unnamed trailer build journal

[pbrunicorn]

I have been researching and studying the design of tear drops on and off for the past year. I am finishing up my AAS in Welding and Metal Fabrication this spring and figured one of my projects could be a tear drop build. I started drawing the trailer up in CAD yesterday and as of today I am at a point in cad where I have a basic shell or frame made of the trailer, the walls, ceiling and galley hatch.



larger image can be seen here http://www.flickr.com/photos/moomoocow/4008599949/

When designing this I decided on a couple of things:

Simple - This is my first build and first project of this size. I can save the fancy stuff for my next build. I am a firm believer in the kiss method for everything.

The cabin needs to be big enough for me, my fiance and our two med/large dogs.

All we know is tent camping, we are not looking for a lot of luxuries other than making camping easier and slightly more comfortable than where we are now.

With these things in mind we decided need a king size sleeping area to accommodate us and the dogs. I am planning on getting two twin mattresses and turning them 90 degrees to give us nearly a king bed. We will put a foam topper on top of the mattresses.

We are not looking for a water tank, being able to power a microwave, mini fridge, kegerator or anything outside of the tent camping spectrum. We take coolers, our dutch oven and our grill when we camp.

With my current design the outside width is 82" and the length of the camper is 104" plus the tongue being just under 40". I will have a storage box on the tongue as well as a propane tank. The sleeping area will be 80" long. I will also need to alter my current design and remove some of the extra horizontal supports that are currently there.

WHEW looks like more work in Autocad today.

[madjack]

...nice looking start and a heck of a project...the only things I see are a lot of complicated and possibly unneeded metal and fabrication in the floor frame...I would consider dropping the tongue under the floor frame and running it back to the second crossmember and the same with the tongue side braces...you could probably eliminate a couple crossmembers that way and the side braces would double as the same thing as those front diagonal braces, eliminating them as well...keep in mind at 80"s plus width, you will need additional marker lights to be in compliance with DOT regulations........
madjack

[pbrunicorn]

...nice looking start and a heck of a project...the only things I see are a lot of complicated and possibly unneeded metal and fabrication in the floor frame...I would consider dropping the tongue under the floor frame and running it back to the second crossmember and the same with the tongue side braces...you could probably eliminate a couple crossmembers that way and the side braces would double as the same thing as those front diagonal braces, eliminating them as well...keep in mind at 80"s plus width, you will need additional marker lights to be in compliance with DOT regulations........
madjack

Thanks, I am playing with that right now. The braces are currently set on 16 centers by the recommendation of the dept head. From what I have seen I believe I can spread those out a bit further and still have a sound trailer. I am going to talk to one of the instructors here who has built a few trailers and see what he recommends also.

The square tubing around the outside of the trailer frame is 2x3 and the inside is 2x2. This leaves just enough room to drop 3/4" plywood down and have a level floor.



larger image here http://www.flickr.com/photos/moomoocow/4008782807/

Thanks for the input and feedback

[corncountry]

I agree with madjack on the frame. I see you have already changed the sides.
What are you going to side it with? Aluminum sides will also add strength to the frame.

Jim

[pbrunicorn]

I agree with madjack on the frame. I see you have already changed the sides.
What are you going to side it with? Aluminum sides will also add strength to the frame.

Jim

I am going to work on a few floor changes tomorrow so I can get materials for the trailer ordered through the school and get started welding in the next week.


I am up in the air about how I will skin the inside and outside.

How can I attach the aluminum to the steel frame? Rivets? I have also thought about 20 -24 gauge steel as the outer skin then painting it.

Any ideas??

[pbrunicorn]

at the final stages of of frame design, havent built in the shelves or cabinets yet



larger image is here
http://www.flickr.com/photos/moomoocow/4011663019/

The weight of the trailer frame without the flooring or axle is 330 lbs. The weight of the teardrop frame is 207lbs.

