Rubber banding geometry

Anyone know how to correctly setup the geometry (or the physics behind it) for rubber bands on a dr4b to maximize efficiency of the lift?
For example why are c-channel extenders used on this lift and why is the triangle shaped the way it is @meng :
Screenshot 2017-09-30 at 10.07.49 PM.png

In Vex, it is known as uniform tensioned rubber band (or elastic) system.

The detailed analysis can be found here.

https://vexforum.com/t/uniformly-tensioned-rubber-band-system-analysis-guide/28402/1

We have shamelessly adapted from the earlier work done by those teams mentioned in the thread.

Edit: it was a very popular technique used by many teams during sack Attack and skyrise.

Edit 2: think the thread that I mentioned is a good example of the quality of technical discussions that many oldies (ie. I am one of them) in the forum were talking about.

Thanks a lot I wouldn’t have found that guide on my own. Kinda wish vex had like a better organized forum with folders for really useful technical help / quick tips that stayed organized via relevance not date

You are welcome.

Guess to be fair to my team… don’t think they saw this thread before too. They figured it out on their own.
But when they tried explaining it to me about it, I knew it is a variation to the idea of uniform tensioned system.