Model: 127 Vertical Paddle Propeller Wheel
This is the most efficient type of paddle wheel. The green driver arms are the supports for the rotating paddles. The red arms are attached by crank arms to the green arms. The red driver is eccentric to the green driver. The rotating action of the two causes the paddles through the crank arm connections to be held always in a vertical position with their surfaces always meeting the water at right angles to their travel. This is the most efficient angle for driving.
[Virginia Downward & William M. Clark, 1930]

[Editor’s Note: This device is essentially four coupled, four-bar mechanisms similar to the parallel guides in the Reuleaux-Voigt model T14. While the application to paddle wheel vehicles may be dated today, in helicopter blade mechanisms the angle of the rotor is changed in a predetermined orientation with respect to the vehicle as the blade rotates similar to Reuleaux models, T14 and models U1, U2. The Clark model 127 was copied after the Figure 489 in the 1868 catalog of mechanical movements by Henry T. Brown. One can see the evolution of kinematic ideas from the age of steam to modern aircraft mechanisms. FCM]

Francis Moon 2005-00-00