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Jean Thibodeau




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PostPosted: Thu 18 Mar, 2021 7:45 pm    Post subject: Another Tod's videos relative power of lowbows.         Reply with quote

Tod here has another of his testing of " simulated " longbows using 3 different crossbows standing in for 3 levels of power with Longbows: A) 160 pound draw weight B) 120 pound draw weight C) 75 pound drawweight simulators.

For those who haven't viewed any of his previous tests simulating longbows, he is using the same weight of arrows that one would use with a longbow using crossbows that produce the velocities that one would typically get from the same arrow loosed by a longbow ..... The targets don't care if the arrow was loosed by a crowbow or a longbow if the mass and velocity of the arrows is close to identical.

In this video he has made a new mid-sized modified modern crossbow to simulate a medium power period longbow of 125 pounds of draw weight, and he compares the results on the same shield in penetration with his original " Lockdown Longbow " that simulates a 160 pound longbow, and also compared to his least powerful crossbow that he initially estimated simulating a 100 pound longbow, but that he has corrected his evaluation to it being closer to a 75 pound draw weight longbow.

There is also an " expensive " and " unfortunate " OOOPSY accident that is funny, but not as funny for Tod .... Wink Laughing Out Loud

Have a look at the Video, I'm not giving a " spoiler " for the OOOPSY .... Wink Razz

bhttps://www.youtube.com/watch?v=9SUpufShBVg

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Jonathan Dean




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PostPosted: Thu 18 Mar, 2021 9:39 pm    Post subject: Re: Another Tod's videos relative power of lowbows.         Reply with quote

I'm glad he has three levels of power now, because that adds a lot more room for context than just using the higher end of the common Mary Rose bows, some of which were definitely in the 100-130lb range. The 70lb bow (I think it's more like a 80lb bow based on the efficiency of Joe's bows, but 70lb is close enough) is also welcome as the minimum useful standard for much of the Middle Ages.

All I'd like to see now are aspen shafts for 15th-16th century arrow types - aspen being the primary wood according to written and archaeological sources - some 10-11mm arrow shafts for the "Little Brother" (matching early 14th century diameters from Holm Hill and Faccombe Netherton), and some ~9mm arrow shafts for the "Baby Brother" (matching large numbers of LM16/M4 arrowheads, the most common 11th-13th century LM7/M8 arrowheads, and the LM13 arrowheads from Dyserth Castle). I'm not entirely sure whether ash or aspen is more appropriate for 11th-14th arrows, as a number of hunting arrows in records are made form ash, but one Anglo-Norman arrowhead from Holm Hill had traces of aspen or willow in the socket. Unfortunately, almost none of the securely dated finds from Holm Hill had enough wood fragments in the socket for identification, and I've yet to find another report that provides wood types where they were found. Pine, a favourite of Scandinavia, might be a good middle ground for the 11th-14th century arrowhead types in terms of compromise between the two extremes of weight.
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Andrew Gill





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PostPosted: Thu 18 Mar, 2021 11:54 pm    Post subject:         Reply with quote

Brilliant!

As well as being very entertaining, these videos are a goldmine to those of us who like being able to put numbers to things.
Thanks Tod!
(and Ouch! Collateral damage Eek! )

Andrew
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Pieter B.





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PostPosted: Fri 19 Mar, 2021 4:12 am    Post subject:         Reply with quote

Great to see how Tod is making lockdown manageable for us!

I also wonder if the lockdown longbow has anything like the 'archer's paradox' and I wonder if that would (materially) affect a similar weight and velocity projectiles shot from either?
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Duncan Hill




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PostPosted: Fri 19 Mar, 2021 6:49 am    Post subject:         Reply with quote

Pieter B. wrote:


I also wonder if the lockdown longbow has anything like the 'archer's paradox' and I wonder if that would (materially) affect a similar weight and velocity projectiles shot from either?

