Project Extended Pop-Top Aerodynamic Camper Shell ('99 Tacoma)
 

Update with current photos:
http://ecomodder.com/forum/member-a8...0-img-2658.jpg
http://ecomodder.com/forum/member-a8...8-dscn0704.jpg
http://ecomodder.com/forum/member-a8...9-dscn0708.jpg

Next steps are:
* Build back door for shell.
* Build lift Mechanism and canvas sides.
* 2nd layer of fiberglass on outside
* Finish sanding, primer, and paint
* Misc stuff.

-------------- First Post Below ---------------

I Had a shell on my truck a few years ago, but it cost me ~4mpg, per the scanguage. I'd really like to have something to sleep under on trips and stuff, so I'm working up designs for a pop-top aero camper shell.

Design Criteria Are:

• Lightweight and Aerodynamic - Improving my MPG rather than hurting it!
• Extend to end of lowered tailgate so I (6'2") have room to stretch out under it
• Have enough room for me to have a raised floor to hide snowboards/other gear while still having room to sit up and move around comfortably (about a 3' lifit)
• Follow the body lines of the truck
• Simple and convenient to use

I'm planning on using fiberglass over 1/2" pink foam construction. In the CAD drawing below, I'm working on the cross-sections that I'll lay the foam over to get the shape right. I'm using a single radius curve for the shape right now. Given the non-agressive shape I'm using, do I need to think about the complex curves used in the aero template?

CAD drawing (will keep this updated) is here: https://docs.google.com/open?id=0B4K...0thT2F5VDV6WUE
If you use chrome browser and google docs, you can install the "AutoCAD WS" addon and view/edit the drawing in the browser. Pretty cool stuff.

http://ecomodder.com/forum/member-a8...ns-ill-use.png

http://ecomodder.com/forum/member-a8...le-overlay.png

Looks like a great project--win-win on functionality and aero. I don't know about the need for compound curves or not. But I have two annoying non-helpful comments:

1) I was confused by the title [EDIT: but I'm not anymore], "pop-top". To me, that means a camper that uses a combination of a hard shell and tent material to make something that stows for driving and expands for sleeping, like the top of an old VW camper bus. I gather[ed] this is a rigid shell that doesn't get reconfigured [EDIT: But I was wrong--It does pop up!!]. I mention that mostly in case someone else reading this thread gets unconfused faster by reading this note. [EDIT: see a8ksh4 a few posts down explain what he really has in mind]

2) Did you know that pink foam (and blue foam, both XPS (expanded polystyrene)) has a high global warming potential? It's foamed with HFC or HCFC, which have global warming effects thousands of times greater than CO2. Polyisocyanurate is a much better alternative. I can't post a link, but you can find an article by googling "Calculating the Global Warming Impact of Insulation"

Why not build a "top" and a "bottom? The bottom piece would start at the top of the frame rails, and extend to (and follow) the curvature from the end of the cab back to the tail gate. The top piece would fit over the bottom piece and, once inside, could be extended up; perhaps on actuators. Think of a box (with no top), fitting beneath a box (with no bottom). This would allow the top to be in the lowered position while driving, and in the upward extended position while camping.

looks like a winner!

Foam is hard to get into curves but is cheep and works well.

@ cris - Maybe pop-top is the wrong way to put it... it's more like pop-shell. I'm putting a lift on each corner, similarly to how the pop-up campers work. They'll raise the entire camper shell off of the bed of the truck by 2 or 3 ft. There will be a vinyl/nylon skirt between the shell and bed to fill the gap. Unless I find a more economical way to do it, the lifts will probably be built out of a couple segments of strut channel and bolted together using strut channel trolleys. Unfortunately, I this might be the most expensive part of the proejct, buying these roller trollies... Maybe I can get away w/ using loosely bolted claps to connect each segment and deal w/ the friction... I have a pair of trolleys on order, anyway, to see how they work/fit.

http://ecomodder.com/forum/member-a8...lift-maybe.jpg

I'm not sure exactly, yet, how I'm going to build a door on the back that fills the gap and works properly when the shell is lowered or raised... might have some ideas though.

