Great flying bodkins - longbows again

[Erpingham]

A recent addition to the wikipedia English Longbow site reveals this Polish study.  Interestingly, this one is based on computer analysis rather than experiment.

I was a little worried by the reconstruction pictures at the beginning of the article (if you can't tell mid-15th century cavalry from mid-14th century, what hope is there? ) but press on into the meat and it is more interesting.  For those among us who like ballistics and materials science it is a treat.

To cut to the chase, it reveals small penetration of plate armour out to 225m using a 150lb longbow.  Where i find it a bit awkward is that, while the conceptualisation of the steel for the mid 14th century armour is right, the conceptualisation of 14th century armour is wrong.  There were very few large steel plates on a 14th century armour.  It was a layered combination of coat of plates, mail and fabric armour.  However, armour of the type modelled was more common by the early 15th century, so the results could be applied to Agincourt.  However, even then, armour was worn over an undergarment whose arrow stopping potential needs to be taken into account.

Worth a look for another way of approaching the problem, though.

[Patrick Waterson]

One of the aspects which struck me is the way the velocity of the arrow decreases so little with range (from 52 m/s at start to 46 m/s at 250 m (c.270 yards).  (Velocity vs range graph, p.76.)  Gravity seems to add back in what wind resistance takes out.

[Nick Harbud]

To cut to the chase, it reveals small penetration of plate armour out to 225m using a 150lb longbow.  Where i find it a bit awkward is that, while the conceptualisation of the steel for the mid 14th century armour is right, the conceptualisation of 14th century armour is wrong.  There were very few large steel plates on a 14th century armour.

Not only that, but it was only during the 15th century that one found plate armour made from properly tempered steel rather than soft iron.  It makes a big difference.

[Nick Harbud]

I just re-read the paper in more detail and I notice it uses a drag coefficient of 1.1, which is significantly lower than a typical bodkin arrow of 2.1-2.75 or a broadhead arrow that is around 3.5.  (See the appendix of Hardy "Longbow: A Social And Military History")  This would undoubtedly explain the small drop in arrow velocity seen in the theoretical analysis.

Regarding the effect of gravity on arrow speed, this is quite correct and significant, including when the arrow is shot up or down hill.  It can even be observed in the practical experiments undertaken by Mark Stretton that are referenced in the paper here.  Stretton also observes the increased penetration resulting from the velocity of the target as it charges towards the archer.

Incidentally, Stretton has also tried to practically determine the number of shots that a longbowman can reasonably make against a cavalry target charging from 220 yards.  He reckons that he can get in 3 shots, but notes that it is extremely hard to hit the target beyond 170 yards.

[Erpingham]

I just re-read the paper in more detail and I notice it uses a drag coefficient of 1.1, which is significantly lower than a typical bodkin arrow of 2.1-2.75 or a broadhead arrow that is around 3.5.  (See the appendix of Hardy "Longbow: A Social And Military History")  This would undoubtedly explain the small drop in arrow velocity seen in the theoretical analysis.

Which in turn affects the KE of the arrow and its effect.  The paper's results do seem at the more effective end of the spectrum, so this may explain why.

I agree it is well worth a look at Mark Stretton's experiments.  They can be a bit Heath Robinson-ish and I'm sure Paul Bardunias would comment on their replicability and variable control but they do offer useful pointers to performance.

[Patrick Waterson]

Incidentally, Stretton has also tried to practically determine the number of shots that a longbowman can reasonably make against a cavalry target charging from 220 yards.  He reckons that he can get in 3 shots, but notes that it is extremely hard to hit the target beyond 170 yards.

This would of course depend upon where in the walk-trot-canter-charge cycle the oncoming cavalry would be in the 220-170 yard range bracket, and the skills of distance judging and deflection calling of the longbow officers.

Sorry if that sounds obvious.

[Jim Webster]

Incidentally, Stretton has also tried to practically determine the number of shots that a longbowman can reasonably make against a cavalry target charging from 220 yards.  He reckons that he can get in 3 shots, but notes that it is extremely hard to hit the target beyond 170 yards.

This would of course depend upon where in the walk-trot-canter-charge cycle the oncoming cavalry would be in the 220-170 yard range bracket, and the skills of distance judging and deflection calling of the longbow officers.

Sorry if that sounds obvious.

Obviously you have to take into account the trajectory of the arrow, the flatter the trajectory the easier.
And of course the mass of the target, because the more cavalry, the more tightly bunched, the easier the target.

[Erpingham]

There are plenty of issues generated by the experiments.  For example, 10 yds per second would be faster than the drill gallop of 18th-20th century cavalry (between 340-440 yds per minute).  It is highly unlikely that medieval cavalry moved this fast or, if they did, it wouldn't be over 200 yds.  It is more likely they would come on at a trot (about 200-225 yds a minute) for most or even all of the distance (as patrick points out, there was a cycle to this).

