Long before electrical systems, in a time when airplanes were simple and so were the pilots that flew them, a technique was used known as "hand propping" to get the engine started. This poor man demonstrates perfectly how dangerous a skill it is in five easy steps.
After surviving the long walk from the golf cart to the airplane, he nearly succumbs from exertion trying to spin the tiny, wooden, single-bladed propellor. A quick break reveals he's still breathing and willing to endure the life threatening task of starting his buddies airplane. Life number three is promptly used as the engine comes to life and the props swing desperately close to his feeble body. Unscathed, cardiac arrest seems likely when he becomes shocked and surprised by this whirly thing stuck to the front of the plane that suddenly starts spinning mere inches from his balding dome. That was a close, "Now let me bend over and grab these wheel chocks." He thinks to himself as he leans over, bowing dangerously close to the deadly and invisible spinning disk. Seems a shame to burn five lives in such a short moment.
But all's well that ends well, so once your adrenaline has lowered to a calming euphoric level, please enjoy the lovely ride around the patch in this antique Taylor J-2 Cub that follow the short moments of excitement.
Aside from the crazy old man and the gorgeous vintage aircraft, the one-blade propellor is surely an ingenious feat of engineering. With a motor only producing 35 horsepower, prop efficiency is of utmost concern and this unique design proved superior to its double-bladed cousin. This Everal propellor is able to pivot on its hub allowing the blade angle to automatically adjust for optimal performance based of the phase of flight because science. This means that during climb, the propellor will streamline for a higher RPM/horsepower and then during the cruise portion of the flight take a bigger bite of air which will slow down the engine while still producing enough power to keep the airplane moving. As engine technology improved producing more power, this complicated design was abandoned in favor of the simple, fixed pitch, double-bladed propellor. Check out this document explaining in detail how the thing works, written the Mr. Everal himself.