First Post from Louisiana

[sdtripper2]

Sushidog:

You also have to keep in mind the side mirrors.
You won't be using the rear mirror and the side mirrors must be functional.
A 6' trailer besides drag will most likely make it mandatory for you to extend
your side mirrors for functionality.

[sushidog]

Welcome Sushidog!

Sounds like you have some really interesting plans; it'll be fun to watch them develop.

Okume plywood is great for its weight but it is not a very durable wood, which is why it's usually encapsulated in epoxy or glass/epoxy. If you treated the Baltic Birch as you would the Okume I believe you'd get similar results.

Gee, I thought the okume was marine ply - the kind they build boat hulls out of with just a little paint to seal the surface. I'm not about to pay $55 a sheet for something I've got to glass to use - this defeats the purpose.

What's the lightest material you would suggest using for the roof and body?

Thanks for the help.

[Tear Les]

I wouldn't tow anything as large as 15ft with a Cobalt, even an empty flatbed. The TV just doesn't have a long enough wheelbase and weight for something that large. Your proposed plan will probably surpass the GCWR before anything else.

I don't agree. The Cobalt has the same wheelbase (103") as a Toyota Tacoma and I doubt anyone would worry about seeing a 15' long trailer behind that (but I'll admit it looks more "right" since it's a truck).

I could put a 10' load behind the Cobalt that would scare the driver to death; I could also put a 20' load back there that would track like a dream. It's all about balance and geometry and not about absolutes like weight and wheelbase alone. All of them come into play and every combination of tow vehicle and trailer is going to be different.

Sushidog...don't change your design from strictly a length standpoint. You need to keep doing the research you are to find out what combination of elements will give you the trailer you really want. You may find the limitation is weight, you may find it's length, you may find it's width, or any number or factors. As Andrew points out the shape of the unit has quite a lot of influence on its stability and how much it may "wag its tail".

I can tell you from personal experience that a 25 foot boat tows a heck of a lot better than a 25 travel trailer. There are many factors at play in that situation but certainly one of the major ones is the balance of the trailer and where the axles are relative to the hitch and to the overall mass of the load. Fifth wheel travel trailers were a boon to the industry because they don't severely fishtail and flop over nearly as often as poorly loaded (or poorly desgined) tag-a-longs. The tongue weight needs to be right as well as the overall balance of the load.

Weight is important. Regardless of how much you beef up an engine to haul a load the frame or unibody of the vehicle must still deal with the loads inflicted on it and the brakes must still stop the vehicle (downhill in the middle of the night with it raining cats and dogs). Electric brakes on the trailer will help a lot. The Cobalt isn't a very heavy vehicle, put brakes on your trailer to make sure it keeps following the tow vehicle rather than trying to lead.

Have fun with your design!

[angib]

I think it's weight that may be the problem with this design, sushi. You've got fixed loads totalling 660lb, add say 150lb for clothes, food, stores, etc and you're at 800lb - and that's in addition to the trailer itself. Making a 15ft long 5ft wide pop-up trailer body and frame for under 1200lb is no doubt possible, but it's not easy.

You want to take everything with you, so I would like to see at least a 20% weight margin for 'growth' during the build as well - that means planning on a 1600lb total weight today, as that may grow to 2000lb by the time you're finished. So you need to believe the body and frame will be under 800lb, which is edging close to impossible.

And that gets you a trailer that's twice the tow rating of your tow vehicle. You might well be able to tow it, but if you have a collision, I imagine your insurance will be void, even if the police don't prosecute, eh? Yes, cars on the same floorpan in Yurp can tow 2200-3000lb, but that's with a hitch weight that would be considered dangerously low in Merka.

It seems to me that you're trying to get a quart into a pint pot.

Andrew

[doug hodder]

Sushidog...there may be some info here that will be of help to you...I used 4mil Okume on my last woody, but it was laminated on top of the 1/2" ply wall. I dyed it and coated it out in epoxy for the look...If you are going to paint, I'd think there are going to be other materials that would be more cost effective... FAQ on ply, mostly for the boat building crowd http://www.boat-links.com/plyfaq.html Doug

[sushidog]

It seems to me that you're trying to get a quart into a pint pot.

Andrew

Yessir, I agree with your evaluation of my dilema. When I started this thread, I acknowledged that my requirements will be next to impossible to satisfy. But you see, I have no other choice. Besides, I like doing the hard stuff.

Let's look at the alternatives:
1. The best gas mileage I could get out of a $40-60k class C motorhome (with a toad) is probably 10-12mpg.
2. A travel trailer (even a trail manor) towed behind a v8 pick-up will probably yeild similar results, considering I wouldn't have a 30+mpg vehicle to run errands with while the travel trailer is parked.
3. Forget the class B's. For upwards of $90-100k (for a Roadtrek) they provide the same or less space than my proposed rig, yet still only return 15-20mpg at best.

Given a $500 a month gas budget (just to pick a round figure), this equates to only 100 gallons in gas assuming $5 a gal. avg. (which I think is realistic over the next 10-20yrs.) At 10mpg I could only travel 1000 miles a month (33miles/day) - totally unacceptable. But If I can average 30mpg, this would give me a more reasonable 3000mile/mo range or 100miles/day.

If I must cut creature comforts, such as smaller holding tanks, batteries, etc. then so be it. I have already removed the rear seats from my tow vehicle to free up more interior space and completed some other weight saving mods.

This might free up a couple hundred lbs. from the trailer as I relocate some goodies to the car, such as the generator. I could also increase the size of my car battery and mount the inverter in the car, so I could go without this 90lb+ wt. in the trailer.

I really need to think outside the box for this one. I need to design this like I'm building an ultralight aircraft, stricking to lightweight aluminium for the frame (you wouldn't build an aircraft with a steel air frame), composites, and possibly even balsa wood, carbon fiber or other exotic materials to add strength at critical points, while saving weight.

Regardless how much I have to spend on the trailer (it will certainly be less than a good used class C,) I think the fuel savings alone vs a class C could pay for the entire trailer in a couple years (est. $24k fuel savings in 2 yrs.) If you consider the insurance, and maintenance savings vs a class C, I'm way ahead of the game. The difference in tires alone will save me a bundle.

Anyway, this is my reasoning behind my decision. Foolhardy? Maybe, but I'm welcome to suggestions if anyone has a better/cheaper way to live full time on the road - with at least some comforts of home, such as an inside: toilet, shower, a/c, kitchenette, tv etc.

[BillyLandry]

Hi Sushidog
Glad to see another LA man enter this craziness. Welcome. Sorry I can't help you on fulltime mobile living. Just read a lot of this stuff on the forum.
You will come up with something. I am from Franklin, LA.

[sushidog]

Hi Sushidog
Glad to see another LA man enter this craziness. Welcome. Sorry I can't help you on fulltime mobile living. Just read a lot of this stuff on the forum.
You will come up with something. I am from Franklin, LA.

Dear Billy,

My mother was Anola Landry from Opelousas La. We might be kin.

It's good hearing from you. I'll be researching and planning for quite a while before I start my build. I want to make sure I get it right the first time. It looks like I'm going to need to use a lot of high-tech stuff like SIPs, aluminum alloys, etc and some solid engineering to keep the weight down. These materials can be very expensive - leading to very expensive mistakes if I'm not super careful.