I went to youtube to try to get a better idea of how this worked but all I found was scenes from a video game (many pages) and Britney Spears.

It's things like this that make me bemoan not having easy access to a place where I can try it out.

It reminds of the swiss arrow, but it also seems importantly different. I'm not quite sure how the release works, but I guess it seems to me that the string doesn't serve to accelerate the projectile at all, rather just to hold it in place in some way. Have you tried using this torc?

Its a half hitch. You wind the cord once around the shaft till it crosses over itself. Pull tight until the knot tries to slide under the crossing and cannot. You now have a noose that will hold as long as there is tension on it. The notch is opposite the knot so the noose doesn't slide along the shaft.

Glad to see I'm not the only one that it caught attention from, both book and item.

When I was a boy in the early 1950's we made whip darts similar to this.  Lots of fun.

from this site
http://www.primitiveways.com/shingle_dart.html

  I don't think it would be a good idea to make these with a point, if for any reason the arrow stuck and didn't release from the string guess where it will be going? right back around to you.  Otherwise they are kind of neat, might give it a try sometime.