Reflex/Deflex Longbows

[kernowtom]

thankyou Alan - you have given me my first chuckle on this site for some time! You are quite right, of course - all my clever sums are for nought - your logic is impeccable:-)
thanks!!!!!!
tom

[alanesq]

Originally Posted by kernowtom

thankyou Alan - you have given me my first chuckle on this site for some time! You are quite right, of course - all my clever sums are for nought - your logic is impeccable:-)

LOL :-)

That's the benefit of having had a poor education, I have to figure things out the easy way ;-)

[steve58]

Originally Posted by kernowtom

It is with some trepidation that I venture to say anything contentious on this site as my last such post attracted some, umm, attention. However, I feel that with science on my side I can make at least one minor contribution to this debate. The kinetic energy of a projectile is caculated, in joules, as half the mass (in kilos) times the velocity squared (in metres per second). Using one of the sites quoted above we get a 60 gram war arrow with a terminal velocity of 40-45 metres per second. Being generous and using a velocity of 50 m/s gives a strike energy of 75 joules. For comparison let's take a full metal jacket .38 special round with a weight of around 8 grams and a velocity of 250 m/s. This gives a strike energy of 250 joules. Though perfectly capable of killing you dead, the .38 special was replaced by the .357magnum to provide a round for police use that would penetrate the early body armour. A .357 magnum round has an energy of over 733 joules. if stopped by a good piece of body armour it will not kill you (though, having shot .357 magnum rounds I would not want to be on the other end, regardless of what I was wearing...) Thus a war arrow, with only 10% of this energy, must have had to penetrate to wound or kill.
I await the arguments:-)
tom

Not arguing with the science, just quoting Mark Stretton in the Winter 2006 edition of The Glade. He was shooting a 104 gram arrow from a 150lb Italian Yew self bow, giving a speed of 45.4 metres per second. He calculated the impact would be over 100 Joules, when the HSE gives a figure of 80 Joules as being a fatal impact on a vital area. He also calculated that a target on a horse galloping towards the archer at 20mph would increase the effect to over 130 Joules. Not as impressive as firearms, but nasty!

[alanesq]

I guess there is a flaw in my logic, it could be that wearing armour reduced the chance of being killed by an arrow rather than ruled it out?

I must see if I can get a copy of that article, sounds very interesting
I wonder what sort of size dent this would make in the armour if it didn't go through?

[nelly]

I think the logic for the medieval knight would be the same as the modern soldier.

They still put on their body armour every day even though they know its not impenetrable. It just increases, not guarantees, their chances of survival and physiologically helps them face the enemy and fight.

(Arch Duke Ferdinand was wearing the best, most expensive body armour available at the time, easily capable of defeating the hand gun round he was shot with, and the assassin shot him in the neck! )

Then or now no body armour is 100% effective

[steve58]

Originally Posted by alanesq

looking at it from the other side; if arrows would kill even if the armour did stop the arrow then why would they bother wearing it ?

Because it would keep out swords, spears and other nasties and if they could get through the arrow storm and close with the enemy that would be handy!

Nelly; "Unfortunately you also have to factor in the physical properties of the target material, as some materials are weaker at resisting higher speeds and some heavy weights, all with the same total energy."

Nelly, are the characteristics of the projectile also relevant to its ability to penetrate? eg a bullet is copper-jacketed lead (?) and therefore squishy at the sort of speeds it's doing? On the other hand war arrows had hardened steel points (Mark Stretton again), not at all squishy! I think at least some of the bullet's energy would be absorbed by it deforming on impact, like a crumple zone on a car, and it would then be blunt and less able to penetrate anything? The arrow on the other hand applies all its energy to a hard, sharp point...

What I haven't seen any accounts of is testing war arrows against the full protection system, probably something like plate over mail over padded jacket (which I think would have been a likely defence for the chest area). Surely that would spread the impact out as well as resisting penetration better? Wonder if anyone has done testing with pressure sensors to see how well the impact is spread out? Plenty of tests to show that mail and plate on their own could be defeated, but I don't think that was how armour was actually worn? Come on all you historians!

[nelly]

At the kind of speeds modern rifle bullets travel I think the hardness of the bullet is less important, as long as its soft enough to grip the rifling and hard enough not to deform at super sonic speeds, simply the amount of energy it holds will defeat most things. (waters pretty squishy and with enough pressure/energy it can cut through steel)

The other thing to bear in mind is that if the bullet is being used against soft targets eg people you dont want it to hard as it will go straight through (over kill) and not impart the full force to the poor s*d being shot. A certain amount of deformation is considered a good thing.

With the relatively low energy carried by a standard arrow the strength and shape of the head is critical to make the most of the small amount of power available.

[joetapley]

Worth Reading on this topic of energy v momentum

http://www.worldatlatl.org/Articles/...%20revised.pdf

[cuddles]

Originally Posted by Jerry Tee

Had a chat with the club long bow guru today and he has a longbow with the curled up tips and he said that his bow does form a continuous arc when draw and went on to demonstrate and is therefore legal.

This type of bow was an artillerymans bow.If longbow archers want to shoot traditional should they not take off there elastic bands they use as sights.Surely they were not used on the bows used at Agincourt(not sure of spelling)

[steve58]

Originally Posted by cuddles

This type of bow was an artillerymans bow.If longbow archers want to shoot traditional should they not take off there elastic bands they use as sights.Surely they were not used on the bows used at Agincourt(not sure of spelling)

Fair point, but where do you draw the line? Plastic nocks? Fastflyte strings? Platform tabs? And to declare an interest I use all three!
For me personally longbow shooting is about using the simplest bow style as defined under GNAS rules. The challenge is centered on what I do as an archer and the distraction of complex equipment is removed. I am aware of the historical connection, but also that the medieval war bow was a completely different beast, so the link is sentimental/aesthetic rather than anything else.
Somewhere I have seen a quote from Pip Bickerstaffe in favour of modern strings and nocks for safety reasons, which seems sensible.
If the rules said no rubber bands I would re-learn aiming the bow accordingly.
Interestingly the great Victorian archer Horace Ford referred in very disparaging terms to those who used sight marks attached to gloves on the right hand as an aid to aiming, so this sort of discussion is not new!