Laura Hillenbrand, author of the best-selling books Seabiscuit and Unbroken, is renowned for her painstaking research. Unbroken, the compelling story of Olympic athlete and hero World War II B-24 crewman Louie Zamparini, includes a full 50 pages of notes documenting her sources of detailed information.
There was one line, however, where she fell victim to one of aviation’s notorious “gotchas.”
In her account of how Zamparini and his fellow prisoners of war in the South Pacific would gaze skyward at Boeing B-29 Superfortresses flying overhead on their way to Japan and returning to their bases, she related how the bombers would catch tremendous tailwinds as they rode as-yet undiscovered high-altitude wind currents on the return flights.
She wrote: “Caught in what would later be called the jet stream, the planes were streaking along at speeds approaching 445 miles per hour, almost 100 miles per hour faster than they were built to fly.”
Of course, she was citing groundspeed—and as far as structural stress, the airframe could neither feel nor care how much faster the tailwind was making it move over the ground.
For the B-24 crew stranded in the Pacific and later captured in the Marshall Islands, it seems likely the bombers heading to Japan would encounter a headwind, not a tailwind as described unless I, too, have been caught in a “gotcha.”
Malcom Gladwell fell for a similar gotcha in his The Bomber Mafia book, when we said the bombers waited days on a remote island for a strong tailwind so they could get off the runway heavily loaded.
Most non-aviators have a difficult time understanding airspeed vs. ground speed (I don’t confuse them more by describing the different types of air speeds used for different reasons). I simply make a comparison most can relate to: floating down a river in a canoe.
If you don’t paddle and are standing still in a river flowing at 5mph, you are going 5mph in relation to the land around it.If you paddle it at 5mph down stream, then you are going 5mph through the water and 10mph relative to land. So the canoe isn’t really going 10mph, a near impossible feat.
Now I still can’t explain how that episode “Odyssey Of Flight 33” of Twilight Zone with the 707 airliner going faster and faster over the ground exceeding 3,000 knots ground speed but their TAS remained the same (and they went back in time).
No, you are correct there. But Hillenbrand was describing the return flights, and her observation was a “sidebar,” not directly related to what the prisoners saw. Though, presumably, the prisoners might have been able to see the Superfortresses as they flew both ways.
Thanks. I’ll change the copy to be more accurate.