A cargo of birds weighs nothing when they take flight, and then double

If you ’re ram a motortruck full of birds , can you bang the truck and lighten up your load as the birds launch into the air?Mythbusters concluded “ no ” when they tackle this questionseveral year ago — but that ’s because they did n’t have equipment as high - technical school as these Stanford engineers’ . The real answer , it appear , is a fleck more complicated .

The solution is “ yes , ” but only in brief and then the wench end up weighing double as much for a brief bit , too , as the downstroke of their wings generate erect force .

average scale do n’t shape in a flash , so when weighing the avian load they leave out the fast but substantial variation bring forth by a fowl flapping its wing . To capture change over a fraction of a second , a group of Stanford engineers manipulate up a box where each rampart could measure fluctuation in tune press . It calculate measurements 100 times a moment . Then , the researchers countenance a bird into the loge , as New Scientist excuse :

By filming Pacific parrotlets ( Forpus coelestis ) taking off and land inside the box , and measuring the forces the birds engender as they did so , Lentink ’s team confirm that generalist birds like this give almost no vertical violence when they flap their wings upwards – meaning they really are efficaciously weightless .

On the downstroke , though , the bird push on the surrounding air so forcefully that they give a vertical force of up to twice their dead body weight .

So there you have it : The response to how much flying hiss a motortruck weighs is somewhere between zero and twice their usual weightiness . It ’s not a wizardly weight - changing truck , just some unearthly physics . [ New Scientist ]

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