How important are the walls to overall shell integrity?

[Sprouty]

As I see some of the custom remodel jobs done to Airstream's, especially freshly remodeled units that are offered for sale. I noticed quite a few people are removing most or all of the internal wall/dividersand and it just made me wonder if anyone has an opinion on how important those walls are to the overall integrity of the shell? I mean they are riveted to the ribs and screwed to the floor and tied into the other components like the beds counters etc. I look forward to any comments.

[Belegedhel]

Just to be clear, you are asking about the walls that serve as bulkheads to separate one "room" from another, or to form floor-to-ceiling closets and wardrobes, right?

It is hard to give you an empirical answer without creating a 3D computer model of the shell and interior, and experimenting with various loads with and without the support of the bulkheads.

But, since you are asking for opions, I will offer mine. I would suggest that these bulkheads offer some support, but their presence is not critical. Someone might bring up the story about a guy who had a gutted trailer that 2 feet of wet snow fell on and the roof collapsed, but I am thinking that it would have collapsed with the bulkheads in place as well.

In my '73 the bulkheads are made of 1/4" thick plywood. If you put a load on the top end of a 7' long, 2' wide piece of 1/4" plywood, it will bow quite readily. You might argue that the fact that it is fastened to the wall and has some kind of extrusion to pretty-up the exposed edge will make it less prone to buckling, and you are right--to some degree. I'm just thinking that if the bulkheads were really critical to the strength of the shell they would have been made of something recognizable as a structural material.

I can also offer my own real-life data point. I have taken my completely empty trailer on several road trips, walked around on the roof, and installed a roof-top AC unit, all without bulkheads in place, and have lived to tell the tale. There are also all those food vending trailers rolling around out there that are essentially an empty tube where the bulkheads are concerned. They seem to survive just fine--maybe they haven't experience a couple of feet of wet snow....

[dznf0g]

However, I believe the interior skin "wall" are critical to the overall strength of the shell, if that is what you are referring to.

The interior bulkheads are really kind of a "floating" wall.

[cameront120]

Airstreams are a monocoque assembly where the shell (exterior skin, ribs and interior skin) provides the structural integrity. The millwork is added in various configurations, even from the factory, which indicates that all they offer is weight rather than any real structural relevance.

[vito98103]

Airstream is a semi-monocoque construction (attached to a steel frame), unlike most commercial airplanes, whether aluminum or carbon, which is a true monocoque (I built them for 29 years).

The interior skin provides some structure - but not much; it's pop-riveted on, unlike the exterior which is attached with real rivets.

The bulkheads (like those on commerical airplanes) are used to divide the space and that's all.

Many/most larger boats (sail and power) physically bond the bulkheads to the hull and deck, with adhesives and/or fiberglass tape and resin - but that's another topic.

[Sprouty]

Thanks for the comments I see what everyone is saying about them not being very substantial so they probably do not ad all that much to the overall structure. Thanks again Steve

[dznf0g]

They are simply, dividers. Just do the math on weight distribution and customize at your whim.