Shooting at a moving target wouldn't be easy for an inexperienced longbowman.  Like Mark Stretton, they would be good judges of distance but they trained against static targets.  Only those with some combat experience (and maybe poachers ) would have done it.  I still don't buy Patrick's idea of Longbow officers/master bowmen who called the ranges - after the first shot, like Mark Stretton in the experiments, you were shooting by rhythm until somebody shouted "fast" (or a wave of cavalry swept over you).  Even at more realistic approach speeds, there wasn't much time for aiming but experience or practice would tell here - the archer didn't need to think about the shot or even aiming, he just had as he knocked and shot to match target speed and arrow flight time.  Shooting into a mass would make that approximate calculation adequate.   

[Patrick Waterson]

I still don't buy Patrick's idea of Longbow officers/master bowmen who called the ranges

I shall stop selling it, then, and simply give it away.

[nikgaukroger]

Shooting at a moving target wouldn't be easy for an inexperienced longbowman. 

Having done a bit of shooting at moving targets, in my experience you get the hang of it reasonably quickly if you are already a somewhat practiced archer.

[aligern]

I am with Patrick here on two accounts, neither of which is supported by direct evidence, but rather the logic of the battlefield.
Firstly the archers must have some local command that dictates when and at what angle to shoot if they have back ranks who cannot see the target unit. Without this we are probably down to two ranks shooting?
Secondly ( and OK this is a hobby horse of mine 😉) missile  based armies have to exercise strict control over ammunition expenditure and thus 'fire discipline' . They cannot afford to have men loosing off when they feel like it or emptying their quivers and returning to the camp for more , or expending too many shafts at long range when galling an enemy to prod them into attacking.
If there is some system of control that is not archer captains , then what is it?
Roy

[Erpingham]

fair points Roy.  The problems of "archer captains" are two fold when it comes to English style longbowmen.  Firstly, there is no evidence for them and this is an army which has left us a lot of documentation.  Secondly, in the situation we are discussing, how is this master fire controller going to get the information to all the men in the formation in a timely and fully understood manner.  We have plenty of evidence that medieval formations worked on very short, repeated, commands - "Thick and Tight", "Go down (i.e. dismount)", "Forward", "Close yourselves up" - degrees elevation and bearing, target velocity, windspeed every four seconds repeated down the line isn't going to work.  I personally think (and I don't have evidence for it) that archer formations were more self regulating, drawing on the more experienced men, when the shooting started.  Yes, I do think there was a degree of command and control to start and stop shooting - crying "shoot" or "fast" up and down the line would fit how we know they passed orders very well.

As to the effectiveness of the rear ranks, we've discussed it before.  The more I think about it, unless you stacked your archers on a hillside (not uncommon) your rear ranks were shooting blind.  Their mates in front could probably pass shooting information effectively in a slow moving situation but not a rapidly developing one.  With a bit of experience, archers could probably work out in their heads how far plodding infantry had got since the last volley at least accurately enough to hit big bodies of men.  Changes of pace, like winding up a cavalry charge, was perhaps less easy.

[Patrick Waterson]

Back in the heyday of Strategy and Tactics magazine, SPI did a game and an article on Agincourt.  Their thinking was that a master archer would shout the range in paces at which he wanted the volley to land (e.g. "Ten score!" or "Six score!"), the archers getting ready to draw and shoot, and when he felt the speeds and angles were right, he would yell "Loose!" (or "Nock, Draw, Loose!") and away would go the grey-goose shafts to land pretty much where he wanted and more or less when he expected.  The target would, unless it had dramatically changed its pace, be underneath.

I never was able to think of a better system than this to combine simplicity, efficiency and effective judgement.  The obvious caveats that the master archer's judgement must be very good and the archers well practised are not formidable hurdles given what we know of English longbow archery practice.

[Erpingham]

Very stirring - it would fit well in The White Company.  Incidentally, I doubt anyone ever chanted "Nock, draw, loose!".  You'd expect the archers to have arrows nocked as they prepared to shoot and draw and loose were a single action, which also included aiming.

It is interesting that we fall back on Agincourt again.  Although it is well recorded, it probably wasn't typical.  For a start, the proportion of archers was high and the field narrow.  They were probably deployed deeper than optimal.  There were more than enough archers that those in the ranks who could see would be enough to beat up a half-hearted cavalry charge through a morass.  They were also not coming head on but obliquely, which would have thwarted simple shouting distances. 

Anyway, enough of Agincourt.  I'm sure we will continue to have our own preferences as to how archers operated, fueled by a lack of solid evidence.

[Patrick Waterson]

I am not sure what SPI's sources were, but they seemed happy with them.  While they did later on do at least one of Hawkwood's battles, I had ceased subscribing so did not get that particular issue and hence do not know if they had any wisdom to add from that perspective.

Regarding Agincourt, I agree it was not a typical battle, given the unusually high proportion of archers, but it would be surprising if the archers there had used a different system from the norm; such would have required improvisation unless there was a range of options practised for differing deployments.

They were also not coming head on but obliquely, which would have thwarted simple shouting distances. 

This raises another point or two: however oblique they were to part of the line, they would have to be head-on to someone, and there were two groups of French mounted, so someone would have to control the shooting against each one.  However we think things were done, the latter matter is worthy of thought.