Blackbird (land sailor)

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The first prototype of the Blackbird , the flags on the ground and on the vehicle show that the true and apparent wind are opposite.

The Blackbird is an experimental sail car (or land sailor) with a large rotor that can act as a propeller or turbine. It was designed to demonstrate that it is possible to sail faster than the wind right in front of the wind .

Blackbird was built by Rick Cavallaro and John Borton , team at Thin Air Designs , and also piloted by Rick C.

The Blackbird project was sponsored by Joby Energy , a company founded after 2007 by JoeBen Bevirt who worked on the development of kite-borne wind turbines in 2010. The project was supported by Sportvision, Met One Instruments and SparkFun.

On July 2, 2010, the Blackbird set the first certified world record in this category with 2.8 times wind speed directly in front of the wind at El Mirage Lake , in the Mohave Desert, California. The wheels drive the propeller. On June 16, 2012, the Blackbird also set the world record for driving in the opposite direction with 2.1 times the wind speed directly against the wind , with the rotor acting as a turbine driving the wheels.

Both records were recognized by the North American Land Sailing Association (NALSA) according to different rules.

As early as 1969, aerodynamicist Andrew Bauer built a rotor glider that drove 1.2 times faster than the direct tail wind. However, since this has never been independently verified, many experts remained skeptical, and some even thought it was physically impossible. Other researchers like Bauer came to the conclusion that such a vehicle in no way violated the laws of physics. To end the controversy, a team set out in October 2009 to build a rotor glider that was supposed to reach at least twice the wind speed just before the wind. The official record runs of the North American Land Sailing Association (NALSA) took place on July 2nd and 3rd, 2010 on the El Mirage salt flats in California . From the tests in which all conditions were met, the one with the highest multiple of the wind speed was selected, which was just under 2.8 (44.6 km / h with 16 km / h wind). As with most other journeys, the device was pushed at the start by a helper on foot with muscle strength, which was permitted under the NALSA rules. The top speed of 51.4 mph achieved in another attempt was also recognized by NALSA in 2012 as a record after revision 4 of the record categories.

A modified version of the Blackbird was driven directly against the wind in 2012 (at New Jerusalem Airport in Tracy ) and reached (in different runs) 2.1 times the wind speed or a top speed of 22.9 mph (records in the relevant NALSA -Categories C3: Propeller or turbine powered sailing craft, maximum speed; C4: Dead Down Wind and Dead Up Wind craft, speed ratio). The rotor does not act as a propeller, but as a turbine, so it delivers mechanical power to drive the wheels. In principle, an identical rotor could be used for both directions of travel - with and against the wind; normally, however, a (statorless) turbine has an opposite profile curvature compared to a propeller.

Individual evidence

  1. ↑ Joby Energy: Official Sponsor fasterthanthewind.wordpress.com, June 20, 2012, accessed October 9, 2019.
  2. ↑ Eric Wesoff: Wind: Joby Energy: The Tale of a High-Flying Entrepreneur greentechmedia.com, April 16, 2010, accessed October 9, 2019.
  3. ↑ Update on June 16 Record Submission to NALSA June 25, 2012, accessed October 9, 2019.
  4. ↑ a b c Direct Downwind Record Attempts . NALSA. Retrieved February 11, 2011.
  5. ↑ Andrew Bauer: The Ancient Interface: Faster Than The Wind (PDF; 4.7 MB) April 26, 1969. Accessed February 11, 2011.
  6. ↑ Photo of Bauer with his rotor car dcss.org
  7. ^ BL Blackford: The physics of a push-me pull-you boat . Accessed on November 15, 2011.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. The article mainly deals with headwind vehicles. For the direction with the wind it sets the simple wind speed as a limit: "On the other hand, the maximal downwind speed under the same conditions would be equal to wind speed (...)"@1@ 2Template: Dead Link / ajp.aapt.org  
  8. ↑ Rhett Allain: Physics and directly downwind faster than the wind (DWFTTW) vehicles . Archived from the original on June 5, 2010. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 15, 2011. "This is the same situation as people trying to make energy from nothing." @1@ 2Template: Webachiv / IABot / scienceblogs.com
  9. ^ Mark Frauenfelder: What I've Learned About Wind Carts . Retrieved October 31, 2019. Quotes physics professor Paul J. Camp with: "Impossible, would violate conservation of momentum and conservation of energy"
  10. ↑ Mac Gaunaa, Stig Øye, Robert Mikkelsen: Theory and Design of Flow Driven Vehicles Using Rotors for Energy Conversion . Retrieved May 2, 2012. "It is theoretically possible to build a wind driven car that can go in the downwind direction faster than the free stream wind speed (using a propeller in the air)"
  11. ↑ Mark Drela: Dead-Downwind Faster Than The Wind (DFTTW) Analysis (PDF; 59 kB) Archived from the original on November 16, 2010. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved February 11, 2011. "This confirms that the DDWFTTW condition V / W> 1 is achievable with a wheeled vehicle without too much difficulty." @1@ 2Template: Webachiv / IABot / www.boatdesign.net
  12. ^ Mark Frauenfelder: What I've Learned About Wind Carts . Retrieved October 31, 2019. Quotes aerodynamics professor Mark Drela with: "Although DDWFTTW seems like it violates physics, it really does not."

Web links

See also