When it comes to improving quadcopter drone performance, no technology is too ‘out there’ or too ancient, as Mark Broadbent reports

A design for a ‘helical air screw’, a helicopter-type flying machine, from the notebooks of Leonardo da Vinci. To avoid anyone reading his notes, Leonardo wrote in a shorthand of his own devising or, as here, using mirror writing
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Quadcopters have been pivotal in the drone industry’s growth.They are now a serious industrial tool, used for inspections, package delivery, aerial filming and emergency services work among numerous applications, as well as being a popular consumer electronics plaything,