Got a Real-World Weapon or Armor Question? Mk. VI

[Spamotron]

I'm looking for a good resource on stick-fighting especially European cane-fighting based on fencing. The self-defense versions, not sport.

Thanks

[Mike_G]

65 m/s is pretty sensible velocity of ~80g bolt from decently heavy crossbow.

With lighter bolts, you could certainly get higher, but not 340 m/s, certainly.

And actually, the rate of velocity decrease would be very important here.

Bolts generally would loose it slower than arrows, but still pretty quickly compared to many other objects.

So, at 65 m/sec, the bolt will take ~3 second to travel 150 yards, without calculating the loss of velocity due to air resistance. So probably a bit over 3 seconds.

Using the 16 feet/second drop from an earlier post, we see that the bolt will fall 48 feet in 3 seconds.

So, to hit the guy in the chest at 150 yards, you need to aim something like 45 feet above his head.

So if that is "flat," it's for a very generous value of "flat."

[Raum]

At sea level, gravity alone will cause a projectile to drop at a rate of 9.81m/s^2. It seems to me the real question is "how fast will a crossbow bolt be going?"

Using the high end of bows mentioned in the thread, an 800kg draw bow will accelerate a 40g bolt to 200m/s in 0.01s. (Do note, I picked a hundredth of a second acceleration time out of the air...I don't really know how long the bolt will stay in contact with the string.) Given these numbers, the bolt will drop ~7.3m at 150m range.

If the bow only had a 100kg draw, a 40g bolt would only be traveling 25m/s and would drop ~196m at a range of 150m...assuming it made it that far.

So it really depends on what the crossbows' draw weights were.

There are lots of assumptions in my math. Constant acceleration for one hundredth of a second being one but it also ignores atmosphere entirely. That said, I'm not sure I'd describe even the ideal 7.3m drop as a 'flat shot'...the crossbow's direct aiming point is more than three times a tall man's height over the target's head. However, it is significantly closer to flat than a longbow's much lower acceleration (even when accounting for a longer acceleration time).

[Galloglaich]

I think the question is more what you are calling a "flat shot." We can easily calculate a lower limit to the amount a bolt will drop. At 150 yards, if we ignore air resistance and say a crossbow bolt travels at the speed of sound (which is an upper limit, I don't think even crossbow fanatics would claim supersonic bolts) we get that the bolt will drop about 4 yards. This is twice the height of a person. But it is still a very small angle (about 1.5 degrees). So the shot can't really be considered flat in that it does drop a significant amount, but the angle is still small.

With more realistic numbers the angle will go up significantly. But I feel confident in saying that the bolt will drop at least 4 yards unless the bolt is supersonic. (In theory if the bolt could get significant lift and make this lower, but I feel that air resistance should be much larger than lift)

Yes I would be amazed if a crossbow bolt achieved even half the speed of sound.

And obviously by "straight" I never meant like a laser.

But let me try to explain it this way. We've already been told on this thread that Muskets arced their shots quite a bit at long range. I think one guy said 10 degrees? But is there any doubt a musket shoots a 200 meter target (relatively) strait or dramatically less arced compared to a longbow?

Crossbows are a notch or two down from that surely in terms of fps, but at 150 meters, at least apparently some folks in period thought they could shot straight, to the extent that they were aiming at individual targets as opposed to just a certain area.

Which is why they seemed to feel that Crossbows were more useful in areas like the Baltic or the Alps where there is dense forest.

Which is the (fairly humble, I think) point i was trying to make.

G.

[Galloglaich]

At sea level, gravity alone will cause a projectile to drop at a rate of 9.81m/s^2. It seems to me the real question is "how fast will a crossbow bolt be going?"

Using the high end of bows mentioned in the thread, an 800kg draw bow will accelerate a 40g bolt to 200m/s in 0.01s. (Do note, I picked a hundredth of a second acceleration time out of the air...I don't really know how long the bolt will stay in contact with the string.) Given these numbers, the bolt will drop ~7.3m at 150m range.

