crankyoldman: "Hermann, you don't have to salute, man." [Pacific Rim] (f the cosine)
2010-10-08 05:05 pm

re: today's xkcd

Since I've gotten asked.

It's about airfoils and misconceptions.

Pretty funny joke, considering that even at a university level some people still get confused about airfoils. The short answer is that fluid dynamics is COMPLICATED. In 3D space, there are a lot of factors in dealing with them.

Why do they get confused? Because the math is right, and math is sometimes hard to translate into language. Particularly the English language, I've learned. (yes, there are languages that make math easier to understand... they are countries that tend to kick the US's butt in math scores. but that's another topic). If the math were wrong, we'd have no planes flying!

But the longer answer in how airfoils create lift is not just based on flow movement; it's based on circulation. The problem with the standard (wrong) explanation is that they just don't describe Bernoulli's Principle right. Bernoulli's principle is really about momentum and circulation. And the base equation is a simplification of much more complicated fluid dynamics, but I won't go into that.

Expandthe longer explanation )
crankyoldman: "Hermann, you don't have to salute, man." [Pacific Rim] (cary grant)
2009-03-29 03:58 pm

Transient Handling is 500x more awesome than engine performance

So I got my tire model to work. And I figured that in the spirit of actually understanding what's going on, I'd share the fuckyeahawesome that is my tire model.

Expandha ha, prolly should cut this for pictures. )
crankyoldman: "Hermann, you don't have to salute, man." [Pacific Rim] (fuck the cosine)
2008-10-06 09:53 pm

LET'S LEARN ABOUT DYNAMICS

Ok, this isn't the end of the week, but I thought this was something fun to share with ya'll. The kind of stuff I remember hearing and thinking, "HELL YEAH I WANT TO BE AN ENGINEER THAT ROCKS".

Alright, so it might not have the same effect on you, but at least it helps me recover from the result of my last exam grade. Ha.

ExpandSo who wants to learn about gimbal lock and why the Apollo 13 movie had so many slide rules? )

So, the moral of this story:

- Don't divide by zero, you could crash and die.
- Some technobabble in movies is based on real things
- Jim Lovell would have made a good pirate
- This icon makes more sense now, doesn't it?

P.S. OMG EULER ANGLES IN MOOOOTION: