First of all, thanks for all your input!
My bad if I misused the word "cross bow. As I saw the "mech-crossbow" and the "sling-bow" sections, I got the wrong idea.
For me, the most important part was to use materials that could have been found in medieval times. I admit, rubber is not part of it but I had planed to replace it with a regular string attached to springs for added "authenticity" and more serious power.
Let me answer your different points.
Your are absolutely right, each time the axle turns, one rubber is released and propels a bolt that is in the quite ugly storage compartiment above. You start out with several bolt in the compartiment and several loaded strings and go from there. I intended to use springs at a later stage to increase the stored power.
I have already worked out the locking mechanism as it was an important part of the design. It's what I call the "main trigger" blocking the rotational trigger and you see in one of the pictures.
If I use a solid string and a spring, will there be the same problem of overdraw? Then again, all depends on the quality of your rubber. When I first built it, I was able to make 3 full turns with the rubbers without breaking the rubber, but again, I can't predict when it will...
You could consider reloading dangerous but each turn, the "Main trigger" blocks the rotating trigger, so unless you push it by mistake, except the tension built up. I agree with your comment on the lock but don't you think that this system of perpendicular pressure will hold up better?
To compensate for the lack of powertool, I though of 3D printing some parts but considering the load it might be plain dangerous.
Incredible! The project was funded so quickly! Quite similar to Jorg's design though... (https://www.youtube.com/watch?v=qxtHtPK2MH8)
Yes I have seen that design with compressed air too. I though up a similar design but using a big torsion spring to store the energy however would that be able to store enough? But I'm getting lost, that was a whole different idea.
Last comment, I think you are right with one major flaw of any design more complicated than a classic crossbow: the weight. But then again, I was really interested in the mechanical working of my idea.
I have watched quite some videos of Jorg's channel, I saw he posted also a bit around here. Indeed he knows his stuff!
I really appreciated all of your inputs and I know it's rather a big challenge, hope I'll have the occasion to work on it some time soon.