kiwinopalWell, this is largely a speculation.
F22 is as aerodynamically efficient, as the the airframe’s LO features allow.
We’re discussing airframe drag here, not weapons influence.
Anyway, we know that common (not Silent Eagle) F15’s top speed with 4 MRAAMs is ~M2.4 (out of ~M2.5) and with additional pair of Mk84s on wing pylons ~M2.2 and all that with ~0.68 times SL thrust of an F22, which looses thrust less than F15, with altitude increase.
What is the use of a Su-35BM or Rafale without weapons?
At the same weight with weapons the F-22 is more aerodynamically efficient than any 4th generation fighter with weapons.
As as we can see it is not just TVC but good design that allows it to turn, it is thrust and lift.
The F-22 with tailplanes also was designed to have less drag see this aspect.
The X-36 has a wide space from wing to canard but the F-22 does not affect the wing it has tailplanes.
At same TWR the F-22 supercruises the F-15 can not that proves you is more aerodynamically efficient
kiwinopalNo, it’s not.
Compare it to Sears–Haack body.
F22’s drag is significantly reduced, but in comparison with F117.Not quite.
For two similar wings, the draggier is usually a more lifting one (due larger thickness), thus providing more lift.Well, I’m pretty sure if you stick a pair of F119s into F15, you might well get ready for a light jump.
The F-22 is aerodynamically efficient and it carries no external clutter in the form of weapon pylons, missiles or fuel tanks.
The F-15 does carry a lot of external clutter and same is the Su-35BM or the Eurofighter and Rafale.
the amount of drag produced by the weapons pylons will degrade greatly the performance.
Conformal fuel tanks still are draggy since were not part of the original design, the original F-15A did not have them.
The F-22 still has a huge wing and tremandously powerful engines at military power allow supercruise and are economically efficient, the F-15 is not like that it well gulp fuel so fast that any aerodynamic gain will be negated by short range.
kiwinopalKiwinopal, you took some time to try to explain your version of what happens at the crest of the cobra maneuver , ie. at 120 degrees. Now let me tell you why I think you are wrong.
At a perpendicular angle of 90 degrees, before the apex of the maneuver is reached, the plane is moving through the air at several hundred miles per hour with its nose pointing straight up, any vortex produced by the LERXs will trail behind the plane, the vortex will NOT make a 90 degree turn downwards to be able to wash over the wing and stick the airflow to provide more lift.
Once it reaches the apex of 120 degrees its nose is pointing past the vertical to a position above and behind it, if we assume what you say is true and the vortex are sticking the airflow to the wing and providing more lift, then that lift will tend to pull the nose of the plane “up”, ie. onto its back. This is not what happens since the plane comes nose-down through the vertical position and back to level flight, so there must be another mechanism at work. or do you also believe in magic?
You are forgeting that the Su-27 has a center of lift and a center of gravity, these act as lever and fulcrum , this makes the aircrat nose heavy.
A couriuos fact so you can see what is hysteresis, if the Su-27 pitch up slowly to 70 or 80 degrees it will depart and enter into a spin, do it fast it will do the cobra
kiwinopalOh yes do you admit T/W rate of F-15 at least equal to F-22？do you admit wing load of F-22 at least similar with F-15?
Could you tell us why F-22 has so much greater turn rate?Certainly, then tell me could you show me F-22 change its nose 180° in 5 seconds without using TVC?
But Rafale can do it even without TVC.
What you are doing is an over simplification of thrust vectoring, aircraft even with thrust vectoring need to obey the rules of aerodynamics, the thrust vectoring inputs are brief, for most of the time the aerodynamic controls are acting in the aircraft.
The F-22 is no F-15, first its drag is minimal, this multiplies its thrust and lift. and even at the same TWR and wing loading the F-15 will be drag burdened while the F-22 won`t, the F-22 in that fact has more lift and thrust available.
Second in order to do the Cobra the F-22 needs relaxed stability, you might think it is just a matter of installing 2D TVC and that is it, however it is not, any aircraft trying to do the cobra needs to be longitudinally relaxed or unstable.
The tailplanes are very important to do the Cobra since they become nose down pitchers as the aircraft switches from tail heavy to nose heavy.
kiwinopalOh? Everything is thrust and lift? Then tell me why the F-22 its wing load and T/W rate is not greater than F-15 but get much much higher turn rate than F-15? No related to TVC?
Besides, when and where I mentioned Viggen was a stable a/c or not?
What I point was if you compare canards and tail plan layouts, you should put them under same condition.