If the bow only had a 100kg draw, a 40g bolt would only be traveling 25m/s and would drop ~196m at a range of 150m...assuming it made it that far.

So it really depends on what the crossbows' draw weights were.

There are lots of assumptions in my math. Constant acceleration for one hundredth of a second being one but it also ignores atmosphere entirely. That said, I'm not sure I'd describe even the ideal 7.3m drop as a 'flat shot'...the crossbow's direct aiming point is more than three times a tall man's height over the target's head. However, it is significantly closer to flat than a longbow's much lower acceleration (even when accounting for a longer acceleration time).

Thanks for crunching the numbers. That is interesting.

I think bolts weighed about 90 grams (though there is some argument about that) so the initial velocity in your model would probably more like 100 m/s, and actually probably more like 70 or 80 m/s since I think 500 kg is more realistic than 800 kg. Nevertheless I think at 150 meters the elevation is still probably under 5 or 10 degrees compared to 45 degrees for a bow at that range.

You could get a comparison of the drop rate from bullet ballistics but I would assume a bolt with vanes would be a bit more aerodynamic than a bullet. Some of them were apparently made to spin which has I don't know what effect. Arrows were in turn also significantly more aerodynamic than bolts.

G.

[Spiryt]

500 kg steel prod crossbow could generally speed ~90g bolt up to about 67 m/s AFAIK.

100 m/s is probably achievable with light bolts and composite prods, but probably won't be really useful that often.

[Galloglaich]

500 kg steel prod crossbow could generally speed ~90g bolt up to about 67 m/s AFAIK.

100 m/s is probably achievable with light bolts and composite prods, but probably won't be really useful that often.

Interesting ... what is your source for that? Or just crunching the numbers?

G.

[Spiryt]

Interesting ... what is your source for that? Or just crunching the numbers?

G.

The source is Die Armbrust that I saw in the net somewhere, I think but can't find it now, and a lot of crunching too.

It's only in German AFAIK, but fortunately at least numbers are the same everwhere.

I remember 67 m/s for 80 g bolt, but with some "adjustments" 90 should go too.

Data is for "halb rustung" prod which would be generally around 500 kg.

[a_humble_lich]

I just did a much more accurate calculation. I wrote a short program to integrate the equations of motion for a ballistic bolt including air resistance. If anyone wants details, or a copy of the program/code let me know. I did not include any lift generated by the bolt, but I contend this should be small.

There are several parameters that go into the program. I used a 80g bolt with a radius of .4cm (this includes the head) at sea level, fired by someone at a height of 1.5m. My big questions are the initial velocity and the coefficient of drag (i.e. how much air resistance there is) of the bolt.

When the air resistance is small (C_d = .2) I find that a velocity of 71m/s is needed to get to 450m, which earlier was said to be a maximum range. This is when the crossbows are shooting at an angle of 30 deg (because of air resistance the angle of maximum distance is not 45 deg). At this speed an angle of 8 deg is needed to hit a target at 150m (and the bolt will fall on the target at on angle of 9.2 deg) after flying for 2.1s.

I like these values for initial velocity and drag. The velocity is about what Spiryt said, and with that drag it gives a maximum range close to what Galloglaich said the Swiss claimed.

What does all this mean? For starters, at ranges of 150m fairly shallow angles will be needed for a crossbow. However, the aerodynamics of arrows/crossbow bolts is fairly complicated. I would like to see some data from an actual bow/crossbow and perhaps a wind tunnel before I would say anything with great confidence. Searching for values on the internet has given a very wide range of values for the speed and drag of both arrows and crossbows (some of which I flat out disbelieve). Not to mention what is the actual effect of lift, the rotation of the arrows, etc.


