A rebel army with limited resources and an army from a somewhat desperate allied country try to create an alternative to firearms, as the explosives logistics have been weakened and become entirely focused on the few bombs, artillery and missiles they can produce. And due to this catastrophic war, the majority of materials and weapons are being made in a similar manner of today's technology (which is almost humiliating for them to admit, as it shows how low the war dragged down their society).
The solution: creating an electrically driven bow/crossbow with draw weight above 200 kg (using reduction boxes and/or pulleys).
- The problems:
Well, there are some problems with this idea: the fire rate is not as good as conventional firearms and (I suppose) the structure of this weapon would be heavier than conventional firearms. However, it is silent and cheap to build (again, I suppose).
But the main problem is the speed of which the elastic/bending material launches the projectile (in this case, an arrow or fin-stabilised-bullet [like a tiny APFSDS]). There is a type of bullet-shooting crossbow, but they use slow and blunt projectiles.
In the case of a conventional firearm, the projectile is propelled by expanding gases, but rubber (or other bending material such as carbon composites and so on) is not a gas, and thus, can't move/launch as fast as gunpowder.
What is the maximum speed it could launch something, and how I could go around this problem?
I don't expect the projectile to compete with a bullet's speed, but it would be useful to know this kind of information since even today's conventional arrows can pierce through bulletproof vests (even by just a little in a limited range).
- Possible designs:
Well, I don't think that showing a specific design for a 200 kg crossbow would help you guys on answering this question, because if is something original, it would be quite difficult to calculate things. So I would suggest you assume it is a conventional crossbow design (compound or recurve), but "on steroids".
However, I will suggest some designs:
- Reverse Limbs Crossbows are very similar to compound crossbows, however, I read in some websites that because of its design, it increases the speed per pound of draw weight, but I can't confirm.
- A Limbless Crossbow could be an interesting option, since it is more compact and have coiled springs on its interior; Which can be made in a variety of ways, or even be entirely replaced by elastics, allowing for a linear pull using elastics, which would be easier to calculate (I suppose).
- There is also a Crossbow called Ravin R500E, it can surpass the 500 fps (feet-per-second) and I watched a video saying this specific product was delayed because of its projectile speed, which would create problems involving local laws (or something among these lines).