Intresting to “learn” that the heavier MiG-29C have a better sustained rate.
At least when data were posted without given speed, height and weight related to that.

Sens

Perhaps you have the idea canards are always better than LERXes and therefore the MiG-29 is in disadvantage, however i will say something that many people here forget
In unstable designs when they pitch up at high AoA, canards not always have better response because since canards are smaller than tailplanes in some conditions can not pitch down the aircraft and tailplanes are better suited to do the trimming and pitch down the aircraft at high AoA due to the fact they are bigger
Canards also reduce the main wing`s lift and vortices in unstable designs some times move the center of lift ahead of the center of gravity at high AoA increasing the need for a pitch down force and trimming, canards since are smaller and reduce the max potential lift of the wing some times are uncapable of pitching down the unstable design, this also explains why the Su-30MKI, Su-34, Su-35 and Su-37 have canards and tailplanes

This probably can be proven with the Su-27 and the Eurocanards, the Su-27 can do the Cobra and it seems the Eurocanards can not do it

What? Have you seen the planform of the Su-33, Su-33UB, Su-30MKI etc,.? The wings appear even less swept than on the LERXd Flankers.

You are the one saying what is not true.

which is true. However, LERX vortice can also flow over the main wing and tail and this also creates buffeting effect.

Between LERX and canard, the vortices in the LERX is more likely to degenerate into turbulence at higher AoA because the LERX is a fixed device and cannot angle to suit the angle of attack. With a canard, the canard can adjust itself to the angle of attack, producing the righ angle or trim that stabilizes the airflow, preventing the vortices degenerating into turbulence.

Somehow you failed to get the picture that canards act as a variable LERX.

Because LERX is fixed, it will always generate drag and wake even in straight flight, but a canard can trim and even out so it presents a straight profile to the airstream, less drag and no wake.

And somehow you forget that airflow to the LERX also burst right at the root of the LERX to the fuselage, where the LERX bends and where the LERX meets the main wing. As a result LERX actually diverts part of the wake right under the wing whereas canards above the wing doesn’t.

And somehow you forgot that canards are blended on the Rafale to the body. J-10 uses body blending on its main wing, which also allows for considerable internal fuel capacity.

You can compare LERXed aircraft of roughly the same internal weight—JF-17 and Ching Kuo vs. Gripen. JF-17 internal fuel volume is roughly the same as Gripen while Ching Kuo is lower, though DSI version of JF-17 now has slightly more fuel because of the internal volume of the DSI bumb itself.

In the MiG-29 and Su-27 the LERXes also help the inlets and intakes;) and you can see it in the Cobra.
LERXes also allow for a main wing of less swept with Flaps;) in fact the MiG-29 main wing has a swept of 40 deg while the LERX has a swept of 73 deg,

However show me where the vortex is bursting at the joint of the LERX and the wing and getting part of the wake underneath the wing? the Vortex clearly is bursting above the wing

The high pressure air from the lower surface of the LEX rolls around the edge to the lower pressure region on the upper surface of the LEX. This motion induces a rotation on the air flow causing it to roll up into a strong vortex. The strength of the vortex grows as angle of attack increases, and the high-speed vortex helps keep the air flow attached to the surface of the wing beyond the normal stall angle. The effect can be calculated and visualized using computational fluid dynamics (CFD) software as exemplified in the following images.

high pressure will go above the wing not underneath and that creates Vortices Crobato and at High AoA it bursts well above the wing and creates buffeting at the fins;)


See the the Vortex burst ahead of the LERX and above it

See the Vortex is bursting on the fins

Source http://www.aerospaceweb.org/question/planes/q0176.shtml

What if the plane sports Carefree Handling, i.e. software restrictions that one cannot ovverride a certain AoA, are there still risk of stalling?

You can do two things to prevent deep stall,

1> Prevent your ac from being stalled using sensors/carefree handling along all its three axis and 6 degrees of freedom.
2> Recover it from stall.

Am i right?

A interesting algorithm, is this relevant to stall? (i had a good report cannot find it)

I dont think I agree with this “generation” analogy definition just by addition of “canards”.

