Thanks for all of the unique thinking folks. Lots of good ideas.

Here's a link to my website that has a photo of the "rolling hawg
shed".

hometown.aol.com/wright1902glider/airshow8.html

I've been thinking about this a lot in the past few days, and I keep
coming back to the conclusion that I've got more of a height-to-track
ratio problem or a CG problem than a sway issue. From my rear-view
mirror observations, the trailer doesn't sway so much as it just rocks
up on one wheel. I can push on the side of the trailer near the tail
end and in 3-5 pushes, rock it up and nearly over.

I'd like to stay with a box-trailer with as few openings as possible.
The reason for this is that Wright machines are covered in raw cotton
muslin, and the fabric braces the wings. If they get wet, they're
toast. I think a glider-trailer setup with internal guides and dollies
is the way I want to go.

Jim, I had been thinking about the ballast system. The local glider FBO
in Boulder, who is also an RAH'er suggested something like this. But
the idea for the pump is the missing link. I can see it helping
considerably on the Interstates. Maybe something like a 12v bilge pump
plumbed between two tanks made from large diameter PVC. Sling 'em low
and to the sides like the external fuel tanks on a CH-53 Sea Stallion.
I've also thought about just adding a concrete-filled steel pipe under
the chassis center to act like the keel of a sailboat. All of this will
require testing of course.

Anyone have any thoughts on how much wider I could make the axle? Keep
in mind, the chassis is on 48" spring centers, using 2-leaf
slipper-springs, and currently has a hubface-to-hubface measurement of
60". I've seen heavy air-compressors, like those you see powering
jackhammers, rolling on 3-4' spring centers with about a 6' axle. But
all of the suspension components looked very heavy. My chasis is so
light that I'm concerned about adding too much axle and overloading the
frame attachment points, shackles, etc. with dynamic loads.

I'm also considering much wider tires. I've seen snowmobile and pontoon
boat trailers running 8"x8" tires or larger. I don't want to go too big
though. Again, overloading things with dynamic forces.

Harry