@Beau - I want to keep the shell all one piece just for simplicity. The shell and bed will meet on one plane, so I only have to cut square pieces of fabric to fit in the middle. I like the builds that a couple folks have done on here where a top section of the shell hinges up off of the cab, but I want more head-room than that. :)

I didn't know about the foam. This brand assures me that they're safe for the ozone layer. :P Not a good sign...

http://ecomodder.com/forum/member-a8...ation-safe.jpg

I marked and cut a template of the cab profile and copied that into CAD. That was used to create profiles of each x-section that I'll cut from foam to lay the outer layer over (hopefully) before fiberglassing.

http://ecomodder.com/forum/member-a8...d-cad-used.jpg

http://ecomodder.com/forum/member-a8...ng-cutting.png

Great project. The aeroshell/ popup camper combo is really cool. I will follow this for sure.
I am working on a fiberglass foam camper as well but it will be non pop-up and nowhere nearly as aero. Pics in album if your interested.
Besides your trolly idea you could look at centre mount drawer slides. They are made to mount under a drawer bottom and are only about 3/8 " thick
Thanks for posting.

Knowing better what you meant, I think pop-top is perfectly appropriate--sorry about that. That will be great. Are you going to have ropes or cables from all four corners wrapped around the same winch so the corners all go up together?

Toothbrush, you're my inspiration for using this pink foam stuff!! Your camper looks awesome. Have you started laying fiberglass over it yet?

Good idea on the drawer slides. I'm going to look at some of those at home depot next time I make it over there. I wonder if I might be able to get some eol server rails from work that would do the trick. They're a lot longer than I probably want... I received a set of strut channel trolleys yesterday so will see how well they fit/slide later, too.

Chrs, yah, the plan is to have a wench on one side that I can crank and lift the whole thing straight up.

I cut x-sections of the shell last night. These are all 1" smaller than I want the external surface of the shell to be, so I should be able to cut, bend, and glue the 1" foam board across them and get the right size shell:
http://ecomodder.com/forum/member-a8...-panel-cut.jpg

My strategy was to carefully measure and cut the largest x-section first. Once I had that, I used it to trace the sides of the remainder. Then I measured the needed height of the remainder and shifted the big one down and traced it's top. I used a round piece of foam I cut to radius the side<->top corners.

http://ecomodder.com/forum/member-a8...shell-over.jpg

When I lined them up, I realized, unfortunately, that I had measured two of the panels incorrectly and will have to re-cut them. I'm glad I figured this out now, rather than after putting the whole thing together and finding that It was crazy unsymmetrical. :)
http://ecomodder.com/forum/member-a8...together-i.jpg

a8, Looks Great! Good job resisting the temptation to bring the back down to the top of the tailgate.

Have you considered just making it to where you crawl in, and just lift it up, to make it "Pop". I mean, for all the time, money & effort you'll put into cranks, guides & pulleys & such with the risk that it may take 2 or more tries to make it work, and the system will take up valuable space. :p You could just make it where you lift it manually on 1 side, then prop it up or fasten it in place, then go lift the other side. That way you're only lifting half the weight at a time while the other side remains attached and controlled. There may be a way to do it where you just stand on the outside, beside the truck, and lift too. You'd just want to be sure to engineer it such that it has the clearances to "Unpack", but I'm sure you'd account for that.

I was considering doing something very similar a few months back and that's what I was going to do, and mine was going to weigh more. Your light construction method using fiberglass should make it a cinch. Something to think about anyhow.

Again, Great JOB!! :thumbup:

I agree . This finished shell could conceivably come in at less than 1 lb. per sq. ft., so it may not need much muscle to lift.

The "pop" aspect of this build makes it pretty unique. Watching with interest.

everybody ought to have a wench or two on the side that they can uhhhh, "crank". :D

a8ksh4 -- I had a long reply all written, but then I found this and I scrapped it. Just go there and you will find all kinds of answers:
Understanding Camping Trailers Roof Lift Systems | Custom Cylinders International Inc.

