MiG-21FL
(Type 77)
The earliest mark of the MiG-21 (NATO Code
Fishbed) to enter the IAF’s inventory in 1963 was the MiG-21F-13, also referred
to as the Type 74. It could carry 2 x K-13 Infra Red (IR) homing air-to-air
missiles (NATO code Atoll) and had a single 37 mm NR-37 cannon and a gyro gun sight
with radar ranging. The role of the aircraft was primarily air defence.
This was followed in 1965 by the MiG-21PF (Type
76) which was the first version to be equipped with an Airborne Interception
(AI) radar, the R1L. The MiG-21FL (Type 77), made its appearance in 1966 and
was equipped with the R2L AI radar. These two versions did not have a gun and
could only carry 2 x K-13 missiles. The small number of Type 74s and Type 76s
were phased out by 1968.
As war clouds gathered over the
sub-continent in March 1971, a podded gun carried at the ventral station was
supplied by the Soviet Union, but only a PKI fixed gun sight was available for
aiming. Trials were then carried out with the Gyro Gun Sight GGS Mk 4 by the
Tactics and Combat Development and Training Squadron (now the Tactics and
Combat Development Establishment) at Jamnagar in mid-1971 but the modification
was not pursued because the sight had to be installed inverted to fit in the
available space. The December 1971 Indo-Pak war convinced the operations
directorate at Air Headquarters that the MiG-21 fleet had to have a gun with a
predictor gyro sight and a request was made to the Soviets for a gun-armed
version of the MiG-21.
The
MiG-21 M arrives
In 1973 the Soviet Union offered an
improved version of the MiG-21, the MiG-21M, which in the IAF was known as the
Type 96. This version had an AI radar (the RP-21M) and a twin barreled GsH-23
internally mounted cannon which could fire 3000 x 23 mm rounds per minute and
had a gyro gun sight as well. In addition, this was equipped with an improved
ejection seat (the KM-1) which had ground level ejection capability. The
Soviets offered this version with a new engine, the R-13-300, which had somewhat
more thrust than the earlier R-11F2S-300 engine which powered the Type 77
fleet. The airframe could accommodate the R-11 engine as well, but the R-13
engine had a second stage afterburner which cut in at Mach 1.6 to improve
supersonic acceleration. However, a large saddle tank spoilt the beautiful area
ruling of the Type 77 airframe and the Type 96 could not match the supersonic
performance of the Type 77. The Type 96 however, had a gun, a radar warning
receiver, could carry 2 x 490 litre drop tanks under the wing, an 800 litre
drop tank at the ventral station and was therefore a more versatile platform.
As license manufacture of the MiG-21M was
contemplated, the IAF had to quickly decide on choice of the engine. In
February 1973 two MiG-21 M aircraft, one fitted with an R-13 engine was
designated MiG-21MF (C-1533) and the other fitted with the earlier R-11 engine,
remained the MiG-21M (C-1531), both positioned at ASTE at Kanpur. Sqn Ldr S
Krishnaswamy (later CAS) and I carried out a comparative evaluation of
performance of the two aircraft with the two different engines between 22 February
and 4 March 1973.
The evaluation consisted of 24 operational
profiles flown at low, medium and high altitude. Acceleration times to various
Mach numbers, up to Mach 2.05 and time to climb to 19 km were compared. On 4
March 1973, I wore pressure clothing and flew two static climb sorties to 19 km
on the two aircraft one immediately after the other. The visibility was barely
1.5 km at Kanpur because of dust haze and the radar surveillance by the radar
unit at Memora, near Lucknow was not very good. I had to go out about 180 km in
a south easterly direction, accelerate to Mach 1.85 in the turn on to
reciprocal heading and then climb to 19 km. On each occasion I reached 19 km
with the 450 litres low fuel level warning light glowing in the cockpit while I
was at a distance of 100 km from base. The prevailing poor visibility, pressure
clothing which restricted outside view from the cockpit, the absence of
navigation aids other than the radio compass and the low fuel state called for careful
handling of the situation. I had to throttle back to idle below 15 km altitude,
descend at 500 km/hr IAS, arrive overhead base with just 300 litres which gave
me three to four minutes to execute the circuit and landing. It was satisfying
to complete the static climbs. The R-13 engine did give the MF version a small
but noticeable edge in performance over the M version at low and medium
altitude. Since the R-11 was already being manufactured at HAL, Koraput Air Headquarters
decided to drop the R-13 on techno-economic considerations.
