Monday, April 17, 2006

Joe Rouse Is Messing With My Head

Joe Rouse from The Horses Mouth is messing with my head. Don't be fooled dear reader by his seemingly helpful, erudite comments to my post questioning some of the widely-held assumptions about how wings and sails work.

I can now reveal all. Joe Rouse, if that is his real name, did not write those comments. He just did some nifty cut and paste work from this site and this one. And here is the really cunning twist executed by the slippery Mr. Rouse... he chose two sites that contradicted each other and had mutually inconsistent explanations for how wings generate lift. Just to drive me crazy. And it's working.

So who should I believe? Mr Rouse's first comment was from the NASA website. You think you would be able to trust these guys. After all they are rocket scientists. But don't forget these are the people that brought us Apollo 13, and the Columbia and Challenger shuttle disasters, not to mention that little matter of mixing up metric and imperial units that led to the loss of the Mars Climate Orbiter.

On the other hand, the source for Rouse's second comment, this article by C Johnson, Physicist, is even more dubious. C Johnson, Physicist tries to impress us with his or her credibility on this topic be letting us know up front that, "I received my education in Physics at the University of Chicago. They seem to have done a good job."

Don't you just hate it when people do that? Do you think that Albert Einstein introduced his paper on General Relativity with the words, "I was educated at the Swiss Federal Polytechnic School. They seem to have done a good job"?

Or when Francis Crick wanted to tell the world about his discovery of the double helix structure of DNA did he boast, "I was educated at University College London. They seem to have done a good job"?

And when George W Bush was trying to convince us that there were WMDs in Iraq should he have started all his speeches with, "I was educated at Yale and Harvard. They seem to have done a good job"? Would that have made him more credible?

No C Johnson, Physicist, I really don't care where you studied physics. I will believe your article if you have good arguments backed up by solid evidence. But if you write spurious pseudo-science I will not be swayed by the fact that you went to some parvenu mid-west school founded by a religious sect and a robber baron.

Oops. That last sentence came out a lot nastier than I intended. See what this Rouse guy is doing to me? He's turning a kindly old grandfather into a mean-spirited old curmudgeon. On behalf of Rouse I apologize to all alumni of the University of Chicago which I am sure is a perfectly fine school if you like that kind of thing.

Where was I? Oh yes. NASA and C Johnson, Physicist. So what do these two papers say?

C Johnson, Physicist, after explaining that "there are many, many, many alleged descriptions of the Bernoulli Effect or of Bernoulli Lift or about how airplanes fly, which are not accurately correct" then goes on to repeat the hoary old myth about two air molecules that start together at the leading edge of the wing and must end up together at the trailing edge after one has traveled under the wing and one has traveled the longer distance over the top of the wing.

I made my own feeble attempt to debunk this nonsense in my post on Geeking Out. So I'm especially glad to see that, on this one, NASA agrees with me and not with C Johnson, Physicist. Here's what the NASA site says ...
The most popular incorrect theory of lift arises from a mis-application of Bernoulli's equation. The theory is known as the "equal transit time" or "longer path" theory which states that wings are designed with the upper surface longer than the lower surface, to generate higher velocities on the upper surface because the molecules of gas on the upper surface have to reach the trailing edge at the same time as the molecules on the lower surface.
NASA goes on to say that the air passing over the upper surface of the wing, in reality, has an even higher velocity than you would suppose from this equal transit time balderdash.

You see what this Joe Rouse character is doing? Looking like he is being helpful but steering us towards sites that contradict each other in explaining how wings generate lift. Oh, this guy is clever. So clever he makes my head hurt.

C Johnson, Physicist's paper essentially breaks down the causes of lift into two components: a Bernoulli Lift caused by the lower pressure above the wing in that (incorrectly described) faster moving air; and a Reaction Lift caused when the wing is tilted upwards because "the air which hits the bottom of that tilted surface is deflected downward (action), which creates an equal and opposite reaction, upward lift, in the wing itself." (Newton's Third Law - Action and Reaction).

At first this sounds plausible as it does explain such mysteries as how airplanes can fly upside down. But wait, what does Slippery Joe's other reference, the NASA site say?
There is also an incorrect theory which uses Newton's third law applied to the bottom surface of a wing.... It neglects the physical reality that both the lower and upper surface of a wing contribute to the turning of a flow of gas.
Once again. The incredibly annoying Mr Rouse gives us a morsel of explanation with the left hand and then takes it away with the right hand. Diabolical!

So who should we believe? NASA or C Johnson, Physicist? What do you think?

Anyway, my brain is hurting from all of Joe Rouse's shenanigans. It's enough to send a sailor spinning wildly into calenture.

I need a rest. No more geeking out on theories of lift for a few days. But I will be back.


bonnie said...

Woo. Out of the mouths of horses...

I was paddling this weekend with a friend who happens to be a) a pilot and b) insanely intelligent. I mentioned my paddles & planes meanderings (which I should still go back & post a warning on, stating clearly "The author has no actual clue what she's talking about beyond the very basic 'duh'-worthy assertion that 'different kinds of paddles act differently').

Insanely intelligent pilot's immediate response was something like "Y'know, everybody thinks they know how planes fly, but we really don't understand it entirely".

Anonymous said...

Argh matey. Me diabolical ways have worked their magic. Now for some grog to fog the mind even more. To quote the Dread Pirate Edward, "I've noticed through my empirical research that when it's windy the boat moves and unfortunately when there's no wind, drift city."

Anonymous said...

I received my education in sailing at Tillerman's weblog. He seems to have done a good job. Now why isn't there an airplane wing on this boat's mast?

EVK4 said...

I've heard that neither bumblebees nor helicopters should be able to fly based on Newtonian Physics. Yet they do.

In theory, my boat should be fast, and yet it's not.

There's a whole new branch of physics out there yet to be discovered.

Anonymous said...

Unfortunately, our understanding of Physics is not as complete as we would hope it was. The Bumblebee is an excellent example... but no one seems to have told the bumblebee that she shouldn't be able to fly.

Helicopters, AFAIK, should be able to fly.

As for boats being fast...there are several components to a boat being fast: 1) Skill and knowledge of crew, 2) Quality of sails, 3) Tuning of the rig, are some of the more common ones.

Did you get your Pineapple sails yet? They might help.

EVK4 said...

New sails are North.....not going to help much. I'm stuck being slow I fear.

Anonymous said...

This clown "C. Johnson" jerked me around a bit too with his daft miscalculations on the Equation of Time.
He even allegedly has a 12 place decimal accuracy figure that is so superior to the only solid public algorithm for it, the NREL's Solar Positioning Algorithm.
Based on traffic to it, his website is worth ~ $40,000 . . .

I'm of a mind to flush out this guy . . .

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