The real advantage of undulating blades !

[Roy Robinson Stewart]

In order to get a feel for the sort of air resistance generated by a wide blade which is stalled ( keeping in mind that tubercules reduce drag even when not stalled ) one can swing a lightweight wooden staff or batten with a similar width. A flat sided batten will work best.


In doing so it's immediately apparent that the maximum speed of the cut is determined by air resistance.


In support of this we can note that air resistance goes up with square as speed increases. Also as discussed the drag caused by the outer part of a completely stalled wide cutting blade is definitely very significant in proportion to the muscular energy available to power the sword.


Once a sword is in a continuous circular arc motion ( excluding air resistance ) it takes a lot less energy to keep it in motion than it does to accelerate it in the first place. Thus continuous arcs are not necessarily very tiring, as long as the air resistance is low.


Air resistance is the catch. Air resistance saps energy very quickly. I've found this also with shorter weapons. For example it is less tiring to do fast whirling staff escrima drills with thin heavy sticks than it is with thicker lighter sticks. When such drills are done slowly the lighter thicker sticks are much easier to use, but once going fast air resistance soon limits the top speed. . . and that's when doing very tight small radius arcs spirals figure eights and so on, it's even more the case with longer weapons. With simple strikes where the weapon travels through a shorter arc ( e.g 90 to 180 degrees ) this isn't as apparent, the lighter stick feels faster as the limiting factor then is inertia during acceleration.


With longer weapons the most energy efficient redirections are larger arcs which maintain the speed of the weapon rather than shorter stop/start turns with greater acceleration/deceleration and consequent energy sapping inertia issues . During larger arc redirections and turns air resistance needs to be addressed partly because the speed is higher and partly because the blade is experiencing relativley high angles of attack even in a large arc turn.


During WWII it was discovered that the spitfire could turn more quickly than the ME109 as even though it did larger arc turns it did so with greater airspeed due to more efficient lower drag elliptical wings. Turning tightly is not always the fastest way to turn, it uses more energy. Of course if anything gets in the way of the fast moving blade during a turn it is going to be damaged a lot more than by a slowly moving stalled blade attempting a tight turn, and that is no doubt a bonus when 'hedge trimming' a wall of opponents




Stall reduction via a wider range of air flow angle of attack is also useful due to the fact that pre stall and stall situations create vorteces which tend to make the wing or blade oscillate uncontrollably. . . so it's good for control as well.


One way of avoiding air resistance and stalling problems is via a narrow thicker blade tip, however with these types cutting efficiency is lost, and the pointed tips create very significant tip drag vorteces which spatulate tips largely avoid. So all things considered, for the control of 360 degrees of territory I'd design a long wide bladed cutting blade with leading edge undulations. . . . .. and behold such types exist !


There is another reason why undulating blades experience less drag, to do with air flow from the strong of the blade to the weak. During cuts ( particularly the long continuous arc type ) the majority of the time the blade is presented strong first, with the weak trailing behind. This creates air flow towards the tip which makes a big increase in the drag inducing tip vortex as the air flows off the blade at the tip. Leading edge tubercules help to prevent this flow to the tip, and spatulate blade tips deal with it better than pointed ones.




.

[Philip Sibbering]

This is an interesting discussion - has anyone tested the theory or plans to?

The only other blade I can think of that has the wave is the kris, which is dagger.

I know it's be mentioned that the wave may improve the cut, but dagger are more about trusting, and I was wondering how exactly the two-hand sword are used?

I suppose you can swing it, but when delving into pike formations I get the impression that they are changing to a half-sword like technique. They are using it more like a spear, but one that can cut along it's full length.

If this is the case what advantages are there to impaling with such a flame blade?

Engineering wise the cross section is wider but for less material, and the wave may aid in get the blade in and out of a body (guessing)?

Is a flame blade a brutal butchering weapon that you can thrust into a pike formation once you've closed and and keep on pushing - were the wave in the blade aids in the piecing cut as you push, and possibility allow you to cut your way out of a body while constantly moving in? Rocking back and forth in and amongst the pike, barging with the shoulders, while using the leverage in the bodies, and the wave in the blade, to cut the pikemen down and move in? To make a hole? Then only switching to swings as they flee - hacking at the back of their legs?

