DMM Dragon Cam Vs 1.3 Ton Boulder

[gryphontaboo]

Does this prove that the cam can pull a boulder out of the wall and onto the climber?

[mxhost1]

That explains how they set a boulder on the pallet...

[wburgboy75]

Aaaaaand... I know sometimes the conversion from metric to standard is a sumbitch, but 1.3 tons, or 2600 lbs does not equal 14 kilonewtons, it equals about eleven and a half kilonewtons. Other than that, it really is a good presentation on how good cams hold in good rock.

[pigvarley]

@wburgboy75 If they're going by the UK definition of a ton, it's about 2,240 lbs. So this 1.3 Ton rock is probably closer to 13kN, though still not 14kN.

[wburgboy75]

@pigvarley I didn't know that the British ton was more than a kN more than the US ton. Sooo... fair enough. Less inaccurate than I thought. You learn something new every day I suppose.

[EdMajinLee199999]

@pigvarley kN is a measure of force, not weight.

[pigvarley]

@EdMajinLee199999 Weight is a force, it's mass that is not. Per the physics definition, Force = Mass x Acceleration. In SI units 9.81 Newtons (N) = 1 kg x 9.81 m/s^2. For American units this translates to Pounds Force ( weight) = Pounds Mass x Gravity, or 32.2 lbs-f = 1 lbs-m x 32.2 ft/s^2. Since gravity is constant on Earth, Mass and Force are interchangeable, as with 2.2 lbs-f = 1 kg. So with that, 1.3 tons x 2,240 lbs-f/ton x (1kg / 2.2 lbs-f) x 9.81 N/kg x (1 kN / 1000 N) = 12.98 kN.

[EdMajinLee199999]

@pigvarley No, we are talking about peak forces over a time period, so the mass of the boulder is not interchangeable with the force the boulder exerts on the cam.

[pigvarley]

@EdMajinLee199999 You're right, the cam is experiencing a force greater than the weight of the boulder while it is accelerating upwards. I was using a simplified static model, as I figured they were simply swapping weight for exerted force.

[wburgboy75]

Rizias is exactly right. The key to the power of cams is the placement. First, rarely will you find a perfectly parallel crack such as the synthetic one shown here (with the exception of a few hundred desert splitters), which is of course what you're looking for when placing cams. Second, and not to knock the people at DMM, but there are a lot of newbs that watch these vids to get an idea of what climbing protection is all about, and that cam was too small for that placement. Tippedoutlobes!

[nategod]

streaky, matee you have a little too much spare time on your hands. any news on ice screws?

[nuclearhudson]

That's awesome. Definitely a unique way to show how strong these things are!

[michdudeada]

Not a very good placement either. The cam was a bit small. It was a bit to open.

Well cool video though!

[rizlas2]

the secret is not in the milk, but in the rock....if the rock structure is not solid and hard, it will crumble...resulting in release of those tools and a fall....

[UndeadSpider]

That's pretty impressive... Can't say that means anything to CLIMB with but impressive nevertheless :p

[EricCant0na]

Woah, that is pretty impressive! I'm gonna have to get me some of these...