Info Favorites Register Log in
myArmoury.com Discussion Forums

Forum index Memberlist Usergroups Spotlight Topics Search
Forum Index > Historical Arms Talk > Javelins Reply to topic
This is a standard topic  
Author Message
Bill Sahigan





Joined: 06 Jun 2008

Posts: 56

PostPosted: Tue 30 Dec, 2008 10:33 pm    Post subject: Javelins         Reply with quote

just a quick question.

does anyone know of a good source for comparisons between javelins and bows in terms of penetration power?

Thanks.
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Wed 31 Dec, 2008 5:41 am    Post subject:         Reply with quote

No quick and simple answer to that one, I am afraid. What bow, what arrowpoint, what target, what kind of javelin point, what range ?? Offhand the arrow with a bodkin point fired from a 50 # plus bow at 25 yards should outperform the hand throw javelin against a wooden shield. However, use a Roman style pilum (the pilum was a throwing spear with a bodkin like head on a thin metal shaft, fixed to a wooden undershaft) as your javelin and anyone behind that shield is in trouble.
View user's profile Send private message
Gary Teuscher





Joined: 19 Nov 2008

Spotlight topics: 1
Posts: 704

PostPosted: Wed 31 Dec, 2008 8:56 am    Post subject:         Reply with quote

An olympic Javelin has been calculated to have a 360 joulles upon release, where a 140 lb longbow has about 100j (alan williams)

As joulles is merely the force upon release, it has nothing to do with the aerodynamics of an olympic javelin ( which weighs 1.76 pounds by the way).

Now there is the run up before release with an olympic toss. But contemporary accounts of saxon/viking battles mention warriors, running in front of the shield wall and throwing a javelin, then retreating behind the shield wall, so this was likely done, and I would think that they could have achieved at least 70% of an olympic toss, or about 250 joulles. This was done prior to the main battles lines contacting each other.

As far as just stepping and throwing, I'm not sure, maybe half at best? 180j or so?

Of course a javelin will lose velocity quicker and have a much more limited range. But at very short ranges, IMO it penetrates better than a bow.

Also, if force determines penetrative ability, this is as said. Some say momentum has as much to do with it. As momentum is less velocity based and more mass based, a Javelin would penetrate even better if this is the case.

Much of it is how it's employed. Early cavalry tactics were cavalry advancing upon infantry, throwing javelins on the move, and retiring to do again, similar to a caracolle. Charging cavalry add the horses forward movement to the velocity of the throw - giving a mounted javelin toss numbers at least equal to that of a running footman, and better range. These tactics ended in most of western europe though by the 11th century or so, though were still used in eastern europe and spain after this time.

Rome of course used a heavy short ranged javelin just prior to contact - once again good penetrative ability, though it's range was primarily just before contact. With the massed formation toss you are going to be limited to more of a step and throw, no run up. THis hurts penetration of course, to exactly what extent I do not know.

As a true missile weapon at range the javelin is far inferior to a bow. When used by mass infantry prior to contact, or cavalry tactics like mentioned above, it is effective, though if facing cavalry I'd rather have a wall of spears or polearms than an initial shower of javelins. That's my opinion, but it seems to be born out historically as far as what was effective against cavalry.

But it was a very good weapon strictly as far as pentrating armour at short ranges IMO, depending on the weight of the particular javelin probably effective for not much more than 25-50 yards. Actually until reading the Williams numbers, I wondered why they were even used, but after seeing penetration numbers it makes more sense.

And of course as Robert mentioned, the type of head has a lot to do with it.
View user's profile Send private message
Bartek Strojek




Location: Poland
Joined: 05 Aug 2008
Likes: 23 pages

Posts: 457

PostPosted: Wed 31 Dec, 2008 9:27 am    Post subject:         Reply with quote

http://www.worldatlatl.org/Articles/TakochCD/...evised.pdf

Unsurprisingly, 'average' javelin have much higher kinetic energy (2 pound javelin listed here as having around 220 J of energy) more momentum, higher sectional density, much higher mass. All those will be higher than even 150 Joules longbows and composite bows, so I would say that in general javelin, especially with heavy, yet thin shaft and acute point will achieve better penetration against most targets than arrow.

Arrows can have times greater velocity though, which is important against targets such as steel.

