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Onager - range/size/load
#1
Does anyone have any notion of the range of a late Roman onager catapult? Is there any evidence about the size of the larger versions, and what weight of projectile they might have used?

There's apparently a note in Joshua Stylites that a catapult at the siege of Amida in AD502-3 threw stones of 135kg (presumably a conversion from whatever unit of measurement Joshua was using!) - how large would a machine like this need to be, and how far might it have been able to throw these missiles?
Nathan Ross
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#2
135kg? There's no way in hell that's right. The Romans noted that their artillery wasn't capable of knocking down walls until the Traction Trebuchet arrives. You simply can't make a Torsion spring assembly that big.
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#3
(03-29-2017, 12:30 AM)Flavivs Aetivs Wrote: 135kg? There's no way in hell that's right.

Admittedly, that was from a very secondary source! (this one) - I've now found the original text of Joshua Stylites, and while he does give the weight as 300lbs (or equivalent - a little over 135kg), it sounds rather more like the Amidan 'Crusher' was a crane used to drop rocks vertically down onto the Persian ram, rather than a catapult.


(03-29-2017, 12:30 AM)Flavivs Aetivs Wrote: The Romans noted that their artillery wasn't capable of knocking down walls until the Traction Trebuchet arrives.

I think the idea was to use artillery to demolish the battlements and wall walks, so the defenders could be driven back with archery and the attackers could bring up rams and ladders. Both ramming and mining seem to be far more effective ways of bringing down walls than direct artillery strikes. I wonder whether a trebuchet would have been any more effective...


(03-29-2017, 12:30 AM)Flavivs Aetivs Wrote: You simply can't make a Torsion spring assembly that big.

300 lbs / 135 kg isn't that heavy - it's about the weight of a very fat man, or the amount that a mule could carry. This man appears to be lifting a 135kg 'atlas stone' (appropriately, the event is sponsored by the Persian god Mazda!)

However, finding estimates of the heavier projectiles that a torsion catapult could throw is quite difficult. Would an onager type one-arm catapult be able to throw heavier missiles than the old-style stone-throwing ballista? Has anyone studied the maximum weight capacity of a torsion engine?
Nathan Ross
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#4
(03-28-2017, 09:41 PM)Nathan Ross Wrote: Does anyone have any notion of the range of a late Roman onager catapult? Is there any evidence about the size of the larger versions, and what weight of projectile they might have used?

There's apparently a note in Joshua Stylites that a catapult at the siege of Amida in AD502-3 threw stones of 135kg (presumably a conversion from whatever unit of measurement Joshua was using!) - how large would a machine like this need to be, and how far might it have been able to throw these missiles?

According to this Article at: http://www.romanarmy.net/pdf/Qasr%20Ibri...0Balls.pdf

Vespasians artillery at Jotapata 69AD fired stone balls weighing one Talent (34kg? I'm not sure about conversion weights here)

Vitruvius Pollio in Book 10 of his books on Architecture gives some interesting measurements the largest of which is for a 360 Ib Stone thrower: http://www.perseus.tufts.edu/hopper/text...ection%3D3

This would be a sandstone ball about 20 inches or so in Diameter....
Ivor

"And the four bare walls stand on the seashore. a wreck a skeleton a monument of that instability and vicissitude to which all things human are subject. Not a dwelling within sight, and the farm labourer, and curious traveller, are the only persons that ever visit the scene where once so many thousands were congregated." T.Lewin 1867
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#5
(03-29-2017, 10:27 AM)Crispianus Wrote: a 360 Ib Stone thrower... This would be a sandstone ball about 20 inches or so  in Diameter....

Excellent! That's slightly larger than Joshua's Amidan 'Crusher' - so if missiles of that weight could (apparently) be thrown by a ballista, could an onager manage the same, or greater?

(I didn't notice whether Vitruvius gives any estimates of range for these various sizes of projectile - does he?)
Nathan Ross
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#6
(03-29-2017, 11:03 AM)Nathan Ross Wrote:
(03-29-2017, 10:27 AM)Crispianus Wrote: a 360 Ib Stone thrower... This would be a sandstone ball about 20 inches or so  in Diameter....

Excellent! That's slightly larger than Joshua's Amidan 'Crusher' - so if missiles of that weight could (apparently) be thrown by a ballista, could an onager manage the same, or greater?