Philip

[Greg Coffman]

In order to get a feel for the sort of air resistance generated by a wide blade which is stalled ( keeping in mind that tubercules reduce drag even when not stalled ) one can swing a lightweight wooden staff or batten with a similar width. A flat sided batten will work best.


In doing so it's immediately apparent that the maximum speed of the cut is determined by air resistance.

The maximum speed of the cut is determined by the ability of the user to accelerate the weapon from rest. This maxes out long before air resistance becomes a limiting factor.

Once a sword is in a continuous circular arc motion ( excluding air resistance ) it takes a lot less energy to keep it in motion than it does to accelerate it in the first place. Thus continuous arcs are not necessarily very tiring, as long as the air resistance is low.

We are hardly ever talking about continuous circular arcs. You change the direction of the arc with almost every cut. You may give two cuts in a row, but that is about it. The change in direction of the cut is what burns energy. You are applying force in a direction tangential to the direction of motion. Except that since the motion is circular, the direction at which you apply force is constantly changing. And we are not talking about spinning a rope with a ball on the end of it. You are applying force at two different points, your two hands, torquing the weapon--applying opposing forces--instead of simply swinging it--providing just enough force to keep it in motion. And you are stepping. And your abs and core are counteracting every motion you do. It's exhausting just writing about it!

Air resistance is the catch. Air resistance saps energy very quickly. I've found this also with shorter weapons. For example it is less tiring to do fast whirling staff escrima drills with thin heavy sticks than it is with thicker lighter sticks. When such drills are done slowly the lighter thicker sticks are much easier to use, but once going fast air resistance soon limits the top speed. . . and that's when doing very tight small radius arcs spirals figure eights and so on, it's even more the case with longer weapons. With simple strikes where the weapon travels through a shorter arc ( e.g 90 to 180 degrees ) this isn't as apparent, the lighter stick feels faster as the limiting factor then is inertia during acceleration.

Here, I might concede to you that air resistance could be a factor, because I don't know how fast you are twirling the stick. Why the heavier is easier than the lighter might be a function of mass. The heavier one has more momentum that resists declaration than the lighter one. You have to supply more force yourself to keep the lighter one at similar speeds. But in ARMA, we don't do whirling drills. We make cuts, thrusts, and attacks. So I hardly think this example is relevant to using a sword with two hands.

[Roy Robinson Stewart]

In order to get a feel for the sort of air resistance generated by a wide blade which is stalled ( keeping in mind that tubercules reduce drag even when not stalled ) one can swing a lightweight wooden staff or batten with a similar width. A flat sided batten will work best.


In doing so it's immediately apparent that the maximum speed of the cut is determined by air resistance.

The maximum speed of the cut is determined by the ability of the user to accelerate the weapon from rest. This maxes out long before air resistance becomes a limiting factor.

Air resistance exists at significant levels at sword speeds during fast turns and whenever the blade is stalled.

I'm not talking about the stop/start relatively short cuts with thrusts technique used in longsword duelling, but of large sweeping cuts through 360 degrees

Longsword duelling is not the be all and end all of Renaissance sword arts.

Once a sword is in a continuous circular arc motion ( excluding air resistance ) it takes a lot less energy to keep it in motion than it does to accelerate it in the first place. Thus continuous arcs are not necessarily very tiring, as long as the air resistance is low.

We are hardly ever talking about continuous circular arcs. You change the direction of the arc with almost every cut.

Of course in your two man duelling scenarios with longswords you don't use continuous arcs.

I'm talking about controlling 360 degrees of space against multiple opponents using a wide bladed two hander as desribed in historical sources. . . it's a different discipline.

Of course these big sweeping cuts include turns, as described in my previous post. It's during fast large arc turns that air resistance is the greatest.

You may give two cuts in a row, but that is about it.

