Recruitable Unit Rebalance Version 7.51 Released.

[Saber Cherry]

Evil Dave said:

but that's how rifles and (some) artillery work today.

I know, field artillery is like that, but they do a bunch of calculations before firing... and rifles have adjustable scopes that account for drop over distance... and medieval xbowmen had neither calculators nor scopes. The only crossbow I've ever seen with a scope was in Deus Ex, and I put it there myself

I think it would be very hard to fire a crossbow accurately with more than a minor (<5 degrees) arc... and any arc-firing requires more training than direct firing, which would defeat the point of cheaply raising masses of untrained crossbowmen. Assuming, of course, that crossbows were used by cheap masses of poorly trained soldiers, which could be another false premise on my part.

Your point on the longer trajectory negating a lower velocity is interesting... it would take several complex integrals to figure out how much energy ends up being saved, if any, by firing at a 30-degree angle or so. It would be much simpler to model in Excel (in .01 second intervals), given the drag formula. I did something like that once, to find the ideal angle to launch a water balloon for max distance, but I have a pretty poor memory...

[Evil Dave]

Saber Cherry said:
I think it would be very hard to fire a crossbow accurately with more than a minor (<5 degrees) arc... and any arc-firing requires more training than direct firing, which would defeat the point of cheaply raising masses of untrained crossbowmen. Assuming, of course, that crossbows were used by cheap masses of poorly trained soldiers, which could be another false premise on my part.

i imagine if you had to train levies to fire crossbows ballistically, you'd do it the way the napoleonics did with muskets: drill a few angles for likely ranges (maximum, half-max, short) and figure that will do well enuf.

[The_Tauren13]

I think gameplay should be way more important than realism. This is a fantasy game, after all.

[Evil Dave]

The_Tauren13 said:
I think gameplay should be way more important than realism. This is a fantasy game, after all.

yup. it's mighty hard to realistically model gods on the battlefield.

the main reason for bringing up realism is folks were asking how weapons "should" work. but another reason is that it provides justification for changing game balance. for example, if you agree with wombats' idea that many pointy weapons should be armor piercing, SCs become relatively less powerful and some regular units become relatively more powerful.

[wombatsSAR]

Sabercherry: "arrowdynamics"

Thanks, great pun
I used to have:

"Incorrigable punster.
Please do not incorrige."

as my sig.

[wombatsSAR]

One last post before my brain explodes.

Arralen, you might be confusing the aerodynamic efficiency of the arrow with the energetic efficiency of the bow. Hardy's book has values of around 80%+ for the longbow. Iirc, modern, compound composite bows are closer to 90%+, while the crossbow is much lower but I can't find any relavent numbers right now. One rather biased source put it at 10% but that's too low considering extent numbers for ranges and projectiles. Xbows may have been capable of storing lots of energy but they really didn't deliver any where near all of it to the projectile.

[Arralen]

energetic efficiency of the bow
I'm not confusing it with the aerodynamic efficiency of the arrow. In fact, I thought to leave it out of the discussion, but I found a nice comparison which should make it easy to understand: "Barrel Length" .. the distance over which the missile is accelerated by propelling forces.
With a X-/bow, it roughly equates to the length of the arrow minus some "overhead", which is 80cm with the Longbow and 25cm with the X-bow. Equations are most likely non-linear ...

examples: (from Payne-Gallway, actually) 85 g bolt shot 420 m from a 550 kg pull medieval crossbow. Longbows attained lengths of ~275 m. Article authors cite another historian claiming 2x pull weight xbows were common, fwiw.

That's shurely a 55kg-Xbow. And 110kg-Xbows where shurely not common before 1475.(Steel Xbows in general date from 1350 and later).
And think about the reloading time: I would rate such a Xbow as a last try to keep up with a)the very heavy armors and b)firearms. And it shurely would have been used in siege warfare only - much to heavy to use it in the field...


aerodynamic efficiency
Can you scan & email me that wind tunnel results? Or give me a link? Think there's some fault in those numbers or the interpretation ...
E.g. using 80 instead of 60 m/s may have greater impact on the results than one would estimate because of special aerodynimc effects (boundary transition etc.)
Because of the differences in energetic efficiency of Long- vs. Xbow, I doubt both sorts of missiles start with the same "muzzle velocity".
=> Normally, something long&slender has always less drag than something thick&short, as long as it points into the direction of flight.

Furthermore, there's a mixup:
A longbow's efficient range is roughly equal to it's maximum range, because of the energy-storing effect of the ballistic trajectory and the lift-generating effect of the long arrow. (Similar to the lift effects on modern olympic throwing spears)
A X-bow bolt, because of the higher drag at high velocities, loses too much energy before it can store as potential energy, respc. loses much more of it's velocity within the first meters of flight.


volume/mass fire
You can fire a X-bow ballistically. But
load time is way to high for volume fire. A longbowmen can fire his 12 arrows within a minute. It takes a minute to fire a heavy crossbow and reload it...
So apart from the initial volley, there wouldn't be any volume to speak of. But without volume, you'll actually have to aim for a target ...

pre-historic "longbows"
Where long bows, but not longbows in a strict sense:
"At least two Neolithic longbows have been found in Britain. One was found in Somerset. It was identified as Neolithic by radiocarbon dating in the 1950s, much to the consternation of some archaeologists at the time. A second was found in southern Scotland at Rotten Bottom. It was made of yew and dates to between 4040 and 3640 BC. A reconstructed bow had a draw-weight of about 23 kg (50 lbf, 220 N) and a range of 50 to 55 metres.


addendum
found it in your post:
From Hardy: (velocity and range, 70 lb bow)
Lozenge Bodkin 46.5 m/sec 180 yd max (sigh, let's mix units)
Long Bodkin 43.6 m/sec 170 yd
Broadhead 38.7 m/sec 150 yd
extrapolation to 150 lbs, still Hardy, ranges should be ~300 yds

But 70lbs = 31,75 kg, which is on the lower range for a longbow, 100lbs (45kg) or even more seemingly where common. Range will not scale linearily, though.
But as you can see from the numbers above, "muzzle velocity" wasn't anywhere near 80 m/s but maybe 55m/s at best. Aerodynamic effects could be quite different ...