I have built the frame onthe trailer so the cross members are an inch shorter than the outside and center beams (if that makes sense) This allows my floor to sit in the frame without having to create a floor frame with 2x4s

Dimensions:

the outside width of the frame is 82" and the length is 104" so this will be a bit larger than most (i think)

comments, concerns, suggestions ?

[Ageless]

Personally; for the size; that's built like a tank!

I'd lose 2 or 3 crossmembers in the frame; and just use one vertical between the door and rear.

[Juneaudave]

I am up in the air about how I will skin the inside and outside.

How can I attach the aluminum to the steel frame? Rivets? I have also thought about 20 -24 gauge steel as the outer skin then painting it.

Any ideas??

Maybe Ageless or someone can chime in, but I've been waiting for a (ahem) test tear to try using some of this 3M VHB Tape for attaching aluminum sheet fgoods to a steel frame... seems like there are some inherent advantages if it works..no rivets or holes to leak, a positive barrier for galvanic action.

[madjack]

...first thing to keep in mind...these trailer are not needed to be ANYWHERE near the strength of a normal utility type trailer...they will never see the loads and are further strengthened by the rest of the framing members on the body including side and cross bulkhead...IIRC put my crossmembers on a varying 30"centers(using 5' ply)...they were 2x1/8th angle, the perimeter frame is 1x2x3/16 "C" channel with center tongue tube of 2x3/16 tube with the "C" channel for side braces...I would seriously consider downsizing your steel and lightening things up considerabley......
madjack

[pbrunicorn]

Thanks for the replies, I'm hearing a lot about weight. What would a normal (5x8) build weigh at this stage - trailer, wood framing, galley door and roof bracing? What is an ideal weight that i should be shooting for with this size (82x104) of a build with a steel frame?

I'm not trying to sound like a defensive jerk, just looking for more advice/opinions. Believe me, I love constructive criticism.

Personally; for the size; that's built like a tank!

I'd lose 2 or 3 crossmembers in the frame; and just use one vertical between the door and rear.

removing 1 vertical from each side of the TD frame removes 25 lbs (12.5 each) I am assuming by frame you are taking about the trailer frame. Each cross weight just over 9.5 lbs. Removing 2 would remove 19 lbs. Is that a significant enough removal of weight to make a difference? From what I am understanding if I make my centers larger on the floor I will have to go with a thicker sheet of wood which will increase weight also. The framing on the wall is also 16" centers because when I skin I only have those points to attach to. I am afraid if I go too wide I may run in to bowing, bubbling, wobbly siding.

Maybe Ageless or someone can chime in, but I've been waiting for a (ahem) test tear to try using some of this 3M VHB Tape for attaching aluminum sheet fgoods to a steel frame... seems like there are some inherent advantages if it works..no rivets or holes to leak, a positive barrier for galvanic action.

That stuff looks nice. I wonder If i can get the college to order it for me and get their wonderful discount. Thanks for pointing my attention to that.

...first thing to keep in mind...these trailer are not needed to be ANYWHERE near the strength of a normal utility type trailer...they will never see the loads and are further strengthened by the rest of the framing members on the body including side and cross bulkhead...IIRC put my crossmembers on a varying 30"centers(using 5' ply)...they were 2x1/8th angle, the perimeter frame is 1x2x3/16 "C" channel with center tongue tube of 2x3/16 tube with the "C" channel for side braces...I would seriously consider downsizing your steel and lightening things up considerabley......
madjack

I think the problem with metal fabrication guys is they build everything big simply because they can. Quality, Craftsmanship, Strength and Durability even if its way more than we need seems to happen with everyone's classroom projects.

My end goal is to weigh less than 1500 lbs loaded. My vehicle can easily tow twice that. At this point I have about 1000 lbs left to floor, install axle/wheels, skin, insulate and shelve with.

After I tack the walls and before I attach them to the frame if I feel I can get away with removing some of the pieces of the frame I will, same with the trailer.



Again thank for your feedback and criticism. My first batch of steel should be in next week so I can start cutting, deburring and tacking a trailer frame together. I should also be able to pick up my flooring material sometime in the next few days and start sealing that up in my garage.

