The Army Explains How Iron Cross is so Hard

[Seiji]

I was reading a reference manual from the army about rappelling. I was reading through the section on anchor points when I came across a chart explaining what happens when two anchors come together and what load each takes.

In other words, your hands are the anchors and they come together at your body.

The chart said this about angles and weight load caused:

0 degrees = 50%

90 degrees = 70%

120 degrees = 100%

150 degrees = 200%

170 degrees = 1150%

Thanks to my research of completely irrelevant things, you all know, through numbers, how much harder an iron cross is than a hang!

It's good insight to know these... and now you can brag about how you are over 10x stronger than most people when you do a cross.

[Nick Van Bockxmeer]

actually from what i can see, this angle would apply to the ring cables, not the arms.

think of hanging a weight from a girder. Two steel cables both attatched to the same point on the girder. The point of attatchment at the mass will determine the tension in the cables required to hold mass up.

the tension will need to have a 'j' component equal to half of the weight of the object. The tension in the cable is a. As theta tends to zero, the tension tends to infinity. A horizontal vector has no force in the vertical direction.

Basically T cos theta = W/2 . which is where he got his numbers from.

In an iron cross, the rings are at about 80 degrees, so the tension is slightly more than half the body weight. The tension in the arms is another story.

[Hayden Whealing]

I decided to have a look GB as a break from my triginometry homework and this happens to be the first thread I look at :twisted:

[Seiji]

I was describing the force required by your shoulders... The force against the rings is the theoretically the same for all static positions. (like you just said)

I'm a bit late, sorry