Bell helicopter has four small tail fans instead of one big rotor

Ewdison Then - Mar 10, 2020, 6:32 am CDT
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Bell helicopter has four small tail fans instead of one big rotor

Helicopters have always looked like the scariest way to fly, with not one but two large and menacing rotors spinning at deadly speeds. Although one of them is probably too high to chop your neck off, a helicopter’s tail rotor may have caused more deaths than its bigger counterpart. That’s why helicopter manufacturer Bell has been working new tail technology that splits a large rotor’s job into four smaller and safer enclosed fans.

A helicopter’s tail rotor does justice to the phrase “small but terrible”. Despite its diminutive size compared to the main top rotor, it is critical to producing the anti-torque that keeps the helicopter from spinning around because of that larger rotor. It is, however, also ironically louder at times and has been the cause of many a gruesome accident.

Bell’s Electronically Distributed Anti-Torque technology or EDAT, turns that concept and implementation on its head. It is purely electric, making the EDAT demonstrator helicopter the first hybrid helicopter, and the four smaller fans are enclosed in ducts that hopefully lessen the chances of people or things meeting their demise in there.

Being electric-powered has other and more important implications, too. Unlike the regular motor, the EDAT fans’ speed can be controlled, because, it turns out, you don’t need the rotor to generate the anti-torque all the time and just let physics do its thing. And during those times that the fans spin slowly or not at all, they become the quietest helicopter rotors you’ll ever hear. Presuming you haven’t grown deaf from the bigger rotor, that is.

Bell’s work on EDAT isn’t just for today’s helicopters either. It paves the way for hybrid and, eventually, fully electric aircraft that will become the airborne taxis of the future. Making sure that they won’t be fatal to bystanders is, of course, the most important first step in that direction.


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