MiG-21M
(Type 96)
The Soviets did not give up efforts to
convince Air Headquarters to produce the R-13 instead of the R-11 at Koraput
and offered an improved version of the R-13, the R-13 F for evaluation by IAF
test pilots. In April 1975, Air Headquarters sent a team of three officers, Wg
Cdr PM ‘Ramu’ Ramachandran (later VCAS), Sqn Ldr BR Madhav Rao, an AE(M)
officer who had vast experience of working on the MiG-21 and myself to
Krasnodar, near the Black Sea to carry out the evaluation. The R-13 F engine was
identical to the R-13 except that it had the provision for an emergency reheat
mode which could be engaged when required by turning on a switch which was just
ahead of the throttle. At Krasnodar
we were not allowed to exceed 1000 km/hr IAS in the local flying area. Ramu and
I could not find any difference in performance in the sub sonic regime. When we
discussed our findings with the Soviets, they turned around and said that the
main advantage could only be seen while accelerating to limiting IAS at low
level or while accelerating through the transonic regime at medium altitude.
When asked to be allowed to go supersonic at Krasnodar, they refused, saying
that the area where they carried out supersonic flights, foreigners were not
allowed to fly! We returned to Air Headquarters and categorically stated in our
report that it was not worth going in for the R-13 F.
Our rejection of the R-13F engine had a very
beneficial effect because when the CAS, Air Chief Marshal OP Mehra, visited the
Soviet Union a little later, his team was shown the definitive MiG-21bis,
fitted with the R-25 engine. The R-25 was a much superior engine to various
engines fitted in MiG-21s so far in IAF service and the MiG-21bis entered
service in 1976, being more capable than the M version because it had a
superior AI radar, the Almaz, and a better engine. Both the airframe and engine
were to be manufactured under license later by HAL.
In 1983 Air Marshal LM Katre was appointed Chairman
of HAL. He set about trying to revive the moribund design bureau of the
company. He ordered the HPT-32 to be re-engined with a turbo-prop, the
Hindustan Turbo Trainer-34 (HTT-34). I had an opportunity to fly some sorties
on this very lively aircraft, which had impressive performance, spun exactly
like the HPT-32 and would have made an ideal trainer for the basic flying stage
in the IAF. Had this aircraft development been pursued we would not now have had
to go to the world market to look for a HPT-32 replacement. The Ajeet trainer
project was given the go ahead and a MiG-21bis modernisation project was
launched at HAL, Nasik. Air Marshal LM Katre was a visionary Chairman and HAL
had an opportunity to dramatically transform itself under his leadership but regrettably,
his tenure at HAL (and later as CAS) was all too short.
MiG-21UM
(Type 69)
Dr Kota Harinarayana who was the Chief
Resident Engineer (CRE) at Nasik joined HAL and was made chief designer of the
Nasik Design Bureau. One MiG-21bis airframe (C-2270) was modified with the
following modifications:
- The
leading edge of the wing was fitted with a vortex plate. This was no more
than a steel plate with a rounded contour to fit the leading edge with a
metal plate about six centimeters in length which protruded from the
bottom of the leading edge into the airstream. This device was a
modification developed by the National Aerospace Laboratories (NAL) after
extensive wind tunnel work at Bangalore and meant to energise the airflow
over the wings at high angles of attack thereby improving turn
performance.
- The
normal two position wing flap was replaced by a blow back flap which
extended in stages as the speed reduced. It retracted fully at about 700km/hr
IAS. This device was also meant to improve manoeuvere performance at low
speeds.
- An
enlarged saddle tank which increased fuel capacity by 200 litres was
fitted. This modification certainly made the dorsal spine behind the
cockpit look fat and ugly!
