martinezSpeed is not related to weight and installed thrust. It sounds strange at first,
i fell to knees after reading this, quite a remarkable statement.:eek: 😮
martinezAgree with Sens.
Making the chart I linked above I learned a lot about thrust over Mach and altitude. These characteristics are very depenedent on the design decisions of the designer. At M1.8, the MiG-23 has a better TWR than an F-16. At M0.8-1.2 it does not. At M1.8 the MiG-23 will have less drag than the F-16, at M0.8-1.2 it does not.
Generally, to design something that flies beyond M2 in tactically significant configurations will have huge drawbacks on all other areas of the design.
The reason for that is more due to the fact that the Mig-23 has been equiped with a variable inlet giving no significant thrust losses at M1.8. The F-16 fixed inlet has a very poor thrust efficiency past M1.6. The same case with the single seater Su-22 vs doubleseater Su-22, one has the variable inlet, other one does not.
I think no matter what speed you talking about the Mig-23 will always have lower transonic/supersonic drag than the F-16.
Top speed and maneuverability are two different shoes. The Soviets opted for the speed (see MiG-23, -25, Su-15). Later they also went for more maneuverability, but retained top speed (see MiG-29, Su-27). The pursue for a lighter airframe did not surface in the Soviet air force. The MiG-29 was very maneuverable, but still they stuffed in all the things the F-16 omitted.
Interceptors were required during that period of cold war bcs of NATO bombers threat, therefore the need for speed overpowered the manueverability. Is that so incomprehensible?
The requirement for a lighter airframe is clearly visible when you studied the Mig-29 development history properly. BUt there is one major aspect you are forgetting, single engine fighter projets were simply rejected, the Soviet AF wanted twin engine fighters only.
Anyway, what you mean with that they stuffed the Mig-29 to weigh it heavy??? a BVR capability the F-16 lacked at the beggining… 😀 😀
martinezHello folks!
I am just reading a book about John Boyd, the inventor of the so-called E-M theory (E-M for Energy Maneuverability), which is said to change the whole fighter business of the USAF in the 1960 and was basis for fighters like the F-15 and F-16.
The thing is, I don’t really understand what this theory is about. As the book is rather narrative than scientific it is more guesswork to understand.
What I learned so far is that Boyd used SEP (Specific Excess Power) to evaluate aircraft performance.
SEP = [(Thrust – Drag)/Weight] * (inertial)SpeedAnother element of his theory seems to be total energy management, this thing that says you have to go nose-down shortly to have the the quickest climb.
Can anybody enlighten me:
- What exactly is the core of Boyd’s theory
- What exactly was revolutionary about that? SEP was unknown before?
- Is it true that all USAF aircraft were inferior to Russian at that time (mid 1960s)?
Thanks for information.
I think there is an aspect here you all missed. Forget all about those relations between thrust and drag, E-M charts, power-egg, specific excess power or babbling about supersonic performance, but better realize why they called him “Forty-Second Boyd” and why still he was unbeaten in dogfights he had flown in the Top GUN school. Then you will see that he did quite the opposite, he liked to throw his aircraft energy away, to slow rapidly down loosing speed and becoming clumsy but still retaining the ability to point his gun-piper to opponent direction. No wonder, the point has always been that by making a surprising counter maneuver,a sudden and fast decelerating one you force your enemy to overshoot and disappearing from his HUD due to high relative angular speed. The speed difference 150knots(280km/h) vs 400knots(740km/h) makes it happen. This is like shooting at slow moving targets like helicopters, baloons, a quite difficult task for fast jets anyway, especially in 60`s, 70`s.
One has to admit that Mr. Boyd was a tremendously skilled pilot and had flown the aircraft at flight regimes that noone tried before. He knew how to fly outside the aircraft’s flight envelope, making him one of the most skilled US jet fighter pilot ever.
copy and paste
http://www.aviation-history.com/airmen/boyd.htm
Boyd was famous for a maneuver he called “flat-plating the bird.” He would be in the defensive position with a challenger tight on his tail, both pulling heavy Gs, when he would suddenly pull the stick full aft, brace his elbows on either side of the cockpit, so the stick would not move laterally, and stomp the rudder. It was as if a manhole cover were sailing through the air and then suddenly flipped 90 degrees. The underside of the fuselage, wings, and horizontal stabilizer became a speed brake that slowed the Hun from 400 knots to 150 knots in seconds. The pursuing pilot was thrown forward and now Boyd was on his tail radioing “Guns. Guns. Guns.”
copy and paste
http://www.sci.fi/~fta/JohnBoyd.htm
The F-100 was not an easy aircraft to fly. Especially the F-100 got reputation as a “lieutenant-killer”, because a quarter of all F-100s were lost in accidents. The most dangerous trait of the F-100 was adverse yaw.
