5x10 Rigid Pop-Up with Foam

[kipa]

Made a new lower insert for the tongue and replaced the top-wind jack with the front-winding one. Pretty easy swap for $50 and I think the space it frees up will be worth it.

As a woodworker, I am thinking I will just build the platform out of cedar and fully treat each board with blended tung oil before assembly.

It won't get much sun or extended moisture exposure really, so I don't see any need to worry about a more durable finish, so it's a strong, light, and relatively inexpensive option that should be easy to rebuild later if needed. I may just do the sides with smooth fence pickets as well, but probably not the top cover. Kinda depends on how it starts to turn out I guess. Cheap materials, easy to work with, yadda yadda . .

Dimensions are 34" front to rear and 60" at the widest point.

 

[Pmullen503]

I'd coat the cedar planks with polyurethane or some other sealant on all 6 sides before assembly. I'd also leave weep holes in the corners in case any water gets in, it has a way to get out.

Imagine the environment for that box at 70MPH in a driving rain behind your TV. Wood rots not because it gets wet, but because it STAYS wet.

 

[kipa]

I'd coat the cedar planks with polyurethane or some other sealant on all 6 sides before assembly. I'd also leave weep holes in the corners in case any water gets in, it has a way to get out.

Imagine the environment for that box at 70MPH in a driving rain behind your TV. Wood rots not because it gets wet, but because it STAYS wet.

I'm less into the idea of surface sealants than penetrants. Just thinking in terms of cedar that lasts the longest outside, a good penetrating finish is easy to apply and hardly requires any upkeep, if not an occasional reapplication. The last thing I want to be doing is sanding years down the road for a recoat, and tung oil is very forgiving in that respect.

That said, I am trying to keep from boxing in end-grain so that it can't hold moisture long when it does get wet.

I am pretty sure I will be building the entire lower box from cedar now that I have started on it. It's only the travel/storage lid that may end up something different.

 

[Falco-4]

@kipa do you have any photos of your floor to trailer frame attachment? I'm building on the HF 5X10 as well and keep going back and forth about how to attach the build to the frame and how to overcome the hight gap between the inter cross members and other frame rails.

 

[kipa]

Currently, it's attached by 4 3-1/2x3/8" bolts directly through the 1/2" ply subfloor through the foam to 90 degree brackets on the U-channel, as well as some extra screws holding the rear deck down. The front will get 2 shared low profile U-channels running vertically between the tub and tongue box for both to attach to. I am planning to also put 1/2" plywood on the inside of the front bulkhead for this purpose as well as damage protection from loose objects under braking.

There is no reinforcement of the tub on the underside because they aren't under any more compression than required to simply hold the tub snugly down. Position is maintained by the extra 1" (total of 3") foam I laminated underneath since the crossbraces are recessed to that depth, so that part sits within the top rails.

 

[kipa]

Currently, it's attached by 4 3-1/2x3/8" bolts directly through the 1/2" ply subfloor through the foam to 90 degree brackets on the U-channel, as well as some extra screws holding the rear deck down. The front will get 2 shared low profile U-channels running vertically between the tub and tongue box for both to attach to. I am planning to also put 1/2" plywood on the inside of the front bulkhead for this purpose as well as damage protection from loose objects under braking.
View attachment 2489929
View attachment 2489930
There is no reinforcement of the tub on the underside because they aren't under any more compression than required to simply hold the tub snugly down. Position is maintained by the extra 1" (total of 3") foam I laminated underneath since the crossbraces are recessed to that depth, so that part sits within the top rails.

This shows the added 1" layer after layup.

5x10 Rigid Pop-Up with Foam

As discussed in my design thread, I am building a popup trailer to tow behind my EV. The primary goal is to minimize aerodynamic drag while keeping weight reasonably low. This model is a rough idea of what I am going for, though I am likely to change the top design as I get the base completed...

www.tnttt.com

 

[Falco-4]

This shows the added 1" layer after layup.

5x10 Rigid Pop-Up with Foam

As discussed in my design thread, I am building a popup trailer to tow behind my EV. The primary goal is to minimize aerodynamic drag while keeping weight reasonably low. This model is a rough idea of what I am going for, though I am likely to change the top design as I get the base completed...

www.tnttt.com

Thanks that helps me visualize how you've handled it. I keep going back and forth between this or wood slats on top of the cross members. Mine won't be fiberglass and doesn't go over the wheels, but otherwise similar idea on floor construction.

 

[kipa]

Box progress:

Because the top doesn't really need to be structural, I am going to use 3/8" coroplast trimmed with aluminum. Hinged on the back with a buckle on the front, it's about a light as I can get with it.

I also think not attempting to slope it down toward the front, though the easier way to build it, is no less aerodynamic based on my previous testing with the temporary foam box and watching the turbulence. Airflow off the roof wasn't hitting the front of the box at all as it was fully within the turbulent wake area.