That's a good point - I don't believe that crossbows have an analogue to the archer's paradox, as there is nothing for them to bend around. I think the angle of the bow and string press on the tiller probably only affects the efficiency of the release, rather than the flight of the bolt. That said, Bichler uploaded a cool video in ultra slo mo of him shooting one of his replicas (485lb draw weight), and you can definitely see the bend of the bolt upon release (due to inertia I suppose) and the resulting oscillation in flight:

https://youtu.be/CV8nujYQM4A
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Andrew Gill





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PostPosted: Mon 22 Mar, 2021 12:36 am    Post subject:         Reply with quote

Duncan Hill wrote:
Pieter B. wrote:


I also wonder if the lockdown longbow has anything like the 'archer's paradox' and I wonder if that would (materially) affect a similar weight and velocity projectiles shot from either?

That's a good point - I don't believe that crossbows have an analogue to the archer's paradox, as there is nothing for them to bend around. I think the angle of the bow and string press on the tiller probably only affects the efficiency of the release, rather than the flight of the bolt. That said, Bichler uploaded a cool video in ultra slo mo of him shooting one of his replicas (485lb draw weight), and you can definitely see the bend of the bolt upon release (due to inertia I suppose) and the resulting oscillation in flight:

https://youtu.be/CV8nujYQM4A


I think that the lockdown longbow will (at least to some degree) exhibit something like the archer's paradox - ie. some arrow oscillations. An arrow is effectively like a long thin rod or strut which has a sudden force applied to one end by the string.
Long struts tend to bow or in extreme cases buckle rather than just getting "squished" slightly shorter by force - this is known as Euler buckling, named after Leonhard Euler, the 17th/18th century mathematician and scientist. Because the force is applied rapidly and then released as it flies free of the bow, to the arrow, the arrow flexes/vibrates/oscillates at its natural frequency until this dies away from internal and aerodynamic damping. A medieval crossbow bolt is much shorter and fatter, and therefore more resistant to Euler buckling, which is why it bows so much less in that slow motion video. With the lockdown longbow, Tod is shooting a longbow arrow, so its going to flex more. On the other hand, the fact that it begins its flight in the arrow groove of the crossbow may help decrease some of the vibration/flex/oscillation. So it may have slightly less than a longbow, but I'd be very surprised if it was completely absent.

Perhaps Tod (or anyone else with some relevant experience) can comment?
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Leo Todeschini
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PostPosted: Tue 23 Mar, 2021 10:51 pm    Post subject:         Reply with quote

Thanks for posting this up Jean and I have just solved my expensive moments; film to come.

These films are hopefully entertaining, but the aim is to try and get some real information, even if in a fairly shallow way, but what is really important is that I do not lie or misrepresent anything. It all started because I watched a couple of You Tube films where aspects of targets were clearly not what was portrayed and so I decided to try and set some reliable benchmarks.

The three bows will be useful and I will try to weave them into the upcoming films as appropriate and maybe revisit a couple of the previous as my discussion about the arms race and bow power from teh first introduction to the "baby brother" is I think valid, so we should be looking at teh lower poundage bows too.

As regards archers paradox, this is a tricky one because I view it a little different to the norm (at least I think I do). An arrow is a flexible and springy object with a weight at the front. Push it from the back and the inertia of the head will cause it to buckle and then spring back and that creates the wobble that you can clearly see in slo mo. People describe the arrow moving around the bow as if it is sentient, but in fact the arrow cannot bend down because of the fist and cannot bend toward the bow, so the inherent instability on launch means it has to bend outward or upward or a combination of the two and it is this bending out combined with the amount of spring i.e. the spine that allows it to pass the bow and allowing it to solve the archers paradox.

From a crossbow the inherent instability of pushing a springy shaft with a weight on the end is still there, it still buckles and springs back and the only significant difference I can see is that the wobble cannot initiate downward because of the deck, but otherwise it is there. In one of my early films about this, you can clearly see slo footage of this wobble.