- Some
Soviet era avionics like the radio, radio compass, radio altimeter were
replaced by Western avionics. To make use of the savings in weight a small
rubberised fuel tank containing 120 litres of fuel was fitted in the area
behind cockpit pressure bulkhead.
After initial flights at Nasik, the
aircraft was positioned at ASTE in early 1985 for a thorough evaluation. I was
the Chief Test Pilot at ASTE at that time and the evaluation was done by pilots
in the Flight Test Squadron. I flew only one sortie on
14 June 1985 to look at the problem areas
pointed out by the evaluation pilots. The vortex plate did improve subsonic
turn rates by about 8-10 % which was good for a passive, low cost device.
Supersonic acceleration, however, deteriorated due to the fat saddle tank and
the combat flap did not significantly improve manoeuvere performance. Air Headquarters
rejected this attempt at modernisation but this was, however, a good learning experience
for the Nasik design bureau.
MiG-21bis
(Type 75)
One of the principal drawback of various
marks of the MiG-21s in IAF service was the absence of a navigation and attack
system. Navigating at low level with only a stop watch, compass and map
required a lot of training and practice to attain and retain proficiency. Weapons
could be delivered accurately in a dive only by adhering to rigid entry and
release conditions which did not allow for any tactical flexibility in the
attack. Lay down attacks with retarded weapons were equally difficult because
the target would disappear below the nose well before the release point. The
final release had to be done by counting down a time delay after the target had
disappeared! This method was not very accurate and so by 1986 the IAF had
started serious search for a suitable navigation and attack system for its MiG-21
fleet.
Evaluation
in Egypt
In 1987, Marconi Elliot of the UK informed Air
Headquarters that they had fitted a nav/attack system in MiG-21Ms of the
Egyptian Air Force (EAF). The system consisted of a Head Up Display (HUD), a
display processor which also did weapon aiming computations and a air data
computer which accepted inputs from the aircraft’s pitot static system and twin
gyro platform to perform navigation calculations. A colour video camera which
recorded HUD symbology to act as a useful mission debrief tool and a keyboard
fitted just below the HUD which was the input device, completed the system. Apart
from the HUD, keyboard and camera which were fitted in the cockpit the rest of
the system was neatly packaged in nose compartment of the aircraft.
Thanks to good relations existing between
the UK, India and Egypt, the company offered to arrange for a no cost - no
commitment evaluation of their system fitted in an EAF aircraft. The EAF wanted
their aircraft to be insured and the insurance company in turn wanted to know
the qualifications and experience on type of the pilot who would perform the
evaluation. Air Headquarters detailed me to do the evaluation and the insurance
company accepted my competence to do the job as I had flown over 2000 hours on
various marks of the MiG-21 by that time!
As I was not in regular flying touch with
the MiG-21M, I requested Air Headquarters to attach me to an operational
squadron for a short while to get my hand back and practice weapon delivery. I
flew seven armament sorties with No. 29 Squadron at Jamnagar between 4 August 1987
and 7 August 1987. I really enjoyed myself firing rockets and guns and dropping
practice bombs over Sarmat range after a long break!
The evaluation was conducted at the Al
Mansoura air base in the Nile delta, north of Cairo between 24 August 1987 and
29 August 1987. I was first briefed on the system characteristics by Marconi
Elliot representatives and the EAF Research and Development department
personnel. I familiarised myself with the system in a system simulator on the
ground and was first given a sector recce sortie in a MiG trainer by Colonel
Ibrahim of the EAF. The early morning haze over the delta was dense and
visibility was barely a couple of kilometers. When we reached Port Said and
started flying westwards towards Alexandria over the Mediterranean Sea, the
visibility improved considerably. Colonel Ibrahim said he would send a chase
aircraft when I flew solo and I agreed because the triangular cross country way
points were small towns in the delta and it would have been easy to miss them
in the haze.
In all I flew four sorties (tail nos 8354
and 8324) to assess navigation performance and did dummy dives over the
airfield to prepare for the weapon delivery sorties. Unfortunately the EAF got
cold feet at this stage and did not authorise me for weapon delivery saying
that the Wadi Natrun range in the desert west of Cairo was “not available”. One or two sorties of weapon delivery would
not have enabled me to collect any statistically significant data and EAF
statistics would have had to be used in any assessment. In my view the lack of
live firing did not affect the evaluation.
