Debunking lift theories
Thread Starter
Join Date: Jan 2006
Location: An island somewhere
Posts: 423
Likes: 0
Received 0 Likes
on
0 Posts
Debunking lift theories
I don't often read Today's Pilot, but for those that have been thoroughly confused by the arguments aired on this and other forums, I would commend you to seek out a copy of the November 07 issue and study John Gibson's letter entitled "Newton, Bernoulli and Lift Theory".
Physically correct and historically accurate, it does the most succinct job I've seen of debunking the amateur attempts over the past ten years or so to re-write aeronautical science around Newton's laws of motion.
It's clearly one of a series of correspondence on the subject but, although I've not seen the other letters, I don't believe that matters ... it stands very adequately on its own. John Gibson has spent a lifetime in aerodynamics at Warton, and in my book that makes him rather better qualified than those guys at Fermi and the University of Washington that have done so much to promote this nonsense amongst the less technically literate.
Physically correct and historically accurate, it does the most succinct job I've seen of debunking the amateur attempts over the past ten years or so to re-write aeronautical science around Newton's laws of motion.
It's clearly one of a series of correspondence on the subject but, although I've not seen the other letters, I don't believe that matters ... it stands very adequately on its own. John Gibson has spent a lifetime in aerodynamics at Warton, and in my book that makes him rather better qualified than those guys at Fermi and the University of Washington that have done so much to promote this nonsense amongst the less technically literate.
Thread Starter
Join Date: Jan 2006
Location: An island somewhere
Posts: 423
Likes: 0
Received 0 Likes
on
0 Posts
SSD,
Sorry, I feel it would be improper to reproduce the lengthy letter verbatim, and to paraphrase could distort its content and accuracy.
It's on the magazine sellers' shelves now, if you're interested you can always go for a browse!
Sorry, I feel it would be improper to reproduce the lengthy letter verbatim, and to paraphrase could distort its content and accuracy.
It's on the magazine sellers' shelves now, if you're interested you can always go for a browse!
Sorry, I feel it would be improper to reproduce the lengthy letter verbatim
Unless of course you work on the circulation promotion side for T's P, in which case it is just pathetic.
FBW
Join Date: Sep 2006
Location: Pittsburgh, PA
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
Fly-by-Wife said:
Why?
Why do you expect Islander2 to reproduce that letter here? Because you're too lazy arsed to go read it yourself? Islander2 says quite rightly it would be improper to reproduce it here - after all, John Gibson did write it to Todays Pilot and not to PPRuNe.
If you feel that strongly that it should appear here then you should contact John Gibson yourself and ask for his permission to reproduce it here. Otherwise just go to the newsagents and read it there.
bollocks
Why do you expect Islander2 to reproduce that letter here? Because you're too lazy arsed to go read it yourself? Islander2 says quite rightly it would be improper to reproduce it here - after all, John Gibson did write it to Todays Pilot and not to PPRuNe.
If you feel that strongly that it should appear here then you should contact John Gibson yourself and ask for his permission to reproduce it here. Otherwise just go to the newsagents and read it there.
Join Date: Oct 1999
Location: UK
Posts: 3,325
Likes: 0
Received 0 Likes
on
0 Posts
I think Islander2's response is quite a correct one. If he doesn't think it can be simply paraphrased, it would be improper to reproduce the letter verbatim on here. I'll go and have a sneak read in WH Smiths!
SSD
SSD
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
Nobody is going to, nor should they, take the time to go to a shop and spend £3.50 or whatever on a magazine, so they can reply to a posting on pprune.
As regards gas flow theories, Newton is right, but that approach is not exactly useful because nobody is going to run a simulation of every molecule moving around the wing or whatever. Approximations have to be made. That is where Bernoulli etc came in, with far simpler and much more usable theories, many years ago.
AIUI, one could derive Bernoulli from Newton. Not very useful but possible.
As regards gas flow theories, Newton is right, but that approach is not exactly useful because nobody is going to run a simulation of every molecule moving around the wing or whatever. Approximations have to be made. That is where Bernoulli etc came in, with far simpler and much more usable theories, many years ago.
AIUI, one could derive Bernoulli from Newton. Not very useful but possible.
Join Date: May 2005
Location: Abroad
Posts: 1,172
Likes: 0
Received 0 Likes
on
0 Posts
FLy by wife
What a stupid and intemperate posting.
What a stupid and intemperate posting.
