Calculating Wing Lift, the Dummy Version

Lift calculation variables

Our research team members all figured out long ago that it's easy to identify freelancers writing well outside the fields in which they've been trained. Let's say, for instance, someone has an education degree (from a diploma mill, no less) and tries to explain a fairly complex problem in aeronautical engineering. It'll be tough to get it right if you don't understand it in the first place, right? Well, that's exactly what happened when Sciencing.com's Melanie Fleury tried to tell her readers "How to Calculate Wing Lift."

We suspect it's lucky that the OQ said "wing lift" instead of just lift, otherwise Fleury probably wouldn't have been able find any references. Lucky for Melanie, she found a simple reference – but then she botched it.

From a purely scientific standpoint, Fleury's post first goes off the rails in her daffynition of lift:

"...lift is the mechanical force generated by a solid object moving through fluid. It is the force that directly is opposite to [sic] the weight that holds a flying object down."

Actually, we think that gravity "holds a flying object down," but that's just us. We suspect that the clumsy definition is, in part, because Fleury had to reword something she didn't understand to avoid being dinged for plagiarism. But anyway...

Fleury attempted to turn the lift equation,

L = Cl * (r V²)/2 * A

into words.

• She got A right: "Measure your wing area."
• She botched r: "Use the density of air. The density of air is approximately 0.00237 slug/ft. cubed. " – It's VITALLY important to use air density at flight altitude! (not to mention that eHowians are supposed to use SI units)
• She messed up V: "Calculate your velocity." – You don't "calculate" velocity, you measure it.
• She botched Cl: "Calculate your coefficient, or CL... CL is two times 'pi' times the angle of attack, in radians. " – This is only (approximately) true for thin airfoils at low angles of attack. That, and the "L" should be lowercase...
• And finally, she blew combining it all: "...multiply density and velocity squared, divided by tow [sic], then multiply by coefficient and wing area..." – Where does that "tow" come from? It comes from Fluery being too unprepared to realize it should be "two." That's not to mention that "density and velocity squared" is ambiguous.

Let's be honest: this is pure twaddle cobbled together by someone who clearly didn't understand what she was writing. Metaphorically speaking, it's pretty much the equivalent of the million monkeys pounding on a million keyboards hoping to write Shakespeare. In other words, Dumbass of the Day quality.

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