where is mathfreak?  he could do this stuff in a second for you.

Duly noted, Dale!   Great work.   Now your mission,  should you choose to accept it....field test the crap out of those swivels!


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I trust you were speaking hypothetically?  As we here at slinging.org are all responsible representatives of the sport,  and we know better than to sling within a half mile of anybody's windows....!


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Think about that for a moment,  one finger supporting 150lbs for even a moment.  Doesn't sound at all reasonable to me.  Now, employing all fingers to accomplish the task for a moment, no sweat......although I would venture to guess that 150lbs is near the exreme upper limit for most.


TS

I just wrote this whole thing out and it got permanently deleted, so this will be less neat, complete, and explained...


E = WV^2/450395

So for a four ounce (1750 grain) projectile:

150 mph gives 188.1 foot pounds
200 mph gives 334.2 foot pounds
250 mph gives 522.5 foot pounds
300 mph gives 752.2 foot pounds


I don't know what this means in terms of, or if it helps at all, with the stress of the swivel.

If it takes 25-40 foot pounds to kill a deer or black bear (this is from archery, so those foot pounds are driving two or more blades, as oposed to lead or a rock), a 250 mph shot with 4 oz is most defineitly going to break whatever it hits.... as though we needed sketchy math figures to tell us that...

hope this can help someone

Please see corrections and comments in in my previous very verbose post above ... OK, on the previous "page" since there are ten posts per "page".

Seems like fingers are stronger than I was willing to believe.  But when I think about it, people put some pretty good stress on just a few fingers.  Think of an archer: two fingers or three, up to a hundred pounds of force to draw the bow, no sweat.  Or think of a hammer thrower; I don't know how heavy the hammer is, so I cannot calculate the force, but it's probably pretty high.  OK, I am convinced.  My figures are right.

TechStuf,
No, unfortunately my neighbor's upper-story windows are quite within range of a rogue shot.  I haven't hit them yet.  I haven't even dropped anything in his yard, yet.  Still, I don't sling anything but tennis balls within range of his yard.

I've been concerned about equipment failure, with those snap swivels ... I thought I was well past the possibility of operator-error rogues ... until yesterday when a snowball slipped out of the pouch, went nearly straight up, and dropped twenty feet away at the feet of my wife and a friend we had visiting!  Missed them both by less than a foot, and I was still looking up and trying to figure out where the snowball had gone.  My wife's look was sufficient to sizzle me where I stood!

I'm a hundred miles from the coast.  The place I bought the 70-pound swivels, also had 200 pound swivels ... but I thought I didn't need anything that heavy.  And I probably don't, since most of the time I'm slinging tennis balls.  But I do sling rocks, and occasionally I want to hit something HARD.  So I'm off the the store to buy the 200-pounders, for the few occasions when I really will be at risk for breaking a swivel.

Fortunately, the nylon "paracord" I use is rated at 300 pounds, and the dacron cord is even stronger.

For those of us that use the metric system it would b helpfull if there can be done a set of calculations with our measurements.
I have read the posts a few times, but ft-lbs/sec2 has no meaning for me.

Willeke

Thanks Dale.
I have done enough maths and physics to understand the calculations, but not enough to repeat it myself.
(Or maybe when I did physics I could have, but now I do not remember how to do it.)

Nearly 70 kilos, that is a lot.

Willeke

Ten circuits per second at 3m diameter is close to 339k/hr and 94m/sec—ouch!—FOUR!

Aside from swivels, a four finger (full hand) retention loop might be more forgiving, depending on individual style. I put the loop around the palm, half way back exiting in front of thumb at hand shake position.
    
Tom