Projectile with high energy, mass, momentum et cet. but low velocity will probably dent or cause vibration to steel plate. Less powerfull, but faster one can punch trough plate as it won't give it time to dent, or absorb energy in other way.
View user's profile Send private message
Gary Teuscher





Joined: 19 Nov 2008

Spotlight topics: 1
Posts: 704

PostPosted: Wed 31 Dec, 2008 10:50 am    Post subject:         Reply with quote

Very interesting PDF, Bartek!
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Wed 31 Dec, 2008 12:58 pm    Post subject:         Reply with quote

Hmmm, well, for penetration, a lot comes down to the area all those joules are concentrated on (PSI) and how much is left on reaching the target. So it's all down to the shape of the point and the velocity determining whether or not it will punch through and then hopefully have enough power left to carry on to do serious damage. In an unshielded body, cutting surface of the projectile is the killing equation, then the javelin really comes into it's own right. It is very difficult to compare the effectiveness of any weaponsystem to one around at the same time, for often both had a different usage and were excellent in their own right under circumstances calling for one or the other
View user's profile Send private message
Ted Parolari




Location: Tennessee
Joined: 22 Jan 2008

Posts: 29

PostPosted: Wed 31 Dec, 2008 2:54 pm    Post subject:         Reply with quote

Shouldn't you also look at what happens after a javlin or an arrow hits the target. Assuming the javlin were thrown at fairly close range (25 ft to 50 ft), I would think you'd have a fairly long, weighty, ackward piece or metal or wood sticking out of the target. If that target were a armed warrior, I'd think in addition to the wound that is caused, that warrior would also have a problem moving and swinging or shooting his weapon. The Javlin would have to be pulled out in order to clear the incumbrance. An arrow with a bodkin point on the other hand, might be cut away and the head left in place until after the battle, and while painful it might not slow the warrior down that much.

It has always been my understanding that the beauty of a Pilium was just that it was easily thrown and caused wounds, but that if it buried itself into a shield, it was difficult to remove, thereby making the shield all but usless. Also metal shaft was made of fairly soft iron which would easily bend. Once bent, it was a fairly useless weapon until straightened out.
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Wed 31 Dec, 2008 3:44 pm    Post subject:         Reply with quote

There are actually quit a few different pilum designs. The main object of the design was to penetrate a shield and plug the person holding it. That is the reason for the shaft being of such a slender form. Once the head is through, there is 60 centimeters to follow through. The added effect of disabeling a shield is somewhat overrated, as it doesn't take you long to jank a pilum (or a javelin) out of a shield if just the head stuck. Just put your foot on it. Yes, any javelin sticking from a shield will make it more cumbersome, but that was not really the intent. As to the shaft bending, I have seen a lot of pilii with shafts that would be difficult to bend by impact alone. I recently did a (forged) reconstruction for the Nijmegen museum of just such a type.
The discussion was on penetrating power and the pilum is a very special sort of javelin. I would not really class it as such myself, having made several Roman javelins. The whole setup ( and mostly the spearhead) is completly different. But as a shield perforator, the pilum is very effective!
By the way, if you take a full body hit by an arrow, that will hurt bad and you will be put out of action pronto, even is you could "snap" the shaft off.
View user's profile Send private message
Jean Thibodeau




Location: Montreal,Quebec,Canada
Joined: 15 Mar 2004
Likes: 50 pages
Reading list: 1 book

Spotlight topics: 5
Posts: 8,210

PostPosted: Wed 31 Dec, 2008 3:59 pm    Post subject:         Reply with quote

Gary Teuscher wrote:

Of course a javelin will lose velocity quicker and have a much more limited range. But at very short ranges, IMO it penetrates better than a bow.



Not too sure about the javelin losing that much velocity as the velocity loss is mostly air resistance and with low velocity missiles air resistance is a negligible factor: Yes there is some velocity lost but the trajectory is mostly a question of gravity and at a low velocity the missile drops quickly compared to a bullet or even an arrow.

If the javelin was thrown in the absence of atmosphere the javelin would not lose any velocity getting to the target but it would drop all the same due to gravity.

With a high velocity projectile like a rifle bullet at supersonic speed the lost of velocity due to air resistance is very high but a heavy low velocity bullet like a .45 pistol bullet the lost of velocity is far less dramatic but the trajectory is very much like a rainbow.

Anyway the penetrating power of a javelin is mostly a question of mass and momentum rather than kinetic energy. ( I think ).

You can easily give up your freedom. You have to fight hard to get it back!
View user's profile Send private message
Mackenzie Cosens




Location: Vancouver Canada
Joined: 08 Aug 2007

Posts: 238

PostPosted: Wed 31 Dec, 2008 4:39 pm    Post subject:         Reply with quote

Thank you for the information in this discussion. It has help me understand the value of the initial spear toss that happens in some forms of German judicial dueling.

