Recent content by jcmrlec

dbill, we design mobile communications cabins for defence forces. the cases and ecus are stored within the cabins during transport and then taken out when they deploy. we have to provide instructions on how to pack them up ready for transport. this includes detailed instructions on how many...

everytime i post on a forum i remember why i dont do it very often. you are not reading my responses. it is not like pulling up on a rope. it IS closer to squatting or benching a bar. the ratchet ends up at about chest height. the slight angle of the strap and the nearness to the case or ecu...

Littleinch think what you are saying. are you seriously trying to tell me that through human variation after roughly 10+ iterations on each scenario where we got 200kg +-15kg everytime on the ECU and 100kg +-15kg everytime on the case that human error or variation is the reason.

sorry explained that badly. i could crank it up to the point where i couldnt operate the ratchet any more. then the case would slowly deform and release tension (about 5-10kg of tension lost per minute). after a little while i could click it again and add more tension. but i could never get the...

IR i agree but as the case deforms slowly i kept trying ot crank it further and further - thought that would negate this?

it is just one load cell. we did the test on one and took the reading. then disconnected that same load cell and used it for the other case.

No chicopee, the cell and technique was the same for all tests. lilliput not sure what you mean?

Thanks chicopee that was my thoughts hence the confusion. The loadcell was the same unit on both tests.

i wish nescius!

Read the OP and look at the picture on the right hand side. Where i have written 1,2,3 and circled them are the 3 locations we moved the load cell to and measured. The ratchet stayed at position 1 for all of the tests. we got pretty much the same tension in each location. btw it is not a...

Of course it proves there's friction. what i am saying is it proves that friction only effects the tension in the section of the rope after the case edge. Look at the picture below. If there is friction T1 > T2. but the tension in T1 should be the same as if instead of a pulley it was a hook...

the equipment has left our facility so i cant retest that. But it is two very smooth slippery surfaces. try running a strap or a rope over something rough and tightening with a tension loop or truckers knot etc. You will get a much higher tension in the rope on the side you are tightening than...

Lilliput why would that help? As in the pic in the OP we tried the load cell in 3 different positions. The ratchet stayed in the same position. When the loadcell is in position 1 there should be no friction loss in that section of the strap. The tension should only be affected in section 2 and 3...

Hi Lilliput1, We thought that that would happen in the situation where the loadcell is on the opposite side of the case, but in the situation where the load cell and ratchet are on the same side friction shouldnt come into it?

LittleInch i understand what you and NASAs evidence are saying but its not that. I can categorically say that it has nothing to do with it. I weigh 70kg and can easily lift more than that. As i have already stated the angles of the strap made it difficult to put my whole weight onto it and for...