4 ms·

Awesome quote: "It was a shock to realize that my teacher and even the library books could be wrong. And it was a revelation that I could trust my own thinking

by shib71 15y ago

Awesome quote: "It was a shock to realize that my teacher and even the library books could be wrong. And it was a revelation that I could trust my own thinking in the face of such concerted opposition."

bulte-rs 15y ago
It's well known - and instructed - within the "pilot community" that the theory taught in most books is oversimplified to the point that it is almost wrong. I understand how it works from the practical and theoretical side; but can't think of a better (i.e. easier) way to explain it to others without this oversimplification.
- Swizec 15y ago
  How about just mentioning that it is in fact an oversimplification. Most people can deal with that, but if you don't tell them then how are they to know?
  - bulte-rs 15y ago
    Well, this is the way I explain it to other people; including the oversimplification part. The real problem - which is probably just my lack of educational experience - comes up when people are really interested and ask about the way it really-really-really works.
    - Retric 15y ago
      A stab at an in between explanation. Flat wings work with a positive angle of attack (EX: paper airplane). The problem with scaling this up is turbulence at the sharp edge. A gently curved surface reduces turbulence and drag. Remove enough turbulence and you get a laminar flow which hugs both sides of the wings. You can deflect a laminar flow down to increase lift. (See faucet experiment.) Control surfaces on the wing redirect the flow to push the aircraft in a new direction. Incresing the angle of attack increases lift until you reach the critical angle of attack ~15 degrees when you lose laminar flow and a sudden drop in lift occurs. Stall speed is the speed below which you can't maintain level flight by increasing angle of attack. High performance aircraft and trade efficiency for performance (EX: an F-15 landed after losing a wing http://www.uss-bennington.org/phz-nowing-f15.html http://www.uss-bennington.org/phz-nowing-f15.html) Super sonic flight behaves somewhat differently. (See faucet with increased pressure.)
Confusion 15y ago
However, also a dangerous one, used by many a crackpot to justify their theories. It only flies when you have sufficiently obvious experimental results at your disposal to cast doubt on a theory.
- run4yourlives 15y ago
  >It only flies when you have sufficiently obvious experimental results at your disposal to cast doubt on a theory. Nonsense. Everything is wrong until proven otherwise. The burden is on the presenter to justify the statement. The moment doubt is raised then the presenter must address it. Someone pointing out a logical error in the presenter's assertion is not required to come up with some other explanation in order to explain that error. Of course if they do they are held to the same standard.
  - Confusion 15y ago
    I think you misunderstand me: I mean that you can only use this argument against a well established, probably experimentally well supported theory, if you have at least some experimental results that are contradicted by the theory (and preferably explained by your alternative). There are many crackpots that 'have been shocked to realize that library books and teachers were wrong and that they should trust their own thinking in the face of concerted opposition'. Only slightly different from the original, but the italicized words make a world of difference. Einstein's (special) theory of relativity faces scores of opponents that 'trust their own thinking', despite not having a single fact that casts doubt on it.

by shib71 15y ago

bulte-rs 15y ago

It's well known - and instructed - within the "pilot community" that the theory taught in most books is oversimplified to the point that it is almost wrong. I understand how it works from the practical and theoretical side; but can't think of a better (i.e. easier) way to explain it to others without this oversimplification.

Swizec 15y ago
How about just mentioning that it is in fact an oversimplification. Most people can deal with that, but if you don't tell them then how are they to know?
- bulte-rs 15y ago
  Well, this is the way I explain it to other people; including the oversimplification part. The real problem - which is probably just my lack of educational experience - comes up when people are really interested and ask about the way it really-really-really works.
  - Retric 15y ago
    A stab at an in between explanation. Flat wings work with a positive angle of attack (EX: paper airplane). The problem with scaling this up is turbulence at the sharp edge. A gently curved surface reduces turbulence and drag. Remove enough turbulence and you get a laminar flow which hugs both sides of the wings. You can deflect a laminar flow down to increase lift. (See faucet experiment.) Control surfaces on the wing redirect the flow to push the aircraft in a new direction. Incresing the angle of attack increases lift until you reach the critical angle of attack ~15 degrees when you lose laminar flow and a sudden drop in lift occurs. Stall speed is the speed below which you can't maintain level flight by increasing angle of attack. High performance aircraft and trade efficiency for performance (EX: an F-15 landed after losing a wing http://www.uss-bennington.org/phz-nowing-f15.html http://www.uss-bennington.org/phz-nowing-f15.html) Super sonic flight behaves somewhat differently. (See faucet with increased pressure.)

Confusion 15y ago

However, also a dangerous one, used by many a crackpot to justify their theories. It only flies when you have sufficiently obvious experimental results at your disposal to cast doubt on a theory.

run4yourlives 15y ago
>It only flies when you have sufficiently obvious experimental results at your disposal to cast doubt on a theory. Nonsense. Everything is wrong until proven otherwise. The burden is on the presenter to justify the statement. The moment doubt is raised then the presenter must address it. Someone pointing out a logical error in the presenter's assertion is not required to come up with some other explanation in order to explain that error. Of course if they do they are held to the same standard.
- Confusion 15y ago
  I think you misunderstand me: I mean that you can only use this argument against a well established, probably experimentally well supported theory, if you have at least some experimental results that are contradicted by the theory (and preferably explained by your alternative). There are many crackpots that 'have been shocked to realize that library books and teachers were wrong and that they should trust their own thinking in the face of concerted opposition'. Only slightly different from the original, but the italicized words make a world of difference. Einstein's (special) theory of relativity faces scores of opponents that 'trust their own thinking', despite not having a single fact that casts doubt on it.