Bows:From the Ground Up

[DouglasCole]

Originally Posted by Nymdok

+10% kinetic to the arrow should be fine. As a matter of fact, its making me think about redoing all the optional rules based on energy, however I dont know how smoothly it will fit it with RAW.

The reason why I was asking is that energy stored in the bow arms is used to restore the bow arms to their original position along with propelling the arrow. Thats why I was curious as to where the energy bonus was measured.

Nymdok

If you do the calcs in terms of energy, esp energy imparted to the arrow, then you can use that energy and the cross section of the arrowhead and/or shaft to put the damage on the same calculation basis as firearms. This will severely (and usefully, I might add) flatten the damage scale with bow ST, so that lower weight bows have a bit more damage, higher a bit less (relative to the ST thr scale), and produce more realistic results.

[Nymdok]

Originally Posted by DouglasCole

If you do the calcs in terms of energy, esp energy imparted to the arrow, then you can use that energy and the cross section of the arrowhead and/or shaft to put the damage on the same calculation basis as firearms. This will severely (and usefully, I might add) flatten the damage scale with bow ST, so that lower weight bows have a bit more damage, higher a bit less (relative to the ST thr scale), and produce more realistic results.

To be fair, thats how I wanted to do them in the first place(Energy Basis). The problem was that GURPS allows trending along length, which sadly has broken down for us, but it was quick and reasonably easy to use.

The energy imparted to the arrow is a bit tougher of a question, because then it also depends on the arrow. Since we will all be using the same size mass arrow (700 grain/.1 lbs as found in BS) we can hold that constant and just use the bow energy.

That said, its still non trivial.

Up to this point, Ive assumed that Drawlength is 1/2 bow braced(Strung) length. But for the Energy under the Force/Draw curve you need to know what the Draw weight is (See upwards in this thread for BLx4, BLx3, BLx2.5 argumetns to determine Draw Weight).

Now the good news is that, as neither of these is defined as of yet, we can fiddle with those numbers as much as we want as long as we're not messing with the RAW,(Length should go up with bulk, ACC should go up with Total Energy (Faster arrows fly straighter) and smoother draw curvers etc.) and that if we put in book values, we should get book results. However, not knowing how aggressivley they were modeled before, fiddling with those numbers and getting them right can be a real challenge.

Dont miss understand, just like the great computer Earth, I am up to the task of calculating it, but it may take a while and you might not like the answer :)

Nymdok
Deep thought aint got nuthin on me.....

[DouglasCole]

Originally Posted by Nymdok

That said, its still non trivial.

Never would claim otherwise. :-)

Up to this point, Ive assumed that Drawlength is 1/2 bow braced(Strung) length. But for the Energy under the Force/Draw curve you need to know what the Draw weight is (See upwards in this thread for BLx4, BLx3, BLx2.5 argumetns to determine Draw Weight).

Right. Well, sort of right. If you just use the draw force in your calculations, regardless of what multiple of BL that is, you can derive the stats (at least in theory) for the bow-arrow as a properly deployed weapon system. That is, a xx pound bow of type Y will shoot the GURPS Standard Arrow at Z energy, which will do full damage out to a certain range, and then lose damage either as per usual or a special rule if required - it seems that you don't really lose half the velocity over many arrows' flight length. So 1/2D doesn't really work for this weapon system.

The argument over "how strong do you need to be to pull a bow of xx draw weight" is important but orthogonal to the weapon system question. Obviously, this gets to ST, translated to force through the BL "equation," and then we just have to figure for bow design, special exercises, and archer skill for a multiplier.

(Length should go up with bulk, ACC should go up with Total Energy (Faster arrows fly straighter) and smoother draw curvers etc.) and that if we put in book values, we should get book results. However, not knowing how aggressivley they were modeled before, fiddling with those numbers and getting them right can be a real challenge.

I'm partially with you, but bear in mind that the multiple of how much the damage of a bow goes up based on the thr damage progression in the human range of ST8 to ST20 is higher than what you'd get with BL going to force and therefore energy. Draw force for a given archer will quadruple from ST10 to ST20, doubling velocity (all things being equal, although they're not, we'll go with this for now). So a bow that does 1d at ST10 should do 2d at ST20 (and 4d at ST40)...basically +1d/10pts of ST.

With the thr progression you go up +1d per 7pts of ST, so damage is increasing at a rate 1.5x too high given the forces involved; thus, I believe, some of the difficulties we have with unrealistic penetration of armor with bows in GURPS at higher ST levels, or with thr+3 and thr+4 bows.

If we can establish a more realistic baseline for damage that's internally consistent and produces properly scaling results, it might be easier to retcon or modify Basic Set. Maybe that's Forbidden, we shall see. But the inherent contradiction in the damage scaling rates that will be derived from ANY application of physics (as you and I have both done) vs using the ST/thr damage scale as printed will foil any efforts to make the results both physically sound AND consistent with the Basic Set values.