I think that you are confusing a judicial duel scenario with the one against many scenarios described in the historical sources. . . . and in which 'two cuts' is unlikely to be sufficient

Air resistance is the catch. Air resistance saps energy very quickly. I've found this also with shorter weapons. For example it is less tiring to do fast whirling staff escrima drills with thin heavy sticks than it is with thicker lighter sticks. When such drills are done slowly the lighter thicker sticks are much easier to use, but once going fast air resistance soon limits the top speed. . . and that's when doing very tight small radius arcs spirals figure eights and so on, it's even more the case with longer weapons. With simple strikes where the weapon travels through a shorter arc ( e.g 90 to 180 degrees ) this isn't as apparent, the lighter stick feels faster as the limiting factor then is inertia during acceleration.

Here, I might concede to you that air resistance could be a factor, because I don't know how fast you are twirling the stick.

With even a 50 inch staff the air resistance is the predominant factor limiting speed in any wide seeping continuous cutting motions which travel through 360 degrees as required by the martial 'one against many' scenario we are discussing.

The staff has LESS air resistance than a stalled blade of similar width.

Why the heavier is easier than the lighter might be a function of mass. The heavier one has more momentum that resists declaration than the lighter one. You have to supply more force yourself to keep the lighter one at similar speeds.

It's a simple matter of air resistance. If the sticks are of the same diameter but different weights, the the heavier ones will always be slower.

The difference is in the air resistance : When the stick is thinner it travels faster even though it is heavier, as it has less air resistance.

This is easy to discover for yourself.

But in ARMA, we don't do whirling drills. We make cuts, thrusts, and attacks. So I hardly think this example is relevant to using a sword with two hands.

This is the crux of the objection, but is based on faulty logic.

Arma concentrate on two man duelling scenarios.

The scenarios I am investigating are of one against many opponents, as desribed in historical texts, and they do involve bigger more continuous cutting motions through 360 degrees. . . exactly the sort of thing which isn't beneficial in a duelling situation.

They are nevertheless legitimate techniques for investigation.

The faulty logic you have applied is as follows: You state that because ARMA do not do 'whirling' drills that they therefore have no relevance to two handed swordsmanship. That is putting the cart before the horse, as historical examples come first.

ARMA tend to use longswords with relatively narrow tips, in duelling scenarios. In such situations air resistance is not a big issue, but I'm talking about longer wider weapons in different scenarios.

Martial arts almost always tend to coalesce into one on one training, for understandable reasons. What I'm talking about is a one against many technique described in historical sources ( even though briefly ) used by the highest paid elite soldiers of the day using what were probably the most expensive weapons available. It's not a studio self defence industry art.

.

[Roy Robinson Stewart]

I suppose you can swing it, but when delving into pike formations I get the impression that they are changing to a half-sword like technique. They are using it more like a spear, but one that can cut along it's full length.

Many of the two handers have spatulate tips, so thrusting was probably a secondary use. The wide bladed spatulate tipped two handers are primarily cutting weapons.

Charging into Pike formations is one scenario desribed, another is defence of a position against many opponents e.g. defending the standard

the wave may aid in get the blade in and out of a body (guessing)?

Many of the undulating blades had very high frequency undulations wich would definitely make it harder to thrust in or out of a body.. . their tips are also clearly not designed for thrusting deeply, certainly not three feet deep !


.

[Vincent Le Chevalier]

With even a 50 inch staff the air resistance is the predominant factor limiting speed in any wide seeping continuous cutting motions which travel through 360 degrees as required by the martial 'one against many' scenario we are discussing.

The staff has LESS air resistance than a stalled blade of similar width.

But the staff has a lot more air resistance than a blade swung to cut, relatively edge-on (even if edge alignment is not perfect all the way around the arc).

I know the feeling one can get when air resistance becomes predominant, it's what you get when you swing for example a pool noodle around: instead of letting it swing you have to push it all through the arc just to keep its speed. If let on its own it slows down very quickly.

I have never had that feeling with steel swords, even blunt, even straight. They feel like they have plenty enough energy to keep moving even though air resistance is there and even if you don't push them at all. I've played a bit with my Montante trainer this week. It never felt like air resistance was a limiting factor, while mass certainly was. Also, it makes very little noise when swung, even with direction changes made to deal with 360° fights; I suppose if there was a significant amount of turbulence due to stalling it would be heard?

