07-13-2007, 12:44 AM
We are probably drifting off-topic in getting into torsion artillery technicalities ( Great Subject though ! :wink: )
To deal with a couple of points however :-
Torsion artillery gets it's power from twisted ropes or 'springs'. Obviously, more twist equals more power. Originally the spring frames were a simple bar "_" shape and once added to the stock/slider gave a "T" shaped (in plan )machine - this was called a euthytone machine.
The next development was to alter the frames by turning them inward, giving a shallow "V" shape to the bar/spring frame, and making the whole machine "Y" shaped rather than "T" shaped(called palintone machines). Although complicated to make, such frames meant the arms swung through a greater angle, = more twist,=more power. The complicated structure was not considered worthwhile for the smaller arrow/dart throwers, which generally remained euthytones . However, a similar benefit was gained by curving the arms. ( e.g the machines described by Vitruvius).
The next development we know of was the cheiroballistra described by Heron and which features so prominently on Trajan's column ( the kind of machine P.Clodius Secundus is interested in ). This machine was a great advance. It had a metal rather than wooden frame, it moved the springs further out, thereby increasing the angle the arms swung through ( like a palintone ) and it introduced the central arch as an aid to aiming, now that the aiming aperture between the springs, originally narrow, was now so much wider. The angle of the arm-swing went from 35 degrees (straight arm euthytone) to 47.5 degrees(curved arm Vitruvian euthytone) to 59 degrees (cheiroballistra).It should be remembered too that these arrow/dart throwers were fairly low velocity ( compared,say, to firearms ) and "direct fire" for them still meant elevations of 10-30 degrees.Modern re-enactors thus find the arch as useful as their ancient forbears.
For much more on the technicalities see Marsden "Greek and Roman artillery - technical treatises" particularly pp229 on, or a simplified version, Warry, "Warfare in the Classical World" p178 or Duncan Campbell's "Osprey artillery volume " which I don't have, so can't give an exact refence - but no doubt Duncan will oblige!
Which brings us to the Hatra machine, which gave rise to the myth of "in-swingers".
Once the cheiroballistra appeared, it would not take long for an astute engineer to realise that the same principle ( moving the spring frames further apart to increase arm swing angle ) could now be applied to stone throwers as well, resulting in the same effect as the "V" shaped palintones without the complex structure. It could thus be made stronger and lighter, and as a euthytone, but had to be wood as metal spring frames that large were impractical. The Hatra machine is one of these ( and for all sorts of reasons, which I won't go into now, cannot be an in-swinger ).
As to range, an army drawn up in battle order is an easy enough target at ranges in excess of 500 yards - just ask any Napoleonic artilleryman, who had similar sighting arrangements ! Or a modern machine-gunner !
To deal with a couple of points however :-
Torsion artillery gets it's power from twisted ropes or 'springs'. Obviously, more twist equals more power. Originally the spring frames were a simple bar "_" shape and once added to the stock/slider gave a "T" shaped (in plan )machine - this was called a euthytone machine.
The next development was to alter the frames by turning them inward, giving a shallow "V" shape to the bar/spring frame, and making the whole machine "Y" shaped rather than "T" shaped(called palintone machines). Although complicated to make, such frames meant the arms swung through a greater angle, = more twist,=more power. The complicated structure was not considered worthwhile for the smaller arrow/dart throwers, which generally remained euthytones . However, a similar benefit was gained by curving the arms. ( e.g the machines described by Vitruvius).
The next development we know of was the cheiroballistra described by Heron and which features so prominently on Trajan's column ( the kind of machine P.Clodius Secundus is interested in ). This machine was a great advance. It had a metal rather than wooden frame, it moved the springs further out, thereby increasing the angle the arms swung through ( like a palintone ) and it introduced the central arch as an aid to aiming, now that the aiming aperture between the springs, originally narrow, was now so much wider. The angle of the arm-swing went from 35 degrees (straight arm euthytone) to 47.5 degrees(curved arm Vitruvian euthytone) to 59 degrees (cheiroballistra).It should be remembered too that these arrow/dart throwers were fairly low velocity ( compared,say, to firearms ) and "direct fire" for them still meant elevations of 10-30 degrees.Modern re-enactors thus find the arch as useful as their ancient forbears.
For much more on the technicalities see Marsden "Greek and Roman artillery - technical treatises" particularly pp229 on, or a simplified version, Warry, "Warfare in the Classical World" p178 or Duncan Campbell's "Osprey artillery volume " which I don't have, so can't give an exact refence - but no doubt Duncan will oblige!
Which brings us to the Hatra machine, which gave rise to the myth of "in-swingers".
Once the cheiroballistra appeared, it would not take long for an astute engineer to realise that the same principle ( moving the spring frames further apart to increase arm swing angle ) could now be applied to stone throwers as well, resulting in the same effect as the "V" shaped palintones without the complex structure. It could thus be made stronger and lighter, and as a euthytone, but had to be wood as metal spring frames that large were impractical. The Hatra machine is one of these ( and for all sorts of reasons, which I won't go into now, cannot be an in-swinger ).
As to range, an army drawn up in battle order is an easy enough target at ranges in excess of 500 yards - just ask any Napoleonic artilleryman, who had similar sighting arrangements ! Or a modern machine-gunner !
"dulce et decorum est pro patria mori " - Horace
(It is a sweet and proper thing to die for ones country)
"No son-of-a-bitch ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country" - George C Scott as General George S. Patton
Paul McDonnell-Staff
(It is a sweet and proper thing to die for ones country)
"No son-of-a-bitch ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country" - George C Scott as General George S. Patton
Paul McDonnell-Staff
