What the chu-ko-nu had in favour of it, was its rate of fire. A single chu-ko-nu was able to lay down a hail of fire, somewhere in the order of 10-12 shots per minute. Compared with the reload rates of regular bows and crossbows at about 1-3 per minute; it's obvious to see why such a low powered weapon was kept around, and used by peasant households to defend themselves.
Now, here's the fun bit, allowing us to use one for real, and for Nerf launching applications.
Myself, personally, this project has been all about finding a decently accurate (20-30' accuracy I'm fine with; I'd prefer 50'+ though), short range, high rate of fire weapon, that can be built out of the most basic of materials; like wood, and string, nails, and wire.
I'm personally going to modify the original chu-ko-nu plans, since the original machine is entirely too cumbersome and bulky.
Original design:
http://www.atarn.org...e/rept_xbow.htm
Footage of a Chu-ko-nu in action:
there's lots:
Demo:
Demo 2: http://www.youtube.com/watch?v=4DaD_HGBoWw&feature=related
Diagram & Process: http://www.chinahist...ko-nu-zhuge-nu/
A brief tutorial on construction: http://www.youtube.com/watch?v=Vf97Fn11_Lc&NR=1&feature=fvwp
A small bit on their function, design, and creation:
http://military.disc...peating-cr.html
Ok, so, now a person can understand what I'm sort of basing my ideas on. The magazine is really the most phenomenal part. The bow is... a bow, it's an ancient, and revered weapon; but it's not adding anything new here. The handle and stock is... just a complicated double hinged lever system. Again, nothing that even the Egyptians didn't invent thousands of years ago.
What I'm going to leave intact is the magazine. The bow arrangment doesn't really impress me (too low, the force on the bolt should be acting along the curve axis of the bow, not at an angle to the curve axis of the bow). Nor does the very clumsy looking stock and handle-lever arrangement. The firers in all of the videos do not have obvious control and direction over the weapon's postion, or how it aims. That's a recipe for inaccuracy. Even a handle under the stock would improve the control that the wielder has over the weapon.
I am shortening the stock, turning it into a handle that rests under the magazine; the "lever" that slides the magazine forward will also be removed, and replaced with a 'pull' handle that will come out of the back of the magazine.
Right now... the prototype is made out of scrap wood, index cards (to fill gaps between the top of the magazine, and the bottom; there was a gap wide enough for an index card folded 4 times to fit onto either side of the bottom 'rail' of the magazine.
The overall design is going to be a bow at the front; the magazine mounted to the back of said bow; a hole drilled into the bow to allow darts/bolts to pass through (I wanted to straighten the alignment of the bowstring and the path along which the bolts fly; a common design flaw in crossbows is that the bow is usually 'lower' than the quarrel groove).
With no handle, or stock the 'reloading' will be done by wrapping wire along the centre of the bowstring (bungee cord really), and 'pulling' it backwards (there's a channel at the back of the magazine to allow the wire and handle to attach to the bowstring.
Without a stock, the magazine won't have an automatic method to 'fire'; I plan on resolving this by making a very minimal stock for the magazine to rest upon, with a handle that uses a reverse clothespin trigger (I need to push -up-, not pull down, to fire the chu-ko-nu).
Right now, overall dimensions are as follows:
magazine: 23cm long 5.2 cm wide 7 cm tall, 8 cm tall at front stopp block
'bow': a length of maple with the grain almost perfectly aligned (the curves of the grain along the axis are all curved towards one side, and the centre of the grain is very close to one of the long, widest, sides of the wood; are pretty much what I'd use if making it into a bow). .... I might eventually upgrade to metal; like a ground down saw blade; but for now, it's a prototype, and going to be all wood construction.
Edited by Judging Eagle, 03 July 2010 - 09:28 AM.
