The autograph doors aren't that mysterious. A friend purchased an end of life coach just to get some for his camper.
It turns out to be a collection of rod ends (outer steering knuckles for golf carts) on bits of tubes. With your skills you could source rod ends and spherical bearings and rig up a parallelogram assembly quite easily.
One point to bear in mind is that these types of hatch have a latch both top and bottom, otherwise they don't stay closed.
Happy hunting.
Agreed that the mystery is not in the technology, rather the act of sourcing a relatively complete assembly in order to keep the custom fabrication (= time & money) to a minimum. But I think I've got good options for the components at this point, as well as an outfit that cranks out "build to suit" assemblies. The internet has made me so impatient: if it takes me more than a day to find anything, I start thinking it might not exist!
As for the latching, the doors will have a 3-point configuration. And I'm still on the fence about using this type of cargo door hinge vs. good ole' continous hinge. As the sketch shows, the advantage is the decreased side clearance needed to access the compartment:
Would you mind sharing some pricing information with us regarding the materials you're using to construct these boxes? The more I see of your project, the more interested I am. Thinking in terms of what's familiar to me, I have been planning on building a steel-framed and skinned trailer box. Will probably end up going that route, but was like to at least make an informed decision.
This will be a long answer, because you may as well get enough information for it to be of value.
The primary components are PPE honeycomb panels, fiberglass pultrusions, 2 oz glass, and laminating resin. There's also a lot of specialized adhesive involved formulated for polypropylene bonding.
The cost per square foot for PPE panels varies widely and is based on the type and thickness of the skins, the thickness and density of the PP honeycomb core, and the lenth of the panels. The ballpark range would be $6-$12, not including shipping costs. Stock structural pultrusions range from $4-$12/lineal foot, depending on the profile and grade. Glass and quality resin are relatively cheap. PP adhesive is very expensive, even by the case, usually around $10-$14for a 200ml sausage.
And for those not experienced with composite panels, there's another word of warning: if you make a mistake with a large component (like cut it too short), it's not very easy to fix- possible, of course- but best to avoid that experience altogether. The material is pricey enough that you don't want to screw up.
Another consideration is tooling and an appropriate (safe and efficient) work space. As I mentioned in my last post, burning through blades is par for the course, but the least of the equipment worries. Thermally bonded PPE panels in the US are limited to 50" width (that limitation does not apply to manufacturers of adhesively-formed foam sandwich panels, which are limited by the width of the skins available), which means you need the tools and technology to join them together to make bigger sheets, as well as tool them as needed for joinery, etc. While I've been fortunate to have a nicely outfitted garage, it took a whole new level of investment to get my brother set up to do this the right way, and he already had a shop outfitted for composite work and years of experience with fiberglass and other composites.
I'm not saying that my type of build can't be done as a DIY project. But I doubt it would be very cost effective. You can use my numbers to run a pro forma and see how it turns out.
Affordability is largely driven by volume. Volume allows economical acquisition of materials, tooling, and labor. It also amortizes those costs over multiple production units. So if I haven't driven my brother crazy with this project, maybe some of you can get together and have him crank out some shells for your projects. In that scenario, it probably would be cost effective. I'm anxious to get mine out on the road to see how they do in the real world. But every day my confidence grows that this is a FAR superior approach to building a strong, light structure.
Back to the build: Among other things, the big goal for the week was to get the bottom half of the cabover "clamshell completed. Mission accomplished:
I am very pleased with the cabover design. Even though the math said I had nothing to worry about, I was still nervous. Not anymore. The goal was a cabover floor that would be solid enough for 3 adults to stand up (because it's a pop-up) without worries. That is one bomber "box", and great illustration of beam-strength calculations. It is 8' wide (inside) and 5'4" deep. The pop-up concept was a late addition to the plan, but I'm very glad I made the move. It's really going to be a nice living space.