Regards,

[Roy Robinson Stewart]

It's not possible to deny that undulating blades ( whatever else they do ) give an aerodynamic advantage in wide cutting blades , as the laws of physics dictate that it is so. The only issue is how large that advantage is. In my own field of design and construction I go to great lengths to make even small gains in efficiency, and I think it's perfectly possible that swordmakers were prepared to do the same if paid enough. That's not to say that the advantage is necessarily small. Anything which helps one to prevail must be of immeasurable practical value, whatever the cost. Small gains can lead to large results, larger gains can also.

The ARMA philosophy ( as far as I understand it ) is that the Renaissance sword makers and users were intelligent masters of their arts, and that every aspect of their swords was designed for functional martial reasons . Given that this is the case the current state of the ARMA lore ( in the archives at least ) regarding undulating blades ( that they are there to look scary but serve no practical purpose ) contradicts the ARMA philosophy.

.

[Roy Robinson Stewart]

With even a 50 inch staff the air resistance is the predominant factor limiting speed in any wide seeping continuous cutting motions which travel through 360 degrees as required by the martial 'one against many' scenario we are discussing.

The staff has LESS air resistance than a stalled blade of similar width.

But the staff has a lot more air resistance than a blade swung to cut, relatively edge-on (even if edge alignment is not perfect all the way around the arc).

Hello Vincent,

Please keep in mind that a wide thin cutting blade will stall at very low angles of attack ( probably 5 to 10 degrees ) and thus will certainly be stalled during fast redirections ( by fast I refer to blade speed )

During turns such blades don't have the angle of attack capability required to avoid stalling.

Once the blade is stalled it will have more air resistance than a staff.

I know the feeling one can get when air resistance becomes predominant, it's what you get when you swing for example a pool noodle around: instead of letting it swing you have to push it all through the arc just to keep its speed. If let on its own it slows down very quickly.

I have never had that feeling with steel swords, even blunt, even straight. They feel like they have plenty enough energy to keep moving even though air resistance is there and even if you don't push them at all. I've played a bit with my Montante trainer this week. It never felt like air resistance was a limiting factor, while mass certainly was. Also, it makes very little noise when swung, even with direction changes made to deal with 360° fights; I suppose if there was a significant amount of turbulence due to stalling it would be heard?

The Montante trainer is extremely narrow, the fact that little air resistance is felt with it even when stalled at speed is hardly suprising and supports what I've been saying. It's not a good example of a thin, wide, two handed cutting sword . It does not resemble a wing as wide cutting blades do.








Regards
Roy

[Vincent Le Chevalier]

It's not possible to deny that undulating blades ( whatever else they do ) give an aerododynamic advantage in wide cutting blades , as the laws of physics dictate that it is so. The only issue is how large that advantage is.

Actually I'm not completely convinced yet that the kind of undulations we see on sword blades give an aerodynamic advantage, because they do not look exactly like those that were shown to have that effect (in particular in terms of undulation frequency vs. 'wing' width). Another issue is indeed whether an aerodynamic advantage is necessary or significant at all, which could make the first point moot.

The ARMA philosophy ( as far as I understand it ) is that the Renaissance sword makers and users were intelligent masters of their arts, and that every aspect of their swords was designed for functional martial reasons . Given that this is the case the current state of the ARMA lore ( in the archives at least ) regarding undulating blades ( that they are there to look scary but serve no practical purpose ) contradicts the ARMA philosophy.

Can't speak for ARMA as I'm not a member but there clearly were decorative elements even on blades. A psychologic effect is functional as well; not everything is physics in martial arts (as I think a recent ARMA article discussed).

Your theory does not explain either why there were other swords, rapiers and daggers with undulating blades, as pointed out before. If the reason for that was not physical functionality then why couldn't it be the case for two-handers as well?

Regards,

[Roy Robinson Stewart]

It's not possible to deny that undulating blades ( whatever else they do ) give an aerododynamic advantage in wide cutting blades , as the laws of physics dictate that it is so. The only issue is how large that advantage is.