As for the bit about not having a scanner, that was a brilliant insult. Should see them more often
Anyway, Newton didn't explain how aerofoils work, whereas Bernoulli (and Prandtl et al) did, however Bernoulli and Prandtl were building on Newton's theorys, not tearing them up and starting again.
A
I've no doubt that Danny is concerned about the laws of copyright, even if others here would be happy to disregard them.
British copyright law has a set of exceptions to copyright known as fair dealing. Fair dealing is much more restricted than the American concept of fair use and only applies in tightly defined situations -
s29.—(1) Fair dealing with a literary, dramatic, musical work … for the purposes of research for a non-commercial purpose does not infringe any copyright in the work provided it is accompanied by a sufficient acknowledgement …
s30.—(1) Fair dealing with a work for the purpose of criticism or review, of that or another work or of a performance of a work does not infringe any copyright in the work provided that it is accompanied by a sufficient acknowledgement and provided that the work has been made available to the public.
Discussion on PPRuNe is non-commercial use, and can certainly be considered criticism or review (although perhaps not research, but I have left s29 in, as others might consider it applicable). Since the letter was published in a magazine, then it has been made available to the public. Simply acknowledging the author and the magazine is all that needs to be done.
When (if) I have the time and am near a newsagent that stocks Today's Pilot, I will buy the issue and scan the article for your benefit. Then perhaps we can have a discussion about lift theories (interesting) and not copyright (PITA).
FBW
Join Date: May 2005
Location: Suffolk
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
I almost didn't post, but then thought that PPRuNE might be pleased if posters avoided infringing copyright.
FBW has fallen into the trap of reading a statute as if it existed in a vacuum - s. 30 is more complex than that, as its meaning has been elaborated over the years by court decisions. In simple terms:
1. S.30 only applies for the purposes of criticism or review by the person copying. If FBW copies the letter to allow others to criticise or review it, s. 30 will provide no protection.
2. S.30 also requires fair dealing in the copying. Posting a long letter with the comment: "Good/Rubbish innit" would not be fair dealing. You only get the right to copy the parts you need to undertake your criticism or review.
If posters start copying large chunks of copyright works to the site, PPRuNE will begin to receive formal notices requiring these posts to be deleted, and will have to do so to avoid liability. In some countries (and these fora are available pretty much everywhere except Burma at the moment) PPRuNE might be liable even without receiving such a notice.
Better to seek permission, or to write your own post.
FBW has fallen into the trap of reading a statute as if it existed in a vacuum - s. 30 is more complex than that, as its meaning has been elaborated over the years by court decisions. In simple terms:
1. S.30 only applies for the purposes of criticism or review by the person copying. If FBW copies the letter to allow others to criticise or review it, s. 30 will provide no protection.
2. S.30 also requires fair dealing in the copying. Posting a long letter with the comment: "Good/Rubbish innit" would not be fair dealing. You only get the right to copy the parts you need to undertake your criticism or review.
If posters start copying large chunks of copyright works to the site, PPRuNE will begin to receive formal notices requiring these posts to be deleted, and will have to do so to avoid liability. In some countries (and these fora are available pretty much everywhere except Burma at the moment) PPRuNE might be liable even without receiving such a notice.
Better to seek permission, or to write your own post.
ProfChrisReed,
Thanks for clarifying those aspects of s30.
Perhaps you can answer a further question or two:
When a person writes a letter (as opposed to an article) to a periodical or newspaper for publication, who owns the copyright, the author or the publisher - or both?
If not the author, then would not (even) the entirety of the letter be considered to be only that part of the entire publication (the magazine) necessary to carry out the review?
And if it had been a very short letter, would we even be having this discussion?
FBW
Thanks for clarifying those aspects of s30.
Perhaps you can answer a further question or two:
When a person writes a letter (as opposed to an article) to a periodical or newspaper for publication, who owns the copyright, the author or the publisher - or both?
If not the author, then would not (even) the entirety of the letter be considered to be only that part of the entire publication (the magazine) necessary to carry out the review?
And if it had been a very short letter, would we even be having this discussion?
FBW
Join Date: Jan 2006
Location: Cambridge, UK
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
"If you start from first principles, Newton, Bernoulli and circulation theory are all one and the same, excluding the effects of viscosity."
True, but without viscosity, you can't have any circulation and therefore lift is zero.
True, but without viscosity, you can't have any circulation and therefore lift is zero.