Thoughts on my design

[Miriam C.]

Andrew, is it possible to put a curve on the roof to prevent the build up of standing water? I realize this will make sealing a challenge though.

[wlivesey]

The simple, flush-when-down, one-piece pop-up is a lovely idea but I think you should assume it's impossible - it certainly is at least as hard as all the rest of the teardrop put together.

That sounds like a challenge to me... Make it a double-dog dare and I'll have no choice but to make it happen!

Seriously though, I haven't done the detailed design. I haven't come-up with an idea that seems good enough to warrant the design effort.

As I'm certain you're aware, other popups use hinged sides that fold up to create a tight seal that is raised a few inches off the roof. This seems to work with an angled or slanted popup because the popup is anchored to the roof at one end. My design has a four sides which makes things more complicated still... I'll keep scratching my head on this but you're probably right. If automakers use a channel to draw water away then that is probably where I'll end up and all the problems you mentioned will still exist.

It's fun thinking about just the same... Thanks for the input!

Bill

[Miriam C.]

Andrew, is it possible to put a curve on the roof to prevent the build up of standing water? I realize this will make sealing a challenge though.

Let me add to this. Andrew how much lip is needed to make this work?

The simple, flush-when-down, one-piece pop-up is a lovely idea but I think you should assume it's impossible

[ARKPAT]

Andrew that I the same thing I was working on on the pop up section of my roof on the standy. I just plan to slope the gutter to either side and then to a drain pipe in the wall to the bottom of the trailer. Always us plenty of slope to your gutters it will help keep them clearer and always have them acccessable to be able to clear them if needed in the future.







Pat

[doug hodder]

Ya know...and it's just an idea...you could do a trolley top. It would open up a lot of space from the front to the rear depending on your design. This is what I've done, but the principal/engineering can be modified to suit your needs, and I don't think the work would be that much more than trying to do a lift top, and the + is open the door and it's there, doesn't need to be raised. Doug

[angib]

Miriam, the problem isn't shedding water off the top of the pop-up, it's where it goes afterwards - generally that will be towards the seal between the pop-up and the body.

I've adapted some sketches I did ages ago when someone was proposing to do just this using the seals made for trailer slide-outs - other seal types could be used, but if the pop-up is to be lowered inside the body, they will all have similar problems.



The red pop-up is sliding inside the blue trailer body. There are problems in both the up and down positions:

- When the pop-up is up, water will run down the side of the pop-up and collect above the 'wiper' in the green area.

- The wiper isn't intended to be a perfect seal, so some water will get past it and collect in the pink area.

- When the pop-up is lowered, both the pink and green areas will drain into the body.

- If the pop-up is to be flush in the down position, rain water will also collect in the yellow area.

To overcome these leaks or water build-ups, drains can be used and this design would need some on the (fixed) recess as well as on the (moving) pop-up:



To cope with all the possible combinations of trailer level, up to eight drain tubes may be needed - two in each of the four corners.

It's not simple any more, is it?

There is also water lying in wooden 'gutters' and the last bit of that water won't want to flow down the drain tubes and will instead try its utmost to soak into the wood (it's pernickety stuff, that rain water). Does the word 'rot' spring into your mind too?

And that's when the drain tubes are open - in reality as soon as your back is turned, something will fall into the tube and block it, which you'll know about only after the trailer has got half an inch of water in the bottom!

Andrew the Pessimist

[Miriam C.]

Andrew the Pessimist

Thanks Andrew. I had forgotten how pessimistically correct you can be.

Happy New Year

[wlivesey]

I've been thinking about the poptop design a bit more. I've accepted that a perfectly flat roof with the poptop in the down position is not a reasonable idea. I decided that a three or four inch "bump" in the roof will be fine if the edges are tapered down to the roof and are not completely verticle. I think with this design I can have a fairly water tight seal in both the up and down positions. Thoughts?

Thanks for all the input, everyone. -Bill

<img src="http://docs.google.com/FilePage?id=dfs967x9_19cxjpxkhp">

[angib]

Bill, that looks to be a sound plan (and a nice animation too). I like the way two of the panels fold 180 degrees as that avoids you having to stow one set of panels above the other, so you can get a lower roofline to the pop-up.

Two more steps are needed to get it perfect, though you may well have thought of them already:

- Sealing the pop-up to the roof in the down position shouldn't be too hard to achieve - a flat underside with some weather strip would do it - but it's good to include a step of say at least 1/2" over which water would have to flow to get inside. On all pop-up roofs, we need to think of what happens when the roof is lowered when it's raining.

- Sealing the upright panels to each other needs thought as there has to be a gap between them so they can move freely. Here's a section through one possible joint design, looking downwards, with the blue panel being the last one to be moved into position:



The grey strip is a 1/8"x1.5" aluminium flat bar that provides a seat for the weather strip on the blue panel to seal against. This means it sticks below the hinge line when folded down, so it must come down outside the frame that the 'walls' are hinged to. Did that make sense?

Andrew

[Miriam C.]

Oh well you both lost me I think. If you build it please take step by step pictures for those of us who would love to copy but lack the engineering thought process.

KISS was invented for us.

[Kurt (Indiana)]

wlivesey, I like the concept and the design.
What about a fold up table top inside for dining? Maybe off one of the side walls.

Just a thought.

Looks good so far

[wlivesey]

Andrew, Do you think something like this would work? It doesn't have the the aluminum mounted externally - it's laying flat against the inside edge of the folding sections.

I should mention that I plan on using some sort of latch on the inside that would pull the folding sections together. That should, in my thinking, ensure a tight seal.

<img src="http://docs.google.com/FilePage?id=dfs967x9_215szjw7ff">

[wlivesey]

wlivesey, I like the concept and the design.
What about a fold up table top inside for dining? Maybe off one of the side walls.

Just a thought.

Looks good so far

Thanks! This is what I was planning for the table... Hows that look?

<img src="http://docs.google.com/FilePage?id=dfs967x9_23cd6zb2ss">

[TheDuke]

Really like what you've done, with the concept, animation and all. One thought: what about the water that collects on the outside of the walls, grooves around window seals, hinges, etc.? There's always some (maybe a lot), and it will end up inside when the mechanism folds, no matter what seal you use.

[wlivesey]

Really like what you've done, with the concept, animation and all. One thought: what about the water that collects on the outside of the walls, grooves around window seals, hinges, etc.? There's always some (maybe a lot), and it will end up inside when the mechanism folds, no matter what seal you use.

Thats a very good point and not one I had considered. My focus has been on keeping things watertight when open and closed - not in between. I knew this could be complicated but it seems to be getting more complex every day.

I've always liked a good challenge. -Bill