Actually I'm not completely convinced yet that the kind of undulations we see on sword blades give an aerodynamic advantage, because they do not look exactly like those that were shown to have that effect (in particular in terms of undulation frequency vs. 'wing' width). Another issue is indeed whether an aerodynamic advantage is necessary or significant at all, which could make the first point moot.

In wind tunnel tests undulation frequency was found to have very little effect on the results. Amplitude has a bigger effect, and there is a an enormous range in terms of tubercule amplitude and frequency ( as well as differences in shape ) which show beneficial results.

Swords also show a very large range of undulation frequencies, in short changes in frequency have little effect on the lift/drag advantages of undulations.

However we are aware of the effects which changes in amplitude have and I'm happy to discuss those.

The ARMA philosophy ( as far as I understand it ) is that the Renaissance sword makers and users were intelligent masters of their arts, and that every aspect of their swords was designed for functional martial reasons . Given that this is the case the current state of the ARMA lore ( in the archives at least ) regarding undulating blades ( that they are there to look scary but serve no practical purpose ) contradicts the ARMA philosophy.

Can't speak for ARMA as I'm not a member but there clearly were decorative elements even on blades. A psychologic effect is functional as well; not everything is physics in martial arts (as I think a recent ARMA article discussed).

The fact is that blade undulations will give an aerodynamic advantage even if they look nice. . . in fact in swords good looks are usually the result of function not the other way around, also I doubt if blade geometry would be changed at big expense just for looks in battle weapons.

Wind tunnel tests on historic blades are a distinct possibility.

Your theory does not explain either why there were other swords, rapiers and daggers with undulating blades

That's true.

The effect of undulations is more than just 'my theory' though, it's well tested fact.

as pointed out before. If the reason for that was not physical functionality then why couldn't it be the case for two-handers as well?

You might be assuming that the influence went from dagger and rapier to two hander, not the other way around. Rapiers and daggers are items of dress as well as weapons so are possibly more subject to fashion ( i.e. copying the mighty two handers of battle fame ) than expensive swords used by soldiers.

I'm speculating there, but the physics of historical blades cannot be changed and can be tested, that's what I'd like to see.

.

[Greg Coffman]

I'm not talking about the stop/start relatively short cuts with thrusts technique used in longsword duelling, but of large sweeping cuts through 360 degrees

Longsword duelling is not the be all and end all of Renaissance sword arts.

Of course in your two man duelling scenarios with longswords you don't use continuous arcs.

I'm talking about controlling 360 degrees of space against multiple opponents using a wide bladed two hander as desribed in historical sources. . . it's a different discipline.

I'm not talking about longswords and I'm not talking about dueling. I'm talking about making large circular and continuous cuts with a doppelhander. So everything here about me not understanding because I'm thinking about dueling or about longswords is rubish.

You may give two cuts in a row, but that is about it.

I think that you are confusing a judicial duel scenario with the one against many scenarios described in the historical sources. . . . and in which 'two cuts' is unlikely to be sufficient

No. No, I'm not. I'm talking about not standing and cutting the same cut more than twice in a row. You cut to different openings, different lines of attacks. You don't sit there and just swing the sword in the same circle over and over again. You vary the strike.

Air resistance is the catch. Air resistance saps energy very quickly. I've found this also with shorter weapons. For example it is less tiring to do fast whirling staff escrima drills with thin heavy sticks than it is with thicker lighter sticks...

Here, I might concede to you that air resistance could be a factor, because I don't know how fast you are twirling the stick...

But in ARMA, we don't do whirling drills. We make cuts, thrusts, and attacks. So I hardly think this example is relevant to using a sword with two hands.

This is the crux of the objection, but is based on faulty logic.

Arma concentrate on two man duelling scenarios.

The scenarios I am investigating are of one against many opponents, as desribed in historical texts, and they do involve bigger more continuous cutting motions through 360 degrees. . . exactly the sort of thing which isn't beneficial in a duelling situation.

They are nevertheless legitimate techniques for investigation.

The faulty logic you have applied is as follows: You state that because ARMA do not do 'whirling' drills that they therefore have no relevance to two handed swordsmanship. That is putting the cart before the horse, as historical examples come first.

