Teardrops n Tiny Travel Trailers

by **shawnkfl** » Wed Mar 19, 2008 8:05 pm

i can give you the basic cross section dimensions of the i-beam i will use, but i cannot post a drawing. i should note, that the i-beams we use are not standard i-beam profiles. they are profiles designed specifically for trailers. more specifically, boat trailers. now, if you had one of our trailers, you'd have the cross section. i just cannot post it or give out drawings. kind of crazy huh? the design of the side rails, cross members and tongue play a good part in the integrity of the trailer, but one key component is the axle. without the correct axle size, the frame is compromised. that goes for steel frames as well. you can take it even farther down and look at tires. they are load rated specifically for trailers. they don't really have as much of a factor in light tears though. i will post up my intended frame design as soon as i'm happy with it and i'll post up what materials i'm using and where. hell, i'll post up my fully dimensioned frame drawing in case someone wants to use it. i will have axle size and load ratings with my drawing, along with spring ratings and torsion arm ratings. i'm going with torsions, but i'll design for either. i'm designing a pretty broad safety factor, so my frame will seem overkill, to me anyway. but it will be light, that's for sure. i'm actually, thinking it may be too light on the highway.....guess i'll have to test that after it's built.

by **G-force** » Wed Mar 19, 2008 8:51 pm

Brian-bp: good posts, thats what I came here to say. The article appears to be more of an observation than facts. It sounds like the Horse trailer industry switched materials without re-engineering the designs for the new material propertys, and thus had failures.

by **shawnkfl** » Thu Mar 20, 2008 3:20 pm

i've got the frame pretty much done now. i can print it off to a .pdf file. can someone convert that to a .jpg file so i can post it up?

by **shawnkfl** » Thu Mar 20, 2008 5:38 pm

ok, coreyjhen was kind enough to convert my .pdf file into a .jpg for posting here. it should be up soon. feel free to offer up any suggestions for any improvements that i could do. i will take any opinions into account, but will still have to maintain the integrity of the frame. i don't have the axle in yet. it's done, it's just not shown on the frame drawing. so, have a look when it's posted and tell me what you think. my design goal was based off the 1800 lb harbor freight trailer, except i wanted bigger and lighter. i got both and still came out with a higher load figure.

by **angib** » Thu Mar 20, 2008 5:45 pm

Or leave it as a PDF, so the detail is readable and then upload it to a teardrops.us account that you can set up for free - click on the link in the menu at the top of this page.

Failing which you can email the PDF to me and I'll make a jpg.

Andrew
angib (at) blueyonder (dot) co (dot) uk
(yes, two dots - we Brits just have to be different, dammit)

by **prohandyman** » Thu Mar 20, 2008 8:02 pm

Made 2 different trailers out of structural aluminum. It is extrusion that is bolted together for all kinds of applications - sort a like a giant "erector set". Made a canoe trailer, and a 4x8 flat bed utility trailer. Bosch has unique bolts and nuts that don't back out. I used to sell it, so I got it cheaper than retail - awfully expensive, and because of the profile, was not any lighter than steel! Pretty cool stuff though!
Here is the linkhttp://www.boschrexroth.com/country_units/america/united_states/en/products/brl/product_overview1/mge/index.jsp

by **shawnkfl** » Thu Mar 20, 2008 8:08 pm

yeah, that stuff is heavy. i've used the 8020 and Item versions of that. it was all hardcoat anodized too, making it very tough and rigid.

by **emiller** » Thu Mar 20, 2008 9:21 pm

In all my metal building I'm not to familiar welding alum, I do know that I was turned away from putting a alum radiator in my streetrod because it was alot harder to find a shop or person to repair one over brass and copper. I have seen alum welds crack in areas of flex. I just hope if anyone has a problem to let us know. We don't want to be going down the road just to have your own trailer pass you up. Keep us posted with pictures of your progress and happy camping.

by **shawnkfl** » Sat Mar 22, 2008 8:39 am

i think i figured out how to convert a .pdf to a .jpg, so here goes my attempt to post the file...

by **brian_bp** » Tue Mar 25, 2008 7:25 pm

Excellent

Thanks for sharing the design.
It looks like the brackets are bolted to the webs of the I-beams, and the crossmembers are enough shorter (in height) than the I-beams that they can be just cut off square on the ends and butt up to the I-beam web.

Are the diagonal tongue/frame braces to be welded to the lower flange of the I-beams and sides of the central tongue tube? It would be nice to be able to do the whole thing bolt-together.

by **shawnkfl** » Tue Mar 25, 2008 8:34 pm

brian_bp wrote:Excellent
Thanks for sharing the design.
It looks like the brackets are bolted to the webs of the I-beams, and the crossmembers are enough shorter (in height) than the I-beams that they can be just cut off square on the ends and butt up to the I-beam web.

Are the diagonal tongue/frame braces to be welded to the lower flange of the I-beams and sides of the central tongue tube? It would be nice to be able to do the whole thing bolt-together.

you are correct. the crossmembers will bolt to the i-beam flange with angle brackets. i'm going to use carriage bolts so it looks nice from the outside. the tongue and a-frame members will also bolt in place. i havn't shown that yet though. my plan there is to just drill down through and bolt them. i made it 120" long, so my tear will be slightly longer than that and 60" wide. i'm not going to cover the i-beam with the side rails.

i have it all modeled in Autodesk inventor, if anyone would like the files, or i can modify them to suit your dimensions. the frame shown is what i'm building, but i would be more than happy to modify them for anyone. they'll be more completer and will include material and cut lists.

by **oldtamiyaphile** » Wed Sep 02, 2009 4:57 am

Hi Shawn,

I'm planning a very similar chassis to yours, my only real concern is mounting the axle. Basically, I have no idea how to do it. Bolting into the 3/16 cross member with six bolts doesn't seem enough.

Should the cross member be thicker or possibly just reinforced with flat along the bottom, adding strength only were needed.

I'm also unclear on how to attach the braces to the drawbar, I was thinking about a plate top and bottom that bolts to the tongue and side beams.

Also, what alloy are you designing for? Most of what I can get is 6060 T5, with some 6001, 6063, 6005A and 6082 (T6). I suppose it's not really critical, but do you have any suggestions on what to put where?

Thanks,

Bert

by **Shadow Catcher** » Wed Sep 02, 2009 6:54 am

The Mega-Mini has an all aluminum frame and I have inspected the TIG welds that are clean and appear to have good penetration. I will periodically do an inspection.
The construction is a 1 ½” by 3” box tube.
The horse trailer article was interesting but as pointed out is by a steel frame manufacturer. A number of the criticisms are not apropos to a teardrop, I hope I do not approach the 1000lb weight of a horse 
One of the things that hits me, is that most trailers seem to be over built. While frames are either over built or under built.

by **bobhenry** » Wed Sep 02, 2009 7:39 am

This is a frame real similar to the one I have corralled for my next build

A retro 4x8 on an all aluminum wave runner trailer.

by **oldtamiyaphile** » Wed Sep 02, 2009 8:08 am

I can't say I'm a fan of the Vee, unless it can be used for something? :thinking:

Teardrops n Tiny Travel Trailers

has anyone went with a aluminum trailer frame?

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