ive also double checked my byzantine manual,
it says that in archery there are three goals to shoot accurately to shoot powerfully to shoot rapidly

nowhere does it explicitely mention the ability to cast the arrow at long range as being really important, it sounds like from this that, archers seem to be expected almost to be kind of like snipers, rather than just bombarding an area.

it gives a great deal of emphasis regarding the method of draw, and puts emphasis on POWER rather than range specifically.

curiously it talks about archers shooting while moving but it doesnt seem to specify or hint at whether the instructions are meant for foot or mounted archers..

are there many sources or indeed ANY for training crossbowmen or describing how crossbowmen were trained.

Well, it seems you've just forgotten to divide it by 2.

Velocity squared times bolt mass gives 124 - and by 2 we're getting 62.

And yeah, I meant that with just "velocity varying from...." there's a lot of assumptions, they had also mentioned that their bow had rather quickly taken significant set - dunno if inducement in velocity is already factored in.

Well, I must say after reviewing the Composite Crossbow tests from the aforementioned site, it seems that 400 pounds of draw is roughly equivalent to a 100 pound longbow based on the info given in Soar regarding Mark Strettons testing.

The only thing is the Composte Crossbow testing is rather vague in it's numbers, failing to mention which bolts were used.

I wish there would be more specifics on the crossbow testing, but at least it is something to go by.

So if at Crecy the English longbows were the 150 pound variety drawn to about 30", they should have outranged the crowwbows drawn by a simple belt and claw which might be in the 300 pound range. The heavier ones that would require a pulley as a mechanical aid would be approximately similar to a 150 pound longbow, perhaps a bit stronger.

Much as I have thought the crossbow was superior to the longbow in strength, I must say the little bit of testing that is out there points the other way.

Note that the bow Stretton used in Soar's book performs somewhat worse than the Mary Rose replicas tested in The Great Warbow and that the composite crossbow figures discussed above are likely anomalous. The efficiencies are just too low. I suspect at least the better quality period crossbows performed much better. There's no reason why Payne-Gallwey's 1200lb steel crossbow should be more efficient than a 616lb composite crossbow. If you apply a crude measure of that steel crossbow's efficiency (kinetic energy divided by power stroke times weight) to the composite, you get 173 J minimum. That strikes me as a better figure for a 616lb composite bow. We know crossbow bolts routinely pierced mail, so they must have managed at least 120 J.

Well, in what sense is 616 composite crossbow is more efficient than steel crossbow of 1200 pounds though?

Pound for pound it would be on average quite probably more efficient both in storing energy and transfering it to the arrow, but total output would be still way bigger for 1200 pounder, due to two times bigger draw weight, obviously. Just not two times.

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There's no reason why Payne-Gallwey's 1200lb steel crossbow should be more efficient than a 616lb composite crossbow. If you apply a crude measure of that steel crossbow's efficiency (kinetic energy divided by power stroke times weight) to the composite, you get 173 J minimum.

I remember that Harmuth in "Die Armbrust" was reporting something along those 170-180 J for ~1100 pounds steel bows.

Dunno if it's available somewhere in the net, I've never really read it due to my German being abysmal, though. Joules and numbers are universal, at least. :D

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It's very possible a more bodkin style head could pierce at 90j.

There probably would be quite interesting variation and dependency between shape of the head, overall mass/dimensions and dimensions/construction of the rings.

Some thin bodkins would probably be best answer for larger rings, just to try to 'slip' trough indeed.

Interestingly, in already linked test, lightest and least powerful bolt is only one to penetrate at least a bit - and it's indeed the slimmest one!

By using velocities of 10% below maximum for the Heavier composite, and middle of the road weight on the bolts (65g), we are looking at 102 joules from the projectile.

We can use "Die Armbrust" values of 175 Joules for a 1100 pounder with a 10" draw, 3" brace, 7" Powerstroke.

The heavier Composite is a 8" power stroke, use the same 3" Brace, 11" Draw.

The 1100 pounder stores 458 foot pounds, the Composite stores 282 foot pounds.

On a joule to foot pound ratio (LOL), the 1100 pounder comes in at 38%, the Composite at 36%.

(It's amusing I look at joules for energy released but foot pounds for energy stored, but comparatively it works fine)

The formula used to calculate stored energy is not 100% accurate, as it includes the brace as part of the draw, but it is accurate from a comparative standpoint.

