|||
Blackbird Rick Cavallaro via Wired
Which sounds weird but actually makes perfect sense.
A couple of years back, Rick Cavallaro and his wind-powered
car--Blackbird--silenced an online debate about whether its possible for a
wind-powered vehicle to move downwind faster than the speed of the wind itself
by going
out and outrunning the wind. Now, Cavallaro and company have reconfigured
their car to travel upwind and proved that it’s possible to travel upwind at
more than twice the speed of the headwind, setting
what has to be a record for upwind terrestrial sailing.
That’s not quite as big of a bombshell as the downwind run back in 2010, in
which a lingering and sometimes vitriolic physics debate was quashed when
Cavallaro recorded downwind speeds at 2.86 times the speed of the wind. But this
time he’s managed to log 2.01 times the speed of the wind going upwind--still a
significant feat.
And also a counter-intuitive feat, though when you really think about it the
physics are the same as a sailboat tacking upwind. The turbine blades act as
sails, turning to create power. Rather than having a keel to counteract the push
of the headwind and maintain the proper upwind direction, Blackbird’s
transmission and wheels have been designed to do that job.
Archiver|手机版|科学网 ( 京ICP备07017567号-12 )
GMT+8, 2024-12-26 22:03
Powered by ScienceNet.cn
Copyright © 2007- 中国科学报社