Medieval Torsion Catapults

[Koyuncu]

Evidently the modern author infers a draw weight of 1.500 kg by assuming 75 kg per person. This is highly interesting. Do we have data on the draw power of ancient catapults/ballistae, either derived from ancient sources or won through experimental archaeology?

PS: Seems like one Liebel in Springalds and Great Crossbows (Royal Armouries Monograph, 1998) did some calculations. He arrives at 800 pounds for a cheiroballistra and nearly 4.000 pounds draw power for a springald.

I am curious about that too. In ancient machines cocking mechanisms were usually linear ratchet or ratcheted wheels. Peter Purton, in his book, Late Medieval Siege, claims that screw drawing mechanism of medieval springalds enabled engineers to build more powerful machines compared to ancient torsion weapons. In this point I can't see why ancient mechanisms were not enough to handle late medieval springalds. Also, casting the screw bar would demand great craftsmanship and good sum of money thus much simpler ratchet design could be more preferable. Could this change only depend on power of machine? If that so, could we conclude that medieval weapons were much powerful than ancient counterparts? I am doubtful about this since ancient weapons could launch much heavier missiles thus requiring more power.

Also, How did you get the 4000 kg value? I failed to find it over net.