Looks like the Petzl team have been busy whilst promoting the new Maestro (not a device I’d expect to see LCMLAs using) and looking at haul systems, mechanical advantages and friction.
In the usual Petzl stylish way of clearly illustrating complex techniques the following web pages are well worth a look at.
- How to Calculate Mechanical Advantage
- How to calculate the MA
- Pulley Efficiency Tests
- Realistic figures on the effort needed to pull a 100kg load through a Maestro, ID (so you’d assume a RIG as well), Pro and Micro Trains, Rollclip & crab