Author Topic: History Channel: Stealth techology  (Read 1019 times)

Offline indy007

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History Channel: Stealth techology
« Reply #15 on: January 11, 2005, 11:18:06 AM »
The original math theory was done by a Russian. However they discarded it, and it was stumbled on by the Skunkworks. Then along came Have Blue (F-117 prototype), and later the B-2 competition.

There's alot of little things y'all people debating it didn't include though. The supercooled exhaust ducting, the radar absorbing paint, the canopy's layer that keeps the pilots head from showing up on radar, etc, etc. A Russian came up with the theory for the shape, but Americans were the first to make it work like the popular conception of it tells us it works.

Offline straffo

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Re: Re: Re: Re: Re: Re: History Channel: Stealth techology
« Reply #16 on: January 11, 2005, 12:00:00 PM »
Quote
Originally posted by Spooky
Not to mention  that on october 9, 1890 Clément Adair was the first man to fly (a tiny hop but still the thing flew!) a steam powered , bat-looking machine called "Eole".

the wright bros in 1903 achieved the first SUSTAINED flight .

nitpicking I know, this will turn in a dickie waving contest anyhow...


mouips ....

et Clément Adair avec son pote Can à fondé la société CanAdair ?

C'est Ader rondidju ! pas Adair ! kelle Fôte !

Offline Angus

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History Channel: Stealth techology
« Reply #17 on: January 11, 2005, 12:11:05 PM »
Wasn't the German Gotha designed as a stealth machine?

And anyway, the Mossie was known to make a weak radar signal.

But that was back then, with the radar back then if you see what I mean.
It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline Sabre

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History Channel: Stealth techology
« Reply #18 on: January 11, 2005, 12:55:18 PM »
Okay, here's the low-down on modern stealth aircraft development (I've got a Masters in it).  The Russian you refer to, Ufemstef (forgive the spelling...not near my reference material), didn't invent stealth, or even the "math" of stealth, not directly.  What he came up with is a simple mathematical forumula for predicting the electromagnetic scattering signature of a triangular plate.  Up to that time, the only shapes we could accurately and efficiently predict the radar signatures of were a sphere, a square plate (though with some limitations), and a cylinder of infinite length.  It's very difficult to produce an aircraft that will fly using only these few, simple primatives.  So, while we understood the principles of radar scattering, the computers of the day were not up to doing iterative predictive necessary to design a flying combat aircraft.  This is all a gross simplification of the extremely complex issues surrounding the problems.  So, even though some aircraft had somewhat stealthy features, this was more often a case of getting lucky.  The SR-71 Blackbird is one example where the unique aerodynamics required actually helped, rather than hurt, its stealthiness...in most cases, it does just the opposite.

Now, along comes a young engineer at Lockheed's famed Skunkworks.  He is purusing foreign recently translated scientific journals when he comes across a fairly inoccuous artical by an equally inoccuous Russian mathematician in an unclassified Soviet journal.  In an epiphany that must have sent Stalin rolling over in his grave, he realizes he has the answer to a question that has been plaguing aerospace engineers since radar was discovered.  You see, you can build a plane out of triangular facets, and still make it fly.  Because of the simple genious of Ufemstef's equations, it is now possible for the computers of the day to design an incredibly stealthy airframe in a virtual environment.  Now, instead of taking months for a supercomputer to arrive at a dubious signature prediction -- for every design concept -- it is possible to test hundreds of different plan-forms in the course of weeks, and at multiple radar frequency bands.

Combining the new radar cross-section (RCS) prediction algorithms with American know-how and ingenuity, they quickly develop the Pave Blue prototype.  This forms the basic blueprint of the F-117 Nighthawk.

The B-2 is also owes its design to Ufemstef's equation.  Both the 117 and the B-2 were predicted using mathematical models made up of triangular facets.  The difference is, when the F-117 was designed, computers limited the number of facets that could be reasonabley used in a radar cross-section prediction to around 200.  That's why the F-117 is so blocky looking.  However, by the time the B-2 was under full-scale develpment, computers and computer programing had pushed the number of triangles/model up into the millions.  Makes the triangles small enough, and it begins to approximate a smooth surface.  So, the B-2 was made with smooth curves because it could be "predicted" with enough tiny triangles to adequately approximate that smooth surface.