Just looking at this, it indeed seems to me the composites should come out better. They should bleed less efficiency due to their projectile being heavier compared to stored energy (Unless the Die Armburst bows are using a 120 gram or so projectile), and most deem composites to be more efficient than steel bows.

I would think the Composites should compare better than the steel bows, maybe at the 40-44% range or so. This may have to do with the manufacture of the composite by a "rookie", and it may also have a bit to do with the vague numbers we have regarding velocities and weights of the projectiles in the composite tests.


ETA - I wonder what the maker of the crossbows in the testing could do if they spent all of their time making these crossbows and trying to perfect them, testing for velocity? I wonder if 10 years from now, the performance of their crossbows would be better?

Oh, it's also worth noting the Die Armbrust numbers involve a 80g bolt. Between those tests and Payne-Gallwey, we can conclude that heavy steel crossbows surpassed the all but the heaviest longbows shooting the heaviest arrows. Only with a 113.4g arrow does a 150lb Mary Rose bow manage even 146 J. A 180lb longbow with the same arrow shouldn't deliver more than 160-170 J, and I don't believe there's any evidence for heavier arrows (or bows, for that matter). Only a truly exceptional English archer could loose arrows as potent as bolts form a heavy steel crossbow, and the bolts would still be faster and thus doubly more accurate. (The crossbow's design facilitates accurate shooting, which faster projectile speed further enhances.)

On the other hand, these calculations simultaneously show that heavy steel crossbows had no reasonable chance of piercing high-quality breastplates or helmets. If I recall correctly, a 2.5mm breastplate of the very steel with padding requires around 400 J to defeat. All of this stands consistent with later period accounts of the crossbow and longbow, especially Fourquevaux's. Crossbows hit harder than longbows, but not necessarily as much harder as is often assumed.

The other thing as well - if we take the 288 pound draw bow, and apply the same efficiency numbers that we did to the heavier composite, we should see 119 Joules.

With a 65 gram bolt, we have 60.5 meters per second for the lighter bolt.

This puts the lighter composite as very similar in performance to a 150 pound pull longbow.

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Only with a 113.4g arrow does a 150lb Mary Rose bow manage even 146 J.

I must add this is very heavy for a longbow arrow, from what I remember the estimated weights of arrows was in the 900-1500 grain range. The above arrow would weigh in at 1750 grains.

I am sure with much heavier bolts, crossbows could generate more joules, but using what is historically "accurate" is more important.

I think I agree with you, Ben. The Composite bow test listed, while interesting, seems to be off in regards to performance. At worst a composite crossbow should be equal to a steel bow in efficiency. It should theoretically be a lot better. The Composite has a recurve structure, which should make it more efficient, the materials used for a composite bow are better in terms of energy transfer. Last but not least, maybe most importantly, the composite bows should be much better in terms of weight of bolt to force applied ratio, this holds true in all bows, the Karpowicz bow testing is one of the best examples regarding this.

My guess it is something in the construction, perhaps they did not het the glueing process right or something else.

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If I recall correctly, a 2.5mm breastplate of the very steel with padding requires around 400 J to defeat. All of this stands consistent with later period accounts of the crossbow and longbow, especially Fourquevaux's. Crossbows hit harder than longbows, but not necessarily as much harder as is often assumed.

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Williams unless specified otherwise) Energy to defeat, in Joules: Arrowhead vs. Buff Leather 30 J Lance vs. Cuir-boulli 30-20 J Lance vs. Padding (16 layers linen, 60g for 16 x 21 cm) 50 J Arrowheads vs: Modern Mail (mild steel) alone 80 J Modern Mail & Jack Penetration 100 J Modern Mail and Tailor's Dummy 100 J (Soar et al) Modern Mail, Jack Penetration, and 35 mm penetration of Plastilene behind 120 J 15th c. Mail (low carbon steel hardened by quenching) two links broken and jack behind completely penetrated: 120 J 1 mm mild steel plate (perpendicular impact) 55 J for 45mm penetration 1. 5 mm mild steel plate 110 J 2 mm mild steel plate 175 J

I'd think probably the 250 joule range would be more accurate based on the above numbers - but this is only with perpendicular impact. If not perpendicular, it's a lot tougher.

But still, if the Payne-Gallwey bow generates 206 joules, this would still make the wearer pretty safe.

Of course I don't now how superior the harness you mention is to mild steel.

And I think the head Williams used may not have given the best results for mail penetration, it would seem more accurate for me in regards to plate penetration, as the longer bodkin types would struggle with mail, and an arrowhead more like Williams tip would be better against plate.