From below article it appears that 21 can still hold its own in dogfight:



Try to point at and shoot well flown MiG-21!

Predrag Pavlovic, dipl.ing. and Nenad Pavlovic, dipl.ing, JAT Airways


Maneuverability of modern fighter is measured by how slow it can fly and how high angle of attack it can sustain and still turn. During some war situations, US evaluation and Aggressor use, MiG-21 has shown it can keep pace with modern planes in this area. Aircraft manufacturer at one time considered this irrelevant and imposed restrictions on angle of attack. Flying above allowed 28-33 degrees local angle of attack at low speeds makes possible to relatively safely achieve a maneuverability once considered privilege of modern fighters.


Couple years ago reports and testimonies appeared in the media about a dogfight during the Israeli-Arab War '73. when the Egyptian MiG-21 pilot managed to do a Split-S maneuver at the start altitude of 3000 feet, less than half minimum airspace the manual says (about 6750 ft). Appropriate simulation can be found on the internet:

http://www.youtube.com/watch?v=bQMzK...layer_embedded




Figure 1.


Initiated by this event, some American and Israeli enthusiasts (once pilots of their AF fighters), one of which has a private squadron of various Russian fighters, attempted to replicate that minimum altitude needed to complete Split-S figure in the two-seater MiG-21. Previous consultation with Israeli ace, who participated in that dogfight in '73. war, did not help test to be successful. Attempts were carried out at the higher altitude (5 km) and the height loss during the figure was in accordance with flight manual. It remained unclear whether ’73 event was result of "special skills or superhuman strength of the Egyptian pilot needed to withstand the required g-loads”.


Recently disclosed files of the official MiG-21 evaluation in the U.S. revealed some unexpected capabilities that can be correlated with the "inexplicable" ’73. maneuver. MiGs were brought to America via Israel, in the late '60s as a result of pilot error or fled from Iraq and Algeria. Later they were bought from Indonesia. The MiG-21 in the U.S. Air Force is designated YF-110.
The report of a MiG-21F shows nothing particularly unusual, except for maneuvering capabilities and behavior/handling at low speeds described as "class above competition”. Besides that, if competitors tried to follow MiG-21F at high alpha, their engine experienced shutdown or compressor stall. MiG could perform "hammerhead" turn (wing over/stall turn/renversement) at 100 knots (knot = 1.853 km/h), figure where at the end of the vertical climb pilot add rudder (with the opposite aileron and forward stick) to push the plane in the dive. Rudder is effective from 30 knots. With the stick fully backward, the plane flies at 210 km/h, the rolling oscillations are present, but there is no lift breakdown or the tendency towards spin. If during the evaluation, loss of control due to uncoordinated controls occurred, it was in the form of roll-off (usually for 180°) instead of much more dangerous yaw-off. To put the plane back under control it was necessary only to release controls. MiG-21 proved to be docile, safer to fly than MIG-17. During the hundred flight tests engine compressor stall was never experienced.
U.S. of course, used MiGs in dogfight evaluation against their aircraft. Latter, they formed "Aggressor" squadron of MiGs and other fighters for the dogfight simulation with regular American aircraft.





Figure 2, 3. MiG-21 on testing in the U.S.

During MiG testing, it was clear that U.S. pilots have not relied on Soviet pilot’s manuals or they did not have one at the beginning. That is why the aircraft ability was fully exploited. Test pilots had thousands of flight hours experience on dozens of types of aircraft. Those who have survived the testing of U.S. supersonic fighters
F-100/101/104/4 (many of planes were called "widow makers"), learned to recognize the pre-stall/spin signs and use rudder for rolling the aircraft at higher angles of attack.