[madjack]

Brian, my first crossmember is centered 30" from front, the second at 60" and the third splits the difference to the back...I used two SINGLE sheets of 5x5x1/2ply to make up the 5x9 floor floor, I then place a sheet of 1" blue foam board on top of that and then my 6" mattress...there is no bow/flex to the floor from our use...I too, would recommend the use of #M VHB(very high bond) tape to put the sides on...this stuff is used in the automotive industry to apply trim, medallions and such to the body, it is tough stuff...
madjack

p.s. my trailer frame w/torsion axle and tongue, less wheels, weighs in around 150#s...the total weight, loaded up is around 1000=1200#s...keep in mind, no matter the tow vehicles capabilities, for each unneeded pound, you will pay a fuel mileage penalty....mj

[pbrunicorn]

Brian, my first crossmember is centered 30" from front, the second at 60" and the third splits the difference to the back...I used two SINGLE sheets of 5x5x1/2ply to make up the 5x9 floor floor, I then place a sheet of 1" blue foam board on top of that and then my 6" mattress...there is no bow/flex to the floor from our use...I too, would recommend the use of #M VHB(very high bond) tape to put the sides on...this stuff is used in the automotive industry to apply trim, medallions and such to the body, it is tough stuff...
madjack

p.s. my trailer frame w/torsion axle and tongue, less wheels, weighs in around 150#s...the total weight, loaded up is around 1000=1200#s...keep in mind, no matter the tow vehicles capabilities, for each unneeded pound, you will pay a fuel mileage penalty....mj

noted - when my steel comes in I will play around with configurations and see what I like. Thanks for the advice

[pbrunicorn]

My order for steel is in (i think he did it today) im not sure when it will arrive, I am hoping by weds next week. I designed a storage box for the tongue today.




http://www.flickr.com/photos/moomoocow/4015066390/

Then used the plasma cnc to to cut my pieces out.



http://www.flickr.com/photos/moomoocow/4014450943



http://www.flickr.com/photos/moomoocow/ ... hotostream

after the pieces were cut, I cleaned them up with the wire wheel

<img src="http://farm3.static.flickr.com/2578/4015299246_65f95d3504_m.jpg" width="240" height="180" alt="1015091513.jpg" />

http://www.flickr.com/photos/moomoocow/4015299246/

then tacked up the inside of the bottom of the box



http://www.flickr.com/photos/moomoocow/4015452332/


Tomorrow I will clean/deburr the lid sections and get them tacked together. The possibly start welding.

[caseydog]

I just started reading your build thread. One bit of advice garnered from reading a lot of build threads... Darn near everyone overbuilds their first teardrop.

Keep in mind that the rigidity of the finished teardrop is greater than the sum of the parts. Your frame doesn't have to be rock stiff all by itself. Can your CAD program show the effects of adding a skin to your framework?

Anything you can do to keep the weight down will make you happy, in the long run. Whether it is better gas milage, easier towing, or just being able to move the thing around by hand when you gat to camp, you will appreciate light weight.

CD

[pbrunicorn]

I just started reading your build thread. One bit of advice garnered from reading a lot of build threads... Darn near everyone overbuilds their first teardrop.

Keep in mind that the rigidity of the finished teardrop is greater than the sum of the parts. Your frame doesn't have to be rock stiff all by itself. Can your CAD program show the effects of adding a skin to your framework?

Anything you can do to keep the weight down will make you happy, in the long run. Whether it is better gas milage, easier towing, or just being able to move the thing around by hand when you gat to camp, you will appreciate light weight.

CD

I am sure I will overbuild it but at the same time this will be an excellent learning situation while I am in school and for future projects (whatever they may be) I have the flexibility to change plans if I need to. I should be getting my plywood for the floor tomorrow. I will play with centers at different areas and change as needed.

I used autocad 08 at home and autocad 09 at school. I can draw and apply a skin to it and will eventually when I get to that part of the build.