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Simon Van Der Spoel
Location: Australia Joined: 10 Jun 2008
Posts: 22
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 Posted: Sun 16 Aug, 2009 11:57 pm Post subject: Technical Data on Jousting Lance Impacts |
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Hello Gentlemen, (and any ladies on deck)
as you may or may not know I am working on a Jousting Documentary and it has been brought to my attention that we have made no reference to actual data of a jousting lance impact, and that's due to the financial restraints I face as an independent film maker, I do not have the resources to do a practical study of lance impacts, other than at tournaments, and not as a scientific data analysis project.
Does anyone know of any studies or data on lance impacts (modern or medieval) where they actually recorded data like pounds per square inch or kilograms force or tonnage impact, that I may reference in my film, as the majority of the film is coverage of tournaments and the people competing, but the educational side of the doco will need this data.
I look forward to any comments people may have and do truly appreciate the helpful response of this forum,
Kind Regards
Simon Van Der Spoel
Creator of the History Channel Documentary: "Spitfire Guardians"
http://www.youtube.com/watch?v=nLyNZgA0_iM
http://www.youtube.com/watch?v=rTIFoQ1m2LM
Director: "Mounted Steel" Jousting Documentary
http://www.youtube.com/watch?v=MIqrkN29HVQ
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Bjorn Hagstrom
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| Posted: Mon 17 Aug, 2009 3:58 am Post subject: |
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I do not know of any studies to refer to (sorry to say) but to give the audience an estimate of the force of a lance-strike you do not need that. Pure laws of physics would be quite enough. Mass of the horse(s) and rider(s), speed at impact, surface area of the lance head is all you need. The angle at which the lance hits the opponent if you want to take that into account.
This should be information available to you already or a phone-call away. Then let someone with basic skills in physics run the numbers to get kinetic energy, momentum and so on. Not as good as a full scientific test, but cheap and should put you in the right ballpark. I guess the challenge is that you have to somehow convey the correctness and assume the authority that you are doing these calculations instead of referencing an outside source.
There is nothing quite as sad as a one man conga-line...
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Nat Lamb
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| Posted: Mon 17 Aug, 2009 4:16 am Post subject: |
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I second Bjorn on this one, the basic physics should not be too dificult to work out. If you want to go beyond the raw numbers, perhaps you could go the "mythbusters" route and run a simulation based on the raw numbers, wooden shaft with lance head on a rig with x force striking shield/curved metal plate (tempered), cant imagine it would be prohibitively expensive. For a bit of show you could alway stick a watermelon behind the plate (or a pig carcass if budget permits... or the work experience kid if local labor laws alow)
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Timo Nieminen
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| Posted: Mon 17 Aug, 2009 5:33 am Post subject: |
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| Bjorn Hagstrom wrote: | I do not know of any studies to refer to (sorry to say) but to give the audience an estimate of the force of a lance-strike you do not need that. Pure laws of physics would be quite enough. Mass of the horse(s) and rider(s), speed at impact, surface area of the lance head is all you need. The angle at which the lance hits the opponent if you want to take that into account.
This should be information available to you already or a phone-call away. Then let someone with basic skills in physics run the numbers to get kinetic energy, momentum and so on. Not as good as a full scientific test, but cheap and should put you in the right ballpark. I guess the challenge is that you have to somehow convey the correctness and assume the authority that you are doing these calculations instead of referencing an outside source. |
Stuff like the masses, speeds, etc isn't the important thing. What will be important will be how much force is needed to break the lance. You're not going to exert more force than this, and we know that there is enough force to do so.
There are other weak points too, such as the riders' seats, and (for sharp points), the resistance of the armour to penetration. Assuming a good hit, at not too slow a speed, either a rider will be unseated, the target will be penetrated (not so likely with a blunt tournament lance), or the lance will break. A less good hit, and you get less force - the point slides off, for example.
A wide range of forces will unhorse a rider (i.e., just unhorse the rider, or unhorse the rider and add perhaps considerable extra energy), so that would be hard to come up with numbers for. But breaking the lance looks like it provides a pretty good upper limit to the force. No, I don't have numbers for this, and one would need many numbers to get a good idea of the range of forces, since lances will have a certain degree of variability.