So does the launch system make a difference to arrow penetration performance? I very much doubt it.

Tod

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Jonathan Dean




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PostPosted: Wed 24 Mar, 2021 11:00 am    Post subject:         Reply with quote

Tod, I was wondering, do you have/will you be testing any handmade (as in, from scratch) mail? Most tests are done with Indian mail, which for a variety of reasons is not a good representation of historical mail, and the only test I know of where both the mail and the padding are historically accurate has a target that leaves something to be desired compared to how you've been handling things. I'm very interested to see what energy threshold is sufficient to penetrate good mail.
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Andrew Gill





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PostPosted: Wed 24 Mar, 2021 11:19 am    Post subject:         Reply with quote

Leo Todeschini wrote:


As regards archers paradox, this is a tricky one because I view it a little different to the norm (at least I think I do). An arrow is a flexible and springy object with a weight at the front. Push it from the back and the inertia of the head will cause it to buckle and then spring back and that creates the wobble that you can clearly see in slo mo. People describe the arrow moving around the bow as if it is sentient, but in fact the arrow cannot bend down because of the fist and cannot bend toward the bow, so the inherent instability on launch means it has to bend outward or upward or a combination of the two and it is this bending out combined with the amount of spring i.e. the spine that allows it to pass the bow and allowing it to solve the archers paradox.

From a crossbow the inherent instability of pushing a springy shaft with a weight on the end is still there, it still buckles and springs back and the only significant difference I can see is that the wobble cannot initiate downward because of the deck, but otherwise it is there. In one of my early films about this, you can clearly see slo footage of this wobble.

Tod


Yay! I'm not insane! That is more or less the conclusion that I came to, but which I articulated much less clearly (and I don't think I'd thought it through quite as far as you had, Tod). Thanks!

And believe me, the information from your tests is incredibly useful and interesting.

Andrew
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Leo Todeschini
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PostPosted: Sat 27 Mar, 2021 11:25 pm    Post subject:         Reply with quote

Jonathan Dean wrote
Quote:
Tod, I was wondering, do you have/will you be testing any handmade (as in, from scratch) mail?


Yes I will be and very soon. I keep getting distracted by other things, but I will be conducting some tests using maille from Isak Krogh under the Lockdown Longbow banner, but these will be indicative tests looking at a particular aspect of arrow heads.

However we are planning another "arrow vs armour" test later in the year that will look at maille attached to a helmet, and some of this will be handmade by Nick Checksfield and some will be commercially produced bought for cost reasons.

There will be a Kickstarter fund raiser for this one as we are going full out for four films at present culminating in so meshing pretty special.

Tod

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Markus Fischer




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PostPosted: Sun 28 Mar, 2021 12:12 am    Post subject:         Reply with quote

Hi Tod

First of all I would like to say that I really love your testing videos. Nobody on YouTube or even on TV has done such amazingly well thought out, well planned and accurate testing of medival arms and armour.

You have solved a lot of myths concerning the english (welsh) longbow that even specialists among the topic thought of as true.


The point I want to adress is that I think you also should be testing swords,spears and bladed melee weapons in general against the armour.

Because so far you have basically only been testing bows...the english longbow almost exclusively...but the bow was just one weapon in medival times, sure an important one, but armour was build to protect you from all types of weapons, and therefore I think you should also test all types of weapons against it.

This is quite important to me, because I think the way you are doing it now is very good in terms of the gathered information concerning bows and crossbows against armour, but it leaves a very big gap.

And this big gap of information may lead to a big misunderstanding of the effectivness of the armour.
For example in your upcoming mail testing video....I am very sure that most of the arrows will punch straight through the mail, as we have seen in the famous breastplate vs 160lbs english longbow video with Joe Gibbs.

Now some people will say something like "Oh well, that mail stuff isnt that great after all, right ?", because they dont know that a sword would be simply glancing of the mail without doing any damage, as we have seen in other videos, which they probably havent seen.

