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December 2024

Q: You’re playing a game that requires you to turn over five playing cards, each with a different phrase on it. You must turn back over any card(s) bearing unrelated phrases, and craft a sentence that shows the relationship among the remaining phrases. Your cards say: “The horn of a passing train.” “Spectroscopy.” “Reynolds Number.” “19th Century Austrian mathematician.” “Moving Target Indication.” Which cards would you leave face up, and what would your sentence say?

Send a response of up to 250 words to aeropuzzler@aerospaceamerica.org. By responding, you are committing that the thoughts and words are your own and were not created with the aid of artificial intelligence. DEADLINE: noon Eastern Dec. 10.

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FROM THE NOVEMBER ISSUE:We asked you to describe the phenomena that birds and jets take advantage of when flying in formation. Haithem Taha of the University of California, Irvine reviewed your answers and selected two winning responses.

WINNER: Vortex surfing is an aerodynamic phenomenon that birds and jets take advantage of when flying in formation. They use it to ride the spiraling air created by its wing, commonly known as wake vortex (caused by the pressure difference between the top and bottom of the wings). When a bird generates lift, it creates wingtip vortices that create upwash (rising air) and downwash (descending air) around the wingtips. By positioning themselves in V-formation, where each bird lies in the upwash region, trailing birds or jets benefit from this additional lift. This reduces their own induced drag while avoiding downwash areas, conserving energy for long-distance migrations. Similarly, jets in V-formation use vortex surfing by maintaining a precise position relative to the lead aircraft’s vortices, which increases its fuel efficiency.

Madhusudan Pun, AIAA student member

Lalitpur, Nepal

Madhusudan studies aerospace engineering at the Institute of Engineering’s Pulchowk Campus in Lalitpur.

WINNER: Flight occurs because of a balance of forces when the flying vehicle or animal produces enough lift to overcome weight and enough thrust to overcome drag. Lift is generated by higher pressure below the wing than above it. This higher pressure air flows around the wing tip, producing a wing tip vortex that trails behind the vehicle or animal. For commercial aircraft, this represents an energy loss and increased drag, which is why they have winglets. While wing tip vortices are disadvantageous for aircraft and for birds flying solo, they’re advantageous for birds flying in formation and save them energy while migrating. The lead bird in the formation bears the full burden of breaking the wind, while the birds behind benefit from the upwash created by the wing tip vortices. The trailing birds synchronize their wing beats and can experience up to 30% energy savings. Birds alternate flying point so that no single member of the flock is overburdened.

Taylor Swanson, AIAA lifetime member

Tullahoma, Tennessee, USA

Taylor is an aerospace engineer at theArnold Engineering Development Complex.