(I didn't notice whether Vitruvius gives any estimates of range for these various sizes of projectile - does he?)

The chapter refers to Artillery in general I think so should include Onagers...
http://www.perseus.tufts.edu/hopper/text...ection%3D9

No range given that I'm aware off though he does say "BALLISTAE are constructed on varying principles to produce an identical result." so one assumes the range for all would be similar, though this seems unlikely to me, but then I'm no ballistics expert...

   
Ivor

"And the four bare walls stand on the seashore. a wreck a skeleton a monument of that instability and vicissitude to which all things human are subject. Not a dwelling within sight, and the farm labourer, and curious traveller, are the only persons that ever visit the scene where once so many thousands were congregated." T.Lewin 1867
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#7
It seems that ranges of 4-500m are entirely possible with this largely being the maximum for any given machine...

Experiments by Schramm produced the followings results:

Two-cubit arrow-shooting catapult 370 metres
Three-span arrow-shooting catapult (based on the remains found at Ampurias) 305 metres
Small stone-thrower (with 1 1/2-mina stone) 184 metres
Small stone-thrower (with 1lb. lead shot) over 300 metres
Smaller onager over 200 metres
Larger onager over 300 metres


However:

"I acknowledge with admiration Schramm’s notable achievements. I am certain,
however, that it is possible to improve upon his ranges substantially for the following reasons.
Payne-Gallwey constructed an onager which hurled an eight-pound
shot about 500 yards, and this impressive superiority in performance over
Schramm’s one-armed stone-thrower was due, as I have suggested elsewhere,
to the much greater angle through which the arm and the spring
were allowed to operate. In his two-armed, arrow-shooting, euthytone
catapults, too, Schramm only seems to have given the arms an angle of
37 1/2 degrees through which to recoil.
This is approximately correct for a Mark IIIa or IV a arrow-firer,
but the arms of a Vitruvian euthytone can work through an angle exceeding 45 degrees,
and this must produce a significant increase in performance. Also, Schramm’s interpretation of.
the design for the hole-carrier of a palintone stone-thrower
only allows the arms movement through about 45 degrees,
whereas it should be possible to produce an angle of 50 degrees.
This will again lead to a significantly greater output of power. Incidentally, Schramm’s two
armed stone-thrower was a very small one by any standards, and small
models usually fail to match the performance of larger originals."


Source: Greek and Roman Artillery: Historical Development E.W Marsden 1969 Oxford Pg86

Ancient Sources for Artillery(German/Greek):

https://archive.org/details/philonsbelopoiik00philuoft

https://archive.org/details/heronsbelopoiika00hero
Ivor

"And the four bare walls stand on the seashore. a wreck a skeleton a monument of that instability and vicissitude to which all things human are subject. Not a dwelling within sight, and the farm labourer, and curious traveller, are the only persons that ever visit the scene where once so many thousands were congregated." T.Lewin 1867
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#8
(03-30-2017, 09:36 AM)Crispianus Wrote: Larger onager over 300 metres

Thanks again! I see that in his comments on the siege tower of Demetrius Poliorcetes, Vitruvius writes that it was intended to 'withstand the blow of a stone weighing three hundred and sixty pounds shot from a ballista' - this implies that 360lbs was the maximum weight of shot. Is Vitruvius generally held to be reliable in his measurements?

If so, and if we could assume that the largest sort of single-armed onager could throw a missile of the same weight as the largest sort of twin-armed ballista (and if not, why switch to an inferior weapon?), then it does seem that this sort of weight of shot would be feasible - and perhaps over 300 metres too.

Would a single-armed onager allow a higher trajectory shot from its sling than a stone-throwing ballista, perhaps? If so, then we could be looking at an even greater range.
Nathan Ross
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#9
(03-30-2017, 10:04 AM)Nathan Ross Wrote: Would a single-armed onager allow a higher trajectory shot from its sling than a stone-throwing ballista, perhaps?

A good many years ago, Eric Marsden came to lecture the Roman Army course organised by Durham University on Roman artillery. An old artilleryman, B. G. Harris, put it to him that the ballista was a gun but the onager was a howitzer and Marsden agreed.
Michael King Macdona

And do as adversaries do in law, -
Strive mightily, but eat and drink as friends.
(The Taming of the Shrew: Act 1, Scene 2)
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#10
(03-30-2017, 11:08 AM)Renatus Wrote: the ballista was a gun but the onager was a howitzer

I was thinking along those lines myself. However - if it's correct that the Romans abandoned the stone-throwing ballista at some point in (probably) the 3rd century, using the word instead to describe an arrow-shooter, and changed to the onager for their stone-throwing, then surely the onager must have been able to shoot on a rather flatter trajectory as well.