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Bjorn Hagstrom
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| Posted: Mon 17 Aug, 2009 5:48 am Post subject: |
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| Timo Nieminen wrote: |
Stuff like the masses, speeds, etc isn't the important thing. What will be important will be how much force is needed to break the lance. You're not going to exert more force than this, and we know that there is enough force to do so.
There are other weak points too, such as the riders' seats, and (for sharp points), the resistance of the armour to penetration. Assuming a good hit, at not too slow a speed, either a rider will be unseated, the target will be penetrated (not so likely with a blunt tournament lance), or the lance will break. A less good hit, and you get less force - the point slides off, for example.
A wide range of forces will unhorse a rider (i.e., just unhorse the rider, or unhorse the rider and add perhaps considerable extra energy), so that would be hard to come up with numbers for. But breaking the lance looks like it provides a pretty good upper limit to the force. No, I don't have numbers for this, and one would need many numbers to get a good idea of the range of forces, since lances will have a certain degree of variability. |
That is good points, The theoretical approach would only give reliable estimates on maximum potential energy delivered at the moment of impact. After impact the influencing factors are just too many to decide what energy will be absorbed by what and when (elasticity of the lance, shield displacement of rider and target etc just as you mention) It is good to keep that in mind.
But the only way to get real numbers is to verify it practically. But I would think that the theoretical calculations would be "good enough" to do some colorful comparsions with other forces that we have data upon, such as musket-balls, arrows etc
But if we consider the OP's needs of numbers, would it be easier to approach the problem from the lance pointof view? If we consider the upper limit of force transferred to be what the lance can take before it breaks?
In that case we could try to stress-test lances of various lenghts and materials, not exactly cheap or simple but would eliminate the need of trained horses..
There is nothing quite as sad as a one man conga-line...
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Timo Nieminen
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| Posted: Mon 17 Aug, 2009 6:27 am Post subject: |
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| Bjorn Hagstrom wrote: | | Timo Nieminen wrote: |
Stuff like the masses, speeds, etc isn't the important thing. What will be important will be how much force is needed to break the lance. You're not going to exert more force than this, and we know that there is enough force to do so.
There are other weak points too, such as the riders' seats, and (for sharp points), the resistance of the armour to penetration. Assuming a good hit, at not too slow a speed, either a rider will be unseated, the target will be penetrated (not so likely with a blunt tournament lance), or the lance will break. A less good hit, and you get less force - the point slides off, for example.
A wide range of forces will unhorse a rider (i.e., just unhorse the rider, or unhorse the rider and add perhaps considerable extra energy), so that would be hard to come up with numbers for. But breaking the lance looks like it provides a pretty good upper limit to the force. No, I don't have numbers for this, and one would need many numbers to get a good idea of the range of forces, since lances will have a certain degree of variability. |
That is good points, The theoretical approach would only give reliable estimates on maximum potential energy delivered at the moment of impact. After impact the influencing factors are just too many to decide what energy will be absorbed by what and when (elasticity of the lance, shield displacement of rider and target etc just as you mention) It is good to keep that in mind.
But the only way to get real numbers is to verify it practically. But I would think that the theoretical calculations would be "good enough" to do some colorful comparsions with other forces that we have data upon, such as musket-balls, arrows etc
But if we consider the OP's needs of numbers, would it be easier to approach the problem from the lance pointof view? If we consider the upper limit of force transferred to be what the lance can take before it breaks?
In that case we could try to stress-test lances of various lenghts and materials, not exactly cheap or simple but would eliminate the need of trained horses.. |
The strength of wood is of much practical interest, but mostly for supporting static loads for a long time, not for resisting sudden impact. So, it might not be easy to find useful numbers.
So, yes, testing lances (or shorter pieces of the same woods - one could convert the results, perhaps even meaningfully) might be the way to go. Given proper test equipment (and free access and labour), this would be cheap and easy enough.
