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The fastest mechanical launcher?

Posted: Sun Dec 19, 2010 9:46 am
by boyntonstu
In Middleton's book "Man-Powered weapons and ammunition, page 184, he staes that Rudiger Koltz compound crossbow of unique design shot a bolt at speeds between 650 fps and 800 fps.

Modern crossbows have recently surpassed the 400 fps barrier.

Are you aware of any other high speed mechanical launchers?

Posted: Sun Dec 19, 2010 9:55 am
by Technician1002
Some current air springer are near SOS.

Posted: Sun Dec 19, 2010 10:02 am
by boyntonstu
Technician1002 wrote:Some current air springer are near SOS.
Correct.

Let me restate the question:


Are you aware of any other high speed mechanical launchers that are without barrels?

Posted: Sun Dec 19, 2010 10:07 am
by Technician1002
A good old fashioned horsewhip exceeds the SOS to make the crack. I'm not aware of any that were designed to throw a projectile. The whip was the first man made mechanical device to break the sound barrier.

The speed of David's sling from biblical times is not known, but it was lethal.

Posted: Sun Dec 19, 2010 10:57 am
by boyntonstu
Technician1002 wrote:A good old fashioned horsewhip exceeds the SOS to make the crack. I'm not aware of any that were designed to throw a projectile. The whip was the first man made mechanical device to break the sound barrier.

The speed of David's sling from biblical times is not known, but it was lethal.
The whip tip at the end of its travel when it makes the U turn is where the crack occurs.

Posted: Sun Dec 19, 2010 11:19 am
by Ragnarok
Technician1002 wrote:The speed of David's sling from biblical times is not known, but it was lethal.
Any decent slinger can be lethal with the right placement and a degree of luck. In the absence of any empirical data, it has to be assumed it was no faster (and likely slower) than modern slings. This does not make it a competitor.

Besides, Goliath was not a particularly exceptional target. Based on the oldest available manuscripts, "Four cubits and a span", as opposed to the two extra cubits added later on (much like the Red Sea/Reed Sea dealie). So only about 2 metres. Tall, but I've met taller - my old headteacher was roughly that.

~~~~~

Anywho, the fastest mechanical launcher I can think of right now is the DREAD centrifugal machine gun concept, although I do not know whether it has reached a production/prototype stage.

Supersonic, but I'm not sure by how much.

Posted: Sun Dec 19, 2010 11:30 am
by boyntonstu
Anywho, the fastest mechanical launcher I can think of right now is the DREAD centrifugal machine gun concept, although I do not know whether it has reached a production/prototype stage.

Supersonic, but I'm not sure by how much.

Gotta do it again:

Are you aware of any other high speed human powered mechanical launchers that are without barrels?

Posted: Sun Dec 19, 2010 11:54 am
by Ragnarok
Any mechanical system is inherently limited in terms of velocity.
With the criteria that you're writing in, and the likelihood that you will write out other suggestions on more technicalities*...

No, with present technology, you're not going to find anything better than compound crossbow designs as an answer for the question you want to be asking.. There may be better layouts that can improve velocity, but in mechanical terms, it has the greatest potential.

*It would be possible to build a single shot "flywheel" version of the DREAD that was hand powered. Not that it really matters

Posted: Sun Dec 19, 2010 1:15 pm
by Gaderelguitarist
What about the atlatl?

Maybe not so high speed, but it allowed an individual to hurl a spear several times over what they would normally be capable of.

Posted: Sun Dec 19, 2010 1:41 pm
by saefroch
How are we defining "man-powered?" Maybe I'm missing something, but it seems to me that if we can consider a crossbow man-powered, a pneumatic is also man-powered if the pump is operated manually. A crossbow uses energy stored in the bent limbs, and a pneumatic uses air stored in the compressed air. Both have a manually-operated trigger mechanism... They seem pretty similar to me.

Posted: Sun Dec 19, 2010 5:26 pm
by jackssmirkingrevenge
saefroch wrote:How are we defining "man-powered?"
It's the "barrel less" criteria which throws pneumatics and spring piston airguns off.

The problem with this category is that some part of the launcher (the bowstring in a crossbow for example) has to be travelling as fast as the projectile, and that has to be halted somehow without destroying itself.

There's a practical limit to this, which is why when more "muzzle" energy was needed, the same design is usually scaled up to fire a much larger projectile at a similar velocity but higher energy by virtue of its greater mass.

Posted: Sun Dec 19, 2010 7:36 pm
by saefroch
Couldn't a captive sabot design be considered "barrel less," especially if the projectile is of a smaller diameter than the housing for the sabot?

Posted: Mon Dec 20, 2010 2:14 am
by jackssmirkingrevenge
saefroch wrote:Couldn't a captive sabot design be considered "barrel less," especially if the projectile is of a smaller diameter than the housing for the sabot?
Since boyntonstu defined the "high speed human powered mechanical launchers that are without barrels" criteria, ask him ;)

Posted: Mon Dec 20, 2010 6:16 am
by Hotwired
I strongly suspect that what boyntonstu wanted to exclude was gas propulsion which is the primary reason for having a barrel at all.

So back to hammers, tension, centrifugal and/or lever combos...

Posted: Mon Dec 20, 2010 6:32 am
by jackssmirkingrevenge
It seems the author of book in the original post didn't exclude pneumatics:
the amazon blurb wrote:David slew Goliath with his slingshot: for millennia that was the norm, as men used a variety of non-explosive weapons to fire small stones and carefully rounded bullets of clay, glass, and even steel and lead. This unusual study explores in practical detail the many ways, old and new, in which man shot projectiles without recourse to gunpowder. They include the bow and arrow, a favorite for the last 10,000 years; pump-up air guns; blowpipes; catapults; and homemade lead musketballs.
Seems like an interesting read :) could this be similar?