JOEY

In my humble opinion since i am not aerodynamist i guess the LCA of all the aircraft of the fourth generation is the one with the most potential to become closer to a fifth generation fighter, number one, the aircraft is simple, produces the minimun of drag, no tail plane no canards,

Depending in the relation of the Center of lift and the center of gravity a fighter needs canards, canards were designed to ensure enough lift ahead of the main delta wing once the center of lift shifted backwards, behind the center of gravity making the aircratf nose heavy, in the case of the LCA i guess they did not fit canards simply because most likely the control system and the center of lift-center of gravity relation have been arranged to give the max of agility without the need of taiplanes or canards.

Also its wing its not exactly a purea delta probably it generates enogh vortices to allow high AoA, besides with thrust vectoring the LCA must be a quit difficult opponent.

Reading the article it is understood that this is true if the canard/delta aircraft is built statically stable. As none of the 4th gen delta canards are stable it does not apply.

When? Where?

Except that the LERX’s are much larger, heavier, draggier and much less flexible. And as I’ve mentioned before, tailplanes adds weight and drag as well. The delta/canards make do without them.

The canards has the same benefits as the LERX’s, and none of it’s weaknesses. Why shouldn’t they be able to do a cobra manouver?

It’s more important to have a long slender (tailless) tail in order to achieve low drag(and reduced weight). Either way, the wing fuselage blending on the Gripen is excellent.

Who says the Eurocanards have lower STR’s because they have canards? Give the MiG-29 the same TWR as the Gripen and see if it can sustain a 20 deg/sec turn rate.

It still has to kill lift in order to turn.

Robban

I mentioned before that exactly that the Gripen has better instantaneous turn rate than the MiG-29A but it has not better sustained turn rate.

Your article claims the same, canards give you excellent instantaneous turn rates but not good sustained turn rates, that is true in one of the books i have about the MiG-29 and another i have about the 5 and 4.5 generation aircraft titled super fighters they give you a few turn rate, also the one of Fomin about the Su-27 gives you a few more turn rates and effectively the Eurofighter is not better than the MiG-29A in sustained turn rate and is worse than the MiG-29C.

The Gripen has a instantaneous of 30 deg/s and the MiG-29A one of 28 deg/sec; nevertheless the sustained turn rate the gripen has is lower than that of the MiG-29A that has a sustained turn rate of 22 deg/s and much more inferior to that of the MiG-29C has a sustained turn rate of 23.5 deg/s, because the Gripen has a sustained turn rate of 20 deg/s.

And you are incorrect LERXes also have benefits that tha canards do not have, one is they are better for fuselage-wing blending specially in an aircraft like the MiG-29 since they blend the fuselage and the main wing in a single lifting body;) also the LERXes in the MiG-29 and Su-27 help the Inlets at high AoA, LERXes also help the aircraft to have more internal capacity for fuel and equipment with the least of drag and aerodynamically they do not produce a wake because they are not located in front of the wing and instead they give lift simply because they are part of the main wing and fuselage lifting body;) why do you think in the latests Su-35 they deleted the canards but not the tailplanes? also LERXes allow for a less swept wing with higher aspect ratio allowing the wing to be better suited for low speed handling

Canards don’t produce more drag(unless when more drag is needed, like shortening the landing run). Deleting the tail offers the possibility to position the wing more forward making it easier to optimise area ruling. A long slender tail cone can be designed, and with the absense of the large area a horizontal tail brings with it, drag can be avoided even more.

Excerpt below from here http://www.mach-flyg.com/utg80/80jas_uc.html

The aerodynamic advantages derived from the close coupled canard configuration, foremost its good vortex flow stability up to high angles of attack (AOA), that can be translated into a very high instantaneous turn rate, and which in conjunction with pivoting canards that are automatically trimmed to give optimal lift-to-drag (L/D) ratios for all cg positions, Mach and AOA.

The MiG-29 is certainly a great design, but it’s still a generation older than the Gripen. Even if you put new systems into it, it’s infrastructure and aerodynamic design is still not up to par with the newer generation which includes the Gripen, Rafale, Eurofighter and F-22.

LERX´s don’t offer nearly as much as a moving canard does, as they are fixed they have a rather narrow field of use, the tailplane adds unnecessary drag, and kills overall lift when they are used, and flaps adds complexity and weight, not to mention TVC. The unstable delta/canard designs make do without all this. While they can’t do somersaults, they can move in and out of manouvers much more rapidly. Giving true agility.

