Super Quick/Sketchy Pony Physics Calculation: How much power IS one wingpower? (spoilers)

Feel free to check my work in case I'm derpy.

Assuming that pegasi are light (because they fly) and aerodynamic (because, um, magic), I am using 270kg (avg mass of Newfoundland ponies, the lightest pony breed according to Wikipedia) as the average mass and 0.3 as the average drag coefficient. (Cars have drag coeff of 0.25 to 0.45 so I took the average; now ponies ain't aerodynamic so it's really probably 0.75 or something but hey, magic.)

Newfoundland ponies are about 11 hands / 44in tall, and MLP ponies are about 1:3 width to height, which gives a frontal area of 0.4 square meters.

Fluttershy spend 2 seconds traveling across the screen, which is the width of about 4.5 pony heights, which means that she was maintaining a speed of 1.23m/s. (Which btw is about 2.75mph). Assuming wingpower is a measure of power (rate of work wrt time) we can use http://upload.wikimedia.org/wikipedia/en/math/b/c/3/bc327e14052e5a0aea56f4feda12d90b.png to find the amount of power a pegasus needs to generate to maintain a speed of 1.23m/s. Since she scored 0.5 wingpower I just doubled the drag equation to find twice the amount of power she generated to determine the power of one wingpower.

2P = 0.2 * 1.225 * 1.23^3 * 0.4 * 0.3 = 0.0547watts = 7.22*10^-5hp = 0.0000722hp

This means that... one wingpower is 0.0000722 horsepower.

Okay, so ponies aren't aerodynamic, let's triple Fluttershy's coeff of drag. This triples the power needed to overcome drag and so one wingpower is... 0.00022 horsepower.

Let's just round it up to 0.00025 for the hell of it!

800 wingpower would be... 0.2 horsepower. That's the amount of power needed to create a tornado and carry a reservoir's entire contents into the sky.

Because magic.