In an asside, I actually met Dr. Ufemstef.  He was brough in by the university to lecture us.  He was a charming and humble man, with a great sense of humor.
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Offline Furball

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Re: Re: Re: Re: Re: History Channel: Stealth techology
« Reply #19 on: January 11, 2005, 01:15:41 PM »
Quote
Originally posted by Holden McGroin

Therefore the Wright brothers cannot be said to be the inventors of the airplane as they used Bernolli's theories.


actually....  Sir George Cayley could be credited with that.  Remember, the Wright brothers were not the first to fly, but first powered flight.

http://www.wam.umd.edu/~stwright/WrBr/inventors/Cayley.html




Quote
Sir George Cayley was a genius of science whose works in aeronautics pioneered the conquest of flight. From youth, when he devised a three-bladed propeller and placed it on a toy top causing it to fly until his death he devoted himself tothe development of craft to carry man aloft.

A true scientist, he maintained meticulous records of his observations and findings, documentation which was to show the way to later pioneers. Observing that birds soared long distances by simply twisting their arched wing surfaces, he deduced that fixed wing machines would fly if the wings were cambered. in 1804 he flew a model of such a glider, and in 1808 a successful full scale version was flown as a kite. A small boy whose name is not recorded, became the first person in history to fly when in 1849 he made a short flight in a Cayley glider. In 1853 the first man-carrying Cayley glider rose from Brompton Dale with his coachman as its passenger.

Cayley recognized and began the search for solutions to the basic problems of flight: the ratio of lift to wing area; determination of the center of wing pressure; the importance of streamlined shapes; the recognition that a tail assembly was essential to stability and control; the concept of a braced biplane structure for strength; the concept of a wheeled undercarriage; and most importantly the need for a lightweight source of power to broaden the utility of the simple glider. In his half century of aeronautical investigation and experimentation, he gave the world the basic elements of a practical aircraft.

Cayley's genius embraced many disciplines and pioneered the way for later advances such as combustion engines, spoked wheels, the caterpillar tractor, finned missiles, railway safety devices, and medical equipment.
 
« Last Edit: January 11, 2005, 01:18:07 PM by Furball »
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Offline genozaur

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History Channel: Stealth techology
« Reply #20 on: January 16, 2005, 12:27:39 AM »
Quote
Originally posted by G0ALY
What about the first stealth aircraft, a clever Russian design that although it was foreign to the environment, operated in Germany without arousing suspicion, even appearing as though it belonged there.

Below is a top-secret picture of this aircraft codenamed…

The OPTICAL ILYUSHIN!



Was this OPTICAL ILYUSHIN the same one which was downed by the american laser gun NAYEBALL
from the killer satellite RONALDO THE GREAT?:lol

Offline genozaur

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« Reply #21 on: January 16, 2005, 12:50:45 AM »
Quote
Originally posted by Sabre
Okay, here's the low-down on modern stealth aircraft development (I've got a Masters in it).  The Russian you refer to, Ufemstef (forgive the spelling...not near my reference material), didn't invent stealth, or even the "math" of stealth, not directly.  What he came up with is a simple mathematical forumula for predicting the electromagnetic scattering signature of a triangular plate.  Up to that time, the only shapes we could accurately and efficiently predict the radar signatures of were a sphere, a square plate (though with some limitations), and a cylinder of infinite length.  It's very difficult to produce an aircraft that will fly using only these few, simple primatives.  So, while we understood the principles of radar scattering, the computers of the day were not up to doing iterative predictive necessary to design a flying combat aircraft.  This is all a gross simplification of the extremely complex issues surrounding the problems.  So, even though some aircraft had somewhat stealthy features, this was more often a case of getting lucky.  ....

Now, along comes a young engineer at Lockheed's famed Skunkworks.  He is purusing foreign recently translated scientific journals when he comes across a fairly inoccuous artical by an equally inoccuous Russian mathematician in an unclassified Soviet journal.  In an epiphany that must have sent Stalin rolling over in his grave, he realizes he has the answer to a question that has been plaguing aerospace engineers since radar was discovered.  You see, you can build a plane out of triangular facets, and still make it fly.  Because of the simple genious of Ufemstef's equations, it is now possible for the computers of the day to design an incredibly stealthy airframe in a virtual environment.  ....

