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#91
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The Swedish Model: How to build a jet fighter.
On May 9, 3:28*pm, Mike wrote:
The Weekly Standard The Swedish Model How to build a jet fighter. by Reuben F. Johnson 04/30/2008 11:45:00 PM Linköping, Sweden ON WEDNESDAY APRIL 23, Sweden's Saab Aerospace rolled out what may become the fighter aircraft that sets the standard for the future of the military aerospace business. What Saab is calling the "Next- Generation Gripen" (Gripen N/G for short), is a substantially modernized version of its JAS-39C/D model, the fighter currently in service or in the process of being delivered to the air forces of Sweden, Hungary, the Czech Republic, South Africa, and Thailand. As fighter aircraft go, the Gripen does not have the look of a super- stealthy, new-age marvel like the two most recent Lockheed Martin (LM) platforms--the F-22A Raptor or the F-35 Lightning II Joint Strike Fighter (JSF). The new Gripen N/G will also not feature an entire bevy of brand-new, designed-from scratch on-board systems, although there are some 3,500 new components that are part of the aircraft's configuration. The notable changes to the JAS-39 in its new incarnation are the replacement of its single Volvo RM-12 engine with one General Electric F414G, a variant of the same engine used as a two-power plant propulsion system on the Boeing F/A-18E/F Super Hornet--a 25 per cent increase in thrust. The airplane also will have a new active electronically scanning array (AESA) radar set, a technology that has now become a more or less standard requirement for any new fighter aircraft. (This new radar will feature a Saab Microwave Systems PS-05 design on the back end of the radar set, with a Thales active array similar to that used on the Dassault Rafale fighter's RBE2 radar on the front end.) But the change that has perhaps the biggest impact on the Gripen's performance has nothing to do with high-technology weaponry or sensors. The landing gear have been displaced from the undercarriage to the main wing pylons. This frees up a large space in the center fuselage section of the aircraft and provides room for additional fuel tanks. This gives the new Gripen and unrefueled range of 2,200 nautical miles, 500 more than the unrefueled range of the F-16. What is remarkable about this Swedish product is that despite being produced in rather modest numbers--and then add in the high rates of taxation and super-expensive Scandinavian welfare state in which the plane will be produced--this jet will still end up costing less than half of the price of a Joint Strike Fighter, perhaps as little as one- third. Moreover, customers of the Gripen are going to have full access to the aircraft's software source code and will be able to make their own modifications and integration of weapon systems. But, the most interesting fact about the Gripen is what it says about the fallacy upon which most modern-day military aircraft programs are based. There are about six fighter jets in the world that could be classified as "new-generation designs." The Gripen, France's Dassault Rafale, the F-22A and F-35, Russia's Sukhoi Su-35 Super Flanker, and the four- nation consortium (UK, Germany, Italy, and Spain) Eurofighter Typhoon. (A sixth player that can in some respects be considered a new model is Russia's modernised version of the Mikoyan MiG-29, which is designate the "MiG-35," although it retains almost the same basic platform as the MiG-29 it does contain an AESA and a host of other new systems in it its configuration.) Of these six aircraft, three of them are designed and built by several companies or several nations cooperating together. The F-22A is a joint program between LM and Boeing, with several subsystem contractors also on board as major partners. The Eurofighter is largely a product of the aerospace industries of the four original partner nations. The F-35 is the biggest cooperative program of them all, pulling in the aerospace firms of the United States and the United Kingdom, plus industrial partners from many of the other nations that are also part of the program. Military airplane programs that are produced by these "teams" of companies are structured this way because--as the rationale goes--it is "too expensive for one company or one country to go it alone." Sharing the costs of designing, testing, building, and validating new technologies--and giving each country or company that part of the program where they have a competitive advantage--is supposed to make these airplanes cheaper to procure for all of the participants. Except that just the opposite has occurred. The F-35, a single-engine stealthy aircraft, is projected by a recent report from the U.S. Government Accounting Office to cost in the neighbourhood of $130 million per copy. This is a program that, when it was developed, was specifically designed to be "cheap," as in around $35-40 million per copy, and that the designers were to make maximum use of commercial-off-the-shelf (COTS) components in order to achieve that efficiency. So, why does it end up costing more