the info on installing a dense light weigth foam sheeting that was fire resistant sheet (from spruce) between floor angles. "Sorry got to busy to continue". Glue the foam to the floor and cover with aluminum sheet. I believe they were saying .040 aluminum cover and also to glue to the foam to make a sandwich. foam should be slightly taller than angles so you don't get any vibrations to your feet. I than bought very thin (and I mean very thin light weight) foam backing mats from kitchen and bath store that came close to my color and made hooks to keep in place but removable. If you lived near Corona California, I would give you my aboundant amout of left overs. Yea, it works great and I just go to the store an $20 later have a new floor color.:cool:
 
rzbill said:
I saw that in an RV-6 some years ago. I should have put some stainless on the belly but I was not thinking about it as a solution when I built my chariot. I chose to make 3/4" thick aluminum foil encased "pillows" of McMaster Carr ceramic batting to nest in-between the floor stiffeners and turn a few inches up the firewall. I covered the pillows with a couple of floorboards I made out of some Kevlar I had from years gone by. Made a nice flat floor.
Click to expand...

I have used McMaster's ceramic fiber insulation to insulate the firebox on several bbq cookers and can attest to the insulation and fire-resistant qualities of it. I have welded steel right over it and it did not faze it. It is good stuff.
I am curious, what did you use for the aluminum foil? And where did you get it?
Thanks for the idea!
 
DanH said:
Heat Shield mat on the front side and black foam rubber on the cabin side. Yeah, let's put that combo on the test rig. How about it Vince? Need 2'x2' of each material.
Click to expand...

No. The black foam would undoubtedly fail in a spectacular fashion, as would just about anything that isn't stainless steel, ceramic, or other elemental material.

Materials used to insulate the cockpit side of the firewall present many unique problems, including flammability, moisture retention, oil/fuel absorption, durability, and material hazards during installation due to inhalation of fibers, etc.

Dan, I appreciate your work, but there are compromises everywhere in aviation. For me, the materials I chose are a reasonable compromise between cost, durability, ease of installation, and performance. And they are safe to work with, and won't degrade into carcinogenic fibers.

For full disclosure, we sell the Heatshield Mat. Used properly, it should present no real hazard. We do NOT sell the black foam, mainly due to Dan's concerns and data. He is absolutely correct that it could be a risk, but so are the 50 gallons of gasoline that we sit between.

Like Dan, I'm not new to aviation either. I am usually appalled by the insulation found in many GA planes. You'll find putty, tar, loose fiberglass, and other horrible (but cheap) choices that the manufacturer made.

I absolutely HATE the nasty fiberglass insulation in my Debonair and other GA planes. The fibers undoubtedly are a chronic hazard. Personally, I'll take the relatively small risk posed by the black foam behind my RV firewall over those other materials every time.

YMMV. Use my techniques at your own risk!
 
vfrazier said:
No. The black foam would undoubtedly fail in a spectacular fashion, as would just about anything that isn't stainless steel, ceramic, or other elemental material.
Materials used to insulate the cockpit side of the firewall present many unique problems, including flammability, moisture retention, oil/fuel absorption, durability, and material hazards during installation due to inhalation of fibers, etc.
Click to expand...

Correct, which is why the cabin side of a firewall should have nothing on it, not even paint.

Dan, I appreciate your work, but there are compromises everywhere in aviation. For me, the materials I chose are a reasonable compromise between cost, durability, ease of installation, and performance. And they are safe to work with, and won't degrade into carcinogenic fibers.
Click to expand...

Reasonable compromise suggests a rational balance. What exactly do you get in trade? What is the benefit so valuable that you would risk blazing rubber and thick black smoke in the event of an engine compartment fire?

Personally, I'll take the relatively small risk posed by the black foam behind my RV firewall over those other materials every time.
Click to expand...

You have a relatively small risk of engine compartment fire. The plastic or rubber firewall/floor insulation is a huge risk, because there is a high probability that it will escalate an unpleasant event into an unsurvivable event.

