Wooden floor size suggestion please?

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

rv7charlie

Well-Known Member
Joined
Nov 17, 2014
Messages
544
Location
Jackson
To meet the clear span goal,

Are you familiar with steel-clad exterior doors, as used in the USA? 1.75" of foam, with very thin steel glued to each side. (image attached) Same concept as most plastic a/c these days (Glassair, Lancair, etc). I built a hangar addition using 5' long, 22" wide 'scraps' of those doors, with the structure on 5' centers. You can jump up & down on those 5' spans and they barely deflect.

If you use 1/4" or 3/8" foam, and skin it (using full coverage structural cement) both sides with even .016 aluminum, it'll be pretty strong. If you use 1/4" ply, you could probably use aluminum flashing material (~.010") for the skin. The wood core would give better impact (dent) resistance and compressive strength, and the aluminum would provide the tension element. Edges could be capped with U-channel formed from the flashing material to keep water out & stiffen the edges. 'Composite' construction, but using wood/aluminum instead of foam/glass.

Charlie
 

Attachments

AdrianS

Well-Known Member
Joined
Jul 5, 2014
Messages
481
Location
Australia
To meet the clear span goal,

Are you familiar with steel-clad exterior doors, as used in the USA? 1.75" of foam, with very thin steel glued to each side. (image attached) Same concept as most plastic a/c these days (Glassair, Lancair, etc). I built a hangar addition using 5' long, 22" wide 'scraps' of those doors, with the structure on 5' centers. You can jump up & down on those 5' spans and they barely deflect.

If you use 1/4" or 3/8" foam, and skin it (using full coverage structural cement) both sides with even .016 aluminum, it'll be pretty strong. If you use 1/4" ply, you could probably use aluminum flashing material (~.010") for the skin. The wood core would give better impact (dent) resistance and compressive strength, and the aluminum would provide the tension element. Edges could be capped with U-channel formed from the flashing material to keep water out & stiffen the edges. 'Composite' construction, but using wood/aluminum instead of foam/glass.

Charlie
Some of those foam cores emit toxic fumes if burned.
We use them in the factory at work, and got a warning about keeping welders and grinders away.
 

rv7charlie

Well-Known Member
Joined
Nov 17, 2014
Messages
544
Location
Jackson
Some of those foam cores emit toxic fumes if burned.
We use them in the factory at work, and got a warning about keeping welders and grinders away.
No doubt. I suspect that the same caution would apply to any plastic a/c, including the certified ones.
 

Mad MAC

Well-Known Member
Joined
Dec 9, 2004
Messages
523
Location
Hamilton New Zealand
I've seen aluminium faced sandwich panels with various cores sold for outdoor signs, of all things.
I can't remember how I found them.
I have seen 2 types of those sign board materials, aluminum facing on a solid plastic core about 3/8" thick (which might actually work for this) and 3/4" thick alumnium honey comb with aluminum facing, would recommmend advoiding the later for anything remotely structrural, its uses a really soft core and facing and a low temperture glue which means any insert hard points will have a really low structural capicity, and if anyone thinks it is a proper honey comb panel and hits it with a bit of heat to get the insert out or the like, the whole will just de-laminate (go on ask me how I know).
 

Mad MAC

Well-Known Member
Joined
Dec 9, 2004
Messages
523
Location
Hamilton New Zealand
Sorry I believe it was Grenfell...
Several hundred vertical meters laid out in a chimney shape changes the burn properties somewhat.

Would be interesting to see if it would pass a Part 23, appendix F burn test (it might, thick paper probably would). Flat on the floor would mean it probadly only burn about the edges without a fire sufficient break through the clad, at which point the cockpit contents would be char-grilled.
 

rotax618

Well-Known Member
Joined
Oct 31, 2005
Messages
768
Location
Evans Head Australia
Yes Mad Mac you are right, many of the materials we use in homebuilding are combustible, and they are safe. I really haven’t looked at that cladding material as far as its mechanical properties are concerned.
 
Group Builder
Top