Mackenzie
View user's profile Send private message
Xan Stepp




Location: Ithaca, NY
Joined: 19 Dec 2008

Posts: 54

PostPosted: Wed 31 Dec, 2008 8:22 pm    Post subject:         Reply with quote

I thought I'd chime in here, and put my physics degree to some use. The primary component in determining penetrating power is pressure, but penetrating power is not always equivalent to damage. However, determining the pressure on an object can be somewhat complicated. Pressure is simply the area derivative of force, and while the definition may be straightforward, the physical situation is fairly complex as both the force and area are changing as the projectile drives through the target. As a result, the geometry of the projectile plays a huge part. Ideally the projectile will have a small a cross sectional area as possible during the greatest change in force, so even though the point of the projectile has the smallest area, the change in force is smaller. Therefore a graph of distance on the projectile vs. pressure would resemble a gaussian, but the exact shape is very dependent on geometry.

Much has been made in this discussion about the value of momentum in penetrating power, but momentum only plays an indirect role. The principal contributor to the force exerted on the projectile is what is known as impulse, or the time derivative of momentum. So where momentum becomes important is not in how much momentum the projectile possesses, but rather how quickly it changes. This would be dependent not only on geometry, but also on the nature of the material being penetrated.

Thus, without actually running the math (which is something I REALLY don't want to do) my inclination would be that penetrating power would prefer the javelin in some circumstances and the arrow in others. I know it may not be of much help, but hopefully it goes to illustrate some of the complexity involved in the question.

Deyr f, deyja frndur
deyr sjlfur i sama;
en orstr deyr aldregi
hveim er sr gan getur.
View user's profile Send private message
Bill Sahigan





Joined: 06 Jun 2008

Posts: 56

PostPosted: Wed 31 Dec, 2008 11:59 pm    Post subject:         Reply with quote

Thanks guys, lots of interesting tid bits here. Can anyone confirm the bit about pilum? I've always heard the encumberence is what kills the shield, not actually the penetration.
View user's profile Send private message
Xan Stepp




Location: Ithaca, NY
Joined: 19 Dec 2008

Posts: 54

PostPosted: Thu 01 Jan, 2009 1:49 am    Post subject:         Reply with quote

I don't know if this qualifies as a confirmation about the pilum, but Caesar describes this effect in 1.25 of De Bello Gallico.
Deyr f, deyja frndur
deyr sjlfur i sama;
en orstr deyr aldregi
hveim er sr gan getur.
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Thu 01 Jan, 2009 4:36 am    Post subject:         Reply with quote

Well, yes, a pilum firmly stuck in a shield will be a nuicence, but there has been a lot of debate on the "bending" on the Roman forum. The pilum bends when it strikes the ground, as the wooden shaft causes a lot of leverage. This makes it unusable to throw back. Some pila have a thick shank, which will not bend much. Hitting a shield, it penetrates the shield and goes on to penetrate what is behind the shield. Like I said before, the reason for the thin shank behind the bodkin shaped head. Just keeps on going once the head is through. Pila are mankillers, not shieldkillers. There have been quite a few experiments throwing pila at shields, the end results seem pretty conclusive ...
View user's profile Send private message
Bartek Strojek




Location: Poland
Joined: 05 Aug 2008
Likes: 23 pages

Posts: 457

PostPosted: Thu 01 Jan, 2009 5:43 am    Post subject:         Reply with quote

Robert P. Wimmers wrote:
Pila are mankillers, not shieldkillers. .


I always wonder why those two must be excluding. Throw the pila, try to kill/wound the guy, if it won't happen at least there's a big chance of making his shield useless.
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Thu 01 Jan, 2009 6:50 am    Post subject:         Reply with quote

Well, it will not be totaly useless, but yes, dragging a rather cumbersome piece of iron and wood around could well ruin your day. If it is firmly lodged, stepping on the protruding spear will also bring down the shield pronto, exposing head and upper torso to a nice solid stab WTF?!
The point I was trying to make is that there is a misconception of what the pilum was all about, and that was not to disable shields or bend, but to penetrate deeply. Any type of javelin hurled into a shield and sticking there will encumber the bearer of that shield, the pilum is however special in another respect, namely designed to penetrate shields
View user's profile Send private message
Gary Teuscher





Joined: 19 Nov 2008

Spotlight topics: 1
Posts: 704

PostPosted: Thu 01 Jan, 2009 10:10 am    Post subject:         Reply with quote

Jean Thibodeau wrote:

Quote:
Not too sure about the javelin losing that much velocity as the velocity loss is mostly air resistance and with low velocity missiles air resistance is a negligible factor: Yes there is some velocity lost but the trajectory is mostly a question of gravity and at a low velocity the missile drops quickly compared to a bullet or even an arrow


Yeah, I guess what I was meaning but incorrectly saying is the javelin, being as low velocity as it is, requires a different trajectory, even at shorter ranges.