Figure 4. Some of the results of MiG-21 testing in the United States



Reportedly, if Vietnamese pilots had adequate training, the U.S. fighter shot-down ratio figures would be much worse in that war. In the hands of the well trained pilots, MiG would always outmaneuvered Phantom. US unveils graphs depicting not only far better instantaneous turn performance of Fishbed C compared to F-4D but also better sustained maneuverability. MiG-21 Aggressor pilots respected only the most modern fighters because they do not lose so much speed in turn even at low speeds. However, appearance of all-aspect infrared missiles reduced the importance of sustained turns (M2000, F-18E, Gripen …are not brilliant in the maintaining speed in turn). If MiG-21 had R-73 missile, it could easily take advantage of first shoot opportunity at close range against any new fighter.
The F-5E, fighter which does not fly above Mach 1.5, MiG-21 simulator, reportedly has shade better subsonic sustained turn maneuverability, but inferior controllability at low speeds. Maneuverability is the ability to change speed and direction of flight path (velocity vector pointing) and controllability - ability of change aircraft attitude (pitch/roll/yaw - nose pointing) and thrust (engine response - spool up time matters). When the aircraft initial flight path in dogfight is anti-parallel flyby, combat will inevitably develop so that someone goes in a climb with rolling scissors - turn reversals along the opponent’s flight path to remain behind the opponent. If the F-5E does not gain an advantage before the speed drops below 200 knots, MiG will start winning. First look at the configuration of the aircraft, MiG – delta with the sweep near 60°, and Tiger with nearly straight wings, would suggest the opposite, that MiG is in trouble at low speed.

Even the mighty F-15 Eagle had no solution in dogfight below 150-250 knots against MiG-21 in US Aggressor hands. At the beginning of dogfight, at the speed of 400-500 knots MiG-21 will turn at max g loosing 70 knots per second, ending at the speed of 70 knots in less than 90º of turn (deceleration of 3.5 g, more intensive than Harrier’s VIFF turn). Reportedly, no other aircraft can do that. This way MiG will remain behind every opponent still having sufficient controllability for gun tracking using rudder rolls. Opponents would think that at this speed MiG can only bring down the nose and dive, but the MiG at less than 100 knots has sufficient pitch authority to raise the nose at enemy. If F-15 tries to follow, ’21 should execute 'barrel-roll ' to remain behind the Eagle.
It is obvious that MiG-21 'Aggressor' pilots pulled full aft stick in turn regardless of the lateral oscillations, roll-off and temporary loss of control.





Figure 5. Scissors maneuver

Latter, the F-15 pilots learned (in a hard way) not to accept maneuvering at slow speeds, not to allow to be drown into a series of turn reversals, but to withdraw and re-attack at higher speeds using 3D turns and it’s higher thrust/weight ratio. F-15 with 45º swept wing and low horizontal tail, at higher angle of attack becomes longitudinally superstable, so it can not achieve more than about 30º angle of attack.

On the example of lift and stability of the aircraft with the 45º swept wing and high-set horizontal tail it can be seen that the lift begins to decline at 10º (buffeting starts), the wings are stalled at the 20º (the airflow separates from the wing), and max body lift is at 35-40º after which it decreases. Delta wing of MiG-21 with sweep of 57 º retains stable airflow to very high angles of attack.
Longitudinal stability is positive where the curve has a downward slope. In this case, the position of the horizontal tail is causing longitudinal instability at 15º, and at 35-40º angle of attack aircraft is trimmed without tail deflection. MiG-21 has no problem with longitudinal stability (except with air to ground armament with low fuel) and the plane in the example would have a limit at 15º angle of attack.
Yaw stability curve shows that the aircraft is unstable at 15º, what is not uncommon. Few modern fighters are stable at over 20º, but it is not a problem if the aircraft maintains lateral stability i.e. roll due to yaw. Roll stability curve is increasing as the lift increase, so it similarly comes to the instability, in this case at about 20º angle of attack. Shall the plane have a tendency toward spin (at no deflection of the control surfaces!) show the curve of dynamic directional stability where factors are static yaw and roll stability along the inertial characteristics of the aircraft. In this example, the plane is at stall just above 20º angle of attack, while MiG-21 is stable at well over 30º at low Mach numbers.
Curves correspond to a particular Mach number, at some other speed they can vary significantly.