Made some more progress today. I re-cut the couple of x-sections that I messed up and then started assembling the skeleton. Once I got a couple pieces attached, I put it on the truck so I could make sure it was square when I started gluing.

http://ecomodder.com/forum/member-a8...glass-over.jpg

I used two runners, flush with the bed, to attache everything to. All of the x-sections except for this front one and the rearmost will be removed after the outside of the shell has been glassed over. I'll probably cut a big hole in this front panel and glue on a lexan window.

http://ecomodder.com/forum/member-a8...on-details.jpg

More done...

http://ecomodder.com/forum/member-a8...-more-done.jpg

Started adding some bracing. This is as far as I got before using up an entire tube of glue. I left it on the truck like this for a few hours for the glue to start to set, and then moved it indoor.

http://ecomodder.com/forum/member-a8...ng-bracing.jpg


Sooo... next steps...
* Will go ahead and start skinning this pretty soon. I want to see that it's actually going to work and look okay before I start purchasing materials for the rest of the work.
* Since this thing extends out past the end of the bed, I need to build a simple sub-frame to give me somewhere to attach the bumper further back and to hold on the panels/hardware that will extend the bed. Have to get dimensions of the mount points that will be used and do up some drawings of this.

One of the design features that I haven't mentioned yet is that it's going to have a long recessed compartment on the driver side of the shell where I'll keep a fold out awning. :P I picked up an awning rail today and have a 7' awning coming in the mail soon. Lol, I don't want to over-complicate this, but this is a feature I really want to incorporate. Also, my pie in the sky idea at this point is to glue/clearcoat in a bunch of solar cells on the top similarly to how the all-electric race cars do... Need to see the light at the end of the tunnel before I really even think about this.


For the lift - just grabbing it and lifting it up might be an option. I'll have to think about how it'll latch in the up position if I do this. It really needs to be on sliders/rails of some kind so that it doesn't jerk around and break if it's windy out. The center pull slides didn't excite me too much, but ball bearing drawer slides look perfect. They seem sturdy enough and are way cheaper than the strut-channel & trolleys that I was planning on using before.

Thanks for the link, freebeard. The telescoping Coleman setup w/ pulleys and cable was exactly what I was intending to reproduce.

I'm helping! :)

It looks like you don't have stake pockets for side racks. They call that a pickup? But that means your not limited to that 2x4" dimension.

How do you propose to fix your lift mechanism into the bed? Permanently attached or lift off with the aerocap?

Nope, no stake pockets, but they do have built-in tie-down points at each corner of the bed that seem pretty sturdy. The suspension in this 2wd taco isn't stiff enough to haul a half-cord of wood... I'm not sure what good raised rails would be on it. :P

The lift mechanism would be permanently attached, as in, it'll be bolted to the truck bed. I hope I don't have to remove this thing very often.

Hay bales?

Looks really good, making it go long will help too. Have you thought about tilting the forward most panel forward to match the angle of the back glass? It isn't that big a deal, but would look better for sure. Pay attention to whether the back glass bows out a bit as it does on my 2000 GMC Sierra, that was an "Aw Heck" moment when the topper I made was touching on spot on the back glass. Here's a pic to see what I mean.

http://i49.tinypic.com/29uznt1.jpg

Even in the picture it's tough to see, but the glass is closer to the bed in the middle than on the sides.

Great project! A very low tech solution may be to lift it manually (I think it will be very light) and prop it up with a couple of rods or poles. As long as they are wider at the bottom by the tailgate hinge, the trapezoid shape should stop it from shifting in the wind. However, you may want to add some straps to tether it down so the wind cannot lift the whole thing while it is set up. It is amazing how quickly the wind can come up when you are camping.

Small update...Added screws to each corner of the skeleton so I could set the side-to-side offset behind the cab:

http://ecomodder.com/forum/member-a8...ton-behind.jpg

then I cut a 2' x 8' strip of foamboard that would go from the cab and front-most x-section of the shell to the second x-section. With it centered behind the cab, I could start cutting to get a flush fit. Will have to get some better photos of this later.

http://ecomodder.com/forum/member-a8...behind-cab.jpg

And then had a first try at getting the panel to flex along the 3" radius curve that joins the sides of the shell and the top:

http://ecomodder.com/forum/member-a8...nel-around.jpg

I started with lines 5/8" apart and about 5/8" deep, but found that this wasn't enough. I think I need to make them deeper and maybe do them every 5/16" instead. Turbothrush, do you have any recommendations here, for forming around the 3" radius? :)

Can you make it a "45°" thing and then sand it?