From NTSB #LAX99LA063....a very good pilot, flying a Rocket, with fire developed in the traffic pattern:

The passenger stated he saw light gray smoke in the cockpit and notified the pilot. The pilot secured the master switch and turned onto the base leg. At this point the passenger did not observe flames or feel any heat. As the airplane turned wings level onto final, thick black smoke that smelled like burning fiberglass or plastic filled the cockpit. After the airplane came to rest, he observed flames around the pilot and felt high heat. He yelled to the pilot to open the canopy, but the pilot responded he could not get it to open. Momentarily, the canopy opened halfway.

As the rescuers arrived, flames were still coming from under the cowling. The front cockpit was so filled with smoke that they could not see if the pilot was still in the airplane.
 
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DanH said:
From NTSB #LAX99LA063....a very good pilot, flying a Rocket, with fire developed in the traffic pattern:

The passenger stated he saw light gray smoke in the cockpit and notified the pilot. The pilot secured the master switch and turned onto the base leg. At this point the passenger did not observe flames or feel any heat. As the airplane turned wings level onto final, thick black smoke that smelled like burning fiberglass or plastic filled the cockpit. After the airplane came to rest, he observed flames around the pilot and felt high heat. He yelled to the pilot to open the canopy, but the pilot responded he could not get it to open. Momentarily, the canopy opened halfway.

As the rescuers arrived, flames were still coming from under the cowling. The front cockpit was so filled with smoke that they could not see if the pilot was still in the airplane.
Click to expand...

How about going to ICO and shutting off the fuel selector?
 
Aluminum honeycomb

I used aluminum honeycomb. It weighs almost nothing and incredibly strong. The same stuff gulfstream uses in their jets for floorboards.
 
Aluminum honeycomb face sheets are bonded, with pressure, to the core honeycomb with a thermoplastic adhesive. One of the adhesives used for that purpose is a thin film called FM-73. Do you know what temperature it bonds at?

250 degrees F.

Which suggests that if the honeycomb panel is used for insulation against a fire, that it'll separate into its parts long before other materials are damaged.

I'd regard that as a relatively poor choice of material if high temperatures are a consideration.

Dave
 
Charles in SC said:
I have used McMaster's ceramic fiber insulation to insulate the firebox on several bbq cookers and can attest to the insulation and fire-resistant qualities of it. I have welded steel right over it and it did not faze it. It is good stuff.
I am curious, what did you use for the aluminum foil? And where did you get it?
Thanks for the idea!
Click to expand...

Well, the original find was from Dan's thread on firewall insulation a few years ago. I think it was noted in that thread that the insulation was fragile and dusty so it needed to be enclosed (True). While I have seen heavier gage aluminum foil in the food industry, I was too lazy to order early and too impatient :rolleyes: when it was time so I used a roll from the kitchen. That foil is pretty thin so I have to handle the pillows gently during annual inspection.

I still think the best fix is to put a sheet of stainless on the belly. Maybe extend it backwards about a foot. That would protect the area I saw melted under the rudder pedals on that RV6
 
rzbill said:
I still think the best fix is to put a sheet of stainless on the belly. Maybe extend it backwards about a foot. That would protect the area I saw melted under the rudder pedals on that RV6
Click to expand...

Or, you could go to ICO and turn off the fuel selector?
I guess I am still having trouble understanding how these fires get so out of control.
For goodness sake, there are millions of flight hours in tube and fabric machines with little more than a piece of 1/4" ply under foot.
Hey, maybe that is the solution?
 
Noise damping?

Walt, or anyone, my floorboards are naked. I'm looking at the Classic Aero carpet and wondering how much sound damping you get out of their carpet/backing system. I've noticed how noise in the cockpit changes when anyone moves their feet around on the floor which makes me think the floor is really resonating. How much real difference does floorboard carpet make in damping noise? John//
 
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JonJay said:
Or, you could go to ICO and turn off the fuel selector?
I guess I am still having trouble understanding how these fires get so out of control.
Click to expand...
My guess, and it's just a guess, would be oil- and fuel-covered/soaked fiberglass and rubber FWF and unsuitable materials in the cabin. You can shut off the fuel, but it there's other stuff already burning you day is only going to get worse.
JonJay said:
For goodness sake, there are millions of flight hours in tube and fabric machines with little more than a piece of 1/4" ply under foot.
Hey, maybe that is the solution?
Click to expand...
I consider an in-flight fire to be an event with a very low probability of occurrence, but the penalty for ignoring it is very high. I don't think I'll go to paranoid extremes, but this thread and others like it have been very interesting and helpful. I'd thought about a little Dynamat or something on the firewall, but have since decided that NOTHING will go on it that could catch fire or produce a lot of smoke. I'll probably use a little stainless to shield the belly as well. It seems a simple and reasonable preventive measure.
 