The very difference between Viggen and F-15 is that Viggen’s canards is not all-moving surface whereas that tail-plan on F-15 is all-moving. I never ever said stable or unstable either Viggen or F-15!See, what are you going to say just is an agreement with I posted: Cobra is a maneuver but maneuver not merely is Cobra.
All Eurocanards own the >30°/s ITR on average which are unstable compare to all unstable tail-plane MiG-29 23°/s, F-16 26°/s, Su-27 28°/s, F-18 22°/s so get 24.75°/s on average ITR,
For STR, all Eurocanards own the STR significantly above 20°/s, but all tail plane all below 20°/s despite F-16 22°/s.
Both of Eurocanards are capable to do supersonic fly without afterburner, but none of unstable tail-plane can do. This is what I pointed, Canards gets greater advantage on trim force, esp. the more speed the more advantage.Really??
If no TVC, which advantage F-22 gets compare to F-15 which even is a stable a/c.? wing load? or T/W rate? Dare to list? I bet you not!The only thing I do enough to against you will be to copy your words below:
Drag is a force working against lift and thrust you can not expect the F-15 to have less drag than the F-22, the F-22 is not a christmass tree in terms of drag like the F-15 is, besides the F-15 has no leading edge flaps.
Plus the F-22 has relaxed stability, the F-15 is stable longitudinally.
kiwinopalhttp://www.youtube.com/watch?v=RJO0KzTgcMI
http://www.youtube.com/watch?v=GrBx6G2O6A4
What’s neat with Dozer’s cobra is that nose authority is maintained throughout the maneuver, unlike the Flanker cobras.
I have to say your explanations about the difficulty of making stealth aircraft with canards make me realize many things, i agree with you completly about that.
kiwinopalNot to beat a dead horse, kiwinopal, but you do realise that at 120 degrees, the Su-27 in a cobra maneuver, is 2/3 of the way to being backwards.
Now since vortex don’t ‘burst’ but are alway present if there is a difference in pressure between top and bottom of an airfoil or LERX, please tell me how the vortex can wash over the wing when the wing is 2/3 of the way to swapping ends?
The things i am saying have valid aerodynamic proof, but i will explain you so you can get out of doubts.
The pitch up of the nose has to be fast because the Vortex lags to react, it is not automatic as you think.
The low preassure won`t disappear inmediately, if you do the pitch up slowly then the Vortex will migrate and burst at the same rate of the nose pitch up.
It has been proven that as the aircraft pitch up the nose the Vortex burst position will move forward, from the vertical fins to close to the LERX, that is true, but the Hysteresis of the vortex means that as the speed of the pitch up increases the delay of vortex migration through the wing appears, so it will move slower than the nose pitching up.
so you can have at 120 deg of pitch up a Vortex of a lower pitch up value and that is what happens in the Su-27 so you won`t have a strong pitch up force at 120 degrees but a more stable aircraft longitudinally.
A canard also creates vortices, true, the F-16 and F-18 have also LERXes, true but the lift they produce at least in the Eurocanards and F-16 and F-18 is not enough to allow the Cobra.
You can not expect the low preassure gradient to disappear inmediately as the pitch up speed increases.
That makes the Cobra Possible in the Su-27
kiwinopalIn these two posts, you made same mistake:
1)Viggen and F-15 are not same generation fighter according to common opinion. Notice the canards on Viggen is not all-moving surface but tail-plane on F-15 is completely all moving, ergo this is unfair firstly
2)When you make a comparison, you must put all objects under same condition. Here F-15 got much much powerful engine so that it is almost double T/W rate than Viggen. This is your double standard secondly.
Remember you also said:You be force to admit this seemingly!
Really? So what do agility do? What is different between agility and maneuverability?
Yoohoo, in this same page we saw exactly contradictory post here:
What makes you so incoherent?
1st step: same wing area, same wing shape and same fuselage, but only difference is canards and tail-plan.
you pick two teams of aircraft with completely far away T/W rate even neglect other differences.
2nd step: close T/W rate and both all-moving trim surface.
you avoid behind Cobra.
3rd step: Cobra ≠ combat ability.
you run turn rate comparison. That’s fine, I tell you UNDER SAME CONDITION INCLUDING PROFILE, Eurocanards run significant higher turn rate than F-16 or Su-27 no matter instantaneous or sustained. Then you go to agility.
4th step: agility ≠ maneuverability
Before you write, you’d better know agility means capability of nose direction changing, you turn or climb also changing your nose direction but if you want to changing faster, you have to use two methods, one is correct layout normal to canards, and you want faster much more higher, you must get TVC.
