The problems with the Flippac and torsion bar setup, as designed, are two-fold. First, the torsion bar is subject to very high stress as it rotates + or - 90 degrees from the neutral position. Compare this with a typical automotive front suspension torsion bar which maybe rotates 20 degrees or so. My rough calculations showed me that the stress in the Flippac bar when it's rotated to the open or closed positions is about 100,000 psi. Applying a nominal safety factor of 3 means you need a steel which is heat-treated to about 300,000 psi (300ksi). Not unobtanium by any means, but not a job for the village blacksmith (with all due respect to blacksmiths).
Second, all that load is fed back into the structure of the camper shell and lid. I am not quite sure how long the brackets that the t-bar is splined to, extend into the lid and the shell, but I'm pretty sure they're less than a foot long. That means there is over 1000 lbs force, maybe more, being reacted into the camper over a pretty small area. So if the t-bar doesn't break first, the shell will eventually fail as the fit loosens and/or corrosion weakens the structure. And there's plenty of evidence that this is a "when" not an "if". However, in my experience the torsion bar delete really does make it difficult to deploy the Flippac lid, so it's not really a universal solution.
What I think is needed is a combination of a stronger t-bar material, but a less stiff spring to reduce the stress in the spring, with the result being less assistance when opening the lid and less support (counter balancing) when it's fully open. Then, compensate for the reduced assistance with a longer crank handle (or better yet, a geared handle); and offset the reduced support in the open position with stronger support rods that are attached more securely to the lid, and to the vehicle (bumper brackets or sturdy cowl brackets). It would be good to add some kind of damping to slow the descent of the lid as it approaches horizontal - even friction would help. It's all feasible ... it just needs some real engineering. For example, since the t-bar rotates 180 degrees and is neutral at 90 degrees, why all the splines? There's no need to "degree" it in to preload the spring. A simple square end fitting into a square opening would be much cheaper and easier to grind to shape, especially if the bar is made from a stronger (harder) steel which is otherwise difficult to machine.
Anyway, just some thoughts ...
-dman93
