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The Travels of Mr. Fowler

Gemini Sparkle

Key Takeaways:

  • Invented around 1920 by Harlan Davey Fowler, the eponymous flap uniquely enhances lift by sliding aft to significantly increase both wing area and camber, rather than just deflecting.
  • This design provides superior lift increase, especially beneficial for takeoff due to lower initial drag, and has evolved into complex multi-slotted systems in many modern aircraft, including those by Lockheed and Boeing.
  • Despite its effectiveness in increasing lift, Fowler flaps are structurally complex, require robust actuation mechanisms, and can pose operational challenges, such as reducing braking effectiveness on landing due to sustained lift.
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The Fowler flap was invented around 1920 by one Harlan Davey Fowler, an engineer who was then in the employ of the U.S. Army. An internet search for his name turns up, in addition to various references to his accomplishments in aeronautical engineering, a volume on the use of camels — the two-humped variety — as pack animals in the old West (Three Caravans to Yuma: The Untold Story of Bactrian Camels in Western America) and another on certain aspects of Christianity (Behold the Flaming Sword). I don’t know whether all these are the work of the same person, though there is no reason why a man cannot be an engineer, an historian and a religious adept in one lifetime. But there is also no reason two people cannot be named Harlan Davey Fowler. At any rate, I am less concerned with Fowler’s camels and swords than with his flaps.

The historical context is interesting. John Anderson of the Smithsonian, and other historians of aeronautics, have pointed out the curious lack of connection between the evolution of early aircraft designs and the pure science that anticipated them by many years. Theoretical aerodynamicists had scant contact with the designers and builders of actual airplanes. Flow phenomena had been studied in the laboratory decades before they were encountered anew on the flying field by scientifically illiterate builders and pilots; on the other hand, it sometimes happened that innovations were investigated in the laboratory only after they had appeared in the field. The development of lift-enhancing flaps displays that irregular intercourse between workshop and laboratory.

FLYING Staff

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