Not at all. Not at all. We don't take sticks and do whirling drills because that's not how swords of our period of study, including dopplehanders, were used. If you want to do that with sticks, fine. Go ahead. But cutting continuously in circular arcs with dopplehanders is not analogous to whirling drills. To restate, we don't do whirling drills because there is not historical evidence for them.

The ARMA philosophy ( as far as I understand it ) is that the Renaissance sword makers and users were intelligent masters of their arts, and that every aspect of their swords was designed for functional martial reasons . Given that this is the case the current state of the ARMA lore ( in the archives at least ) regarding undulating blades ( that they are there to look scary but serve no practical purpose ) contradicts the ARMA philosophy.

Some aspects were purely decorative. Some swords were purely decorative. Of the three the museum swords in the pic you posted, I'm not sure that any of them were intended for functional use. This undulating blade form did not emerge based upon technological adaptation due to changing blade forms in terms of larger and larger blades. We know this because it was applied across the same time period to a wide variety of sword lengths, including most importantly, foyning rapiers. Or course rapiers don't move through air anything like how a dopplehander does. Rather, the emergence of undulating blades is a stylistic device. They were put on swords as decoration, especially on the sword that was meant increasingly for show and decreasingly for function, the dopplehander.

[Roy Robinson Stewart]

Not at all. Not at all. We don't take sticks and do whirling drills because that's not how swords of our period of study, including dopplehanders, were used.

I beg to differ.

The use of two handed swords against many opponents is described and gives clear evidence that such cuts were used to defend when surrounded by many oponents.

Even basic pell practice uses a circular motion through 360 degrees as shown by John Clements.

Al these terms: 'whirling, circular arcs, wide swinging motions, large arc turns etc are used looseley to describe the kind of large continuous cuts we are talking about. They obviously are not meant to suggst a single non stop arc in one plane like a propeller.

If you want to do that with sticks, fine. Go ahead. But cutting continuously in circular arcs with dopplehanders is not analogous to whirling drills. To restate, we don't do whirling drills because there is not historical evidence for them.

There is historical evidence for the kind of cuts we are describing, but regardless of that whenever a blade is at speed and turns it operates at a positive angle of attack and will benefit from tubercules.

Cutting continuously in circular arcs, sprials and figure eights with two handers is exactly what I mean by 'whirling drills' .

The stick exercise is merely used to show the effect of a stalled blade, by increasing surface area and reducing weight.

Some aspects were purely decorative. Some swords were purely decorative. Of the three the museum swords in the pic you posted, I'm not sure that any of them were intended for functional use. This undulating blade form did not emerge based upon technological adaptation due to changing blade forms in terms of larger and larger blades. We know this because it was applied across the same time period to a wide variety of sword lengths.

Just because the undulating form appeared suddenly in European swords does not mean that it was therefore a decorative addition. Many technological advances occur suddenly as the result of inspiration or serendipitous events.

Regardless of that we are still left with the indisputable fact that tubercules greatly improve the aerodynamics of wings and that the wide bladed of double handers behave as wings due to their shape and the speeds at which they operate Thus the wavy bladed swords have a distinct practical advantage over the non wavy types.

The introduction of wavy blades to rapiers will also provide some advantage, but it will be less than for wide blades.

Or course rapiers don't move through air anything like how a dopplehander does.

Rather, the emergence of undulating blades is a stylistic device.

This is a faulty argument: It doesn't follow that the differences in handling between rapiers and wide blades two handers entail that undulations are merely stylistic, as they could easily have been adopted on rapiers in imitation of the new breakthrough in two handed battle swords. Furthermore the wavy blades on rapiers would still give an advantage when he blade is swung from side to side as sometimes happens.

Even if they were intended as decoration on two handers ( which I don't agree with ) the laws of physics dictate that the two handers became more functional as weapons with the introduction of tubercules . . . . we can't change the laws of physics by conjecture. The laws of physics are the bottom line here.

They were put on swords as decoration, especially on the sword that was meant increasingly for show and decreasingly for function, the dopplehander.

