Hello everyone. I'm just getting started on a project that involves developing a computer controlled winch that will vertically raise and lower a payload. The winch drive will be located on top of a structure or cliff and will be lowering (and raising) the payload vertically from that position. I have very basic mechanical knowledge but am no engineer. Since I'm developing this project from scratch I'm hoping that I can run some ideas past the experienced and knowledgeable folks here. I'm sure some of my questions will be very elementary for you so hopefully its not going to bore everyone to tears! So...I think I have the basic concept worked out for how it will function and am now working on determining what I need for a drive motor. This requires knowing the torque requirement and that will depend on the mass being moved. The winch will be using steel cable of some kind to raise and lower a payload that I estimate will weigh about 15 kg up to (theoretically) 100 m of height. I need to be sure that the cable I am using meets the required safety factor so I have done the following calculations for three different thicknesses of cable (Bright wire, uncoated, fiber core (FC) wire rope, improved plow steel (IPS)). I have estimated that I'll want to be able to accelerate the payload straight up at a maximum 5 m/s/s which is where I get the 15 m/s/s I use in the equations: 3/8â€ Cable: Weight of 100 m = 36 kg Assume weight of inspection head = 15 kg So total weight = 51 kg Safe weight = F/a = 10.9 kN/15 m/s2 = 10900/15 = 726 kg Safety factor = 14 5/16â€ Cable: Weight of 100 m = 24 kg Assume weight of inspection head = 15 kg So total weight = 39 kg Safe weight = F/a = 7.56 kN/ 15 m/s2 = 7560 / 15 = 504 kg Safety factor = 12.9 1/4â€ Cable: Weight of 100 m = 16 kg Assume weight of inspection head = 15 kg So total weight = 31 kg Safe weight = F/a = 4.89 kN/15 m/s2 = 4890/15 = 326 kg Safety factor = 10.5 So, assuming my calculations are correct, what kind of safety factor would an engineer be looking for when designing something like this? I should also ask whether the type of cable I have specced is suitable for an outdoor application like the one I have described.