(Aside)
Trying to calculate the initial velocity given the force of the bow seems doable, but in practice I think it would be hard. Mainly, the force on the bolt is not constant, the force will be greater at the beginning and goes to zero as it leaves the crossbow. It is not obvious (to me) how this works and I'd want to know more about crossbows work before trying to think about it.

[Spiryt]

Eh, it's pretty complicated indeed, and I can do some basic calculations with bows, but I'm not sure how crossbow work...

The energy delivered to the bolt would depend on so many factors.... It's not easy with the bows, as I said, and with crossbows we have much more powerful prods, that are much less efficient due to draw length, but on the other hand bow arms have much shorter road to go, impact is more violent, vibrations are somehow absorbed by the handle.

Anyway, those are interesting calculations...

What velocity decrease ratio it gives?

I've seen a data about replica of longbow about 24 kg - so about 55 pounds - speeding arrow up to 44 m/s.

Decrease of velocity in flight is 0,13 (m/s)/m.

Unfortunately there's no data about arrow, even it's weight at very least, in this example.

EDIT: Anyway, as far as I know, resistance of air is quite a.... female dog for bolts and arrows. Feathers produce a lot of it to stabilize.

Just seeing both modern and ancient flight arrows - they universally have possibly minimal feathers.

[a_humble_lich]

The figures you give confuse me, because with the numbers I've been using I have a velocity decrease ratio of about a fifth of what you give (when you say 0,13 you mean the same thing as me saying 0.13, right?) While I'd expect arrows to have less drag that the crossbow bolts. I'd like to know more actual data, however what I can easily find on the internet seems contradictory. What I'd really like to see would be for a given bow/crossbow both the initial speed and the maximum range. Without more numbers I don't feel good using this analysis to compare longbows and crossbows.

What I do feel more confident in saying is that the angle a crossbowman would need to hit a target 150m away is in the range of 5-10 deg, while a bow (at 44m/s) would need an angle of more like 25 deg. At that range I don't think aerodynamics is too important of an issue yet. But it should be noted that even an angle of 5 deg at 150m mean you are aiming 13m (!) above the target. That does not sound easy (not that I disbelieve, but that I'm quite impressed).

[Spiryt]

Eh, the problem is that such data is not easily achievable...

People don't seem to record initial velocity and distance traveled at the same time.

Obviously though, you're probably underestimating the influence of fletching, vibration of the shaft and other factors. Arrows and bolts are indeed quite rapidly slowing down projectiles.

Then comes the balance, some arrows were better suited to achieve stable position at high arc shots, to travel far.

Bolts, as far as I understand, would generally be more stable after leaving the bow than most arrows, but not really well suited for long distance shooting.

Arrows

[Yora]

I would like to know more about asian armor. All I'm really familar with are Oyoroi and Ashigaru armor, and even that isn't much.
Does anyone about you here know about indian, chinese, or korean armor and can reccoment some sites to read?

[Mike_G]

What I do feel more confident in saying is that the angle a crossbowman would need to hit a target 150m away is in the range of 5-10 deg, while a bow (at 44m/s) would need an angle of more like 25 deg. At that range I don't think aerodynamics is too important of an issue yet. But it should be noted that even an angle of 5 deg at 150m mean you are aiming 13m (!) above the target. That does not sound easy (not that I disbelieve, but that I'm quite impressed).

Which synchs up fairly well with my "aim 40 feet over his head" theory.

All I was ever trying to say was that at the range that a longbow arrow will be significantly arced, so will a bolt. I was fine until the "kettle hats will protect you from the falling arrows but the bolts will come straight down your throat" commentary. Past a hundred yards, everything is coming in at an angle.

[Spiryt]

I would like to know more about asian armor. All I'm really familar with are Oyoroi and Ashigaru armor, and even that isn't much.
Does anyone about you here know about indian, chinese, or korean armor and can reccoment some sites to read?

Well, that's broad topic, to say at least.

Dunno what you know about Japanese ones, but there are two articles that seem fairly professional.