I think there are 2 problems here, one is a 30 degree trajectory for a javelin at maybe 30 yards or so would be a 5 degree trajectory for a bow (exact numbers are off I'm sure, but I think you get the idea). A 30 degree trajectory is londer, putting more drag in the equation.

Of course I guess countering this idea is that an arrow is higher velocity, and due to that faces more drag. I think doubling the velocity triples the drag or something like that, so it effects higher velocity missiles more than lower velocity one's.

Of course there is force vectoring too - the arrow has only 5 degrees not going forward, the javelin has 30 at this supposed range. The other portion of the force is going up countering gravity. I know gravity minus drag brings some of that force back to the equation, though I'm not sure what the end result would be.

Xan wrote:

Quote:
thought I'd chime in here, and put my physics degree to some use. The primary component in determining penetrating power is pressure, but penetrating power is not always equivalent to damage.


Absolutely. The size of the impacting weapon has much to do with it, meaning for the "wound trough" or something like that. Of course, exaclty where it hits is a big issue. You can get hit in the abdomen and get lucky - if it hits mostly muscle or fatty tissue. Or you could get unlucky, severing veins or even worse an artery, or other organs. Same impact and penetration, two different results.

A narrow thin object may penetrate deeply - but miss vital organs. A wider "broadhead" design may not pentrate as deeply, but the wider wound trough will coause more general damage and increase the chance of hitting a more vital thing like vein, artery, etc. The idea with a thinner object is that the deeper penetration may strike an organ lesser penetration may not get to.

Very similar to modern guns using a hollow point vs armour pircing round - the hollow point lose much of it's penetration when it's force goes into "mushrooming" itself, but creates a larger wound cavity, hopefully doing more damage with a greater chance of hitting a vital organ. An armour piercing bullet may well pass through the body, perhaps hitting a vital spot, perhaps not. With a bullet it's a bit different though - it has so much velocity and KE that it will get enough penetration on a human body barring any armour.

Of course a direct hit to the skull with either type and you are pretty well done for.

What's also interesting is different armours deal with pentrating power differently. Plate (or at least the earlier type, not the renaissance thincker softer type as much) relies more on taking the force and stoipping it wihout much give. Mail and padding "give" much more in their resistance to being pierced.

Not sure how this equates - as too what type handles velocity better, which handles a more mass based attack better.
View user's profile Send private message
Robert P. Wimmers
Industry Professional



Location: Dieren, The Netherlands
Joined: 24 Nov 2008

Posts: 44

PostPosted: Thu 01 Jan, 2009 1:45 pm    Post subject:         Reply with quote

Wow!

OK, perhaps we should take one step back and decide on what we are penetrating in the first place (i.e. the target).
Lets keep the timeframe to the era when both javelin and arrow were commonplace in the theater of war.
The pilum is 1st century, start second at the latest. A change in tactics swings the preferred speartype carried into battle by the Romans to the hasta, predominantly a sturdy stabbing spear (it can be thrown, as can any spear, but it is rather heavy and has limited range). Javelins did stay around in the shape of lancea, which had long, slender triangular point of about 30 cm bladelength and the smaller type, also with a triangular shaped head, used by light troops and cavalry. Then there is the plumbata, a small "spear" weighted with lead (plumbum) and with a lethal barbed head, that comes around in the third century, as far as I have been informed. These could be thrown under and overhand. So we also have to decide on what type of javelin (head) we are talking about.
Mind you, in the late Roman era of the third century armour was no longer the thing to wear, at least not by most Roman troops.
View user's profile Send private message
Xan Stepp




Location: Ithaca, NY
Joined: 19 Dec 2008

Posts: 54

PostPosted: Thu 01 Jan, 2009 3:47 pm    Post subject:         Reply with quote

Quote:
Jean Thibodeau wrote:

Quote:
Not too sure about the javelin losing that much velocity as the velocity loss is mostly air resistance and with low velocity missiles air resistance is a negligible factor: Yes there is some velocity lost but the trajectory is mostly a question of gravity and at a low velocity the missile drops quickly compared to a bullet or even an arrow


Yeah, I guess what I was meaning but incorrectly saying is the javelin, being as low velocity as it is, requires a different trajectory, even at shorter ranges.