5th step: put the TVC away
If not being AoA bigger than 45°, canard run absolute advantage including trim drag, Cl coefficient and speed flexion within any maneuver/flight situation, simply because it is a moving deflective surface rather than LERX merely is a high swept wing.
I did not contradict my self you are using excuses to further a dead cause.
If the Viggen does not win you say it is stable, i proved you the F-15 is stable too you say it has more thrust then you say is not fair my point was everything is thrust and lift not the canard or tailplane differences what gives the edge.
the Cobra can be used in combat, but if is not used properly it s a drawback and disadvantage rather than an advantage, a Su-27 can use the cobra against a Eurofighter, well used offsets the advantage of the enemy aircraft, use it in the wrong way it will kill you.
The Rafale, Eurofighter and Gripen of course are good fighters and in some ways are better than early MiG-29s and Su-27s, latest generations are better on par the with Eurofighter like the Su-37 or MiG-29M to put and example.
Just remember the regular old MiG-29A and MiG-29Cs had STR of 23-22deg/s depending in the variant and ITR of 28deg/s, the newer MiG-29M had relexed stability and the MiG-35 upgraded engines so you can expect higher ITR and STR besides TVC if needed.
You can expect the Su-35BM to have also improved ITR and STRs because it has newer engines.
By turning the nose the Su-27B and MiG-29A are not behind and the Eurofighter and Rafale have higher instantaneous turn rate but not very high STR more ore less on par with a Su-27B and MiG-29C, but the pointing of the nose is not inferior in the Russian fighters and the Cobra is an example.
What you can not believe is the F-22 has good aerodynamics, it does, what happens most people think everything is related to its TVC, but it is not, the F-22 must have good turn rates simple because of its thrust to weight ratio and wing area.
Add TVC and the F-22 can do more than that in fact the F-22 has done the cobra as a regular air show routine, show me videos of any eurocanard doing it
kiwinopalStill a gossip, no concrete evidence just the desire of people expressed as fact, by the way by 2014 even with let us say 40 Su-35BMs the Russian air force wil have a force multiplier.
Consider the MiG-31 can shoot down aircraft at really high speeds no J-10 will be able to shoot down them with high rate of success and the Su-35BM will be armed with new long range missiles and the most important thing they will tire with supercruise the J-10s and J-11Bs to catch a Su-35BM will be almost an impossibility, the kill ratio of Su-35BM against J-10s is in the Russian favour probably 6:1 either in WVR or BVR and same will be any for Su-27 built in China by 2020 that will be higher probably 10:1 or higher with the T-50
Remember the kill rates of F-22 against F-15s.
Put the Su-35BM and T-50 in the world market and you have aircraft that will sell well against the F-35
kiwinopalyour assesment is more or less correct but your forget Russia is not only ahead technologically but has excellent SAMs S-400s to which the J-10 will no suffice to say the least, Russia already has flying Su-34s which even as a bomber can fight, Tu-160s that will have the edge over the obsolecent Tu-16 that China flies and a last fact Russia is the major nuclear power in the world, here is not that Russia fears China that certianly they do not having a bigger nuclear arsenal, here is the Russia still has the technological edge and they want to continue selling aircraft.
Russia fears losing money from Chinese Su-27s and they certainly are looking for more markets one is India, the T-50 shows in terms of future sales Russia still is ahead, because in the international markets a Su-35 is the best option and already they are selling 200 fifth generation fighters to india and more than 150 Su-30MKIs.
The J-10 won`t be able to compete in markets where the F-35 will squeeze it, the J-11B still can not compare withthe Su-35 and China has no answer to the F-35 and T-50 as a major product and the J-10 might be advance for China but is not so advanced in 2010 and it won`t be in 2017 when the T-50 and F-35 are for sale
The whole issue for Russia is selling and for that they know they need the technological edge.
kiwinopalWhat have this all to do with stealth?
Su-27, F-15, F-14 etc. are are greate RCS nightmares.
Su-27 straight inlets ducts with moveable ramps and gaps and dents, 90° corner cateye reflector (Tail) and ventral fins.
F-14 straight inlets ducts with moveable ramps and gaps and dents, 90° corner cateye reflector (Tail) and ventral fins. 90° here and there.
F-15 straight inlets ducts with moveable ramps and gaps and dents, 90° corner cateye reflector (Tail) . Somtimes self destrution through longerons untercut or disintegrating leading edges.Against Eurocanards : no cateye reflector, s-curved inlets duct, etc. etc.
it has to do, a lot, but before you ask me questions ask your self these ones, why the canards in the Gripen are above of the wing level, why they have dihedral, why they they are trapezoidal and not triangular in shape, when you answer your self that ask your self why the F-22 has planform alignement.
