Thomas, The bessler is a cool design, but the biggest weighs less than 190 lbs and at 19'' wide it's more ladder than stairs.
Do you need a door/hatch to seal heat/cooling from your second floor? I have one so it complicates a Bessler type design. My stairs end 5' from a wall on the 2nd floor and at 17' long they weigh over 400lbs. so the Bessler style is out for me.
Thomas,
I have the Bessler disappearing staircase in my house. Easy to pull down, rated at 800 lbs, it is a pull down staircase, not a pull down ladder.
Sam
I've seen (videos of) stairs done with gas shocks, and with cable/spring coils.
In addition, my 1949 house has a truly retractable attic stair. The access door is 54" long, and the staircase reaches the 8-1/2 foot ceiling.
When I pull down the access door, the (fully solid, not hinged or collapsable) stairway slides down on tracks. When I'm done, I first push the stairs back up into the attic, then lift them and the access door to the closed position. All is done with cable/spring coils, so no heavy lifting is involved. Note that this requires attic space to store the retracted stair.
I built a retractable stair for a customer this year that uses a set of antique blocks with a sailboat winch. The stair was 36" wide with 13 risers at 7.25" and a 9" run. This made the stairs about 13' long so the last 3' feet fold under in order to fit in the well hole.
The stringers have open treads with no risers so I made the stringers from 12' x 2' LVL and veneered them with 1 piece of 1/4" baltic birch ply on both sides with 1/16" cherry veneer. The treads were solid cherry. The whole thing weighs around 350 lbs.
The block and tackle system work well, but it was originally planned to have a winch. However time constraints made the manual system more simple to install.
I used a heavy piano hinge for the top and made my own hardware for the folding bottom treads.
If you want I could post some photos and get the info on the hardware.
The issue I see with the u-tube design is that the hardware and support system all hang below the ceiling plane. I was not able to have that with my design, so everything goes up into the ceiling and nothing is below the ceiling plane.
J.P.