You forgot to mentioned this
Wind tunnel testing and project work on alternative aft tailed configurations had pointed out many advantages for that particular layout, where perhaps range and sustained turn rate were the most noticeable, granted the technological level of that time.

See very clearly the MiG-29 has better sustained turn rate and the Eurofighter and Rafale barely are on par, this is confirmed by practice.
see that also LERXes have the same physics of canards and the MiG-29 and SU-27 use flaps and tailplanes in a integral fuselage blending
The flow physics are essentially the same. The front surface, being a delta or highly swept strake, gives off a stable detached leading edge vortex that interferes with the vortex flow from the main wing and which mutually reinforces the vortex strength of each other, and therefore burst at a much higher AOA than a lone delta wing would do. This holds true for movements in the pitch plane, but generally not for the other axis, where such flow stability is more difficult to obtain, because of asymmetrical vortex bursting, so modern fighter aircraft generally “stall” first in the lateral and directional axis

The LERXes have good control at AoA and this allows them to point their noses with the Cobra and tail slide in a way the Gripen or Eurofighter probably can not do since i have never hear of these aircraft doing the Cobra.

Remember that contrary to the american designs (despite the F-14 and F-16 have some digree of fuselage blending they do not have it as in the Su-27 and MiG-29) the Su-27 and MiG-29 have integral layout giving an extra 40% lift just in wing-fuselage blending, remember the Su-27 and MiG-29 have two vertical fins and in the Su-27`s case it has two more ventral fins both aircraft use flaps adding more lift and their wings are less swept giving better low speed handling.

This extra lift help the aircraft in a way the Eurocanards can not have since they are basicly using less fuselage blending and do not use the integral layout as the MiG-29 and Su-27 do

The cobra and better sustained turn rates is a good trade off compared to the Eurocanards

remember the Su-27 also uses relaxed longitudinal stability

Flying Controls

Four-channel analogue SDU-27 fly-by-wire, with no mechanical back-up; artificial feel; relaxed longitudinal stability; no ailerons; full-span leading-edge flaps and plain inboard flaperons controlled manually for take-off and landing, computer-controlled in flight; differential/collective tailerons operate in conjunction with flaperons and rudders for pitch and roll control; flight control system limits g loading to +9 and normally limits angle of attack to 30 to 35є; angle of attack limiter can be overruled manually for certain flight manoeuvres; large door-type airbrake in top of centre-fuselage.

The canards are control surfaces. Control surfaces that has the same benefits as a LERX, adding positive lift ahead of the aerodynamic center. They can therefore be used as elevators, offering superior pitch acceleration and more precise manouvering compared to aircraft with a conventional tail. Contrary to the fixed LERX, they have the option to optimise lift and drag at all times. In the picture above, the plane is doing a slow speed fly-by. The canards are pretty much horizontal to the relative airflow, balancing the aircraft, giving optimum lift for this particular situation without the large drag penalty of a LERX. The control surfaces on the trailing edge of the main wing are tilted downwards adding lift. I don’t know if they can be called elevons as they are used for roll and trim only, not pitch.

The benifits of tailpanes and Canards have to be measure as performance and handling benifits, canards might be smaller but they produce more drag and they affect negatively the main wing lift, however they also have benefits.

In my humble opinion the MiG-29OVT or AKA MiG-35 is the best design of the fourth generation in terms of aerodynamics and engine matching, this fighter is more agile than any eurocanard has extra lift ahead of the main wing and induce low pressure vortices thanks to LERXes, uses tailplanes and has flaps, the Su-35BM might turn a better fighter if it includes supercruise.

So far none of that Russian fighters mentioned above have entered service or a buyer.

Yeah and what about the YANKs they have the F-22;) 😀

In a climb with quickest achievement of a tactical energy level of ~35000ft and Mach 1.4, no aircraft will ever have at any time 330 m/sec climb rate. That demands the aircraft to accelerate to supersonic speed close to the ground, which is for all current fighters a bad choice for overall climb peformance.
For the rest: Sens is right.

Could be however all the literature i have read says the Su-27 has a initial rate of climb of 330 m/s, and it is Funny you are basicly claiming the MiG-23 that has a initaial rate of climb of 220 m/s is one of the best climbers better than the MiG-29, F-16, F-15, Eurofighter and so on yeah very believeable:rolleyes: since it is known that many fighters have better rates of climb among then the F-16;)