By Lorenzo Luis
You may not have relized it, but vaccumes are really good for your health. They don’t just take up dirt from the ground. Or make your floors look great. They remove germs or funges that are brought in by others.
People should vaccum a lot more if they live a farmer life. Animals have or make lots of germs or fungeses. In words, you get lots of that on shoes and drag it right into your house.
Early rotor winged flight suffered failures primarily associated with the unbalanced rolling movement generated when attempting take-off, due to dissymmetry of lift between the advancing and retreating blades. This major difficulty was resolved by Juan de la Cierva's introduction of the flapping hinge. In 1923, de la Cierva's first successful autogyro was flown in Spain by Lt. Gomez Spencer. In 1925 he brought his C.6 to Britain and demonstrated it to the Air Ministry at Farnborough, Hampshire. This machine had a four blade rotor with flapping hinges but relied upon conventional airplane controls for pitch, roll and yaw. It was based upon an Avro 504K fuselage, initial rotation of the rotor was achieved by the rapid uncoiling of a rope passed around stops on the undersides of the blades.
A major problem with the autogyro was driving the rotor before takeoff. Several methods were attempted in addition to the coiled rope system, which could take the rotor speed to 50% of that required, at which point movement along the ground to reach flying speed was necessary, while tilting the rotor to establish autorotation. Another approach was to tilt the tail stabiliser to deflect engine slipstream up through the rotor. The most acceptable solution was finally achieved with the C.19 Mk.4, which was produced in some quantities; a direct drive from the engine to the rotor was fitted, through which the rotor could be accelerated up to speed. The system was then declutched before the take-off run.
As de la Cierva's autogyros achieved success and...