Boyd liked the F-100 and became one of the best – or even the best – USAF Super Sabre pilot. Boyd’s specialty was a maneuver called “flat-plating the bird” where you stop the aircraft in the air by pulling the stick all the way back with both hands and hold it there. Once the airspeed is down you stomp full rudder and perform a corkscrew maneuver which forces the opponent in front of you and you can shoot him with your gun camera. Boyd’s message to young F-100 pilots was the essence of using the rudder at high angle of attack. Boyd’s maneuver lead to the birth of the “40-second Boyd” legend. Boyd had a 40 dollar standing bet that he could get to the tail of any opponent within 40 seconds from a starting position where the opponent started from Boyd’s tail. Boyd never lost his bet while he was flying fighters at Nellis.
I wonder who will be first to claim here that Mr. Boyd`s manuever “flat-plating the bird” was nothing more than a sitting duck maneuver or a pointless cobra-like stunt.:D 😀 😀 😀 😀
best regards
M
martinezFulcrum and Flanker showing off the tight turning capabilities…
Lebourget 1989, Su-27
http://www.gamaholding.sk/test/360turnflanker.avi
Farnborough 1992, Mig-29M
http://www.gamaholding.sk/test/360turnfulcrum.avi
martinezI was wondering where Mr. Martinez was. Where were you? This thread was full of aerodynamic tech talk (About 99.99% of which I don’tunderstand….:D 😮 :p)
Sorry pal, been doing rock climbing on Mars;) , no, no kidding, vacation and stuff like that in moutains.
martinez Wooow , this is a really interesting thread, glad I found it. Especially, those WET dreams about the F-22/F-35 having superior non-linear aerodynamics than other aircrafts including Flankers, Fulcrums, Gripens, Rafales, Typhoons or previous US F-series. Reasoning for this claim is quite astonishing.:eek: 😮
One came up with a buzzword “multi-segmented vortex lift” thinking no aircraft on this planet ever exploited interactions among vortices generated by the nose/forebody/wings except the F-22. He fails to mention that this coupling phenomena has been tested since seventies and put already into service with some 3rd, 4th gen. fighters like the Mig-29, canard-delta Gripens, Rafales or the triplane Su-X…etc. I doubt that he ever noticed that the production line Mig-29 has been equiped with small nose chines to gain benefit from interactions between nose and forebody LERX vortices at high AOA flights.
BTW. those nose chines have been added in mid-eighties after extensive high alpha tests and are also deliberately mentioned in the article
“What makes the cobra maneuver possible” by L.E.Erricsson from LM company.
http://pdf.aiaa.org/preview/1993/PV1993_183.pdf
I emphasize ,I have no intent to start another “cobra manuever” flame war, anyone knows it is a stupid and useless airshow stunt. 😉
Even the NASA tested various combinations of nose and forebody strakes on the F-16(YF-16) and studied their impact on the wing lift coefficient, pitch moments and aircraft stability.
Another intellectual here came with even more funny statement that the F-22 “matchless” aerodynamic design is characterized by the immense vapour clouds when performing turns on airshows….:D
I think when talking about the aerodynamics of the F-22(F-35 equivalent) one has to explain it in suitable context. When the ATF requirements have been formulated back in the 80`s with the highest priority to achieve low RCS (Stealth ahead of Supermaneuverability), the whole ATF layout became incompatible with the F-16/F-18 like shaped LERXs(e.g. circular/elliptical forebodies) or canards foreplanes allegedly because of the RCS issues. They`ve decided for a conservative aft tail configuration (F-15 like), therefore to exploit non-linear aerodynamics and to improve the “obsolete” layout they have to come up with something different.
Since 80`s they`ve experimented with chined forebodies coupled with various delta wings. Chined forebodies because they can be designed (from their nature) with lower radar cross section than round ones. They figured out that vortices generated at the chined forebody favourably influence the main wing vortices and these interactions can provide more lift(incrementally) to the main wing or to tailor (delay) the vortex breakdowns over the specific AOA range or to improve the longitudinal and directional stability.
It is needed to mention that all those improvements above can be provided with movable foreplanes e.g. canards mounted in front of the main wing and they really do perform with optimal efficiency to given AoA. Whereas the flow separation on the F-22 forebody is fixed by the chine shape itself, thus the vortices interactions are strongly Angle of Attack/Angle of sideslip dependent unless you have something (e.g. canards, actuated forebody strakes, pneumatics control nozzles) what can actively manipulate with the forebody vortices, apparently the F-22 doesnt not have.
Once again, it is a matter of compromise between priorities, because LM decided to use the less “vortices flow” capable configuration of chined forebody with a 60degree half-angle symmetric cross section coupled with a moderate main wing sweep angle of 42degree (the same as the Su-27). The F-22 intakes have also got sharp edges similar to LERXs but with less or no area, curving or variable cross section. Vortex flows created above the F-22 forebody and wings feature greater amount of wetted area rather than well defined and build up vortices patterns. This can be clearly seen from recent photos taken at US airshows, very similar to the F-15 when pulling vapour.