JonJay said:
Or, you could go to ICO and turn off the fuel selector?
I guess I am still having trouble understanding how these fires get so out of control.
Click to expand...

In a word, time. You don't know you're on fire until you're already on fire, and you don't know how bad it is until it gets real bad. Ask yourself... would you shut down the engine at the very first sign of smoke, or delay 20 seconds while trying to determine the situation?

Seriously, some of the stuff I've put on the burn rig has a very small time window between the first signs of smoke and serious flame eruption.
 
DanH said:
Correct, which is why the cabin side of a firewall should have nothing on it, not even paint.

Reasonable compromise suggests a rational balance. What exactly do you get in trade? What is the benefit so valuable that you would risk blazing rubber and thick black smoke in the event of an engine compartment fire?[/I]
Click to expand...

I get an airplane that is comfortable AND enjoyable to fly, easy to maintain, and has a known risk related to the firewall insulation. That risk can be minimized by the aqueous fire extinguisher that I carry, or by ICO and fuel shut off. If those fail, there's always a chute. Or it just might be my day to go.

Every mode of transportation has its risks. For example, a passenger elevator could fail during a fire and you'd be trapped. Are you gonna quit taking the elevator just because you might get burnt to a crisp? I doubt it.

We've all got to be comfortable with our choices. For me, the firewall insulation isn't the biggest risk to flying. It's a risk, but a relatively small one. We've all got a far, far greater chance of stalling it in, or spinning out of a cloud in IMC.

As always... YMMV and use my advice at your own risk.
 
JonJay said:
Or, you could go to ICO and turn off the fuel selector?
I guess I am still having trouble understanding how these fires get so out of control.
For goodness sake, there are millions of flight hours in tube and fabric machines with little more than a piece of 1/4" ply under foot.
Hey, maybe that is the solution?
Click to expand...

Of course one could do that. However, I am not entirely sure how I would react in the fire emergency having never been in one. Dan's point above is certainly valid about decision timing. In the case of the RV6 I saw, He was fortunately near the airport. (I was told he was on a midfield crosswind at discovery). The pilot did not turn off the fuel but instead made a fast descending dash for the runway once he realized he was on fire. Maybe his reactions would have been different if not near an airport? I don't know but if another pilot could forget to turn the fuel off in the rush of an emergency, I can certainly imagine myself doing it too.
 
vfrazier said:
I get an airplane that is comfortable AND enjoyable to fly, easy to maintain, and has a known risk related to the firewall insulation.
Click to expand...

Insulate the front side, leave the cabin side bare stainess. It's comfortable (I fly shoes off, feet against the firewall), enjoyable (whatever that means), certainly easy to maintain (stainless steel surface, both sides), and after several minutes of **** itself blowing against the front side, this is the temperature at the rudder pedals...178F.

 
DanH said:
Insulate the front side, leave the cabin side bare stainess. It's comfortable (I fly shoes off, feet against the firewall), enjoyable (whatever that means), certainly easy to maintain (stainless steel surface, both sides), and after several minutes of **** itself blowing against the front side, this is the temperature at the rudder pedals...178F.

Click to expand...

What insulation is this?
 
grayforge said:
What insulation is this?
Click to expand...

Practically any ceramic fiber felt or paper overlaid with 0.002~0.003" stainless foil. Fiberfrax felt from Spruce or Wicks is fine. http://www.aircraftspruce.com/catalog/appages/fiberfrax.php?clickkey=208805

For the belly, a SS (or painted steel) sheet overlay will eliminate burn-through. Sandwich a sheet of 1/16" fiberfrax felt between it and the belly skin if you want to lower heat transfer.

Insulating the inside of the belly skin is really dumb, as it increases the probability of burn-through.
 
DanH said:
Insulating the inside of the belly skin is really dumb, as it increases the probability of burn-through.
Click to expand...
Thanks for that but the condition of the belly skin is low on my list. My feet take priority and they are protected.
 