1


2

[Yora]

I know these two. But they are good examples of the fact, that almost all material about asion armor is about Oyoroi and nothing else.
While that's good enough for people who are exited about samurai, it's a bit like researching european armor technology and having it reduced to Gothic Plate Armor only.

However the first one at least talks a bit about the types of armor that evolved into the Oyoroi. It's highly appreciated.

[Galloglaich]

There used to be a good website called "Silk Roads Design Armoury" with detailed information on all kinds of Asian armor but it seems to have been taken down.

At this point I would suggest getting Osprey military books on the specific Asian arms and armor you are interested in. Some examples:

Sikhs
http://www.amazon.com/Sikh-Army-1799...2491900&sr=8-1

Mughul India
http://www.amazon.com/Mughul-India-1...2491941&sr=1-3

Ottoman Turks
http://www.amazon.com/Armies-Ottoman...d_bxgy_b_img_b

Janissaries
http://www.amazon.com/Janissaries-El.../ref=pd_cp_b_1

Mongols 1200-1350
http://www.amazon.com/Mongol-Warrior.../dp/184176583X

Chinese Armies 200-589 AD
http://www.amazon.com/Imperial-Chine...2492089&sr=1-5

Chinese Armies 590 - 1260 AD
http://www.amazon.com/Imperial-Chine..._bxgy_b_text_b

Samurai Invasion of Korea 1592 - 1598 AD
http://www.amazon.com/Samurai-Invasi...2492234&sr=1-3

Some of those Osprey books are scanned on google books.

There is a book called "From Stone to Steel" which covers a lot of Asian and South Asian armor and equipment in a D20 context.

My book "Arms and Armor of the Ancient World Part II" has some Asian armor including Japanese, Chinese, and Turkish armor, but it's not as deeply focused on that as on the European kit.

I think GURPS low tech (3E?) has some realistic Asian kit.

G.

[Psyx]

Crossbows are a notch or two down from that surely in terms of fps, but at 150 meters, at least apparently some folks in period thought they could shot straight, to the extent that they were aiming at individual targets as opposed to just a certain area.

It doesn't really matter what the sources claim as regards the straightness of the shot: Highly demonstrative physics show that it's not even close to being a straight shot. Surely that acceleration due to gravity is not in question here: Aiming three times higher than someone's head is not straight.

But that's not to say it's not accurate enough to pick someone out as a target. Cutting back to several pages ago I tried to make the point that indirect doesn't mean inaccurate. The crossbow marksman of the age were hitting targets despite the angle, because they were good with them. Just the same as the archers were. I completely believe that both weapons were accurate at a range that required a high-level of 'aim off' indeed.

By a bit of maths we're led to believe that both weapons were not point-and-click-to-kill, but ones requiring - At anything more than point blank range - Skill in aiming based on experience. It's just that the longbow also required more physical training as well.

[Psyx]

Is there any reason to face them unarmed instead of taking up a weapon?

'They want to die' is all I can come up with.

[Matthew]

Seems to me on the continuing subject of the crossbow versus bow debate that there are a few salient points:

1) There is a difference between direct and indirect shooting [i.e the distinction is not just imagined].
2) The former is more accurate than the latter in the sense that you aim at a target you can see, though this does not matter over much when targeting a large body of troops.
3) In some instances, some medieval crossbows had a longer direct shooting range than some medieval bows.
4) A direct shot at short range will more reliably penetrate armour than an indirect shot at long range.

In the high to late medieval period (1100-1500) both crossbows and bows were employed on the battlefield, in skirmishes, and at sieges, being favoured by different military groups living in relatively close proximity. That is to say, the relative advantages that they enjoyed were sufficient for both to continue in use without one being completely eclipsed by the other.

The specific degrees of advantage and disadvantage necessarily remain elusive at this time, but we can also say:

1) The more powerful the crossbow the more difficult it is to reload, so that even with the employment of time saving devices you are looking at anything from 6-60 seconds reload time (though 6-30 second might be more accurate).
2) Bows can be shot very quickly, several shots within 6 seconds perhaps, but doing so is tiring, with increasingly powerful bows requiring commensurate strength and training to handle.

