em745, I am also Canadian living in southern Ontario, St. Catharines to be exact, and a sure sign that someone is losing an argument, is when he has no more points to make and dismisses his opponents and tells them to “look it up”. Either you are wrong and giving up or you are right but don’t have the intelligence to convince others. You choose.

As for the Pugachev cobra maneuver, what is this bull about vortex bursting???
During the maneuver, the aircraft’s wing is STALLED!! Now any dictionary defines a stall as the point when a wing stops producing lift perpendicular to the line of flight ( it can still produce drag with an upward vector, Just like a flat plate at a 45 degree angle to the wind ). The vortices help keep the flow energised, ie. at speed, at lower AoA but NOT at 100 degrees (past perpendicular). What brings the Su-27 back to level attitude is NOT related to lift in any way or definition. Came-on, think a little before posting.

You are right on most points but one; at a stall, once the flow becomes turbulent and detaches , the centre of lift does not move back and pitches the wing foreward and down. If this happened all stalls would be self correcting.
What actually happens in a stall, when flow becomes turbulent and detached, is loss of speed of local flow over the wing, resulting in increased pressure on top of the wing and loss of lift ( lift depends on difference of airflow speed between top and bottom and according to Bernoulli, the difference in pressure). Sometimes the plane drops like a stone!!
If you manage to keep the airflow energized, at speed that is, even if not laminar, you maintain the difference in speed and in pressure. One way of doing this is, is a vortex flow over the wing. All wings generate a tip vortex where the high pressure underneath rolls over the top of the wing to the lower pressure. The more highly swept the wing is, the more pronounced is this effect. Delta wings have a good amount of vortex flow over all of the leading edge and so tend to stay stable to higher alphas than conventional wings. We can get the same effect on a conventional wing by having sharply swept extensions ahead of the wing, ie. LERXs, or a sharply swept canard foreplane. If you remove the LERXs from an F-18 it would not have any higher alpha capability than an F-104 or a T-38.

em745, you don’t seem to understand the concept of a LERX, even after numerous people have explaned it to you.
Most LERXs have a negative attitude and produce no additional lift (maybe even some downforce ) in LEVEL flight. As the AoA increases, high pressure air under the LERX tends to move to the lower pressure area over the LERX. This is different from a wing where this is to be avoided as it detracts from lift, but is a design criterea for LERXs. As this air moves from bottom, over edge and to top, it sets up a rotation, or a vortex, of high speed air which washes over the wing and keeps flow from becoming turbulent and detaching at high AoA.
There are many ways to produce these vortex, one way being LERXs (F-5e, F-17/F-18 and F-16). Dassault used strakes on the upper inlets to produce them on the M2000 (vestigial canards) and any canard foreplane (even when canard is below wing plane as vortex are only useable at high AoA) will produce them as there is always high-to-low pressure spillage.
So, to recap, canards provide all the benefits of LERXs and also provide trim and rotation/pitch control which would otherwise require a tailplane.
Let me break it down for you, one surface, the canard foreplane, can replace and provide the benefits of both, the LERX and the tailplane.

I also like the way you dismissed the question put to you about the F-16xl. The F-16, very advanced according to you, since it has LERXs, med. aspect wing and tailplanes, was improved immeasurably to the point where it almost won an order against the F-15, simply by giving it a low aspect wing and removing the ‘advanced’ LERXs and tailplane!!!

By the way, ‘swing’ wings which you dismiss as being so 1960s, are actually from the same time frame as LERXs. Northrop, having recognized the high alpha benefits of the small LERX on the F-5, increased it on the F-5e and then went all out on the Cobra concept which became the YF-17, and some might argue ,went too far with them on the F-18. All of this high tech LERX work was done in the 60s, the mission requirement which would make use of them did not materialize until the 70s (high alpha maneuvering). In the 60s the USAF was more interested in low level penetration, and if there was no stealth technology allowing med or even high altitude undetected penetration, swing wings would still provide the most viable solution for the low level penetration mission

Yes, em745, the F-117 is much less risky than the original design which was a diamond shape and was not guaranteed to fly, even the Have Blue demonstrator/test vehicle was different with inward canted tails instead of butterfly and different wing planform.
I don’t know much about the B-2 competition but I do know that Northrop flew several flying wing designs in the 40s and 50s ( see IAPR ), so a flying wing is not controversial for them.
As for the F-14 all the competitor’s submissions used swing-wings and the only two with practical experience were GD and Grumman (having worked on the F-111B). It didn’t make sense to give it to GD to replace their own failed concept so it was given to Grumman. In effect, the safest choice.

This forum always gets bogged down in definitions. Look, according to any elementary aerodynamics text, to determine stability or instability, you need to disregard the trimming foreplanes or tailplanes and consider just the mainwing. If the centre of lift is ahead of the centre og gravity, the aircraft will tend to depart in pitch, and is said to be unstable. It then needs downforce on the front or upforce on the rear for controlled flight. A digital flight control system applies these forces using canards or tailplanes, thousands of times per second, and has been described as ‘steering a bicycle backwards while sitting on the hood (bonnet) of a car travelling at 60mph’. Trouble arises when the pilot and FCS both make compensating inputs leading to a divergent situation. This is called a pilot induced oscillation and a PIO was responsible for the loss of the Gripen 17yrs ago.

What is forgotten, however, is that as an aircraft becomes supersonic, its centre of lift (pressure) moves back from the quarter-chord point to about half-chord, which may move it behind the centre of gravity and make the aircraft, now stable, require different fore or aft forces.

I do hope the Rafale gets ‘active” cancellation as, in my opinion it is the best way to go, and US stealth is going more in that direction already. It does not impose any constraints on the design of the aircraft like ‘traditional’ stealth does. The plane can be designed for agility, ordinance delivery or even transport for that matter, and stealth qualities added on.
This does not involve masking all the radar reflections from all angles of the plane, just the one reflected in the general direction of the emitting aircraft. It involves considerable amounts of signal processing as the incoming signal has to be analised and the reflection has to be modified/attenuated all in real time, but all it really is , is vastly expanded electronic warfare.
I can see stealth upgrades being offered for all current combat aircraft in 15-20 yrs time, much like current radar/avionics upgrades. If France gets in on the ground floor of this emerging technology, its industry stands to make a lot of profit.

A lot of you guys keep demonstrating your total ignorance of stealth by stating that PAK-FA is stealthier than F-35. I’ll be the first to admit, I DON’T KNOW. As for the rest of you, I’ll repeat, YOU CANNOT QUANTIFY THE STEALTHINESS OF A PLANE BY LOOKING AT IT !!!
Modern stealth design includes internal positioning of metal structures and equipment to reflect and absorb mm-wave radiation (much like cones lining walls of anechoic chambers – internal reflection). The outer ‘skin’, composed for the most part of composite materials, is mostly transparent.
How anyone, having just seen videos of the T-50 and knowing very little else about the plane, can say with any certainty what its degree of stealthiness is, is beyond me

Doctorate of Philosophy is long form for PhD or a 7yr advanced University degree. Here in Canada , anyway we have BSc, 4yr degree, MSc, 5yr degree and PhD. At least in the sciences.