than three times one of the aircraft it is supposed to replace-- the F-16--and almost three times the price of the Gripen? (Not surprisingly, some of the JSF partner nations--namely Norway--are now talking about bolting from the program in favor of a Gripen purchase instead.) The Eurofighter, partially thanks the catastrophic drop in value of the U.S. dollar against the Euro (and if you live in Europe as I do and try to buy groceries and gas with dollars, "catastrophic" might not even be a strong enough description for the situation), is now well over US $100 million. It suffers from the fact that it was organised and planned primarily as "welfare for European aerospace and high-tech industries," as one UK-based analyst described it, "and as a program to produce a fighter as a secondary consideration." The economies of scale that the Eurofighter was supposed to benefit from as a result of being built by a "team" of companies never materialised. Instead multiple redundancies were created that only added to the bottom line and caused the progress of the program to move forward at what seemed like a snail's pace at times. "Don't tell anyone I ever told you this," said a frustrated Eurofighter test pilot to me during a private chat at the Le Bourget air show almost a decade ago, "but there are no efficiencies achieved in this program by having four separate flight test centres--one in each of the partner nations." The Eurofigther also has production lines in each of the four nations, plus ground test facilities, etc. (Having had the experience of the Eurofighter has not caused European industry to rethink the viability of this model very much. The new-age European military transport, the Airbus A400M, will be built in only one factory instead of four, the CASA/EADS factory in Sevilla, Spain, but the costs of the program are still expected to make it the most expensive aircraft of its kind ever built.) F-22A tops them all, however. The program's development has been long and expensive. Admittedly, several technologies were pioneered and matured by the process of designing and testing the F-22A. Many of these technologies--now that F-22A has "paid the freight"--can be dialled into numerous other future programs. But, when these development costs are amortised over the production run of the Raptor, the aircraft comes in at a whopping US $390 million per unit. Surprisingly, the three aircraft that are built by one company in one country--a feat that we have been told for more than 20 years is "no longer affordable"--all cost well under $100 million. These are the Gripen, the Rafale, and the Su-35. All of them contain the latest in on-board systems technology, but they have been designed with stealthy airframe shaping being far less important and with more reliance on electronic warfare as a means of keeping them survivable in the air combat or air defence environment. There is something to be said for the fact that the emphasis on a stealthy, low radar cross section (RCS) aircraft shape does a lot to increase the costs of the F-22A and F-35, and that this is a technology that is the competitive advantage that the United States has over its adversaries. What is sobering to realize, however, is that the one U.S. aircraft that was built with RCS being its primary-- in fact, perhaps its only--consideration was just retired this week after one of the shortest service lifespans in the modern jet age: the Lockheed Skunk Works F-117A Stealth Fighter. The F-117A is now regarded as "old" technology where its RCS reduction methods are concerned and no longer as effective ("its survivability has been eroded" is the operative term) as it once was. Its missions will be taken over by other more modern stealthy aircraft, such as the F-35. One has to ask the question, though, given the significant advances by Russia, China, and other nations in counter-stealth methods and air defence, will the ultra-expensive F-22 and F-35 face similarly truncated service lives? (The fact that the F-117A design is said to be outmoded and made obsolete by these newer model fighters did not keep the US Air Force from continuing to engage in needlessly silly security arrangements. The world's most famous and experienced air-to-air aircraft photographer, Katsuhiko Tokunaga of Japan, was barred from the retirement ceremony on the grounds that "no foreigners at all are allowed." This despite the fact that he has flown more than 1,000 hours in the rear seats of almost all U.S. fighters and has completed some of the most extensive air-to-air photography of the--supposedly-- much more advanced F-22A.) On Monday the Indian Ministry of Defence accepted bids from six U.S. and foreign competitors for the Medium Multi-Role Combat Aircraft (M- MRCA) program. The $10 billion-plus program is the PowerBall lotto of fighter aircraft sales and will be the largest procurement of a military aircraft by a export customer in more than three decades. The JAS-39, ... read more » Oh, weekly standard, surely they know how to build a fighter. |
#92
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The Swedish Model: How to build a jet fighter.