You mention comparison with musket balls and arrow. For these, one usually sees energy as the quoted quantity, not force. This is for a very good reason - the force in an impact will depend on the material properties of the target, while the energy is a characteristic of the projectile. Perhaps energy would provide the best comparison? Alas, this could be tricky to measure. The energy required to break a lance would provide an approximate limit for energy transfer during a fast impact, and might be a very good measure of armour penetration by a sharp lance.
Which might all be a nice fun demo, putting lance points through various types of armour. Perhaps not of much use for tournament jousting, but it would be interesting.
The whole problem is not simple - it's about complex materials and their properties, and complex systems like (flexible, not rigidly attached) riders on horseback. The original suggestion of resorting to simple physics formulas won't get too far - this is more a problem for an engineer, not a physicist, and I say this from the physicist perspective.
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Eric Meulemans
Industry Professional
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| Posted: Mon 17 Aug, 2009 6:45 am Post subject: |
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If you decide to use the breakage of a lance as a measure of ultimate force generated, then you could simply use the known factors of the lance's dimensions and the well documented and available mechanical properties of various woods to determine the threshold of breakage.
It would be important to consider the tapering of the lance, point of typical breakage (studying various actual lance breaks) and of course the specie and state (cured or green) of the wood. There are a number of sources for the relevant moduli, and a quick search yields some data and testing methods.
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Elling Polden
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| Posted: Mon 17 Aug, 2009 1:09 pm Post subject: |
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Kinetic energy is not as important in these cases as energy transfered. The easy way to do this is simply to set up a apropriately powerfull scale, and hit it with a lance, in the same manner as you would measure the power of a punch, or a colision.
"this [fight] looks curious, almost like a game. See, they are looking around them before they fall, to find a dry spot to fall on, or they are falling on their shields. Can you see blood on their cloths and weapons? No. This must be trickery."
-Reidar Sendeman, from King Sverre's Saga, 1201
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Dan Howard
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| Posted: Mon 17 Aug, 2009 4:33 pm Post subject: |
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| Bjorn Hagstrom wrote: | | I do not know of any studies to refer to (sorry to say) but to give the audience an estimate of the force of a lance-strike you do not need that. Pure laws of physics would be quite enough. Mass of the horse(s) and rider(s), speed at impact, surface area of the lance head is all you need. |
This is only true if the horse and rider are one solid mass. This is not the case. The amount of energy delivered is far more reliant on the strength of the lancer. He uses the horse to increase the amount of energy he can deliver but it is nowhere near what one would expect by combining the mass of the horse and rider.
The only useful way is to take readings from a practical experiment. Set up a target with the appriopriate instruments and hit it with lances wielded by different riders on different horses. I don't know whether this type of study has ever been published.
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Simon Van Der Spoel
Location: Australia Joined: 10 Jun 2008
Posts: 22
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| Posted: Mon 17 Aug, 2009 10:48 pm Post subject: |
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Thanks one and all, some very valid points and I do agree with a lot of them, there has been a study undertaken as seen here - www.wpi.edu/~jforgeng/Modeling_the_Joust.pdf
with all these factors taken into account and to be implemented, but the study ran out of time before the data could be put to practical test, something which is definitely disappointing, but the depth they were going to was to help future studies to implement their research, I don't think anyone has though (study was completed in 02) ,
but in a general sense I may have to resort to 'potential' force and the generic physics formula to give an indication of the forces involved just for the general publics appreciation of what jousters are dealing with, and though I fully support a proper scientific investigation in the matter, I too do not have the time or resources to investigate it myself, so I may have to stick to coverage of the experiences of jousting rather than the myth busting approach, and doing experiements
*sigh*
I was so looking forward to creating a rig of some dangerous attributes to smash things with...next time.
Thank you gentlemen for your kind responses,
Regards
Simon VDS
Creator of the History Channel Documentary: "Spitfire Guardians"
http://www.youtube.com/watch?v=nLyNZgA0_iM
http://www.youtube.com/watch?v=rTIFoQ1m2LM
Director: "Mounted Steel" Jousting Documentary
http://www.youtube.com/watch?v=MIqrkN29HVQ
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