Aerodynamic toolbox.

[Cowcharge]

Hey all!
Just joined, this is my first post. As I understand it, I must make five posts before I can post pics, is that true? I'm building a combination toolbox/solar-powered mobile workshop/aeromod for my 2010 F-150.

[Cowcharge]

I've also been rebuilding a '76 Shasta camper to live in full-time, also solar-powered, and the truck will be my tow vehicle, so I figured I'd rig it up so that I can run any tool I own out of the back of the truck.

[Cowcharge]

Originally I was going to build the truck box in the shape of a normal cap, but in one of my online roaming sessions I stumbled onto the aero-modders here and thought "Why not? I can afford to lose a little space to get better mileage," since most of my driving is highway stuff.

[Cowcharge]

Right now I'm living in my Dad's house in Maine (that he built after WW2 and where I grew up) with him and one of my sisters, helping to give him hospice care (he's a 95 year-old WW2 Hellcat pilot with a failing heart). Eventually I'll be moving on, and I like the idea of going mobile in a modest-yet-21st-century, efficient manner. Efficient, but I want to be able to run any darn electrical device I want. I'm not rich, so I'm going to be running on sunshine, and I'm doing all the work myself. There's #4!

[Cowcharge]

I overlaid the teardrop template on a photo of my truck, and did a bunch of trig, coming up with an 11 degree angle for the lid of my box. I'm building it out of plywood and framing lumber. Can I post pics now?

[M_a_t_t]

you might consider (depending on how often you'll be moving or alternate tops IDK) making it angle up towards your camper kind of like a box truck top of cab versus a semi cab (pictured).

I'm still a noobie at aero stuff so I'm not sure how well it would work. or what you would get from it, but something to think about atleast.

[Cowcharge]

Yay, I can add pics!
Before I decided to aerodynamicize it, I was "building" it in Sketchup in a normal cap shape. I'm building drawers between the side walls and the bed walls, a slide-out workbench and drawer in the bed bottom covered by a slide-out cargo tray, side toolboxes on top of the bed rails, and a 210-watt residential panel on the lid to charge four golf cart batteries. I have the panel, charge controller, and a 2000-watt inverter already. I still need the batteries, battery monitor and wiring, fuses, switches etc.:


After I decided to make it slippery, I used the template. I couldn't build the lid curved like that and still keep the solar panel flush though, so I designed the lid to be flat, at an angle of 11 degrees:


The side walls and front bulkhead are 3/4" exterior ply. The walls are as far apart as the wheel wells, I wanted to make sure I could still fit 4x8 sheets, or anything else you'd need a truck for, like lawnmowers or a bike, inside. Here's my start, with some white kilz primer:

[Cowcharge]

Adding the side box bottoms (5/8" ext. ply) and tops (1x I had kicking around). I'm poor, so everything is done as cheaply as possible, but also as strong as I can make it:



I intend the high side boxes to be for hand tools, woodworking to port, mechanical to starboard (in case the truck breaks down, I don't want to be standing in the road while I'm fishing for sockets). Power tools will go in the bottom and maybe the side drawers. Depends how everything fits. I cut the front bulkhead to follow the cab shape, minus 3/4" for the thickness of the side box doors.

[Cowcharge]

Added the rear bulkheads to the side boxes, 3/4" ply. I chose the curve to keep some usable space in the back of the side boxes. Nothing is attached to the truck at this point, nor are the walls attached to the front bulkhead. The hardest design part so far is trying to figure out how to shape the side box doors. I bought a sheet of coroplast to make templates, but I need to make the door frames, and several molding stations, in order to get the proper compound curve as the doors go from almost vertical up front to almost horizontal in the back. I also need to make the doors come out sideways before swinging up to keep them from fouling on the lid, so I'm planning to use "U"-shaped hinges like on a car trunk lid, rather than just hinging them to the top of the boxes. The box tops are cut at an angle on the outside edges, as will be the door and lid edges, so they will wedge-fit together like the lid on a jack o'lantern, with weatherstripping filling the gap. The plan is to laminate three layers of kerfed 1/4" birch ply to make strong, light doors that will line up with the cab sides and the side edges of the lid.

[Cowcharge]

For the last week I've been making the frame for the lid, today I test-fitted the pieces loose, and cut a slice off the top of the front bulkhead between the walls to allow the front lid frame to sit in front of the bulkhead and drop down to the proper height. The edges of the lid are cut to a matching angle with the tops of the side boxes, it's roughly 35-40 degrees. I bought heavy-duty stainless hinges, that will be mounted to the front of the bulkhead and the underside of the front lid frame.
I cut the frames down from three 8' 2x6s on my table saw to ride on top of the side boxes and drop down between the walls, and make an inset space for the 1/2" birch ply lid. I don't have a router, or a dado set, so it was make a cut, slide the board over a blade width, make another cut... Took hours. And doing it that way made for a very rough surface where they ride on the side box tops, as no 2x6 is ever perfectly straight, so the cuts made grooves. I had to chisel off the thin flaps that were left between some of the cuts, then surform-plane the surface to smooth out the grooves made by the blade. I haven't cut the side frames to length yet, but I'm thinking the rear edge of the lid will be even with the rear edge of the bumper to help with the turbulence behind the tailgate.

I used pocket screws to attach the walls to the bulkhead, and put the first couple of carriage bolts in the back of the side boxes through the bed rails, so I could drive it with everything in place. I didn't put every screw in yet, because I still have to take it all apart to make the side drawers. I painted the whole thing with silver grey porch paint on every inner surface, but the outside will be stained to match the truck, then clear-coated.