"Douglas Eagleson" wrote...
Somebody in this review article cites the Wright Brothers. It is disgusting. ?!? They built a canard airplane. It flew. What is "disgusting" about that? The article was a review article that supports a contention. The US policy is to not use canards. This was one of my contentions in one reply in this thread. The article does NOT support that contention. If you think it does, post the appropriate citation. It is disgusting because the refer to the Wright Flyer as analysis of behavior of all canards. It does NOT! It discusses the Wright Flyer as ONE example in a "Historical Overview"! Post the specific citation that you claim supports your statement. And in the article a particular shortfall of the canard was it ability to tumble. It did NOT! It cited the behavior of a SPECIFIC DESIGN -- the XP-55! And tumble as a benefit was ignored. A canard can overcome this shortfall by a properly sized rudder and vertcial stabilizer. And perform one of the manuvers I suggest without failing. A 45 degree banked Condor maneuver. Say what?!? How does a rudder and vertical stabilizer relate to a pure PITCH response?!? Also, how can a canard "overcome this shortfall" if you believe a canard CAUSED this "shortfall?!? You're again talking absolute NONSENSE! |
#93
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The Swedish Model: How to build a jet fighter.
"Douglas Eagleson" wrote...
If you can go to the edge of the envelope and stall safely you can beat nonstallable aircraft. It is an exact stall issue, not flight, but stall. NO!!! That is still utter nonsense! I did generalize about canards. It is allowed because they have a characteristic of their centers of gravity. The NO!! does not make sense to me. WHy does a person fly at the edge of the envelope? If you are in a bad place in the envelope you can not do anything but loose the aircraft. One more time... You are attempting to generalize to ALL canard airplanes a performance parameter that is [maybe] specific to a specific design. We cannot even assume your performance assessment is correct for any specific design, because most of it is utter nonsense. I point out that inverted stall is a SAFE place in a canard and NOT safe in rear stabilizer aircraft. SO you claim my point is nonsense. Why not just say what you only allude to, "inverted stalls in rear stabilizer fighters are safe." Your point is nonsense simply because it makes no sense whatsoever! You claim that a recoverable inverted stall is a "safe place" in a dogfight, but there is NO REASON any pilot would want to be in an inverted stall in a dogfight! That is even beyond your [false] baseline assumption that all canard aircraft are equal. I do not allude to that statement about rear stabilizer fighters anywhere. The ONLY thing I might "allude to" is that inverted stalls in SOME fighters may be recoverable. Again, it is a SPECIFIC DESIGN performance factor! |
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The Swedish Model: How to build a jet fighter.
"Ken S. Tucker" wrote:
The F-22 is vulnerable, I could design a machine that would blow that machine out the sky PRONTO. Wasn't Pronto the Lone Stranger's sidekick? Wasn't that Toronto? They named a town in canada after him. I do believe you're ONTO something! |
#95
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The Swedish Model: How to build a jet fighter.
"JR Weiss" wrote in message news "Douglas Eagleson" wrote... If you can go to the edge of the envelope and stall safely you can beat nonstallable aircraft. It is an exact stall issue, not flight, but stall. NO!!! That is still utter nonsense! I did generalize about canards. It is allowed because they have a characteristic of their centers of gravity. The NO!! does not make sense to me. WHy does a person fly at the edge of the envelope? If you are in a bad place in the envelope you can not do anything but loose the aircraft. One more time... You are attempting to generalize to ALL canard airplanes a performance parameter that is [maybe] specific to a specific design. We cannot even assume your performance assessment is correct for any specific design, because most of it is utter nonsense. I point out that inverted stall is a SAFE place in a canard and NOT safe in rear stabilizer aircraft. SO you claim my point is nonsense. Why not just say what you only allude to, "inverted stalls in rear stabilizer fighters are safe." Your point is nonsense simply because it makes no sense whatsoever! You claim that a recoverable inverted stall is a "safe place" in a dogfight, but there is NO REASON any pilot would want to be in an inverted stall in a dogfight! That is even beyond your [false] baseline assumption that all canard aircraft are equal. I do not allude to that statement about rear stabilizer fighters anywhere. The ONLY thing I might "allude to" is that inverted stalls in SOME fighters may be recoverable. Again, it is a SPECIFIC DESIGN performance factor! JR, you are wasting time and electrons arguing with a psychotic bot. |
#96
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The Swedish Model: How to build a jet fighter.
