While Rick Cavallaro’s Blackbird, “Downwind Faster Than The Wind” (DWFTTW) . . . [or Directly Downwind Father Than The Wind (DDWFTTW)] . . . dates back more than a decade, it’s once again become a popular subject spurred by Derek Muller’s Veritasium channel video: [ Ссылка ].

While there’s endless chatter debating whether or not Blackbird can or does work, it seems clear (at least to me) that it does work as documented in the North American Land Sailing Association (NALSA) report: [ Ссылка ] which established a performance record of achieving a velocity ratio of 2.8 times wind velocity after a period of acceleration during which the cart velocity was always greater than the wind velocity. If you’re skeptical, I’d suggest reading this and these related reports before passing judgement:
[ Ссылка ] Summary of the NALSA test with more links
[ Ссылка ] NALSA test report data during 10 second record data interval

There are many shots at providing intuitive explanations of why Blackbird works and Rick Cavallaro notes that different explanations work for different folk as he discusses in his St. Francis Yacht Club presentation at: [ Ссылка ]. A great watch.

I find the most convincing video demonstration at: [ Ссылка ] (watch the chase car anemometer and wind vane).

While there are many related offerings, here’s a list of a few links:
A brief mathematical explanation by Steve Morris: [ Ссылка ]
A physics exam problem (see problem B2) How would you like to have only 45 minutes to solve this? [ Ссылка ]
[ Ссылка ] A fun Veritasium follow-up with links to more
[ Ссылка ] Video of Blackbird setup before record run
[ Ссылка ] Video shot during the record run

CREDIT
Many thanks to George Junkin who became as hooked on this problem as I have. His questions, thoughts, analytical work and review have been of incredible value. With almost endless emails and phone conversations under our belts, I think we’ve both found this analysis to be a fascinating retirement engineering project . . . in other words, it’s been great fun.

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