Quazi-ultralight the undertaking

[aggie79]

On last question about the torsion box (yea right)

When creating the webbing inside the box I will need to create a span that overlaps the frame. Some of the spacers inside the box will be able to run full length and others will be short ‘filler strips’ if that makes sense- so… should the long pieces run sideways or front to back. I’m considering a half-lap joint at the intersections which may be the best of both worlds. The other option is that I’m seriously over thinking this and I just need to get going.

Rog,

It's good to see you post again.

I think the real answer to your question is "it doesn't matter" how you do the internal strips. Half-lap joints would be nice but time consuming. As I recall, your design overhangs the frame on the sides and front and rear. I would probably run full length strips the width of the trailer. I would stop these transverse strips about a foot or so from the front and back of the frame. Then I would use shorter strips to frame perpendicular from the transverse strips across the front and back frame rails to the distance of the front and rear overhang (less any distance for a perimeter strip.)

Tom

[RogHodge]

Oops- I may have failed to mention that I’m going to go 5’ wide. I know that I mentioned thinking about it but I’m firm on that now. Also two doors- If the wife goes with we will need that and I think it’s better to accommodate her a few times than to alienate her all the time.

Torsion box overhang- as I think about this there is only 6 inches or less off the sides- 9 inches off the back and 2-3 in the front. I don’t think there will be much flex at any of those points.

We have a winner!- Tom posted before I completed a response (I’m slow) I am going to do something very much like he described- stay tuned for updates and actual sawdust.

And now I am going to remove the trailer jack and return it- This ridiculous contraption is such a Rube Goldburg eye sore that I can no longer be associated with it- thought about modifying it, but then came to my senses and ordered a different one- HF #95157 – still needs to be modified probably, and since it’s from HF the quality is suspect- but it will be nicer to look at- I hope. In the mean time I will attach the receiver tube to the back of the trailer.

[RogHodge]

The pergolas-

The first one is huge- 20x30 with doubled 2x12 beams- freestanding- and it survived our Easter earthquake.

The second is my back yard, messy as it is, it is 15x30 and has a funny story or two concerning construction- I’ll buy any one a drink if they remind me to tell the story around the campfire. This offer is only valid in person, while supplies last. or if you prefer

[kennyrayandersen]

I re-read all of the posts and I think I know what you have in mind. Aggie79 has a pretty good idea about what needs to be done. Really, you plywood skins are reacting the bending loads, which due to the overhang are not as obvious [to the bending direction] as first appear.

You’ll have a notch for the wheels, no? So, I think running at least the first few 1X2s the short way across your frame the full width of the tear is an excellent idea. How far you space them will determine how thin you can go on the plywood. If you had a foam core then 1/8 would be no problem as the core supports the facesheet of your box (core reacts the shear). Using the hollow door concept the internal wood strips react the shear – I think it not important which wood variety you choose since any of them can provide this shear strength. The real load is in the plywood skins (although the full width 1X2s near the axles will also pick up a bit of bending load).

The upper skin will have to support human loads which even the 1/8 plywood could do with close spaced internal stiffeners. However, I’ve found that there is usually a bit of a premium on some of the thinner material, so if the upper sheet will be a ¼ inch think you should check to make sure ¼ inch thick isn’t actually cheaper than using (2) 1/8 inch sheets; plus, the ¼ inch thick sheet is MUCH stronger than 2 1/8 inch sheets (not to mention that the deflections will be much less.

[RogHodge]

Wheel wells- yes there will be cut outs. My 1x2s will run full width on ~12 inch centers. I somewhat understand the way a torsion box works (but am open to correction) the compression load on the inner portion of the bend actually provides a lot of the stiffness.

¼ ply is stronger? My thought is that 2 sheets of 1/8 luan ply would give about 6 layers of ply- I would use some glue between the sheets. The 1/4 would be three plys- remember we are talking about big box cheap ply- the ¼ could save me a buck- even as I write this I think two layers up the hassle factor enough to go with the single ¼ sheet. At the clinic we call my present state “analysis paralysisâ€

[kennyrayandersen]

[quote="RogHodge"]Wheel wells- yes there will be cut outs. My 1x2s will run full width on ~12 inch centers. I somewhat understand the way a torsion box works (but am open to correction) the compression load on the inner portion of the bend actually provides a lot of the stiffness.

¼ ply is stronger? My thought is that 2 sheets of 1/8 luan ply would give about 6 layers of ply- I would use some glue between the sheets. The 1/4 would be three plys- remember we are talking about big box cheap ply- the ¼ could save me a buck- even as I write this I think two layers up the hassle factor enough to go with the single ¼ sheet. At the clinic we call my present state “analysis paralysisâ€

[RogHodge]

Spent a little time modifying the frame- Installed a 2â€

[kennyrayandersen]

[quote="RogHodge"]Spent a little time modifying the frame- Installed a 2â€

[aggie79]

Hi Rog!

Any progress?

Tom

[RogHodge]

Not much progress- I’m still crafting a tongue jack out of a HF scissor jack. I’ve been busy with work- teaching and a heavy client load. The wife and I planned a cruise but then reconsidered and will have more time and $$ after the holidays. Thanks for the bump- I’ll get back on this soon.

[Rock]

Couple of points going from memory here though.

I too had bought a HF tongue jack and found it to be combersome, heavy and most of all noisy. Also my tongue weight is like 15 pounds. I just lift my camper off the ball and shove it into place. Then Andrew commented on something for use in such a light trailer - a simple piece of rectangular aluminum tubing with holes drilled in it at intervals. This goes through a short section of slightly larger tubing with one hole in it. Then you just lift the tongue to the proper height and put a pin in the proper hole. I'm fabbing one right now.

I also seem to recall (maybe in the original Ultralight thread) that Andrew said that continous crosswise members are better in the floor for some reason. So that's what I did:



1/4" luan top and bottom, 1.5" framing members ripped from wider framing lumber, thickened epoxy adhesive and staples, and ultimately fiberglass and epoxy top and bottom. No frame at all. This floor is flat to within 1/16".

Eric

[RogHodge]

Rock-
I think your floor is more than I want/need to do- yes I know that you have no frame. The fiberglass is a nice touch for a frameless model- I bet ageless or someone of similar experience could tell us what extra strength that adds.
I wish I would have seen the tongue “jackâ€

[RogHodge]

Any one do Anza Borrego ?

I did an overnight with a friend and his son to the Anza Borrego desert for New Year’s Eve. FROZE MY A** OFF. Tent camping sucks! It was in the low 30’s and a tent with a cheepy nylon sleeping bag and 2 quilts was not enough. Slept about 4 hours and worried that I would find my daughter a frozen popsicle in the morning. All that to say I am once again in pursuit of my project.

[aggie79]

Hi Rog,

Sorry to hear about the frozen camping experience, but good to hear your TD build is "back on."

Tom

[S. Heisley]

Hi, Rog,

It's good to know that you are back on the build. Once you get the deck on, you'll have another milestone to tout and you could get the trailer licensed and use it as a flatbed to carry building materials for the next step....walls!

We're cheering for you and waiting for those progress pictures!