POD: Homebuilt foam core fiberglass skin pop-up camper build thread

[pods8]

Update (234hrs): Lower shell is all taped together. I did some carbon reinforcement work around the door frame but still getting a bit more flex than I want so I'll need to ponder how I want to handle that, whether its just more carbon or some other route (just tested it tonight so I haven't composed my thoughts).

Here's a shot with 320lb loaded at the front end of the cantilever. The tip of the cantilever dips down 1/4" which is fine with me however I'm displeased with the flexing I'm getting in the door gap. The door opening width at the top spreads about 5/16" with that load on it and may can door fit/seal issues.

 

[Billhilly]

Looks good outside. Haven't got any bright ideas for the door gap spread at this stage. A 'night time bar' that tweaks it up while you slumber....

 

[JamesDowning]

The roof should add some stability right?

 

[bob91yj]

Old school strut/shock from the front of the overhang to the fender to help support the overhang?

 

[pods8]

The roof should add some stability right?

If I use the folding walls over the cabover to tie the roof to the bottom they could share some load. At the moment I'm looking over the numbers of how many additional plys of various materials across the door gap would be needed to reduce the deflection my a magnitude or two. Looks like a bit more carbon with a fiberglass cap could make fairly easy reinforcement (I had just done some localized 5.5" wide strips before, probably would add a couple 24" wide ones now).

Old school strut/shock from the front of the overhang to the fender to help support the overhang?

I'd like to get the structures to perform acceptable and independently so nothing is relying on a specific installation.

 

[EuroJoe]

supporting U

How about a steel plate 1/4" thick surrounding the lower door in a U shape? Some flanging to keep it square or let the wall hold it. Or thinner steel but a "fatter" U

 

[SChandler]

Is the floor bowing up under the door when you do the load testing of the cabover, or is the top of the door frame opening up? If the floor is bowing up, the solution could be as simple as putting a mounting bolt through the floor into your (future) flatbed, along with some reinforcing to prevent the bolt head from tearing through the floor. If you haven't checked this yet, maybe you could try adding some weight to the floor at the doorway and reload the cabover and see if the door opening distortion is reduced any.

 

[pods8]

Yes it is the floor bowing and I confirmed it by adding a stack of weight in the doorway (while there was a load on the cantilever) and it closed the gap back up and if I go ahead and stand there too, adding another 200lb, it shrinks the gap another 1/8" the wrong way. Bolting it to the flatbed is a solution but I'm going to work on fixing it the right way first by adding some additional plys to the schedule to stiffen the floor. Probably will use some more UNI carbon and then cap it with some fiberglass to tie it in and also protect it when I'm sanding.

 

[SChandler]

Sounds like you've got a plan for reducing the flex. It will be interesting to see how much the additional plys reduce the flexing.

 

[eugene]

If its the floor flexing, why not reinforce with a piece of steel angle?
How far does your cab over stick out?

 

[pods8]

It will be interesting to see how much the additional plys reduce the flexing.

It all will depend on how much extra is added. What will be really interesting is seeing how well the theoretical additions play out in reality. IE if I double or triple the stiffness from where I'm at now, using theoretical numbers of the materials on both will it translate into the deflection being cut in half/third like it should?...

If its the floor flexing, why not reinforce with a piece of steel angle?
How far does your cab over stick out?

Steel would require mechanical fastening only (otherwise epoxy doesn't bond well long term with it, esp. due to thermal/mechanical cycling) and I'm unsure if that would pick up the stiffness needed in these small deflections. I'll try fixing the right way before bolting on fixes. Would have been easier to incorporate stiffening means during the construction of the floor but hindsight is 20/20.

My cabover is sized for a queen sized bed so it's ~60" cantilever.

 

[bee]

POD do you know the effects of having different material on either side of the sandwich core. An example would be. If I remember correctly you used 1/8" plywood and 2 layers of fiberglass on both sides of your floor. How does that compare to using 1/4" plywood with 2 layers of fiberglass on one side, and only 2layers of fiberglass on the other side? Same amount of material, but not evenly distributed.

BTW What kind of flat bed are you mounting this on? Are there going to be provisions for isolating frame flex?

Also for anyone who has been planning on doing some fiberglass work. Advanced Composite Traders did have great pricing, but after 4 phone calls, a few emails and 1.5 months I am giving up on ever receiving any fiberglass. At least he never charged my credit card. Luckily I am not in a big rush to begin my build. Looks like Thayercraft will get my business now.

 

[pods8]

I'm fairly tired these days (1month old in the mix now) so pardon any hacked up thoughts:

You can look at the strength of the new composite panel if you really wanted to get into it, the neutral axis would shift towards the wood side and it wouldn't be a symetrical profile for calc purposes. There would be less strength/stiffness on the glass side with the wood removal but you'd be able to take some credit for the increased distance from the nuetral axis (which means you can do more with less). That is what would actually happen in the panel if you had a load case you wanted to look at it against.

I just did the 1/8" on both sides mainly because both sides of the floor would tend to see more abuse than the rest of the structure.

If I buy a commercial flatbed I'd probably get a UTE, not sure if I'll build one though. Haven't composed all my thoughts on that front yet.

What was the issue with ATC, too hard to coordinate getting a big/heavy roll shipped to your receiving location? I never used them personally yet, they were just a source I had eyed up.

 

[pods8]

Camper update: No progress. Well a TINY bit, while family was visiting I took advantage of the extra set of hands to rip up a bunch of plywood strips to start putting together the upper camper core.

Between sneaking out for a little hunting and these two I've been fairly tied up/tired. Hope to start ramping back into some progress as the year wraps up and the new one starts sleeping longer:

 

[Jeep]

Very cool.