So, if discharging a large volume of missiles in a short period of time is the aim, then a bow will generally be better suited to the task. If volume is not the issue, so much as the ability to hold and aim for a long period of time, or shorter training periods, then a crossbow will probably avail better. Out of context, though, that is pretty much irrelevant.

What else can be said? Not much, I would guess.

[Galloglaich]

It doesn't really matter what the sources claim as regards the straightness of the shot: Highly demonstrative physics show that it's not even close to being a straight shot. Surely that acceleration due to gravity is not in question here: Aiming three times higher than someone's head is not straight.

But that's not to say it's not accurate enough to pick someone out as a target. Cutting back to several pages ago I tried to make the point that indirect doesn't mean inaccurate. The crossbow marksman of the age were hitting targets despite the angle, because they were good with them. Just the same as the archers were. I completely believe that both weapons were accurate at a range that required a high-level of 'aim off' indeed.

By a bit of maths we're led to believe that both weapons were not point-and-click-to-kill, but ones requiring - At anything more than point blank range - Skill in aiming based on experience. It's just that the longbow also required more physical training as well.

It's interesting that you and I apparently several of the same posts with all the math stuff and came to radically different conclusions.

I may have to review the thread after a couple of weeks maybe I'm too immersed in the discussion and I'm missing something.

G.

[fusilier]

"Flat" shooting is a relative and subjective term. A high-power rifle may need very little elevation to hit a target at 150m, whereas crossbow may require 10-15 degrees or so (just a guess, I don't actually know). However, a bow may require 30-40 degrees at that range. So relative to a bow the crossbow is shooting flatter. For that matter, it's still possible to "aim" the crossbow at 10-15 degrees, whereas at 30-40 it's probably not practical (I assume one would aim before elevating). Although, typically one would be shooting at mass targets, so precision aiming isn't necessary.

"Point blank" on the other hand is different, and point-blank range for a crossbow was considered to be around 80 yards.

[Mike_G]

"Flat" shooting is a relative and subjective term. A high-power rifle may need very little elevation to hit a target at 150m, whereas crossbow may require 10-15 degrees or so (just a guess, I don't actually know). However, a bow may require 30-40 degrees at that range. So relative to a bow the crossbow is shooting flatter. For that matter, it's still possible to "aim" the crossbow at 10-15 degrees, whereas at 30-40 it's probably not practical (I assume one would aim before elevating). Although, typically one would be shooting at mass targets, so precision aiming isn't necessary.

"Point blank" on the other hand is different, and point-blank range for a crossbow was considered to be around 80 yards.

You can aim an elevated bow by looking through the lower half of the bowstaff at your target. I've seen bowstaves with lines on the lower arm corresponding to ranges. You elevate the bow until the correct line is level with the target, then loose. You don't look along the arrow, at the cloud above the enemy formation, you look past the bowstaff at the target. The premise is no different than the volley sights on a rifle.

[Fhaolan]

I'm looking for a good resource on stick-fighting especially European cane-fighting based on fencing. The self-defense versions, not sport.

Thanks

There are many forms of European cane-fighting, but from the description you're interested in one currently known as Bartitsu. There is a Bartitsu society which has published a few books on the subject. There are also some self-defence schools that teach it, but they are few and far between, and all the ones I know are in Germany.

Other forms of stick fighting that you may be interested in would be the Irish form Bataireacht, and the French form of Bâton français. Doing web searches on these terms will show lots of 'stuff', but there I haven't found any really good manuals or teaching aids for any of it.

