The last blog for the year. This one is being written at our holiday destination. Had to drive to our destination as rowed airship did not start?
This was the first attempt at a whirligig, or a wind powered object for amusement. It did work in a gale force breeze, but not suitable for a permanent installation on the highveldt. More of a coastal variety ornament, but I don't live at the coast.
The short video shows the first attempts at testing the "whirligig" in a breeze. As can be seen it was a strong breeze that got the bits moving. This shows a 4 bladed propeller driving the gears. This was marginal, so the propeller diameter has been increased and an extra blade added. This has not yet been tested in real conditions. Overall it has not been a very successful experiment, but it has been fun and launched 3 other propeller driven monsters.
This is a black and white photo taken later during the video sessions showing the upgraded 5 bladed propeller. The propeller is turned using a custom flexible drive supported by 2 wire helpers (or basically bearings supports). The photo was taken with a Mamiya C330 twin lens reflex camera with expired Kodak film. Development time was effectively extended by not compensating for warmer developer temperature and increasing the exposure time by stop when the images were captured. In the background of the image is a tin shack, which was added to provide some context for the monsters. The shack is constructed out of aluminium foil laminated with aluminium tape, and corrugated using a tool designed for card making. The frame of the shack uses bamboo skewers and ice cream sticks. The intention is to expand on the background buildings as time goes on.
The monster is basically an airship powered by 4 rowers. The propeller goes through 2 reduction gear boxes and chain drive to reduce the torque requirement. This allows the propeller to turn in the wind, but unfortunately means that the rowers cannot be accused of an over energetic display. The video is taken with the motor drive going at full pace, but the movement is still slow. During the short demo with the wind providing the power, the propeller turns somewhat faster and the rowers are closer to the speed I would have liked. So if this were to be powered by external motor the whole time I should reduce the gear ratios. I think I will rather wait until I move to a windier place and mount it outside. In the meantime it can collect dust.
This image shows the detail in the propeller hub and five bladed propeller. The brass plate is attached with miniature brass panel pins, to add some typical aeronautic detail, as well as keep the plate in place. The plate holds a brass tube, which fits over the propeller shaft and is secured with a steel pin (actually bent piece of wire). This allows the propeller to be removed for repairs as required, as well as allowing the power to be transferred to the mechanism efficiently. In the back ground the first of the reduction gear boxes can be seen. This serves 2 purposes. The first to reduce the torque required from the propeller shaft, and the second to move the drive shaft to the bottom of the airship. This was required to allow for sufficient offset for the rather large chain gear, and still keep the drive mechanism close to the center of the airship. Just looks more balanced to have the drive at the center of the shape, otherwise it would feel as if the airship would pull up or down as the propeller speed is changed.
The final reduction drive can be seen above, where a bevel gear is used to change the direction of rotation through 90 degrees for the rowers mechanism. The drive arm uses a triangular trussed beam to transfer the power to the four rowers, as a simple linkage would not have been stiff enough.
The four rowers are linked to each other with simple wire links driven from the back of the airship. The bodies of the rowers are constructed from wire twisted in a random pattern to form narrow waisted, broad shouldered rowers. They have obviously doing this for awhile. The heads of the rowers are once again crab claws, which basically defines the monsters.
The paddles are hinged on vertical wire shafts attached to the air-frame, and attached on one side to where the hand of the rower would be. The linkages between the rowers are attached to the hands. The bodies of the rowers are hinged at the hips and the shoulders with the arms attached to each other with a shaft through the shoulders. This allows the heads of the rowers to move forward and backwards as the oars are moved.
The oar blades are painted with a pattern of crosses which vaguely hints at a union jack like origin, whereas the tail of the airship has dark Germanic like crosses. This is allowed as I have ancestors in both camps and I like the effect.
So this is the last of the whirligig inspired monsters, which was made first, and the only one to briefly demonstrate the concept of wind powered objects with bits that whirl.