Thusly?

http://i45.tinypic.com/14lil94.jpg

Assume 1" material; then if the inner radius is 3" the outer radius is 4", difference in circumference is ~6 1/4". Around a 90° corner the difference is ~1 1/2", so 1.5 divided by the width of each cut gives you the number of cuts, spread across 1/4 of the inner circumference — 4 1/2".

...approximately.

a8 . Great job so far. Have you considered skinning your shell lengthwise. That way if you had access to a tablesaw you cut your kerfs with that. At any rate to get a 3" radius you will need to cut deep enough so that only about 1/4 " of foam remains and for the spacing use freebeards formula. I found that the foam has a slight natural bend to it so you need to use that to your advantage.

The idea in theory is have the spacing so that after bending to the 3" radius the kerfs will will be closed on the inside. I found that in reality that if after bending you have kerf openings they can be filled with epoxy/micro mix and the fiberglass cloth can be layed directly into that mix . On the nose of my camper which is 2" foam bent to a 2 3/4' radius I used this method and it worked great.

If you decide to cut the kerfs on a tablesaw you should make a simple throatplate splitter.I will post a pic later of one I made. Hope this helps

Ok, cool... I'll have to approx double the number of cuts I'm making, and go a little deeper to get to the 1/4" depth.

I thought about going lengthwise, but decided it would probably be easier to go horizontally and blocksand along the length. We'll see... I don't have a tablesaw, so don't worry about the throatplate splitter. :)

New stuff tonight, probably!

Well, I had a couple more tries at getting the bend in the foam to work, but kept breaking it... might be cause I couldn't really cut clean grooves w/ the dremel. :/ Anyway, the new strategy will be laying the panels lengthwise, letting them overlap at the corners, and just sanding in the curve like Chaz suggests.

No new pics today, but I put the rest of the bracing in between each x-section for the shell and should be ready to cut & screw on the top and side panels using the alternate method in the next couple of days.

a8 Well I guess a tablesaw is better for the job of cutting the kerfs. If your going with Chazmt's method (and you may already know this) you can just cut the foam with a saw and then sneak up to your line with homemade sled like this and get a perfect angle. This is one for 90 degrees but with a simple spacer you can make any angle you want.Attachment 11498

Just in case someone is interested in what can be done if they have a tablesaw and at the risk of going too far on your thread I thought I would post a few more pics.

1" foam around a coffee mug ( 1 3/4" radius )
Attachment 11499
Attachment 11500

Throat plate splitter
Attachment 11501

I cut the side panels for the shell last night. Started by tracing the top profile onto a side piece. Then offset the line down 1" so that I could lay the top panel over top of the side panels.

http://ecomodder.com/forum/member-a8...side-piece.jpg

Copied to other side:

http://ecomodder.com/forum/member-a8...other-side.jpg

And then glued a second strip of foam along the top of each side panel so that I could sand far enough into them to get the curve I want. The pic isn't so good, but you can see the glue coming out along the curved top of each panel:

http://ecomodder.com/forum/member-a8...-each-side.jpg

I'm going to be out of town all weekend, so next update, attaching side panels and top, will be next Monday. Happy Friday!

Excellent. So essentially you will have 2" or so of foam but just where you are going to sand your radius right? Also it looks to me from the pics that you screwed the pieces together until the glue set. Is this the case?
Thanks for posting

With 2" of material you can only get ~1" radius without weakening the edge. But you could cut blocking out of you scrap and glue it on the inside and get whatever radius is required.

@ turbothrush - Yah, I cut two inch wide strips of foam to layer and back up the corner. I would lay glue in zig-zags where pieces of foam overlap and then screw them together to dry...

http://ecomodder.com/forum/member-a8...oin-pieces.jpg

This glue works pretty good... When joining the pieces, it's difficult to use enough screws to get a good seal, but if I go along w/ my hands and squeeze the glue out along the entire edge of both pieces, they don't separate afterwards. The glue joints also sand well once two pieces of foam board are joined together... When I sand across a glue joint, it tends to ball up before the pieces separate, so the joint stays steady and solid.

Per freebeard, I may not have made the corner foam thick enough... I glued an extra layer of foam on yesterday to add some thicknessm, but I might still need to add some spray foam to the inside before I lay the inside layer of fiberglass. We'll see how rigid it feels after doing the outside layer.

