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Theory on lift

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Theory on lift

Old 24th Aug 2012, 03:43
  #101 (permalink)  
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But I'm only an average jock with low level test work under my belt. Not up the the standard of a real TP.

I have no problem with the pencil trick .. it's just that I get confused when upside down during an I/F loop and it's still telling me I'm straight and level ... just one of my many shortcomings, I guess .. all happily married men are well aware of their many shortcomings ..

that was his back up on a round the world venture.

OK if it's a TSO'd pencil on a string ..


We still have to catch up for that beer at Jack's ...
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Old 24th Aug 2012, 04:04
  #102 (permalink)  
 
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I had no ground school, just bought books until my instrument rating. Worked great for me. I even got my instructors rating reading a book. I went to take the test because I wasn't sure how to study for the test because of all the philosophy of teaching BS. Well, I passed so never learned it. Taught my self aerobatics out of a book, then taught it for Art Scholl, one of the best, with his school. Books are great if you can do it without someone to help you.

My first job when I got my commercial license was crop dusting with zero training. Loved it. After soloing with 5 hrs total I was doing solo spins and finally a loop solo before 10 hrs. It was fun learning that way. With 5 hrs back then you could fly cross country anywhere you wanted to go so would go out and land in the desert on the sand just for fun. I had a AAA map for nav, no aviation charts and did just fine. That 15 degrees variation didn't bother me a bit because at that time I didn't know what it was. Well guess it was in one of the books.

Ended up flying with the largest airline in the world at the time flying a B727. Ended up in the B757 and B767. Funny how things can end up mainly reading books, isn't it.
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Old 24th Aug 2012, 04:19
  #103 (permalink)  
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Naught wrong with reading good books, my friend.

I am in two minds about the internet, though. On the one hand, it opens up a mass of links to all sorts of good stuff .. but, at the same time, it isn't a patch on lounging back in the rocker and flicking through a good book.
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Old 24th Aug 2012, 04:19
  #104 (permalink)  
 
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I guess what I am saying is don't blame who trained you if you don't train yourself and use your own initiative. We should all take it upon ourselves to be as competent as possible and not throw that responsibility on your company. Take charge yourself.
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Old 24th Aug 2012, 04:36
  #105 (permalink)  
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We are in heated agreement.
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Old 24th Aug 2012, 04:43
  #106 (permalink)  
 
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JT, my first instrument class was at a junior college and was a total waste of time, had to go back to the books. I know things are different now but this was in the 60's. Usually the ground school teacher reads the book and repeats it soon after the best he can.

My roomate when I was flying a Jetstar was teaching ground school in a high school and I told him he was teaching it wrong. He passed the private pilot written exam but didn't understand what he was teaching. His students would have been much better off reading the manual than listening to him.

I went to Flight Safety in Teterbero in the 70's and he was explaining how to use reversers on a Falcon 20. He said pull the TR levers back then advance the throttles. My Mexican students were going into the sim that night and I said just pull the thrust levers back, don't advance the throttles. They both said no, he said push the thrust levers forward. I just said see you in the morning. Of course the next morning I asked did you push the thrust lever up and they sheepishly said no.

Sometimes reading the manual is the best thing if your instructor is weak.
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Old 24th Aug 2012, 04:56
  #107 (permalink)  
 
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JT, I agree. Us old timers grew up in a different time and it doesn't work this way now. Now we have a lot of rules that I am happy 9 yrs ago I could leave at 60. I loved the profession but it wouldn't be as much fun now with all the new stuff. I spent my last years flying into Tegucigalpa, Honduras just because the only way we could land was to break all the present rules like 1200 fpm to flair or you couldn't land. We had to fly beside a hill and were not wings level in a B757 until 100 ft, loved it plus the 70 ft cliff at the end of the 5400 ft usable runway made you do it right every time. That is the only part I miss.
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Old 24th Aug 2012, 05:06
  #108 (permalink)  
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Then, at some stage, we should have a convivial ale and reminisce on such things.

Certainly, having done a lot of class room teaching over the years ranging from tertiary aviation/engineering through secondary math/science and on to pilot training, unless the instructor is many levels above the student in technical competence, it is a waste of time. No point in the blind leading the blind.
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Old 24th Aug 2012, 07:23
  #109 (permalink)  
 
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Mr. Abraham it was a semi rhetorical question re: AoA...

I taught myself how to fly...of course legally you need an instructor but for the most part it was a game of Simon says...i.e
CFI says do this...ok
CFI says, do this...ok
do this....no, no,no, need to use the checklist first

Mostly me and my instructors talked about girls, life, plane crashes, etc... never the task at hand...I almost miss those days...
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Old 27th Aug 2012, 16:55
  #110 (permalink)  
 
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Snoop

Originally Posted by Lyman
Math hates RATE...... It's why pilots use their hands to explain things, and mathematicians use a pencil
Originally Posted by md80fanatic
Originally Posted by roulishollandais thread Report out - Rumour and News
All the flying birds fly without rudder nor fin.
Fortunately, birds do not have rigid tails. Being supremely skilled at "hand flying" they do not appear to be in need of many protections.