I think there are 2 problems here, one is a 30 degree trajectory for a javelin at maybe 30 yards or so would be a 5 degree trajectory for a bow (exact numbers are off I'm sure, but I think you get the idea). A 30 degree trajectory is londer, putting more drag in the equation.

Of course I guess countering this idea is that an arrow is higher velocity, and due to that faces more drag. I think doubling the velocity triples the drag or something like that, so it effects higher velocity missiles more than lower velocity one's.


Air resistance is a mathematical beast, and a pain to deal with. Technically, the force exerted on a moving body in air is only represented in a Taylor series of the form:

F= -b (dx/dt) - c (dx/dt)^2 - d (d/dt)^3 -...

(By the way if anyone knows how to insert mathematical symbols in the forum, let me know!)

However, in most cases one of the elements in the series dominates because the drag coefficients (b, c, d, etc.) tend to be much smaller with each member of the series. So for objects with the velocity of a baseball the first term dominates, but the second term dominates in the realm of bullets and such. (To my knowledge, the higher order terms are rarely important.) A javelin would certainly be in the realm of the linear term, but I'm honestly not sure about the arrow. My inclination would be that it is either in the range where the linear term dominates, or in the really annoying area where both the linear and quadratic term are important.

However, I still think that an arrow will experience a much greater drag force than a javelin. First of all, the linear drag coefficient is going to be much larger for the arrow. The coefficients are based on geometry, but the arrow has the fletchings which are designed to increase drag and thereby increase stability. Also, the arrow would be much less massive than the javelin and an equal force would result in a greater change in the velocity of the arrow.

I'm fairly convinced that the arrow does experience a greater drag force, but it really may not be that much of an issue. First of all, it will experience the greatest force when the velocity is the highest, i.e. right after it leaves the string. And while the exact mechanics would be difficult to guess without the math, it shouldn't make a difference. It is true that the difference in trajectories (and ranges for that matter) will result in a greater comparative reduction in velocity, but I think I'd be safe to say that the velocity of the arrow would be greater at all times except in the most extreme conditions (heavy wind, shooting down a high cliff.)

Then again, we have been treating both the arrow and the javelin as rigid bodies. In reality there would be a differential drag along the surface of both projectiles as vibrate. But the rigid body approximation is probably good enough, and I don't even want to THINK about the math otherwise.

Finally, Gary what did you mean when you said:

Quote:
Of course there is force vectoring too - the arrow has only 5 degrees not going forward, the javelin has 30 at this supposed range. The other portion of the force is going up countering gravity. I know gravity minus drag brings some of that force back to the equation, though I'm not sure what the end result would be.


I'm just not really clear as to what you are trying to say.

Deyr f, deyja frndur
deyr sjlfur i sama;
en orstr deyr aldregi
hveim er sr gan getur.
View user's profile Send private message
Jean Thibodeau




Location: Montreal,Quebec,Canada
Joined: 15 Mar 2004
Likes: 50 pages
Reading list: 1 book

Spotlight topics: 5
Posts: 8,210

PostPosted: Thu 01 Jan, 2009 6:12 pm    Post subject:         Reply with quote

Xan;
Quote:
Of course there is force vectoring too - the arrow has only 5 degrees not going forward, the javelin has 30 at this supposed range. The other portion of the force is going up countering gravity. I know gravity minus drag brings some of that force back to the equation, though I'm not sure what the end result would be.

Quote:
I'm just not really clear as to what you are trying to say.


I think he means that the arrow has a flatter trajectory ?

Flatter trajectory affects aiming and the " beaten zone " where a target is in danger of being hit: A high trajectory means that an error in aiming as far as range is concerned will either miss by falling short or being too high and going over the target to fall behind" The beaten zone being the length where a standing opponent will be in danger of being hit.

With a very flat trajectory the beaten zone is very long, with a high trajectory the beaten zone is narrow: This was something though to be very important in the 19th century for artillery or massed rifle volley fire. ( Not sure if I'm explaining it correctly though ) here is a better explanation: http://en.wikipedia.org/wiki/Field_of_fire

Terminal effect of a javelin or arrow, if it hits the target, is unrelated to the advantages or disadvantages of how flat the trajectory is.

You can easily give up your freedom. You have to fight hard to get it back!
View user's profile Send private message


Display posts from previous:   
Forum Index > Historical Arms Talk > Javelins
Page 1 of 1 Reply to topic
All times are GMT - 8 Hours

View previous topic :: View next topic
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum






All contents © Copyright 2003-2020 myArmoury.com — All rights reserved
Discussion forums powered by phpBB © The phpBB Group
Switch to the Basic Low-bandwidth Version of the forum