Saying that F-22 aerodynamic configuration is ideal and provides optimal lift for any given AOA of the main wing is just someones wishful thinking. So, believe or not the F-22 is not going to make any hole in the non-linear aerodynamics, bcs this is the aircraft of BIG compromises.
Best regards
Martinez
martinezYou aren’t seriously saying that you think the way they loaf around at airshows is the limit of their quickness are you? Tell you what, go here:
http://www.youtube.com/watch?v=Q1H1vN2tnPM
go to 5:31 and observe the turn. I challenge anybody to come up with a video where either the Flanker or Fulrum changes it’s direction of flight (not simply the direction it’s nose is pointed) 180 degrees as quickly.
LOL:) , no offence dude but how often do you see aircrafts like flanker or fulcrum per year? Here is one Mig-29 turn from a local airshow, recently grabbed the video from my camcorder. Note the centerline fuel tank was installed, the pilot had to take care of the g-limit, so you are about to see a 6G “vanilla” 180deg turn. It’s just a pity there’s no moisture in the air making nice clouds above the wings, especially at airfields with elevation 2500 ft above MSL. 🙁
Despite of that they both did the turn within 5sec, do not see any difference between them. Of course, as you`ve said before the F-22 upper fuselage is buried in vapour so it does automatically mean its turning abilities has to be superior. 😀 :rolleyes:
http://www.gamaholding.sk/test/180degturn.avi
the video weights only 2.5MB, divx codecs
martinez….well we did…and in 1968 events, our army was put under secret semi-mobilisation state and all the eastern brigades had their conscripts suddenly given reall ammunitions and send to the woods in unscheduled “exersises”…
haha, you are funny, and what you achieved by doing so? Actually you are saying that hidding in woods of Finland is the same thing as to start fight with Soviets…:D
P.S. Hungarian tanks came to my hometown during that intervention.
martinezHmm perhaps a bit offtopic and risky to ask, But as for the 1968 events, I have always wondered why didnt the Checks figth back? Were there any change for it? What where the main and biggest reason for Checkoslovakian army to be paralyzed so easily? Or is there any explanation to it?
I dont want to be distrespectfull to Checkoslovakians people or claim that it was their fault, but just curious over the reasons that made the whole mess possible
The military got strict orders from the Czechoslovak communist leadership not to mess with the intervened WP force, that`s all. They didnt attack us, didnt bomb us, didnt shoot into people. Why would we need to fight back?
After all, people felt that way too and blamed the military for being inactive and acting like cowards, but what sense would it have to start a fight with the whole Warsaw pact?
martinezGuys,
What is the HAL Paintd c/n on the port fuselage side? can we seen an example?
now that we figured out that the HAL built ac has a oem c/n and a 30L number, where would the original oem c/n plate be on the ac? we know its paintd , so the cn plate should be somewhere…
Painted c/n can be seen on the airframe, that is usual for Migs and Sukhois. The c/n plate can be also seen on the fuselage frame when you remove the wing fairings or better you disconnect the wing from the fuselage, but you can barely see it on the airshow.:diablo:
yes, the Indian MKI 042 on RIAT had the c/n visible good enough.
martinezI got the Flanker story from Icarus books, Old Saybrook, CT, U.S.A
http://www.icarusbooks.com/frmain3.htm
but they do not offer the book right now. 🙁
martinez😉
zeroyon04: hope you don’t mind me going off-topic.
Guys, where on earth can you get Andrei Fomin‘s books. Amazon and others give me ‘0’ results :rolleyes: . Even my not so legal ways of acquiring books 😀 are firing blanks 😡 Though the name Yefim Gordon and several others are plentiful.
the third edition…
http://www.aviapress.com/viewonekit.htm?IRV-002
…or get it on the MAKS2007
martinezI told him the same thing on another forum, I think he’s following me 😀
I see, a futile effort when the handbrake is released.;)
You don’t know of anywhere that the English version is still available to buy, do you? People are asking me where they can get one, and they can’t have mine!
Hmm, I got the English version in 2001, I have to look the invoice because I do not remember the bookstore name, but I`m certainly sure it came from the USA. The English version(mine) is the second edition, so I can understand why it vanished when the third is on the market for quit a long time. As I remember the third edition is in Russian language only.
martinezMIGMan,
The first MIG-23 with its serial blacked (picture is mine, btw!) out is not an ML; it is a UB version. I might be able to get you a very good pic. Give me few days. The second one was taken in Assab airport. I know the mechanic who was working on it prior to the abandonement of the base.
do you have any possibility to get the ML cockpit pictures, also some details of aircraft aerials with visible stencilling ? thanks
martinezIt might just be me but I find the second pic rather intriguing. Most of the aircraft looks dirty and faded but the nose cone looks immaculate, its also a kind of ‘modern’ grey color.
Anybody else notice this?:confused:
The Mig-23ML is a wreck, crippled, not flightworthy for a long time.
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