Therefore I think it is utterly important to always try to cover the hole spectrum if possible.
And often enough it is possible!
What keeps you from hitting that mail with a sword or a battle axe, in your next testing video?
Or if you dont feel qualified enough, just ask some expert of swordsmanship to come over and do it, like you did it with Joe Gibbs....
The same thing you could have easily done in case of the breastplate, the brigandine etc.

Maybe you have in fact planned to do sword testing in future videos, but that would be a waste of resources in my opinion, as you would have to buy the same armour again.



My intention is not to downgrade your videos. I very much like them and think that they are the best testing videos of medival arms and armour that I have ever seen.
This is just meant as constructive criticism.

Thank you for understanding,

Markus
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Jonathan Dean




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PostPosted: Sun 28 Mar, 2021 12:15 am    Post subject:         Reply with quote

Leo Todeschini wrote:
Jonathan Dean wrote
Quote:
Tod, I was wondering, do you have/will you be testing any handmade (as in, from scratch) mail?


Yes I will be and very soon. I keep getting distracted by other things, but I will be conducting some tests using maille from Isak Krogh under the Lockdown Longbow banner, but these will be indicative tests looking at a particular aspect of arrow heads.

However we are planning another "arrow vs armour" test later in the year that will look at maille attached to a helmet, and some of this will be handmade by Nick Checksfield and some will be commercially produced bought for cost reasons.

There will be a Kickstarter fund raiser for this one as we are going full out for four films at present culminating in so meshing pretty special.

Tod


Fantastic, thank you! Even if they're just indicative tests, actually seeing properly made mail being tested will be a treat.

I'll also eagerly look out for the Kickstarter. You did great work on the first Medieval Mythbusters film, and I'm excited to see what your next four will be like.

Side note: if you're testing any textile armour in them, have you talked to Sean Manning? He's been compiling a list of references of textile armour, some of which provide hints to the construction, even if the precise terminology is hard to reconstruct.
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Jonathan Dean




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PostPosted: Sun 28 Mar, 2021 2:12 am    Post subject:         Reply with quote

Markus Fischer wrote:

You have solved a lot of myths concerning the english (welsh) longbow


Can I just say that the idea that the "Welsh" longbow was somehow special and that the English adopted it from them is a myth that needs to go away? It's been continuously challenged and demolished since the 1970s so that, while we do see an increase in the use of archers in the 1290s, we still have no evidence that the Welsh archers were using bows that were different from the English bows. Even then, English archers were employed during the 1270s and 1280s against the Welsh, and the early 14th century arrowheads from Holm Hill and Faccombe Manor don't have sockets outside of the range shown in France at the same time.

Some changes absolutely happened, with the Waterford style of short-bow falling out of use by the early 1300s, horn nocks appearing in the mid-14th century and quite possibly a switch to a 30" draw for military bows about the same time (although in the 1470s civilians were still allowed to have a 27" draw in Ireland, and 16th century civilian bows are implied to have the same draw length), but these changes happened under Edward III and, so far as we can tell, were entirely unrelated to the Welsh.
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Andrew Gill





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PostPosted: Fri 02 Apr, 2021 3:13 am    Post subject:         Reply with quote

While digging for published data on my research into crossbows, I found an interesting and (I think) relevant physics paper containing some measured data for (modern) bow and arrow performance. There's also a mathematical analysis of the archer's paradox, which I found interesting, given the earlier discussion:
https://arxiv.org/pdf/1511.02250.pdf

It also seems to support many of Tod's measurements (and my calculations) regarding aerodynamic drag (with the caveat that modern arrows will differ aerodynamically from longbow war arrows - the heads were different, as was the fletching (this paper notes that roughly a third of the drag is contributed by the fletching).

The parts dealing with the modern compound bow are, of course, less relevant.

Andrew.
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