After having flown the inertial nav/attack
system in the Darin Jaguars, I thought this system on offer was primitive. It
may have been state of the art some years earlier but it was clearly out of
date. I did, however, find flying the MiG-21 with a HUD a pleasure and the
video recorder debriefing tool of immense value. Air Headquarters now gave up
its search for a nav/attack system for the time being.
The need
for comprehensive upgrade
When AOC, AF Station Gorakhpur in 1989, I
was sent on a short course on Systems Analyses at Metcalfe House in old Delhi.
I found this course very informative and useful because it taught one how to
develop quantitative criteria to aid decision making. In 1991 when I was
Commandant ASTE I was asked by Air Headquarters to carry out a study on operational
effectiveness between Soviet-origin and Western aircraft. Amongst other things
this study clearly brought out the need to upgrade as many systems in an
aircraft as possible if its effectiveness was to be improved. To meaningfully upgrade
the MiG-21 fleet, a number of improvements had to be made in one go
particularly pertaining to its primary sensor, the AI radar, and then navigation, weapons, weapon aiming
and airframe life extension which was required for reasonable exploitation of
the upgraded fleet.
The Soviet Union had passed into history at the end of 1991
and now the Russian Federation offered an upgrade package for the MiG-21bis
fleet in 1992. At about the same time, India established diplomatic relations
with Israel and defence ties with that country started to develop at a rapid
pace. Israel Aircraft Industries (IAI) offered an upgrade of the MiG-21, which
they had developed for the Romanian Air Force. In May 1993 I was sent to Tel
Aviv to evaluate this proposal. The first topic I raised with the IAI engineers
was about airframe life extension. When asked whether they had the structural
data of the MiG-21bis airframe to carry out the life extension they replied in
the negative and said they expected the IAF to provide the data. I then flew a
sortie in a Lavi test bed aircraft to evaluate the Elta 2032 radar which was
being offered for the upgrade. Unfortunately the radar failed after only 10
minutes of flight and I was not able to evaluate it. When I submitted my report
to Air Headquarters stating these
two important factors, the Israeli proposal was rejected.
MiG-21bison
In July 1993 I was posted to Air Headquarters
as Director Air Staff Requirements and the MiG-21 fleet upgrade problem dropped
into my lap. The Mikoyan design bureau had offered a very attractive upgrade
package at reasonable cost. The package consisted of new radar called the Kopyo,
Beyond Visual Range (BVR) missile carrying capability, latest Close Combat
Missiles, an Inertial Nav/Attack System (INAS), Counter Measures Dispensing
System (CMDS) and some EW capability. In December 1993, I led a team of IAF, HAL
and DRDO officers for a first round of talks on the upgrade proposal with the
Mikoyan design bureau and had the pleasure of interacting with Mr Beliakov who
was Chief Designer of the bureau.
I had a group photograph taken of the team
and him standing near the bust of Artem Mikoyan, the famous designer who had
founded the design bureau. The Indian team visited several other plants where
other systems on offer were being manufactured. Of particular interest was the team’s
visit to the Vympel missile design bureau at Tushino and the Sokol plant at
Nizhny Novogorod (old name Gorkhy) dedicated to the manufacture of MiG designs.
This was the plant where upgradation of the first two airframes would be
carried out. We spent two weeks in the freezing cold of Moscow but returned to
Delhi convinced that the Russian package was the manner to go. In July 1994, I
led another team for the second round of talks and we were able to finalise the
technical specifications of the upgrade. Commercial negotiations followed and
the contract was signed sometime in 1996.
In
pristine shape: the MiG-21bis
The IAF positioned a team of test pilots
and technical officers at the Sokol plant at Nizhny to oversee the upgrade programme.
Wing Commander N Harish was the first IAF test pilot to fly the upgraded
Mig-21bis now called the Bison (son of Bis!) in 2000. MiG-21 Bison squadrons
are now in operational service and so the long and tortuous upgrade saga of the
MiG-21 recorded its final chapter.
Article
by Air Marshal Philip Rajkumar