[Galloglaich]

Another good one is Jogo Do Pau, which is a pretty big sport in Portugal and the Canary Islands

http://www.youtube.com/watch?v=gSDSsereOdg

http://www.youtube.com/watch?v=ze1SpAUk1zI

http://www.youtube.com/watch?v=1xxHR...eature=related

here you can see some training being done, drills

http://www.youtube.com/watch?v=WaiZg...eature=related

There are some articles here:

http://www.jogodopauportugues.com/program/articles.html


If you are real interested in Bartitsu I know one of the main guys who teaches it in the UK, pm me and I can send you a link to his website, I don't want to post it here due to the high traffic volume.

G.

[Galloglaich]

You can aim an elevated bow by looking through the lower half of the bowstaff at your target. I've seen bowstaves with lines on the lower arm corresponding to ranges. You elevate the bow until the correct line is level with the target, then loose. You don't look along the arrow, at the cloud above the enemy formation, you look past the bowstaff at the target. The premise is no different than the volley sights on a rifle.

I guess it's a "glass half empty" / "glass half full" kind of discussion.

One thing is for sure, I said longbows vs. armor were an internet fault line, I've now learned the lesson that longbows in general, period, are an internet fault line. I won't make the mistake of mentioning them in a forum again. I apologize to anyone I offended in this thread, you get kind of carried away in these intensive debates.

I really appreciate all the number crunching that was done at the end though I got some really useful data out of that and learned some nuances I didn't know before.

G.

[a_humble_lich]

I glad you enjoyed it, I leaned the physics of arrow flight is much messier that I thought. Mainly I was surprised at the wide range of values with regards to archery which exist on the internet. Things like air resistance, arrow speed, range vary by an order of magnitude depending whose speaking.

And I don't think the discussion was a mistake, I sure learned a lot.

[Spiryt]

I glad you enjoyed it, I leaned the physics of arrow flight is much messier that I thought. Mainly I was surprised at the wide range of values with regards to archery which exist on the internet. Things like air resistance, arrow speed, range vary by an order of magnitude depending whose speaking.

Because it all depends on bow, it's quality, arrow shape, fletching, mass, flexibility quality..

So possible characteristics can naturally vary a lot, there are thousands of combinations.

[fusilier]

You can aim an elevated bow by looking through the lower half of the bowstaff at your target. I've seen bowstaves with lines on the lower arm corresponding to ranges. You elevate the bow until the correct line is level with the target, then loose. You don't look along the arrow, at the cloud above the enemy formation, you look past the bowstaff at the target. The premise is no different than the volley sights on a rifle.

I did not know that. That's pretty cool, and would certainly be helpful for volley fire. I don't know much about crossbow sights, I do know they existed, but I suspect that many crossbows were simply sighted over the bolt.

But do you see what I'm saying about flatter shooting? I'm inclined to believe that even a fairly powerful crossbow, would require a fair amount of elevation at 150m, but significantly less than a bow. That seems to fit with the first hand accounts.

[Mike_G]

I did not know that. That's pretty cool, and would certainly be helpful for volley fire. I don't know much about crossbow sights, I do know they existed, but I suspect that many crossbows were simply sighted over the bolt.

But do you see what I'm saying about flatter shooting? I'm inclined to believe that even a fairly powerful crossbow, would require a fair amount of elevation at 150m, but significantly less than a bow. That seems to fit with the first hand accounts.

I was always willing to accept "flater" but the feeling from many posters, and the misconceptions fostered by bad rules discussions that "Arrows=Arced flight, Crossbows=straight flight" is fundamentally wrong.

It's all projectile motion. A powerful bow shoots flatter than a weak crossbow. Not many crossbows were weaker than bows, but turning the bow sideways and nailing it to a stick doesn't make it shoot flatter. Increasing the velocity of the missile makes it shoot flatter.

I think maybe this discussion got heated, but I did learn a few things I didn't know, and I'm happy that somebody broke ouit the physics and crunched some numbers.

I think the biggest bones of contention revolve around the fact that there really aren't standard bows or crossbows or good reliable tests, so we all tend to interpret the incomplete data in a way favorable to our own suppositions.