Supersonic sling projectile!
Is it possible?  What kind of forces would be required?

Does a whip tip break the sound barrier?  Why not put a small pouch with a tiny tungsten projectile?

What would be the force on ones arm when the sling projectile reached MACH 1 at sea level?

At 10,000 feet?

What would be the best design?  Could even a treb do this?

I don't know the specifics of it, but you would have to have one hell of an arm on you to do it. I've gotten stones to fly out of my slings with a thrumming sound, which I understand, is basically the same principal of mass molecular displacement of the air surrounding the rock and I have had the tip of my sling crack like a whip, but the rocks were far below being supersonic by any means. And I don;t know of any trebuchet powerful enough to do that. It seems like the power to do that would rip the trebuchet apart at the seams before getting a projectile off.

I think we first need to know how much we need to improve. No one really knows how fast a sling projectile is going (yes i know about all the figures and test), but they are not exact. What is the gueniss book of world recorders was coming to your house to see you throw and they ask you how fast are you throwing. You say well somewhere between 50 feet per secound to 300 feet per secound. They are going to laught at the person because they want exact numbers. Could someone do it, proably. But first we need to know exacty where you stand on speed so we know how much to improve and what works in the test with different sling designs.

It would be really hard for a projectile from a sling to go faster than the speed of sound.  I remember from an earlier thread that for a rock to be thrown 500 yards (about 450 m), it'd would be traveling at about 200 km/h.  The speed of sound is roughly 1100 km/h.  A dart from a crossbow can go as fast as 300 ft/sec or 330 km/h.  As you can see, we are no where close to the sound barrier.

The tip of a whip can go faster than MACH 1 because the whip is tappered.  It is much heavier at the handle and really light and the tip, so when you swing it you create a wave that accelerate through the length of the whip.  If a tungsten projectile is added to the tip, however, that little weight would change the balance of the whip and hinder the acceleration.

If Supersonic sling projenctile is to become a reality, I'd expect the ammo to be really small.  May be 5mm in diameter.  The design of the sling may look like a whip but the release must be different from a normal sling.  having a release cord that double the length of the device at release would slow down the pouche.  Perharps a release that is similar to Yurek's dart throwing design may work. ???

Tint,

Your analysis is inspiring.  Now to design one?

Who can do it?  Of course, if we are talking about a dust particle, perhaps a whip has already sent one past MACH 1.. but how to scale this up?

Can a machine be made to "crack" a giant "whip" ?

Sling a tungsten ball earthward from a balloon gondola 100,000 feet up and I bet it'll hit mach one.

I'm not a physics expert but things can only fall so fast. Things speed up as they fall until a point where they reach terminal velocity.

some man jumped bl from a o balloon from really k high because the air e was thinner he went past the speed of sound

I think 5 mm would be leathal if it is traveling at the speed of sound,  some lead bullets are that size, aren't there?  May be 9mm is possible too!  I am only guessing here.

If you are thinking about using a machine then I am sure it can crack a big heavy whip and scale everything up.  But keep in mind such a design would be hard to aim.  The end of a whip is not only moving fast, it is also changing angles very quickly, that would leave very little margin for timing error of the release.

When it comes to making one, my best guess is to ask Techstuf for advice.   Perharps we have some whip makers on the forum too?

THis would be a close range device.. since hard to aim and the projectile very small, it would require the skill of a whip master to use.  It still, however, needs an inventor.

Once, on some polish forum, a one guy wrote, that his living in a country grandfather, had related when he was a teenager, used to shot stones with a whip. Alas, the guy have never got to know detailes. The grandfather said, that stones were making marks on the wall, like a rifle bullet.

I also read an article, which mentioned about Carpathan stripligns, who used whips to shot stones. No details, only info about kind of a loop made on the whip ending.

I suppose it was rather something like a staff sling in the both mentioned cases, not like a bull-whip. But I might be wrong.

I remember, TechStuff wrote something about his tests with launching from the whip.

Jurek

Jurek,

Thanks for this.  Now, we have work to document this phase of slinging and bring it up to latest technology.

Mike_R wrote on Dec 10^th, 2004 at 3:57am:

I'm not a physics expert but things can only fall so fast. Things speed up as they fall until a point where they reach terminal velocity.

yes terminal volocity is the fastest it canfall when gravity and air resistance meets an equilibrium but if you put force on it to mke it go down I bet it would go faster.

britishslinger wrote on Dec 10^th, 2004 at 4:58am:

some man jumped bl from a o balloon from really k high because the air e was thinner he went past the speed of sound

he had to wear a preasure suit or his blood would boil literally.

wrote on Jan 5^th, 2008 at 11:01pm:

britishslinger wrote on Dec 10th, 2004 at 4:58am: some man jumped bl from a o balloon from really k high because the air e was thinner he went past the speed of sound he had to wear a pressure suit or his blood would boil literally.

It was Joseph Kittinger, an officer of the USAF.  On August 16, 1960, he jumped from the gondola of a research balloon 102,800' (almost 19-1/2 miles!) as part of Project Excelsior.  Check out the photo at

http://en.wikipedia.org/wiki/Project_Excelsior

It must be the ultimate, "It's too late to change your mind!" shot :)

More than four minutes in freefall.  And... oh wow... there are videos...

hmmm the un answered question can a human hurl a projectile at mach1 +

I ran a bunch of simulations a year or so ago, and the answer seems to be that since a sling is straight -- unlike a whip, which flexes during the snap -- the only way you could pull it off would be with a Really Long Sling: at least 150' long, and perhaps much longer.  And even then, you'd have to find some way to deal with air resistance.  But this simulation was far from the last word on the subject, since I didn't handle the dynamics of the slinger's body properly, and I only modeled certain types of throws.

