cutting cockpit noise?

[Geowitz]

From Aircraft Spruce's website. It's hidden at the bottom...

"For instructions and lab flammability test reports from FAA certified lab, click here...

http://soundproofing.org/infopages/soundprf.htm "

From that link...

" It is a closed cell vinyl/nitrile insulating material which will not absorb water or oil. Materials that absorb liquids are not suitable because if they get wet, they will promote corrosion and increase their weight. The mat also conserves and blocks heat because it is an insulator. It has fire retardant qualities and we have the manufacturer’s assurance that, in thicknesses over 1/8″, it meets the requirements of FAR 25.853b. Therefore, it is suitable for aircraft use...

The test procedures of F.A.R. 853.b, U.L. 94 or “Class A” are intended only as measurements of the performance of materials under specific controlled conditions. These tests generally mean the material will burn, but not support a flame, or will not support an flame but will create smoke. You can get a good idea about any material you intend to use by burning a scrap of it with a match. Materials used by aircraft manufacturer’s years ago may not even meet present day “standards.” Generally, if a person is responsible for returning a certified aircraft to service as a shop or mechanic, he should use materials that are FAA approved and follow approved procedures. If it is in the experimental category, you can use whatever you wish. For certified aircraft, a letter is included here in this booklet certifying that it meets requirements of F.A.R 25.853b(3). One may wish to place the letter in the aircraft logbook."


This stuff is on my wish list for a future purchase.

[Esser]

Geowitz, For that closed cell stuff would you just do your firewall? Or are you planning on doing the floor as well?

[wildirishtime]

Mine personally has NOTHING on the firewall unfortunately (well a thin rubberized damper pad about 1/16" so I'll be doing the floors first (easiest) and the toekick area since my muffler sits there.... see how that turns out....

[Geowitz]

I'll just be putting that stuff on the interior side of the firewall. 1/2 inch thick and cutting out pieces to fit between the tubing, but if I had known about it before I covered my fuse I would have put it under the floor as well. Right now I do have 1/2 blue foam board (high density blue board from Lowe's) which should work reasonably well under the floor boards, but it's closed up and permanent now.

[rogerh12]

Geowiz;

I had that blue foam on my 601HDS. It worked great but I took it out after my header tank line leaked on it. Just poor some fuel on it and i think you will see what I mean. It just ate it right up to nothing after a while.

When it comes to foam, the high end memory foam I used later would not hardly burn at all and was more fuel resistant. Even with a lighter on it, it would not burn much and as soon as I removed the ligher, it went out. But the good stuff is not so easy to find (I don't know the chemical composition, it came in the seats).

[rogerh12]

I suggest everyone make their floor boards removable so they can access the flight control mounting bolts (so you can remove the control for inspections, greasing and other maintenance). Also, to inspect the airframe under the floors at annual.
I used the wood floor boards as patterns to make aluminum floor boards and they are split in half to allow removal and access to the second half, which of course is held down by the control mounting bolts (now I can access the nuts on the back side). The half-plates not held down by the control mounting bolts are held in place by using nutplates instead of loose nuts (nut plates are used with the rudder peddle mounts too).
It took me a while to figure it all out, but now the floorboards are tight and don't rattle or anything (plus the look kinda cool).

[jiott]

The SS7 kit's floorboards are easily removable, except for the small piece way forward under the pedal mounts. I used clipnuts on the prewelded floorboard mounting tabs instead of the sheet metal screws that came with the kit. Anyway, on this model, sound insulation could easily be added under the floor at any time.

I wonder if the sound insulation works better on the inboard or engine side of the firewall, without considering ease of installation?

Jim

[Esser]

jiott, that article said to put it on the cabin side. And for additional noise reduction make an engine side with fibreglass batting or any other soft flame resistant material.

[Geowitz]

Yeah, I forgot to mention that. I actually planned on the foam on the inside and a matt like this - http://www.aircraftspruce.com/catalo...ges/coolit.php or similar on the engine side. I think it'll be plenty quiet enough for a Kitfox.

[High Country]

Sorry to get off topic but i was interested in your aluminum floorboards. how thick are they and how much do they weigh compared to the wooden floorboards