After trying to understand how to maximize a crossbows effectiveness I've came to the conclusion that torsion engines are the way to go, assuming you can call whathever it is you made a crossbow after that.
A short search had me stumble onto two very impressive desings from very seperate timelines:
Talisman's Mantis and the manuballista.
Seeing both are effectively reliant on torsion engines I've got convinced that I was on the right path. However I questioned the use of the static limbs used on the tradional and handheld ballistas and apperantly on Mantis. My reasoning is that if you can store enough energy in the engine itself it will be very hard to turn due to the stress. Becoming some sort of an anchor -a riser, if you will- that stores useable energy and allowing the bow limbs to bend and store even more energy.
The obvious problem could be the torsion engine breaking apart due to extreme stress. However I think that can be managed with the modern materials. What truly worries me is that the possibility of the forces cancelling eachother out if the force vectors are not aligned, effectively making the mechanism useless and ineffective.
I realize that this isn't anything traditional, but as I've said: I didn't know where to posts this. Do you think it is possible? Have you seen anything like I've described? Am I overthinking it and it would simply not work due to logical reasons?
TL;DR: Can you combine torsion engines with bow limbs to shoot faster projectiles?