It's a very tight fit on the trailer and really just large enough to be comfortable for intended uses. I would have had to sacrifice the front and rear shelf/rails if I hadn't swapped to the sidewinder jack, but it otherwise probably could have worked. The trapezoid shape being flush from the corner to the center of the ball also doesn't impinge on the hitch angle.

The biggest problem I have now is that I put a lot of effort into making it square, plumb, and symmetric, which seems to highlight the fact that my foam tub isn't! Oh well . .

Obviously it's not intended to be fully air and water tight during travel, but it will hold quite a lot of cargo at 58"w x 32"l x 34"h interior dimensions, so that should work well for hauling chairs, a table, as well as the toilet and other weatherable stuff.

 

[kipa]

 

[kipa]

Not fully done, but road test ready.

 

[kipa]

I did take the trailer out on my standard efficiency loop this evening. There was some improvement. I was hoping for more at 2.4 mi/kWh, BUT, that's up to where I was on my first test, so not a bad result. 65MPH, 75F, no AC, windows cracked, dry, and average traffic.

There was a significant headwind on the way out to the turnaround today though, guessing about 15mph for that, and that will cut into average efficiency despite the tailwind on the return just due to how much worse aerodynamically going 80 is vs. 50. So average efficiency may actually be a small bit better. It hit 2.5 mi/kWh when I slowed to get off the highway (but I didn't actually start the logging for the loop until I was already at 65MPH).

 

[kipa]

I did take the trailer out on my standard efficiency loop this evening. There was some improvement, but I was hoping for more at 2.4 mi/kWh, BUT, that's up to where I was on my first test, so not a bad result. 65MPH, 75F, no AC, windows cracked, dry, and average traffic.

There was a significant headwind on the way out to the turnaround today though, guessing about 15mph for that, and that will cut into average efficiency despite the tailwind on the return just due to how much worse aerodynamically going 80 is vs. 50. So average efficiency may actually be a small bit better. It hit 2.5 mi/kWh when I slowed to get off the highway (but I didn't actually start the logging for the loop until I was already at 65MPH).

A little quick math for my EV6 is that using 75kWh (100%-0) should net about 180 miles at that average. Obviously, slower speeds bump that up, so maybe 200 miles on 55 MPH roads.

 

[kipa]

3 coats of Herculiner. Not sure that is 100% coverage and may still have some print-thru of the pink and some of the glass texture. I have enough to go over the entire thing for another full coat if needed though. (I was convinced that a gallon wouldn't go even this far.)

I'm not a big fan of the gloss appearance it dries to, but from what I have seen that fades fairly quickly, particularly around dust.

 

[kipa]

I also completed and stained the tongue box with Ready-Seal 'Burnt Hickory'. It was leftover from my fence build last year and I know that it dries darker as it ages, so a lot of the orangey-ness will fade over the next year or two.

This is what it looks like on my cedar fence using the same species of cedar.

 

[kipa]

Does it need trim on the lower edge?? The diamond plate aluminum I have isn't really very protective to hard impacts, but just thinking about looks here.

Anyway, another mod I did yesterday was to raise the new jack a couple of inches. It wasn't a problem with the fixed foot, but the wheel was giving me clearance issues connected to the car.

 

[kipa]

Also, the rear stabilizers are going to be moved up on the frame to the higher rail, as well as fairings underneath added front and rear to redirect airflow and cover the fenders. So only the lower 3/5 or so of the wheel is going to be visible from the side. That should help to clean up airflow even more overall.

 

[Pmullen503]

That's a great looking trailer.

 

[kipa]

Thanks. It's amazing how a bit of bedliner immediately removes the appearance of jankiness.

I still need to work on my rain water management before I put much effort into the interior, as it definitely showed leaks in expected places when I washed it before applying the liner, but it's at least functionally at a point where I can actually go do some stuff now.

I think I am going to hold off on doing lower edge trim and just see how it holds up. Obviously, any damage would be easy to cover with it.

 

[kipa]

Still need to permanently anchor the tongue box and add trim to the front corners. No obvious holidays on the bedliner found.

 

[kipa]

Relocated the stabilizers. They were too close to the frame to swing without hitting the rail, so high density plastic (cutting board) works as a spacer. Not ideal for a heavy load, but as light as this trailer is, I doubt that's going to be an issue as these L-brackets are quite beefy.

Even with the spacer, the foot still contacts the filler trim when stowed, but it's easy to swing it up or down with very minor deflection out when moving it.

I could definitely move it up even higher with some more work on it, but it's only the 1" or so of the foot hanging down now, and that is certainly not going to catch on anything I'd tow it over or create much turbulence directly behind the wheel.

All of that aside, lowering the trailer with the smaller wheels made them more difficult to deploy with minimal clearance at times if not inadequate.