try finding the " very best " equipment and pictures being produced for these automated greenhouses. then copy them ....
because they should have better structure ect for more idea's .....
im thinking the tarp will fold up, wrinkle in spots then let in leaks on edges over time. or does the large span of the greenhouse require a support so the center of the long rod w/ tarp does not sag causing massive pressure on the center of your structure. Because in a machine shop all the longer pieces / cylinders always have center support when turning .... so you might need a steel / metal support that holds the center true - its gonna be a stress point for sure over time.
It seems they are designed in a way that keeps the tarp taught. These are my thoughts from looking into this system:
The center of your blackout tarp is pinned to the center ridge (using emt or wood). The "flap" edges on either side of your greenhouse are attached to emt using wiggle wire and base channel. I feel like the weight of this emt roll bar is what pulls the tarp taught between the ridge and the side. In my case our greenhouse is 52ft long so the roll bar is slightly longer.
I can calculate the weight of my roll bar by taking the total weight of a 1ft section of the emt (whatever size I'm using) and multiplying it by the length of my greenhouse. Luckily my brother, who I'm growing with, is an engineer and can do the hard math on how much pounds of pressure this applies to the center ridge where the tarp is pinned.
In most situations I see people having issues with the end wall edge seam. Some growers have overcome this by extending their end-wall film about 2ft-4ft into the interior of the greenhouse along the top. This helps to dissolve any potential light leak. Vic versa the blackout tarp is cut about 2ft longer than the actual greenhouse.
I noticed in Emeralds design that the motor is mounted to a self adjusting pole. This means that the motor can move up and down at will according to gravity. Maybe the weight of the motor will also help to keep the tarp tight.
I have also seen people attach bungies from the bottom of the greenhouse on one side and up to the ridge. Besides the weight of the motor (and possibly added weights?) you would also have these bungies guides keeping your tarp pressed to the surface of your grow film.
So really, besides trying to innovate a bulletproof solution for light leaks at the edge seam near the end walls, I think it would work. The standard factors of the quality of blackout cover would apply and you would need to change it out when it gets worn out. Obviously I wont know until I get into it but I will 100% share my build as we set it up. Getting input from everyone will really help!
Here's a doodle: