Projectile Throwing Engines
Sir Ralph Payne-Gallwey
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Criticism.-This engine was moved into position on rollers and then props were placed under its sides to adjust the range of the projectile.

The end of the arm was secured by the notch of the large iron catch and was released by striking down the handle of the catch with a heavy mallet.

The arm is, however, too long for the height of the crossbar against which it strikes and would probably break off at its centre.

The hollow for the stone is much too large, as a stone big enough to fit it could not be cast by a weapon of the dimensions shown in the picture.

From an Illustrated Manuscript, Fifteenth Century (no. 7239), Bibl.Nat.Paris.

The medieval catapult was usually fitted with an arm that had a hollow or cup at its upper end in which was placed the stone it projected, as shown above in fig. 5.1

I find, however, that the original and more perfect form of this engine, as employed by the Greeks and ancient Romans, had a sling, made of rope and leather, attached to its arm.2 (Fig.6.)

1 See also The Crossbow, etc., Chapters LV., LVI., illustrations 193 to 202.

2 In medieval times catapults which had not slings cast great stones, but only to a short distance in comparison with the earlier weapons of the same kind that were equipped with slings. I can find no allusions or pictures to show that during this period any engine was used with a sling except the trebuchet, a post-Roman invention. All evidence goes to prove that the secret of making the skein and other important parts of a catapult was in a great measure lost within a couple of centuries after the Romans copied the weapon from their conquered enemies the Greeks, with the result that the trebuchet was introduced for throwing stones.

The catapult was gradually superseded as the art of its construction was neglected, and its efficiency in sieges was therefore decreased.

The catapults of the fifth and sixth centuries were very inferior to those described by Josephus as being used at the sieges of Jerusalem and Jotopata (A.D. 70, A.D. 67).






The addition of a sling to the arm of a catapult increases its power by at least a third. For example, the catapult described in Chapters LV,. LVI., of my book,1 will throw a round stone 8 lbs. in weight, from 350 to 360 yards, but the same engine with the advantage of a sling to its arm will cast the 8-lb. Stone from 450 to 460 yards, and when its skein is twisted to its limit of tension to nearly 500 yards.

If the upper end of the arm if a catapult is shaped into a cup to receive the stone, as shown in fig. 5,, the arm is, of necessity, large and heavy at this part. If, on the other hand, the arm is equipped with a sling, as shown in fig. 6,, it can be tapered from its butt-end upwards, and is then much lighter and recoils with far more speed than an arm that has an enlarged extremity for holding its missile.

When the arm is fitted with a sling, it is practically lengthened by as much as the length of the sling attached to it, and this, too, without any appreciable increase in its weight.

The longer the arm of a catapult, the longer is its sweep through the air, and thus the farther will it cast its projectile, provided it is not of undue weight. The difference in this respect is as between the range of a short sling and that of a long one, when both are used by a school-boy for slinging pebbles. This increase of power conferred by the addition of a sling to the arm of a catapult is surprising.

A small model I constructed for throwing a stone ball, one pound in weight, will attain a distance of 200 yards when used with an arm that has a cup for holding the ball, though when a sling is fitted to the arm the range of the engine is at once increased to 300 yards.

The only historian who distinctly tells us that the catapult of the Greeks and Romans had a sling to its arm, is Ammianus Marcellinus. This author flourished about 380 AD., and a closer study of his writings, and those of his contemporaries, led me to carry out experiments with catapults and ballistas which I had not contemplated when my work dealing with the projectile engines of the Ancients was published.

1 The Crossbow, etc.


The Projectile Throwing Engines of The Ancients
Design, Construction and Operation of Ancient Greek, Roman and Medieval Siege Engines and Their Effects In Warfare

Cover of the book The Projectile Throwing Engines of The Ancients Design, Construction and Operation of Ancient Greek, Roman and Medieval Siege Engines and Their Effects In Warfare
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Written by Sir Ralph Payne-Gallwey in 1907,this is the first serious modern work on ancient siege engines and the early history of artillery.  In this book, Payne-Gallwey first cites the ancient writings of Greeks and Romans on sieges and the associated artillery. In order to test the validity of the ancient accounts, he produces his own full size working versions of these ancient machines and tests the construction and performance claims of the ancient writers. Fully illustrated, this book gives extensive details about the design, construction, operation and performance of the three types of siege engines: the Catapult (both the Mangonel and Onager), the Ballista and the Trebuchet.
  • Part I. - Introductory Notes on Ancient Projectile Engines
  • Part II. -  The Catapult
  • Part III. - The Ballista 
  • Part IV. - The Trebuchet 
  • Part V. - Historical Notes on Ancient and Medieval Siege Engines and Their Effects In Warfare
46 Pages, Printable, Print Size 8.5 in. x 11 in.

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