This is your opinion, but as far as i know you can't prove it.

I can prove however that regardless of how they came to be the wavy blades have a beneficial effect on the handling of wide two handed sword blades. Wind tunnel tests have proven it with wings, and the two handed blades are wings whether we like it or not. Not only are they wings they are wings with particularly sharp leading edges and low chord ratios, which are frequently asked to work with angles of attack outside their range. They are thus ideal candidates for the introduction of tubercules.

I think it's clear that because the wavy blades improve sword function, we should assume that swordmakers used them deliberately to improve function. Personally I feel that it is insulting to the makers to imply that they would send their highest paid soldiers into battle with decorative blades.

.

[Roy Robinson Stewart]

So far we've mainly been discussing drag reduction.

Later today I'll analyse the beneficial effects of lift and the advantages of wavy blades via improved lift.

That's the icing on the cake.

[Sal Bertucci]

Gentlemen,

This has been a very a very interesting discussion with good points on both sides. However, we are now entering the point of a circular argument. So until we see wind tunnel tests of comparable wavy vs. strait swords I don't see much merit in discussing the topic further.

Feel free to continue though.

[Philip Sibbering]

I suppose you can swing it, but when delving into pike formations I get the impression that they are changing to a half-sword like technique. They are using it more like a spear, but one that can cut along it's full length.

Many of the two handers have spatulate tips, so thrusting was probably a secondary use. The wide bladed spatulate tipped two handers are primarily cutting weapons.

Charging into Pike formations is one scenario desribed, another is defence of a position against many opponents e.g. defending the standard

the wave may aid in get the blade in and out of a body (guessing

Many of the undulating blades had very high frequency undulations wich would definitely make it harder to thrust in or out of a body.. . their tips are also clearly not designed for thrusting deeply, certainly not three feet deep !

Interesting facts - thanks.

Perhaps a bit of a revision of my concept (and any input in two-hand use vs pike would be appreciated!);

Foundations; a rounded tipped blade will still impale an unarmoured man, and during the era when these where popular, troops had less armour. These weapons would be pushed with both hands, so has quite a bit of power.

Pushing such a blade into a group of pike, I'm guessing that the wielder does not want to go back - ever. This rounded tip could help in a way, even though it's a trusting type of attack, as it could aid in pushing the sword into a group and keep the blade free from being snagged.

To illustrate the concept in my head: image you have a group of skittles/ mannequins (something hard that can catch a point), and trust into that group with a pointy blade it could stick in a skittle. A more rounded tip would instead deflect. The damage would be from the blade sliding in between the skittles. It would be cutting damage but more a draw cut type of damage. A 'skittle' could be a piece of armour, or bone.

Not a perfect analogy but I hope it illustrate the point I'm trying to make. Getting the tip stuck in a body means you have to back out. This fella is in a pike formation, up close and personal, and he does not want to back off.

What I'm thinking is that the two-hander is pushed into the guts and you keep pushing, turning the blade to cut you way out or line then up like shish kebabs . Once amongst the pike formation you can draw another, shorter, weapon. In fact it would be so tight that the second weapon may be very short.

If does make the two-hander a bit of one shot wonder - but no more than a pike. Once the pike formation breaks, the two-handed sword can be recovered.

Now I'm not saying this is a better way of doing things, but I'm trying to think of the way they fight and what benefit they could get, or think they could get.

Combine this with that fact that a serrated blade, as that is what a flame sword really is, is far better at cutting tougher materials, like leather, thick cloth, or padding, and it makes sense.

Not so much an enhancement for hewing cuts, but an enhancement for draw cuts. I'm sure there are times when a person armed with a two-hander will swing it, but it is also true that often it will be used in other ways.

Getting back the topic; your aerodynamics concept is a nice idea, but if true: I think it may be an unintended effect of the design, and the design was for other reasons. It would be very interesting if it were true, but I think that should not blind us to other avenues.

In a swing it could aid speed, and in a draw cut it would definitely aid slicing through tough materials. Perhaps it was designed to improve draw cuts because of the way it was used against pike, but once the sword was made the wielder may have noticed it performs better when swung?

Philip