Trebuchet trials

Over Christmas I refurbished my small trebuchet, giving it a coat of paint & making a few detail improvements to make it easier to assemble & disassemble.  Today we took it to Mark's out-of season & deserted rugby ground to get some more test data.  

The machine disassembles into modules that fit in the back of my little Merc with just the arm on the roof rack.  We were able to set it up right next to the car & even had our own grandstand.

We didn't try for any records as this was a fact finding mission.  We systematically varied one variable at a time:
- Location of the power weights on the arm.
- Amount of power weight.
- Ammo size (0.72Kg bocce balls or 1.7Kg steel balls).
- Sling length.
For any given ammo there is a sweet combination of these parameter where it really flies.  I wanted more data to allow me to better predict what the sweet spot is rather than having to zero in on it by trial & error each time.   After 21 throws I have a heap of data to examine. 
The longest throw was 73m, but we didn't power it up to the max today.  The last time we did that we bent the 20mm steel main axle.  I intend to get some high strength steel rod to replace the mild steel, but haven't done it yet.
We also timed a firing & found we could shoot a round in 40 seconds, but we took much longer than that measuring the distance & retrieving the ammo each time.