Sooo... good progress today! I cut notches in the x-sections to let me lay the sides in tight:

http://ecomodder.com/forum/member-a8...918-195722.jpg

Can see where the corners are going to need to be radiused from the cab to back:

http://ecomodder.com/forum/member-a8...918-201950.jpg

Both sides affixed w/ some screws:

http://ecomodder.com/forum/member-a8...918-195803.jpg

Sanding flush so that I can glue on a top layer of foam that will be cut through at the corners to make a smooth transition from top to sides and from cab on back... (LOL if this looks like crap when I go at it w/ sandpaper later this week...)

http://ecomodder.com/forum/member-a8...lue-smooth.jpg

Both sides sanded flush w/ the top profile so I can glue top panels on and then radius the top->side corners... tomorrow or later this week! :D

http://ecomodder.com/forum/member-a8...glued-down.jpg

the top surface is spherical... so I'm wondering how many pieces I'll need to get the foam to lay smoothly... Ideally, I'd use two pieces, joined along the middle from cab to tailgate. I think the foam has enough flex to do this. Soon we will know!!! :turtle::turtle:

Looking good.

Did you sand it the whole way or start with a coping saw, or electric carving knife?

Nice project and good progress. Keep us posted!

This is a neat build. One thing about cab and beds, that I learned the hard way, is they move independently. The cab is usually mounted to the frame on a 4-6 molded rubber vibration isolators, and the bed solid. The problem is when you bridge the gap between bed and cab, things squeak. This might not sound like a big deal now, but I had a 1/4 'sleeper shell' mounted on one of my trucks that drove me insane, from rubbing and squeaking, until I remounted it, increasing the gap, using a flexible accordion boot to make the connection between the two.

Keep up the good work!

This is coming along nicely!

By "work" do you mean aerodynamically?

Once you get the top foam on and radius the transitions, any plans to do A-B-A testing? I see you have a ScanGauge :)

EDIT: I'm sure you're aware there's going to be negative pressure above the cap at speed; make sure you secure it well to the truck before driving. Hate to see all that work undone following a spectacular lift-off!

This is getting cooler and cooler!

I assume you mean a flush compartment with a door/panel to preserve good aerodynamics? I look at all the campers & RV's on the highway with all their exposed awnings & supports being blasted by the wind... and cringe a little.

And that would be the cherry on top.

Added your build to the front page of the site.

Did I miss the post where you told what glue you are using? It looks like white bathroom caulking but I would like to know for sure. Thanks.

Yah, sanded all the way through.

I'm definately not sure how I'm going to mate this thing up to the cab... This feels like the most difficult part of the shell to cut/shape. I'm trying to cut it close... maybe 1/4" gap plus fiberglass, but I don't want it to rub/squeak. :) If I can find some long-lasting clear tape, I'll cover the paint on the cab where this thing is close and add a foam gasket to the shell that moves and seals.

@Metro... Yah, I'll have to do some ABA testing. I may be reluctant to change much at this point as long as it doesn't hurt my mileage, but I'm really hoping to see a few % improvement. By work, I mean that the aero is there and that I think I can make the finished product look quality.

The compartment/door would deff be flush and smooth. I have to see how ballsy I'm feeling before I'll cut this out of the side... I could mount the awning track on the outside of the shell w/o disrupting flow, as long as the awning bag wasn't hanging off of it, but then I have to think about where to store the bag when I'm not using it, etc... Hmm.

The glue is Loctite PL300 for Foamboard. It's water-soluble and feels like elmers glue, but with more bulk so it can be used to fill gaps.
http://ecomodder.com/forum/member-a8...e4169-glue.jpg

Heh hehe heh heh....He said " More bulk to fill the gaps!!"

http://collider.com/wp-content/uploa...onument_01.jpg

Looks like this foam will flex around a spherical shape just fine, so I'm going to take advantage of the ([edit]In best Bevis creepy laugh: "huh huh huh") tongue and groove and glue 2.25 of these panels butt to butt ("ah huh huh huh") for the top, ~9ft w/ overhang at the back.

http://ecomodder.com/forum/member-a8...ical-shape.jpg

Interesting