![]() ![]() One 2-9/16-inch x 1-inch x 7/16-inch (nominal) pencil eraser.Ends: Two 2-inch x 4-inch x 9-1/2-inch (nominal) pine boards.Base: One 9-1/2-inch x 15-inch x 3/4-inch piece of plywood.Sides: Two 1-inch x 6-inch x 15-inch (nominal) pine boards.Throwing arm: One 1/2-inch-diameter, 13-1/2-inch-long hardwood dowel.Four small screw eyes (3/16-inch-diameter eye or larger).Six 1/4-inch-diameter, 2-inch- long wooden dowels.Axle center: One 3/4-inch-diameter, 10-1/2-inch-long hardwood dowel.Axle pieces: Six 3/4-inch-diameter, 8-inch-long hardwood dowels. ![]() With aluminum and these engines, you can now begin to produce a machine with a high enough power to weight ratio to allow it to go airborne. Once again in the case of the birds, these engines replace the pectoral muscles. It also needed for engines to be developed that had a high power to weight ratio and were efficient enough to only need to carry a small amount of fuel with them yet get a large amount of power out of the fuel, engines such as the two-stroke, four-stroke, and later on the jet turbine engine was what Leonardo needed. The modern-day helicopter had to wait for material science to produce aluminum as it is very strong but lightweight (in the example of the birds above this would be for the skeleton). When was the first helicopter made is on Sep 14, 1939, the world’s first practical helicopter to feature a single main rotor and tail rotor design by Igor Sikorsky. Even during the time of the steam engine, the helicopter was not a feasible machine as steam engines are very heavy and have a low power to weight ratio, we must not forget the weight of the coal and the water needed to produce the steam. Material Science and engine development would not allow such a machine to fly until the late 1800s and early 1900s. However, it must still be recognized as a great leap of the imagination. The lightest materials at the time would have been canvas as the covering for the blades and maybe pine wood for the machine’s main body, this would have resulted in a machine weighing close to, if not exceeding, a tone. Birds also have hollow bones, which lowers their weight substantially allowing them to take flight more easily.Īs we have said earlier, this would never have happened due to the low power to weight ratio of the men, not to mention to astronomical weight the machine itself would have had. Birds have very large pectoral muscles (the breast, below image), this is because these are the muscles that power the flapping of the wings. If you want to look at animals that do have a high enough power to weight ratio for the flight, you need to look no further than birds. Unfortunately for Leonardo, engines had not been invented yet (apart from Heron of Alexandria’s steam engine) and humans have nowhere near the power to weight ratio required for them to produce enough energy to lift themselves against the force of gravity. Leonardo’s helicopter was designed as a human-powered machine. Had Leonardo seen a sketch of Archimedes Screw and designed the helicopter from it? We will most likely never know. ![]() This is a screw pump and it was invented in Ancient Greek times by Archimedes of Syracuse, who was himself a Polymath like Leonardo. The closest thing we need to think about the Leonardo’s helicopter drawing would be the Archimedes Screw.
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