Ultralight Construction...

[dwgriff1]

Maybe if I post again, the computer demons will bump this into the active column!

dave

[mikeschn]

That looked like a bona-fide "bump" to me!

Regarding your question as to why the hatch stops at the countertop... yea, there's a good reason...

First of all, we keep the hatch to a managable size.

Secondly, we maximize the storage under the counter. You can't do drawers, cause it's not deep enough. And cabinet doors would add complexity, and still not give you the maximum storage.

Thirdly, we add structure and rigidity to the teardrop, and end up with a nice place to mount some taillights.

Now, lets be daring and consider the alternative.... A hatch that goes all the way to the floor...

First of all the hatch is long, really really long. Are you going to have any flex problems with the hatch? Sealing issues? How about being able to walk under it without knocking yourself out?

Sure you could build wooden drawers, with wooden slides, and cabinet doors. But you've definitely added complexity, and weight, and still don't have as much storage as you'd like...

You hatch becomes heavier too, using extra members to keep it rigid.

It can be done, but in the interest of keeping it simple and light, I chose to end the hatch at the counter.

Mike...

[dwgriff1]

Thank you Mike,

I am a convert! Short it will be.

BTW, I appreciate your skills in modeling this critter. Thanks for sharing them.

dave

[mikeschn]

Thank you Mike,

I am a convert! Short it will be.

BTW, I appreciate your skills in modeling this critter. Thanks for sharing them.

dave

Modeling it was fun... Building it is a little more work!

Mike...

[dwgriff1]

I understand the work thing. I am an experienced wood worker, with the toys. I am retired, so I should have boundless free time, but it isn't working out that well, quite!

Right now I working around a furniture project for a daughter, and once in a while someone wants me to do a small construction job, and I like their money -- it pays for my tear!

The other thing about keeping it simple is that it really does take less time and money.

I am doing some things different than you suggest. Mine is all wood and it is frameless. I know more about wood than steel. Don't have a heart attack, I know enough about wood to make it work.

I'll post pictures as I get down the road a bit.

dave

[Arne]

Dave, I had a friend with a very complete woodworking shop... after he retired, everyone thought "oh, you have plenty of time to build this for me".

He sold all his equipment and now flies radio control model airplanes for the fun of it.

[dwgriff1]

I am being tempted (by my children) to sell this place and move closer to them where I can work on my art work and spend more time with grandkids.

There are some wonderful reasons to not be able to do all sorts of things.

My generation includes some of the last of the professional "generalists". Nowadays everyone is a specialist.

Wanna buy a shop?

dave

[Arne]

What, and get stuck building armoirs for everyone in the family? No thanks...../g/

[Lobo]

Mike,

Just a hint for when you've finished "Escaping"!

Lobo in West Virginia

[mikeschn]

You mean you want me to work on the Ultralight again? I may consider that!

Mike...

[jimqpublic]

On ultralight construction methods...

Ever since I got interested in teardrops (before I bought my Chalet), I have been amazed about the heft that most people build with. I guess if you're doing an uninsulated 4x4x8 teardrop then the simplicity of using frameless 5/8" or 3/4" plywood for the sides makes sense. Once you join sheets, build internal framework, or insulate I think using heavy plywood isn't a good idea anymore.

My trailer (see avatar) is basically an open-topped box with four folding panels for the walls and roof. The roof panels have aluminum and wood reinforcement along the edges but otherwise are a three-layer laminate of: 1/8" plywood; 1" extruded polystyrene foam; 0.045 Filon fiberglass reinforced plastic. That's it, on a panel measuring 8' x 6', attached by a hinge along one edge.

The additional rigidity of a teardrop with the curved roof, short spans, and cross-bulkheads is much higher.

I think it would be possible to build an adequately strong teardrop with sandwich construction similar to my Chalet and only minimal framing. One interesting possibility for a standard 4x8 profile is to make exposed ring frames on the inside made from a sheet of 3/4" plywood. You would basically take a full sheet of plywood and remove everything that wasn't needed for the frame. I think 3" around the perimiter, doors, windows, and bulkhead would be more than sufficient. If you live in snow country some roof rafters wouldn't hurt, especially if you go with one of the flatter roof profiles. The rafters could sit in notches cut into the ring frames.

DHAZARD's framework is similar to my concept (though with a lot more wood left in place). He used it in the middle of the wall sandwich though and was only able to use insulation in the voids:
http://tnttt.com/album_ ... ic_id=8303

Construction of the walls would be done on a very flat surface with glue and vacuum bagging to ensure a good bond. No fasteners would be used other than to keep the four components in alignment while the glue sets up.

The roof could follow (can't remember who) the "Outside in" technique where the 1/8" ceiling panel would be glued and tacked to the ring frame edges. Then cross-scored extruded polystyrene (XPS) and Filon with or without another sheet of 1/8" ply would be applied. I don't see any way to vacuum bag the roof so I think a good thick adhesive would be the way to ensure good bonding. The roof would held on while the glue cures with some sort of strap clamps along the edges (where there's enough strength).

How about laying another layer of ply on top, then using rachet straps from the frame in front all the way up and over to the frame under the rear of the trailer?

Anyway, I think you could come away with a pretty easy to build, well insulated, extremely lightweight trailer. Due to the thicker sections at doors and windows you could use standard self-trimming RV windows.

The roof trim would need to be wide on the roof portion to allow fastening into the ring frame. With 1" insulation that would be 1-1/2" from the wall face to the center of the framework. Otherwise the trim would only attach to the skin and underlayment (if used).

Thus ends another mindless ramble by Jim.

[Lobo]

Mike,

I've got a set of Dean Tennis' blueprints for his Chummy, and anticipate a variation ..... put his Chummy on steroids.... to accomodate my six foot height and two hundred twenty five pound girdth, let alone my wife and dog.

Anyway, I ran into your thread after the last post was made a while back, and read it top to bottom a couple of times. I'm hanging on your construction looking for bits and pieces, or techniques that I can adapt to my own effort. My Scout Troop will do it's spring camporee next April....that's my target date.

My brother and I are making a pair of couches that required laminating around a form very similar to yours. Except we had to resaw twelve foot long by two inch oak into 1/4 inch thicknesses before we started. We used resorcenol (sp) a two part glue at about $100 a gallon. Yes, well, they're my brother's couches! We'd be much farther along if we didn't live 170 miles apart.

Well, I've rambled enough!

Lobo in West Virginia

[dwgriff1]

[quote="jimqpublic"]On ultralight construction methods...

I think it would be possible to build an adequately strong teardrop with sandwich construction


I just did.

dave

[mikeschn]

Well here it is, just the way I left it eariler this year...

I'll be dusting it off this fall and continuing with the build... I'll continue with the photos as I go... not as fast as Steve W. though...

Originally I planned on making this a 4' wide teardrop... now I'm wondering if it can be turned into a 5' model. Any thoughts?



Mike...

[Gerdo]

Other than the obvious, it will weigh more, I don't see any reason you can't make it 5' wide.