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sahrens said:
I have the roll of fiberfrax for my firewall, and am / was considering placing it on the cabin floor as well. But your saying if the aluminum floor is between the fiberfrax and the fire this will concentrate the heat and result in a faster burn through? By what factor, twice as fast?
Click to expand...

Yes, heat input vs heat escape. The rate of temperature rise would depend on the effectiveness of the insulator.

Is the insulation used in dragsters / race cars a better choice for the floor? Of course this is stick-on material so there is a gassing issue.
Click to expand...

If you insist on insulating the inside of the floor, Bill's choice of ceramic fiber enclosed in a foil envelope is hard to beat...zero smoke or flame risk. Of course, there is also zero smoke or flame risk when you insulate the exterior side of the floor, and you maintain structural integrity.
 
David Paule said:
Aluminum honeycomb face sheets are bonded, with pressure, to the core honeycomb with a thermoplastic adhesive. One of the adhesives used for that purpose is a thin film called FM-73. Do you know what temperature it bonds at?

250 degrees F.

Which suggests that if the honeycomb panel is used for insulation against a fire, that it'll separate into its parts long before other materials are damaged.

I'd regard that as a relatively poor choice of material if high temperatures are a consideration.

Dave
Click to expand...

Looks to be true if you purchase the pre-bonded stuff but I found this site where you can get just the honeycomb material (aluminium) and bond it yourself with something more temperature resistant.

http://www.plascore.com/products/honeycomb-cores/aluminum/
 
I know what an interesting burn test would be. I wonder if the floor would burn through before the fiberglass cowling turned into napalm with glass fibers blowing out of it. Fiberglass burns pretty good.
 
Seems like based on this discussion there's two desired performance parameters here that constitute the "right" choice for floor mats:

1. thermal protection and fire resistance
2. noise isolation

For noise isolation, a mass loaded rubber (like Dynamat) can be used to damp mechanical transmission of the exhaust pulses to the cabin. It's relatively heavy which is why it's usually applied selectively in strips.

As Dan pointed out, the megabsorber material referenced is for architectural applications, sound absorption not vibration isolation. Not really what you want here. The company does offer a product for vibration which is probably similar to the EAR or Dynamat.

I'm getting my interior and carpet from Flightline. Their carpet also utilizes a closed cell foam base similar to the classic aero I believe. Abby said it does make quite a difference in SPL levels in the cabin. Maybe I'll try to make some measurements when I actually get the plane flying! Am I concerned about acrid black smoke filling the cockpit in the event of a fire? Kind of.

For full disclosure, I'm an acoustical engineer and while noise and vibration is not my specialty, "this sort of thing is my bag baby".
 
MK77 said:
Their carpet also utilizes a closed cell foam base similar to .
Click to expand...

Yes, that would be the same, or similar, material as is found in many GA carpets. Will it also burn, char, and smoke furiously when subjected to Dan's inferno rig? I'll bet a paycheck that it will. And I can find it right next to my Debonair's firewall. Incidentally, that firewall is covered with glue to hold on the nasty, decaying fiberglass insulation, and that firewall is full of small holes that leak all sorts of engine compartment air into the cabin. Ugh.

My point is not that Dan is wrong. He isn't. It's that there are compromises to every part of an aircraft... including FAA blessed general aviation aircraft.

Dan is correct to say that it is "dumb" to put these materials on your firewall or floor. It is also "dumb" to have a $80,000 aircraft that you don't like to fly because it's hot, noisy, and uncomfortable.

FWIW, I left out some personal info from my other posts: When I fly, I wear only cotton, wool socks, leather shoes, often with a chute and helmet, and I won't fly in a plane that doesn't have shoulder harnesses. So, I'm not exactly glib about safety!

Now back to material selection, here's a useful link for material comparison:
http://www.fabricmartfabrics.com/Burn-Test-Chart.html

Apparently, if I were to enclose a fiberglass batt in cotton, canvas, silk, or other natural fiber, I'd probably go a long, long way towards having a safer firewall. Hmmmm, just like what you'd find on a lot of military aircraft!

But I'm still comfortable with my choices for performance, cost, ease of installation, ease of replacement, etc. YMMV!

Flying isn't safe. Don't leave the ground. Die in a car wreck instead.:eek:
 
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