Actually massamusi, the helicopter would work, and when they recently built it (last year I belive) straight out of his designes with no external help, it flew. It needed either a cliff or a very good run up (with the aid of horses) to get into the air, but flew without a fuel source for quite a long period of time on basically springs and clockwork. Take the principal of a hang-glider and give it rotrs instead of a wing, there you go.

Almost all of what he designed works, most modern attempts to recreate them failed because they tried to use different materials, saying that instead of light yet strong wood they could use plastic and so on, when the machine was very carefull balanced and the change in weight stopped it working at all.

If you were going to mod it in then it would be interesting to say the least, and many of what you said about was in use in one form or another, as you said, but things like poisons are not efective as they are extreamly difficult to obtain in anything other than miniscule quantities, no use for a throwing weapon then. The grenades? We have naptha throwers already, greek fire or an equivilant would be nice, though I don;t belive there was ever a land based version made.