"Douglas Eagleson" wrote:
http://www.aoe.vt.edu/~mason/Mason_f...AlphaNotes.pdf Here is a study that mentions a critical aspect of the issue of canard flight. High angle of attack allows for very fast roll rates in general. A wing designed for high angle of attack becomes a superior wing in general. Where does it say that? What was the max roll rate of the Wright Flyer? AJ-37 Viggen? A-4E Skyhawk? F-5E Tiger? Several transport aircraft and a few tactical aircraft have been tested using the Coanda effect to allow flight at very high AoA. However, that high AoA capability sacrificed considerable capability at low AoA / higher speed. Show me where a high AoA capability has added to overall wing performance... On page 9-10, regarding the general case, it says: "Control effectiveness tends to diminish as the angle of attack increases." It follows with a SPECIFIC DESIGN case: "Here, differential canard is used to make up for the loss of rudder effectiveness." Note that NOTHING is said about a lack of horizontal stab, or inherent superiority of any general scheme! Note also that several aircraft (e.g., F-14) use differential horizontal stab to augment roll rate, so a canard has no inherent advantage there. Please show me a roll rate vs AoA chart for ANY fighter airplane (or ANY airplane, for that matter, that has higher roll rate at higher AoA! Also, it specifically supports my contention that performance characteristics are DESIGN SPECIFIC! On page 9-5, specifically referencing lateral and directional control of canard aircraft, is: "One of the complications associated with canard aircraft is the wide variation in these characteristics with canard setting. The trailing vortex system from the canard interacts with the leading edge vortices of the main wing, forebody vortices and also the vertical tail. Thus the lateral/directional characteristics of canard configurations play a large role in deciding if a canard configuration is practical." A f-22 uses a special thrust vectoring to achieve high angles of attack, it does not use a superior wing design. A major fact shown was the roll rate as angle of attack is varied. Reliance on thrust vectoring to compensate for a wing design reduces the roll rate. Roll rate is a speed to turn in. And the degree of roll appear amendable to only a f-16 challenge. In dogfights it has a deficiency. In stealth it likely has superiority. Maybe a tradeoff was accepted. As long as pilots know of this limitation they may alter tactics to overcome lower performance ability. In decision making many factor appear and my guess is it is to be termed a fourth generation dog fighter and a fifth generation stealth fighter. Roll rate is another envelope variable and the lack of speed to turn appear to make another maneuver available to be considered. A basic cork screw as a prelude to turn is either to be followed or not followed by the attacker, say an F-22. A leading enemy can expect the F-22 to not follow. An F-22 cannot keep up. As a result all acts to avoid the US fighter can be successful break off maneuvers. If you do not match the cork screw, you also loose. A whole class as a basic dogfight disappears. It is a huge compromise design, the non-canard F-22. |
#97
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The Swedish Model: How to build a jet fighter.
"Roger Conroy" wrote...
JR, you are wasting time and electrons arguing with a psychotic bot. Got nothing better to do right now than review a bit of aerodynamics... |
#98
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The Swedish Model: How to build a jet fighter.
On Fri, 09 May 2008 18:22:55 -0400, "Dean A. Markley"
wrote: Well Ed, I was half expecting a blonde babe from the posting title. I kind of like thinking about Elin Nordegen too but what she has to do with military or naval matters is beyond me. (Anyone who doesn't know who she is can Google) |
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The Swedish Model: How to build a jet fighter.
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The Swedish Model: How to build a jet fighter.
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