After that you will understand a few things that have been said from the begining of of the thread by em745 who has solved the questions and has answered them since a long time.
kiwinopalWhy does it matter if the LERXs are ahead of the wing ? In the cobra maneuver the aircraft is perpendicular to the line of flight, so you can put the LERXs wherever you want, they will not be providing any lift!
You can not imaging the cobra process because you are in a static system, you imaging vortex breakdown and burst in a very static system, effectively at 120 degrees the wing will stall, that is correct, however that is in a static not dynamic system, it means if the Su-27 tries to fly let us say it in an AoA of 120 degrees in an extended period; however the Cobra is in a dynamic system, with this i mean the pitch up and pitch down of the Su-27 nose is very fast and brief, it goes from 0 to 120 degrees and viceversa just for a few seconds, no Su-27 pilot will try to fly the Su-27 for a minute at 120 degrees.
By dynamic we mean, the vortex breakdown and burst will lag enough to have the static characteristics of a lower AoA. So if the 120 degrees pitch up is fast it won`t have the features of 120 degrees but of a lower AoA.
Then the Su-27 will remain stable, and will have controlability, at 120 degrees in the Cobra the Su-27 has the vortex burst of let us say it 50 degrees if its nose pitch up is done very fast.
What you happen to miss is the speed of the vortex break down and burst and its position, in the Su-27 its Vortices are strong enough to allow for enough lift to do the Cobra in the F-16 and F-18 the vortices are not strong enough, and in the Eurofighters too
kiwinopalTVC is overrated. Long range missiles are useful against mostly bigger targets, not as much against 4th gen fighters. But they are in the final stage of development of LRAAM in China too. If su-35 can really do supercruise, then that’s definitely a plus. The other two, not so much
all the flankers can do cobra, you are just putting extra phrases in there with no substance. Yes, MKI can have many countries’ avionics, put together, that doesn’t make it good. If you have real valid positions, why don’t you start pointing out more specifics?
hmm, T-50 still has quite a long way to go before attaining all the targets needed for 5th generation plane. How about let’s wait for a few years for it to come out before bragging so much? I don’t like talking about unfinished projects.
nobody said JH-7A is amazing, that’s why they have J-11BS in testing right now.
Feel free to go to SDF’s engine thread. We have all the latest article on Chinese engine development. I think maybe you can learn something from there rather than wherever you get your sources from? I really don’t know where that is.
There are plenty of photos out there of J-11B flying with all Chinese components. There were some production issues with WS-10A, yes, but they have been sorted out. That happens with all new engines. Nobody expects a pain free process.
The PLAAF air marshall said that Chinese 5th gen would be ready in 7 to 9 years. But I’m sure you know more than him. As for engines for it? They will start by using an improved variant of Taihang. 117S and the 99M series are all improved variants of AL-31F. It’s nothing different. Now, both China and Russia are working on next generation engine (which 117S is not) with a whole new core and such. The current state of Chinese aerospace engine development is actually quite well known. You can see it here.
http://i3.6.cn/cvbnm/8c/64/2a/75ac9738aaab6d2f27a8dcf029acfac7.jpg
This generation consists of WS-10A and WS-13. The next generation is WS-15.
According to the latest news, the core of WS-15 has finished testing on the high altitude test bed, which means it has around another 10 years to go before final certification and production.I would have to dig this up but 5th generation was definitely offered by Ivanov on one of his trips to China. But the domestic project is far along enough that they have no interest in it.
Don’t use wikipedia as your source for Chinese weapons. They are wildly inaccurate.
As I said, the entire stuff about China stealing su-27 is overblown, since they are carrying forward with licensed production, which was never really canceled and China had already paid for all the licenses which they are still building. btw, I love how Russian words are untrustworthy for anyone else. But when they start to bad mouth China, they must be authentic.
As for Taihang, they had production problems in 2008 and 2009, but those have been resolved. And we are seeing pictures that show this.
Here is what i like about your post you contradict your self, you say the J-11B has local engine, now Russia Today (on April 20th 2010)http://rt.com/Top_News/2010-04-20/russian-arms-copycat-china.html which is a Russian TV outlet using expert opinion of Russian defence analysts, say China is copying illegally the Su-27 technology this is because the original contract forced China to use Russian components among them the Al-31.
Later your proudly claim the J-11B is better because it has domestic engine, let me put it in simple words, all the words you add to your post have no veracity about the fact China did violate the Russian intellectal rights of their Su-27.
The Russian themselves are saying it, and they are saying china violated the agreement.
