I have thought about the traditional pop up trailer lift mech. (telescoping w/ cables) (my thoughs on that are: complex to build. Hard to retrofit from an existing trailer. if a cable brakes your out of luck at the camp site. not enough depth in the trailer to hide the rear telescopes. & trailer floor is stepped so the under floor mechanism would be difficult to make work.) I have also thought of the lift mech on the outside. (springed hinged arms) I may end up coming back to that idea if I can't figure out something I like. (the reason i havent gone that route is that I want the trailer to be clean on the outside. So it is obvious that it belongs with a 40 series landcruiser.) thats why even the battery, propane tank, water tank etc., will be mounted inside.
This may sound a bit weird, but at this point I am trying to think outside the box. what I am toying with right now is a 48" inflatable cube that would sit on the mattress & inflate to lift the top. Once lifted the existing steel legs fold down and lock into position. then the air bag is deflated and I proceed to attach the tent material. Take down is the opposite. I found a pool toy online that im going to buy to try the experiment to see if I can get the top to raise. If it works, the next step would be to have a more durrable one made or bought. The advantage to this method is that it will lift a heavier load.( cargo on the roof rack etc.) It could lift the top with a low PSI. It simple. Down side is I would have to incorporate a compressor/tank/ hoses etc. & if it leaks im stuck.
The other idea is a scizzor lift. Like the old wesfallia VW busses. Its a little more complicated as far as building and getting springs & such figured out but I think it would be reliable. Down side is the scizzor could be dangerous if anything got caught in it. And it may be too bulky to fit the way the trailer is built.
So right now im going to try the air bag experiment.
I understand, but should point out that I used my pop up for 9 years and never had any issues with the lifting mechanism. It never failed to raise or lower, as designed, for me in 9 years. And I used an impact drill to run the winch. I did inspect and oil the calbes and struts occasionally. And I used this thing almost every weekend and many long extended trips in it. I flat wore the camper out.
The lifting cables could be easily mounted under the floor of the trailer and only the post comes throught the floor inside at the corners. Then add a drill motor or small elecric winch and you could remote control the thing. That would be out of the box, Kinda! And would keep the outside lines of the trailer clean.
My problem with the air piston rams is they have horror stories going around about how they don't lift evenly. The PU cable systems have pretty much made it impossible to get them out of sync.
The Air bag idea will work well since it's lifting in the center. Storing the thing will be an issue, but nothing insurmountable.
I have a problem with scissor lifts as they tend to collaspe at the most inopportune time and can sever fingers without notice.
I had a Coleman PU with scissor lifts before I bought the Jayco and keeping the assist springs on the lift mechanism was a constant hassle. And it would collapse on one end and tweak the top every time I turned around. That's why I sold it and went to the Jayco with the winch assited lift system. Much nicer to break down and set up. The Jayco is what I enjoyed for 9 years. I hated that Coleman because it was such a pain to set up by myself.
You'll figure it out I'm sure. Your Budget will dictate how fancy the thing gets. So build it to suit yourself and enjoy it while the kids are little. I have a lot of good memories of camping in the woods next to the river with my kids when they were younger.
Best Wishes to you!
Curtis