After all, 'guns' are useful in warfare... [Image: tongue.png]
Nathan Ross
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#11
(03-30-2017, 10:04 AM)Nathan Ross Wrote:
(03-30-2017, 09:36 AM)Crispianus Wrote: Larger onager over 300 metres

Thanks again! I see that in his comments on the siege tower of Demetrius Poliorcetes, Vitruvius writes that it was intended to 'withstand the blow of a stone weighing three hundred and sixty pounds shot from a ballista' - this implies that 360lbs was the maximum weight of shot. Is Vitruvius generally held to be reliable in his measurements?

If so, and if we could assume that the largest sort of single-armed onager could throw a missile of the same weight as the largest sort of twin-armed ballista (and if not, why switch to an inferior weapon?), then it does seem that this sort of weight of shot would be feasible - and perhaps over 300 metres too.

Would a single-armed onager allow a higher trajectory shot from its sling than a stone-throwing ballista, perhaps? If so, then we could be looking at an even greater range.

I think the comments regarding the Heliopolis seems unlikely to me and obviously it was never tested, the solution to it was much simpler in the end, the defenders created an artificial bog (litterally) in front of the wall it was in position to attack and it simply bogged down... I assume though that it would have been rendered proof against red hot bolts etc.
360Ibs is indeed the maximum size Vitruvius gives and think this is consistant with other authors, I would assume this is the maximum practical size for such a machine, it may be that beyond this the machine would be less effective rather then more or simply impractical, the deciding limit seems to be the size of the torsion element..

The ranges given previously are all from "modern"experimental machines, the actual ranges given in antiguity are much more up to 800m for smaller machines, but not as far as I'm aware 360Ib'er, these would probably have a range of no more then 300m(or less) and in a siege may have had to be as close as 150m to attack a wall effectively... which brings its own problems...

Josephus claims Vespasians one talent machines were firing from around 400m+ and were very effective at clearing the walls of defenders, creating a veritable storm of shot... which would suggest that their actual max range was a great deal more..

Maximum range is not the whole answer though every weapon has an absolute maximum and effective max range, accuracy may be the deciding factor and this is likely to be variable at best... so a shorter range may well have been prefered...

Maybe where the Onager scores is ease of manufacture and use, I could imagine that a Ballista with its double torsion element would be more difficult to build and tune... quit apart from that it might be that the single (longer?) arm of the Onager is more efficient.

Personally I think the Gun/howitzer-Ballista/Onager thing is a red herring as both could be used to produce the same result, it should be noted that torsion machines were used during WW1 for lobbing grenades in trench warfare.
Ivor

"And the four bare walls stand on the seashore. a wreck a skeleton a monument of that instability and vicissitude to which all things human are subject. Not a dwelling within sight, and the farm labourer, and curious traveller, are the only persons that ever visit the scene where once so many thousands were congregated." T.Lewin 1867
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#12
Hi Nathan et al.,
Speaking of Josephus, I recall that he complained about the sound of the stones from the siege weapons whizzing by and records how one of the Jewish soldiers standing on the Jotapata wall had his head knocked off by a rock. More disturbingly, a pregnant woman was struck in the womb and her fetus was literally knocked out of her body. Josephus' account suggests to me that the stones were being launched from something other than an onager (i.e., a ballista or scorpion) as they must have been traveling at a very high speed for Josephus to hear the sound, and his graphic description of the fatal injuries suggests a flat trajectory. Below is a link to an article from the Times of Israel with photos and a video showing the siege weapon stones that were discovered in the area where the Romans breached the walls of Jerusalem. If you watch the video, it appears that the stones varied from about the size of a cantaloupe to a beach ball. I have a copy of Marsden somewhere and will see if he has anything to say re the range of the siege weapons including the onager. By the way, why was it called an onager? Did the wild ass have a really vicious kick that the Romans thought was analogous to being struck by a catapult stone?
http://www.timesofisrael.com/archaeologi...lem-walls/
Kurt Zimmerman
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#13
(04-02-2017, 05:49 AM)Dagalaifus Wrote: Speaking of Josephus, I recall that he complained about the sound of the stones from the siege weapons whizzing by

Yes - he also says that sentries on the wall used to shout a warning when they saw the (light-coloured) stones being launched - so the Romans took to painting the stones black. This might imply that the Romans were shooting at relatively long range (Josephus says two furlongs, which is a quarter of a mile, or 440 yards).