They even have denied the sale of Su-33s
Many people say the Russians got impressed about the J-11B production line but the same russian analysts say the only way for Russia to fight the J-11B is by making Su-35BMs and T-50 and this in the economic context alone.
They also say the copy is not better than the original and that means the Su-35BM is better it has Supercruise and TVC just in engine.
Later you say that Russia is still years away but China is not.
Fact number one: china can field a stealth fighter in 7 years time that is a possibility, i agree, but fact number two, they have not a prototype like the T-50, at least satellites or the media have not reported it.
The assumptions you make are not valid until we see a prototype.
The F-22 took to the USA 20 years in the making starting from the early 1980s and with its first flight almost 20 years ago as YF-22.
Russia flew two technology demostrators the S-47 and MiG 1.42, before the T-50, without forgenting all the Su-37 and Su-34 series
They know they still work ahead to field the T-50 and they have their flying prototype.
The US already has started the 6 generation aircraft program with their space plane and the Russian already know they have to do it too.
For the Chinese to catch up is a long way since the americans took 20 years and Russia has the same but both of them have flying prototypes and the US already operational aircraft but China has not.
kiwinopalLets go back to basics. Aerodynamic lift is produced because of a difference in speed of the airflow over the top and bottom of a wing. Faster air flow has less pressure and so lift is generated because the higher pressure on one side pushes toward the lower pressure on the other. The difference in airflow speed is generated by the curvature of the wing, ie. half of a venturi as per Bernoulli.
Now I assume you know all this, so then explain to me how a wing, moving perpendicular to the airflow, at 90 degrees, generates any kind of aerodynamic forces, other than that generated by a flat plate moving through the air, ie. DRAG!!!
Stop reading stuff in magazines or online ( such as ‘vortex bursting’ ) and placing any significance on them, classical, non-relativistic physics, is very common sense, and you can find ‘ballpark’ answers to a lot of problems by thought experiments, ie. think about it.
Oh, and having adegree in physics, the hysteresis I’m familiar with is magnetic, and I don’t see how the two are related. Don’t tell me to look it up, like some other members do, if you’re so familiar with it, explain it to me so I know you’re not just pulling it out of you a*s.As for the Kfir, Viggen, the NG and Milan versions of the Mirage and even the Su-27 series, all are regular planform where the non-moving canard is added to generate some lift ahead of the CoG for various reasons. STO( for the Viggen ), tailplane offloading ( Su-27 variants ), and counteracting aft movement of CoL at supersonic speed which makes the plane even more ‘stable’ and more sluggish in pitch. None of these planes use the canard for actual trim and pitch change as substitute for tailplanes.
So, compare apples with apples and oranges with oranges, use the Typhoon, Rafale or even HIMAT in your comparisons and people who know something may actually consider your viewpoint and what you are saying.
What about Lerxes are not they ahead of the center of gravity?. they are and basicly the give extra lift just look at the MiG-29 or F-18E LERXes well ahead of the center of gravity.
The Delta wing suffers a lot from supersonic trim in aircraft like the Mirage III and F-111 why? well in the Mirage III it has no tailplanes and in the F-111 once it sweeps its wings back (its swept wings get the form of a delta), most of the lifting area and center of lift are well back of the center of gravity , what are the solutions? in the Mirage III are canards; in the F-14, in the case of the variable geometry wing aircraft, wing gloves.
The B-70 is another good example of canards used to upset the supersonic shift of center of lift.
The F-15 is not an unstable aircraft niether the Harrier, only the F-16, Gripen, Eurofighter, MiG-29M, Su-27 and J-10 to put some examples The first truely unstable fighter aircraft in the world was the F-16 by the way, the F-15 it was not.
But still the F-15 will beat the Viggen in dogfights and the Tomcat very likely was either as good or better
By the way if you use a wing of the same size and tailplanes and canards of the same area, the aircraft with canards will have a stronger pitchup force, this will sound better for an aircraft with canards but here is the riddle, why in 1989 when Rafale and Su-27 were present at the Paris Air show the Flanker showed better AoA handling? well by relaxing stabiity the tailplane aircraft fixes the disadvantage but not only that since the LERXes are highly swept, more than canards, they produce stronger vortices, so your Su-27 has the ability to do the Cobra, Rafale A did not do it.
Why? well simple there is no superiority of canards versus LERXes and tailplanes.
kiwinopalThe Kfir was a stable design and had unmoving canards.
F-14, F-15, Harrier all are better than Kfir and Viggen and the F-15, Harrier and F-14, all are longitudinally stable, of course the myth of canards being better inherently than tailplanes still reigns is not it?
Sign In