Thank you md80fanatic for these two beautiful examples of no rudder nor fin


@ Lyman
Just look the shape of the wings in math language.
They have fractal flight law and not continuous function like NS
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Old 28th Aug 2012, 10:51
  #111 (permalink)  
 
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Lot's of credit to man. No mention to the one who understands lift better then all of them put together.Two of his designs pictured above.



Credit where credit due...
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Old 29th Aug 2012, 03:13
  #112 (permalink)  
 
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Ah yes, indeed, flight of animals-immensely complex--it's quite a shame we can't go to the birds to obtain the answers really...

Not sure about fractals and such; they use Newton too...they just know what the hell they're doing unlike us...

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Old 29th Aug 2012, 19:30
  #113 (permalink)  
 
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Less complex that Navier Stokes equations!
We would like to ask the drop of water in the river flowing toward the bridge how they recon their acceleration, speed, position, spin, deformation, ASO!

Newton? Of course! Like for galaxies from HENON and Laurent NOTTALE. The latter uses fractals to join Relativity theory and Theorie quantique (Paris -Meudon Observatory CNR'S Dr of Research) .
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Old 29th Aug 2012, 22:31
  #114 (permalink)  
 
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roulishollandais
I didn't say you were wrong or anything just that I am unfamiliar with fractals as a part of conventional aerodynamics, as I've never seen such a treatment before within the subject...I have some idea about fractal geometry but I admit I'm having some trouble with your line of reasoning...but I guess there's always more than one way to peel a potato...

Bon soir

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Old 30th Aug 2012, 17:32
  #115 (permalink)  
 
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Hi Pugillistic Animus,

I am glad to tell about fractals also known as Theory of chaos.

This excellent and cheap book (1987) tells many things about fractals and mekanik of fluids.

Chaos: Making a new science by James Gleick (1987)
The first popular science book to tackle the emerging field of chaos theory, journalist James Gleick’s Chaos earned the author a Pulitzer prize. Not only did the book bring this complex physics to the public, says our features editor Ben Crystall, “It helped kick-start the subject into a host of other fields”.

This book exists also in French pocket version and new edition is from 2008. (editions Flammarion, 10€ !)

Originally Posted by Pugillistic Animmus
I didn't say you were wrong or anything just that I am unfamiliar with fractals as a part of conventional aerodynamics, as I've never seen such a treatment before within the subject...
Why is the conventional aerodynamics still ignorant of fractals ? You know, for a long time a divorce existed between mathematicians and physicians. Physicians wrote some equations, writing integrations of not continuous functions for example, doing mathematicians angry. But math had other goals, like topology, math for computers, and was late to help physicians. Something changed really in the middle of the 20.century with "fractals".

With fractal geometry and theory, sundely physicians were behind, they were struggling with automation and theory of systems, and mathematicians had advantage. In reality we need to work together... but it is not enough to say that !

Things changed when fractals brought new solutions for non-linear dynamic system, new thinking.

As always in science it needs still 15 years or more to update technology.

Discussing C* about AF447, I discovered that derivating don't go higher than 2. (position, speed, acceleration). Why not tendance of acceleration, for instance ? Every thing needs TIME !


I have seen you are very active in the climate change debate. The meteorologist Edward Lorentz has been a great pionnier of climate prevision and discovering the meteorologic part of fractals...

Read Gleick ! You will get good surprises !
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Old 30th Aug 2012, 17:38
  #116 (permalink)  
 
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I certainly will check it out mon ami---I just hope it's written so that my little brain can understand...engineering and science math is very easy--- just tedious that 'math-people's math is almost incomprehensible to me...i'm no mathematician that's for sure
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Old 30th Aug 2012, 19:50
  #117 (permalink)  
 
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Hi Pugillistic Animus,
You will see birds, rivers, hurricanes, FCS, etc. otherwise after reading James Gleick about fractals ... A good index will help you to sort different matters after a first cross-reading (just a suggestion). Math is often showed as interesting at abstract objects, Nobody knows what an abstract object is ! We have only senses to discover new objects. In our brain we can only play with them !

Some teacher will tell about "linear combination" another about "linear shape" for the same thing : you see, smell, taste, listen, and touch the latter, the first stays a mystery... Go with the good teacher !

Faites de beaux rêves !
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Old 30th Aug 2012, 20:45
  #118 (permalink)  
 
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Je vous voudraise la meme chose

merci beaucoup...
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Old 30th Aug 2012, 21:28
  #119 (permalink)  
 
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Angel Airflow around a rotating cylinder

The picture shown in the FAA explanation makes no sense to me.

To look at the rotational direction, it shows pressure increasing at the bottom and decreasing at the top, hence a resulting up force.

Should this not be the other way around because, the way I understand it,
the cylinder part rotating into the wind creates an increase of the relative airflow speed (pressure drop) over the surface (in the illustration; at the bottom) and the top shows relative airflow slowed down (pressure increase) accross the surface.

Are there effects causing my understanding not to be true ?

Just curious, because aerodynamics have served me well in my 60 years of flying.
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Old 30th Aug 2012, 21:56
  #120 (permalink)  
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121 Sir

Flying is a matter of surfing on a mixture of gases, most of the rest is simply managing the drag using tedious mathematics.

If you rotate a rigid cylinder as suggested there will be more collisions with the gas phase per unit time with that structure than if it were static.

Hence more lift.

Last edited by chris weston; 30th Aug 2012 at 21:57.
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