Camper build using old Hi-Lo

[Hersbird]

So I have been working on the stock structure of this now that the weather is good. I got all of the rotten wood rebuilt and most of the siding back on and the factory lift cables attached and lifting properly. I got a new propane setup on the front, fixed a leaking toilet fill valve, and checked out all the appliances and found them working well. The fridge will freeze inside at anything over 1/2 way up the temp dial. I am replacing all the lights inside with LEDs and will probably add a fan/vent to one of the existing vents.

Now I'm thinking about that boat tail and some work on the front and maybe skinning the bottom. The bottom skin is a little tricky as the lift cables are exposed under there along with stuff like the holding tanks and dump plumbing.

I want to add some racks on the rear bumper for waterproof bins and maybe a firewood rack, and move the spare somewhere else. The bumper already sticks out but I would add another 8" or so. That would allow me to put a 18-24" or so boattail on the back. I thought I could attach it to the upper clamshell and just let it go down and cover and overlap my bumper box. Just have it taper slightly from the top and pinch in from the sides. Put new taillights on the end.

For the front it sits lower then the truck, maybe add a 12" extension off the roof of the SUV, but it does stick out more on the sides, especially the upper part where the upper sides of the SUV start to to pull inward.

I was looking at metal duct work and wondered if a 4" round duct opened up on it's seam and placed as a 1/2 round piece vertically on each edge of the front would work. then make some kind of cap for it blended to the top curve.
I also want to add a nose cone and boattail to the awning tube and tapers for behind the roof vents, remove the TV antenna all together, and make a aero cover for the plumbing vent.

[freebeard]

If you use curved sides on the boattail it will match the curved front. The rack could have an expanded metal mesh floor for the firewood. Would the boattail be hinged like a truck lid so you have access?

When you open up the metal duct, does it have a standing seam on one edge?

I would think the thing to do would be to open it up and flange one edge out, maybe 3/4" to 1" to fit and seal against the curved face, letting the other edge lap onto the outer wall. I'm not sure which edge would be better to flange, or you could snip the standing seam off.

The outer edge may need slits cut to relieve the metal, it depends. There exist crimping tools that you can work along the edge to shrink it. What does the existing edge look like? An aluminum extrusion?

At the top, to terminate the edging, you could cut a lengthways gore in the middle of the curve and overlap and rivet/braze it to make a[n outward] tapering tail. It needn't add frontal area, but right there—it may not make any difference. I'd taper it out at the end of the front face for rainwater run-off.

[Hersbird]

So here is the minimum boattail just to cover the bins.


And here is one a foot longer about 2.5 feet total.


And here would be the side taper


So does decreasing the size of the rear cutoff area from a 7.5'x5.2' area to a 5.5'x4.5' area help a bunch? Are those angles to steep?

[skyking]

I know those are just sticks sitting up there, but the angle depicted on the second one is better than the first. If it is too steep it will separate at the bend and you get little benefit from the tail. Same goes for the side. If you can make two planes out of each so it bends a few degrees, goes half the distance and bends a little more you will have better luck with flow staying attached.

[Hersbird]

Is there a particular degree that works? They don't have to be straight as I was thinking of bending conduit and covering with colorplast or something similar. A sharp cutoff is best as well right? Not rounded like the current upper cutoff. Side benefit is it will keep the rain off the stuff on the back bumper and provide an awning to the back window. That window is the bathroom so it's more for light and ventilation then for some kind of view.

I guess the template would be the way to go.

[skyking]

A curve is certainly the best, but not the easiest. If you go with a couple of angles, do no more than a 5 degree change at a time. It will separate and then re-attach if you keep it within 5.
Making 3 panels with two angles each, and a pair of top radius pieces to join them and you could take it down and put it up, and store it flat on the back when you did not want it sticking out there.
you could build it all in one piece with 1/8" or 1/4" foam and glass/epoxy, and saw it apart and make connectors for it. Lots of options.

[rumdog]

Attachment 17278Great project Hersbird. I think you are going along the right lines there... slight curve, round 10 degrees with a sharp ending. Use the start of the existing curve to begin the roof line panel. And keep it lightweight as possible.
As for the front i like your ductwork idea, but maybe bigger duct, softening that sharp corner, using similar frame to the back but smaller, 8 " radius. ... OR! ... a turning vane over the sharp edge like 'cab over' semis have

See attached quick and dirty sketch, sometimes its just easier to draw it!

[aerohead]

[Hersbird]

The top set seem to apply more. Would a combination of the 3rd and the last pic be even better? I assume the last pic how's a side taper on the boattail, but what is the angle of that?

[freebeard]

rumdog --

ALERT:
Invalid Attachment specified. If you followed a valid link, please notify the administrator

Your choices are curved, angled and stepped. They should all arrive at a cross-section falling on the template curve at the chosen truncation.