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loaderman wrote:With a festiva as a tow vehichle you need really light, and really aerodynamic, and as low as possible. For 4 people and all your gear that is a tall order.
Ok for aerodynamics keep it as low as possible, rounded front tapered to the back. This is considered the optimum shape.
The narrower the better perhaps you could go 4'6" wide? a double bed. Narrow and long is better then wide and shorter.
Also use torsion axles to save weight. and an aluminum alloy frame for the trailer, not straight aluminum as it is considered to soft from my reading. There are also other special considerations in using aluminum so talk to a reputable welder/ trailer maker.
A possibility is a pico light frame design http://www.tnttt.com/viewtopic.php?t=34755
Look at motorcycle camping trailers. they have small weight. To stay in your weight restrictions you will need some sort of tent type trailer. Maybe even a trailer that you put a tent on! So you store your stuff in trailer when traveling, then put it in the car while you sleep in the trailer. Yes I know it is a little work but with your weight constraints....
Here is a roof top design that is good you could adapt the principles for your size.
lthomas987 wrote:For your door thoughts and some design ideas look at the Army Goose build. Foam is really tough. Look at the fate of the first Penguino! You need very little wood framing. Mostly just around doors and windows.
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dancam wrote:I would think a boat trailer or homemade thing would want to twist a lot while driving and living in it and place a lot of stress on your walls and foam frame wouldn't it?
loaderman wrote:I looked up recommended towing capacity for the festiva, it is about 500lbs! by going over 1500lbs you are risking blowing the transmission.
Driving 90km/h (about 55mph) will help a lot.
A 5'" wide trailer (outside measurements) , abuot 7' long, and about 16"' high with a flip lid (another 6" to the height) for a total of 24" max height. The lid flips open to the side, that pulls the tent top up as you open it. So very quick set up. The lid becomes the parents bed. the bed also is the Bench for sitting at a couple of tV trays that is why the 16" height to the main trailer body.
A 16" shelf across the front, gives you lots of storage. 16" by 4'6" under the shelf then stuff on the shelf when parked. So 9' of storage space
2 mats about 27" by 4'6" for the kids bed side by side on the floor or you could put one on the floor crosswise and 1 above with legs under a "shelf" bed for them. This would give you more open floor space at the back inside the door. These can be rolled up or put on the parents bed so not being walked on.
Take a look at the pico light frame link I gave above. Use your axle if you must and then that triangular frame.
do a sandwich floor construction. painted canvas,1/4" plywood, 2" styrofoam, 1/4" plywood, light and strong.
An awning for the entry door would be nice, cause in 3 months you will get rain, shade is also nice.
This could be well under 1000lbs and probably more like 500lbs.
I could do up a 3d drawing if you are interested?
If you do a trip through canada and alaska I would love to meet you. I am Canadian and have lived in 5 provinces, my wife has lived in 6! We are near Dawson Creek B.C. which is the start of the Alaska Highway.
Aerodynamics doesnot affect braking and those little brakes are going to be working hard in the mountains! LOL
KCStudly wrote:dancam wrote:I would think a boat trailer or homemade thing would want to twist a lot while driving and living in it and place a lot of stress on your walls and foam frame wouldn't it?
Absolutely not! (With caveats.) A relatively flat trailer frame does not stiffen the cabin a whole lot. Think of it this way instead, the 3-dimensional structure of a light but sturdy cabin stiffens the trailer! The strength comes from the sum of all of the light weight parts, not from any single part or element of the build. Think Bird Cage Maserati (a race car built with no major frame work, just a bunch of little tubes), not Sherman Tank (a heavily armored vehicle).
Over building (and over accessorizing) is a slippery slope; the heavier you go and the more features you add, the stronger the structure needs to be in order to support itself. With regard to storage for "stuff", I'm reminded of George Carlin's bit.
The caveats are that you need to build with nice tight sound joints, and in a purposeful manner. So do dry fit tests of your joints before you glue and make corrections to fit as needed; clamp, biscuit join, screw or otherwise reinforce your glue ups; don't use rickety hardware store brackets and rough cut lumber w/o any glue; use your bulkheads and cabinet frames as integral structure, or add stiffening ribs (ala GPW's foam arch concept); and secure the cabin through the floor around the perimeter using several modest sized bolts or TEK screws rather than just a few large ones.
The strength comes from the depth of section (mostly wall height and bulkhead width, but also separation of the inner and outer skins on any given member) and the strength of the outer fibers (skins). The advantage of foam over wood is that it is so much lighter, yet relatively non-compressible over large areas; it holds the stronger outer fibers, the canvas, thin ply, or FG skins, where they need to be to do the most good. Think of an 'I'-beam: the flanges do the work while the center web keeps the flanges separated. The deeper the section (taller beam) the stiffer the beam. Now look at the typical cabin box. The walls are very tall compared to the height of the trailer frame tubing or channel. Despite being made from weaker materials, the depth of section is so much larger that the outer fibers have more leverage, in effect, and end up being so very much stiffer. That's also why a 1-1/2 inch thick canvas coated piece of light weight foam is as strong (dare I say stronger) in bending than a heavy piece of 3/4 inch plywood.
Special consideration may have to be given to a Goose style build that has a relatively large opening, but that, too, is doable.
You will be amazed at how rigid a lightly built structure becomes when it all comes together. The trailer is not the foundation to a house, it is merely a bracket that connects the tongue and axle to the cabin.
How many times have you read a builder comment that as soon as they put the roof skins on their cabin stiffened up remarkably? My trailer, made out of 2x2 steel tube, is still out in the yard. If I sit on the back xmbr it flexes about the suspension points just a little bit before the jack lifts off the ground. With the roof on my cabin I can nudge any corner of the floor or walls, or start to lift it and the whole thing moves as one; no flex. None. Solid as a rock, but light enough for me to push around. (Okay, I admit that my build is not going to set any records for being the lightest foamie out there, but the point is the benefits of unit construction work.) So what do you think is going to happen when I bolt it to the trailer frame? That's right, the trailer will be held rigidly by the cabin. (This is also why it is so important to have a sturdy tongue and integrated connection to the trailer frame proper; because the point of flexure now becomes the joint between tongue and front xmbr.)
Trailer frame: Flex.
Cabin Floor: Flex.
Walls up: Flex.
Bulkhead in: Okay, now we are getting somewhere.
Cabinet face frames in: That made a difference, too.
Front wall on: Hey this thing is starting to get pretty rigid.
Roof on: Granite baby! This thing is solid as a rock and isn't going anywhere.
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