This is a continuation of the whirligig theme, going towards a more traditional format. This was created while on a coastal holiday, where the weather favours whirligigs (excuse for not getting previous attempts to utilize wind power during videos). Shown below is the wire contraption in a holiday setup - surrounded by beach cottages close to the sea (sea side is into the sun, not great for photos).
The basic design consists or a 4 bladed propeller directly driving a worm gear. The worm gear allows the running man to run at a realistic rate, as opposed to the road runner style leg motion when avoiding Wile E Coyote. It also increases the torque which is produced by the propeller, allowing for a bit more friction in the mechanism and a little less precision in the gears. The screw gear drives a 9 tooth gear at right angles, which directly drives a crank for the legs. Each leg drives an arm out of phase. The legs have pivoted knees to allow for a realistic motion, but the arms don't have working elbows. This simplifies the design, but still allows for a realistic motion (basically don't flex arms a lot when running, but pump them backwards and forwards). The whole lot is mounted on a piece of trimmed drift wood. I had to do the trimming with a mini Leatherman pocket knife, so the rustic look is preserved.
The whole contraption has a tail added to try and keep the propeller pointed into the wind. This required a little bit of adjustment. The initial design had the pivot point too far forward, so it did not weathercock. This was moved back towards the propeller. It was not quite enough so an additional tail was added below. It sort of works now, but as seen in the video is not quite steady in the breeze. Not sure whether this is entirely due to the design, or due to the wind swirling between the holiday houses. Like the effect in the video of allowing the aspect to change constantly, so have not changed it yet.
A weak point in the design is that the shaft of the propeller, connected to the screw gear is made of 1.6mm wire (the thickest that I had at the time). It hasn't bent under wind power yet, but it just feels like it should have a more substantial shaft. It does mean that the clearance between the propeller and man had to be increased to prevent the propeller colliding with the runners elbows when the wind velocity increases. The actual blades of the propeller have been constructed using aluminium sheet recovered from tin cans (beer and mixers), which are freely available during the holiday season. The aluminium sheet is bent around a wire frame. This is easier to do when the shapes have straight lines and not curves. I'm sure it will improve with practice, but it is functional. The same technique was used to give the arms and legs a little more substance. The rest of the mans shape was hinted at with wire. The head was simplified to show the outline from various angles, with no attempt to complete all the bits. I like the effect as it requires a little more imagination (something that is generally required with wire objects as it requires you to fill in the missing bits).
The final image shows the running mans expression when trying to go forward quickly. Has a nice upright posture with open shoulders. Think he will be a good runner in a breeze.
