www.PSFmagazine.com | March-April 2019 | 27 26 | March-April 2019 | Powered Sport Flying n Parts, Repair, Overhaul n Maintenance n A&P Technicians on Staff n Large Inventory of Engines LEADING EDGE AIR FOILS LLC The Central USA independent SERVICE CENTRE PSF57 Check Our Our Easy-to-Use WEBSTORE at leadingedgeairfoils.com 1216 North Road Lyons, WI 53148 1.800.532.3462 Check the Mailing Label on the Back Cover to See if Your Subscription is Running Out Gyroplane Review FOR 50 POINTS: HOW DOES THIS DIFFERENCE IN WIND – DISSYMMETRY OF WIND – AFFECT THE FLIGHT OF THE GYRO? Take a look at the image above and I'll help you out here with some choices: A) Try to turn? B) Fly tilted? C) Raise its nose? D) No effect? If you answered D, you are correct! There is no effect on the flight attitude of the gyroplane. It does not fly tilted. It does not try to turn. And it only raises or lowers its nose with pilot commanded airspeed changes similar to a fixed wing when the pilot raises the aircraft’s nose to slow down and lowers the nose to go faster. The picture is a subliminal suggestion for you to choose the wrong answer. In flight, there is no difference in attitude between a gyroplane and an airplane in forward flight or with changes in airspeed. Tally up your score and write down how much you wish to wager on your final jeopardy question. And the question is…. WHY DOES A GYROPLANE ROTOR ‘TEETER’? The rotor ‘teeters,’ see-saws on it’s teeter pivot, to correct for dissymmetry of lift that would otherwise be caused by the dissymmetry of relative wind in forward flight. In translational flight (forward or any direction), the advancing blade has more lift and rises. The retreating blade has reduced lift and descends. But, the advancing blade’s lift is reduced as it rises due to its reduced relative wind Angle of Attack as it rises. The retreating blade lift is increased as it descends due to higher relative wind Angle of Attack. The rotor blades are essentially rising from rear to front on the advancing side and lowering from front to rear on the retreating side. This is the blade ‘teeter.’ The rotor disk is actually flying a bit higher in the front than in the back at higher airspeeds. This is called rotor disk ‘blowback’ to help visualize what is happening. So, time to add up your points. How did you do? Next time, Gyro Jeopardy questions will delve more into how the autorotating rotor actually accomplishes its miracles automatically, without active attention by the pilot. That works for me—this stuff makes my head spin! The less I have to think about, the better!•
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