If I can ever find a way to improve the simulation and compare it with actual measurements, I may give it another go...

Let's just make a few "ball-park" calculations Just to see if we're even going to get close. To make it simple we'll ignore the actual weight of the sling and the force that moving it through air at that speed would require, consider only the centrifugal force.

Size and weight assumptions:

A nice long sling length, of 2 metres (78 inches)
Mass of the projectle of 50 grams ( Approx 2 ounces as used by Larry Bray to set the real word record)
Speed of sound approx. 300 metres per second

Centripetal Force   F= m x v^2/r

Plug in the numbers into your faithful calculator and the force required just to hold the rotating cords of the sling works out as 2250 N or a shade under 500 pounds

That's the absolute minimum your little slinging pinkies will have to be holding just to get the sling up to speed. All the complications make that figure worse.

Also translate 300 m/s into rotational speed and that sling is rotating at over 1400 rpm assuming a steady circular motion.

Based on the above I think that we can fairly safely say the answer is no. (Now just watch some clever type prove me wrong.)

With a 50m sling rotating at 60 RPM (one rotation per second), the projectile velocity would a hair greater than Mach 1, and the g-forces would be around 180 g's.  Even for a 50 gm projectile, this would translate to a quite-managable 9 kg (20 lbs).  Unfortunately, if I've done the calculation correctly, the air drag for 1mm paracord would be around 25 lbs, and the slinger would have to generate something like 50 hp to swing the thin at Mach 1.  I'm sure there are some folks on this list who could pull this off, but alas, I am not one of them...

Of course, this is all back-of-the-envelope stuff, done after a glass or two of wine, so it's quite possible I'm off by a few decimal places...

DesertPilot wrote on Jan 7^th, 2008 at 10:27pm:

With a 50m sling rotating at 60 RPM (one rotation per second), the projectile velocity would a hair greater than Mach 1, and the g-forces would be around 180 g's.  Even for a 50 gm projectile, this would translate to a quite-managable 9 kg (20 lbs).  Unfortunately, if I've done the calculation correctly, the air drag for 1mm paracord would be around 25 lbs, and the slinger would have to generate something like 50 hp to swing the thin at Mach 1.  I'm sure there are some folks on this list who could pull this off, but alas, I am not one of them... Of course, this is all back-of-the-envelope stuff, done after a glass or two of wine, so it's quite possible I'm off by a few decimal places...

What is the airspeed velocity of an unladen swallow?  ;D
I think that it's pretty safe to say that there are no sling stones passing the sound barrier. Maybe a projectile smaller than a BB placed at the end of a whip...? Maybe?

Quote:

a shade under 500 pounds

Well the answer is obvious - use a forearm brace to anchor the cord and teach  Mariusz Pudzianowski to sling :-)
http://en.wikipedia.org/wiki/Mariusz_Pudzianowski

It's doable.
And if he doesn't have the bodyweight to anchor the cord then go ask dominic filiou :-)

At over 6'5" (1.96 cm) and weighing in excess of 440 lbs (31 stone)[1], he is one of the biggest strongmen in the world. His biceps measure 24" and his waist measures 48".

Can either of them whiz their arms around at the equivalent of 1400 RPM though?

If all one is measuring, as stated earlier, is 'average velocity' as displayed by an artificially circular sling cast,  I vote Aussieslinger build a kevlar 'Aussiepouch' attached to sturdy kevlar sling cords which are, in turn, attached to a suitable scale propped up at a suitable angle.  Then fire various small caliber guns point blank at the hanging pocket such that the round is caught tangential to the arc of travel.   Video the readout.


:o


I wonder what the results would actually be?   Perhaps only NWmanitou knows for sure?

1400 rpm shoudln't be hard for a car engine! Anyone want to hook up a sling to one of those?  :)

Actually supersonic pojectile speeds are easy. Just get a gun.

I'm more interested in the shooting of stones using a whip. I did think of something like that before, but it's really possible. =O

DesertPilot wrote on Jan 7^th, 2008 at 10:27pm:

With a 50m sling rotating at 60 RPM (one rotation per second), the projectile velocity would a hair greater than Mach 1, and the g-forces would be around 180 g's.  Even for a 50 gm projectile, this would translate to a quite-managable 9 kg (20 lbs).  Unfortunately, if I've done the calculation correctly, the air drag for 1mm paracord would be around 25 lbs, and the slinger would have to generate something like 50 hp to swing the thin at Mach 1.  I'm sure there are some folks on this list who could pull this off, but alas, I am not one of them... Of course, this is all back-of-the-envelope stuff, done after a glass or two of wine, so it's quite possible I'm off by a few decimal places...

.. and you are going to have to have very long arms to keep it moving ;)

anybody know of a working windmill in a hurricane zone ;-)

Give the sling projectile to your local fighter pilot and tell him to take it supersonic, there easy, supersonic sling projectile.

:D

Ah but does it count if it's inside an aeroplane ?
If so any one of us could take a small sling (this is the year of the short sling after all) on their next plane trip and sling a paper ball in the toilet. That missile might then be deemed to have broken the sound barrier.

I'm guessing it doesn't count :-)

How about attaching a sling to a wind generator the big ones certainly have the speed and power to do the job and if a slinger were o strap thmselves to a harness at the tip of  ablade they might get up to speed :-)

Haha.

Strap a slinger to the bottom of an airplane and then sling?

Coenie