Combining the new radar cross-section (RCS) prediction algorithms with American know-how and ingenuity, they quickly develop the Pave Blue prototype.  This forms the basic blueprint of the F-117 Nighthawk.

The B-2 is also owes its design to Ufemstef's equation.  Both the 117 and the B-2 were predicted using mathematical models made up of triangular facets.  ....

In an asside, I actually met Dr. Ufemstef.  He was brough in by the university to lecture us.  He was a charming and humble man, with a great sense of humor.


TY Sabre.
 The name have to be spelt as Dr. Pyotr Ufimtsev. He is credited to be founder of the Physical Theory of Diffraction. :aok

Offline Raider179

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History Channel: Stealth techology
« Reply #22 on: January 16, 2005, 01:17:57 AM »
anybody remember anything on stealth technology being compromised by cell phones. Something like cell signals are everywhere now and if they are not then there must be an aircraft in that spot....

Offline bunch

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Re: Re: Re: Re: Re: History Channel: Stealth techology
« Reply #23 on: January 16, 2005, 05:56:27 AM »
Quote
Originally posted by Holden McGroin
Bernolli's fluid theories are the basis for wing lift.

Therefore the Wright brothers cannot be said to be the inventors of the airplane as they used Bernolli's theories.


I'm not sure Bernoulli can be applied to the thin wing case.   Bernoulli requires a velocity difference for the preasure inequality to be created...works great for the Wright Bros. props, though.

Offline Holden McGroin

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« Reply #24 on: January 16, 2005, 09:29:33 AM »
Bernoulli and aerodynamic lift

My intent on posting the parallel of aerodynamic theory to the invention of the device that uses it was to show that while a Russian mathematician developed the theory, Lockheed made it happen.
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Offline bunch

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« Reply #25 on: January 16, 2005, 06:17:03 PM »
My intenet was to goad someone brainy into explaing to me how Bernoulli explains thin wing planes flying

Offline Holden McGroin

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« Reply #26 on: January 16, 2005, 07:43:10 PM »
Read the link I posted and perhaps someday in the far off future if you study hard enough, you may develop a glimmer of understanding.
Holden McGroin LLC makes every effort to provide accurate and complete information. Since humor, irony, and keen insight may be foreign to some readers, no warranty, expressed or implied is offered. Re-writing this disclaimer cost me big bucks at the lawyer’s office!

Offline lasersailor184

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« Reply #27 on: January 16, 2005, 07:45:41 PM »
When I win the lottery, one of the first things I wanted to do was paint my car in the paint that is on the stealth planes.  It actually absorbs radar a little bit.
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Offline spitfiremkv

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« Reply #28 on: January 16, 2005, 09:52:22 PM »
you're all wrong.
Greece invented stealth technology. Icarus' wings could absorb all radiation.



which didn't do him any good....

Offline Sabre

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« Reply #29 on: January 18, 2005, 01:36:53 PM »
Quote
Originally posted by lasersailor184
When I win the lottery, one of the first things I wanted to do was paint my car in the paint that is on the stealth planes.  It actually absorbs radar a little bit.


Nice thought. However, it doesn't work that way, at least not in the way you think.   The paint absorbs what they call travelling waves, EM waves that strike at a near-grazing angles which then couple to the metal surface and travel as a standing wave along it.  You see, the amount of absorbtion of RAM (radar absorbing material) is proportional to the wavelength of the radar wave.  Even at fairly high frequencies (frequency being inversely proportional to wavelength), the paint has to be many wavelengths thick to absorb a majority of the EM radiation's power.  So for X-band radar, your car's paint job would have to be several inches thick to make an appreciable difference in the detection range:).

80-90 percent of stealth is achieved through shaping (and hiding of cavities like the engine inlets and exhaust, radomes and antennas, cockpit).  The last 10-20 percent of RCS reduction comes by treating details like cracks/gaps, edges, curvature of interfaces).
Sabre
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