Most recent translations give the sentries' shout as 'Baby on the way!' - which sounds like 'military humour' - although apparently Josephus wrote the phrase as 'the son comes', which is more mysterious. This article (albeit with a very religious focus) ponders what the expression might have meant - was 'son' a mistake for 'stone'?


(04-02-2017, 05:49 AM)Dagalaifus Wrote: Josephus' account suggests to me that the stones were being launched from something other than an onager (i.e., a ballista or scorpion)

The single-armed onager was probably introduced in the 3rd century - I think the earliest oblique reference is in Tertullian, who calls it a 'scorpio'. Clearly artillery terminology had changed over the years!



(04-02-2017, 05:49 AM)Dagalaifus Wrote: By the way, why was it called an onager?

According to Ammianus (23.4.7):

"And the machine is called tormentum as all the released tension is caused by twisting (torquetur); and scorpion, because it has an upraised sting; modern times have given it the new name onager, because when wild asses are pursued by hunters, by kicking they hurl back stones to a distance, either crushing the breasts of their pursuers, or breaking the bones of their skulls and shattering them."

But he also says that "a heavy machine of this kind, if placed upon a stone wall, shatters everything beneath it by its violent concussion" - so the word was perhaps more a reference to the 'kick' of the weapon's release than to the effects of its missiles!
Nathan Ross
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#14
(04-02-2017, 10:24 AM)Nathan Ross Wrote:
(04-02-2017, 05:49 AM)Dagalaifus Wrote: Speaking of Josephus, I recall that he complained about the sound of the stones from the siege weapons whizzing by

Yes - he also says that sentries on the wall used to shout a warning when they saw the (light-coloured) stones being launched - so the Romans took to painting the stones black. This might imply that the Romans were shooting at relatively long range (Josephus says two furlongs, which is a quarter of a mile, or 440 yards).

Most recent translations give the sentries' shout as 'Baby on the way!' - which sounds like 'military humour' - although apparently Josephus wrote the phrase as 'the son comes', which is more mysterious. This article (albeit with a very religious focus) ponders what the expression might have meant - was 'son' a mistake for 'stone'?


(04-02-2017, 05:49 AM)Dagalaifus Wrote: Josephus' account suggests to me that the stones were being launched from something other than an onager (i.e., a ballista or scorpion)

The single-armed onager was probably introduced in the 3rd century - I think the earliest oblique reference is in Tertullian, who calls it a 'scorpio'. Clearly artillery terminology had changed over the years!



(04-02-2017, 05:49 AM)Dagalaifus Wrote: By the way, why was it called an onager?

According to Ammianus (23.4.7):

"And the machine is called tormentum as all the released tension is caused by twisting (torquetur); and scorpion, because it has an upraised sting; modern times have given it the new name onager, because when wild asses are pursued by hunters, by kicking they hurl back stones to a distance, either crushing the breasts of their pursuers, or breaking the bones of their skulls and shattering them."

But he also says that "a heavy machine of this kind, if placed upon a stone wall, shatters everything beneath it by its violent concussion" - so the word was perhaps more a reference to the 'kick' of the weapon's release than to the effects of its missiles!
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#15
(03-29-2017, 12:30 AM)Flavivs Aetivs Wrote: 135kg? There's no way in hell that's right. The Romans noted that their artillery wasn't capable of knocking down walls until the Traction Trebuchet arrives. You simply can't make a Torsion spring assembly that big.

The traction trebuchet wasn't capable of knocking down walls, just clearing battlements and an effective anti-personal weapon. The counterweight trebuchet resulted in wall modification - for instance, the north-west fortifications covering the Blacharnae area.[url=https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjr89CHk4bTAhVIKGMKHedYBuAQFggfMAA&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FBlachernae&usg=AFQjCNFxskfXKDtrk3Zr6KhVVq4shZLq-g][/url]
aka T*O*N*G*A*R
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