 |
| Download Papercraft |
The MiG-21 jet fighter was a continuation of Soviet jet fighters, starting with the subsonic MiG-15 and MiG-17, and the supersonic MiG-19. A number of experimental Mach 2 Soviet designs were based on nose intakes with either swept-back wings, such as the Sukhoi Su-7, or tailed deltas, of which the MiG-21 would be the most successful.
Development of what would become the MiG-21 began in the early 1950s,
when Mikoyan OKB finished a preliminary design study for a prototype
designated Ye-1 in 1954. This project was very quickly reworked when it
was determined that the planned engine was underpowered; the redesign
led to the second prototype, the Ye-2. Both these and other early
prototypes featured swept wings—the first prototype with delta wings
as found on production variants was the Ye-4. The Ye-4 made its maiden
flight on 16 June 1955 and made its first public appearance during the Soviet Aviation Day display at Moscow's Tushino airfield in July 1956.
In the West, due to the lack of available information, early details
of the MiG-21 often were confused with those of similar Soviet fighters
of the era. In one instance, Jane's All the World's Aircraft 1960–1961 listed the "Fishbed" as a Sukhoi design and used an illustration of the Su-9 'Fishpot'.
Design
The MiG-21 was the first successful Soviet aircraft combining fighter and interceptor characteristics in a single aircraft. It was a lightweight fighter, achieving Mach 2 with a relatively low-powered afterburning turbojet, and is thus comparable to the American Lockheed F-104 Starfighter and Northrop F-5 Freedom Fighter and the French Dassault Mirage III.[1] Its basic layout was used for numerous other Soviet designs; delta-winged aircraft included Su-9 interceptor and the fast E-150 prototype from MiG bureau while the mass-produced successful front fighter Su-7 and Mikoyan's I-75
experimental interceptor combined a similar fuselage shape with
swept-back wings. However, the characteristic layout with the shock cone
and front air intake did not see widespread use outside the USSR and
finally proved to have limited development potential, mainly because of
the very small space available for the radar.
Like many aircraft designed as interceptors, the MiG-21 had a short
range. This was exacerbated by the poor placement of the internal fuel
tanks ahead of the center of gravity. As the internal fuel was consumed,
the center of gravity would shift rearward beyond acceptable
parameters. This had the effect of making the plane statically unstable
to the point of being uncontrollable, resulting in an endurance of only
45 minutes in clean condition. This can be somewhat countered by
carrying fuel in external tanks closer to the center of gravity. The
Chinese variants somewhat improved the internal fuel tank layout, and
also carry significantly larger external fuel tanks to counter this
issue.
Additionally, when more than half the fuel was used up, violent
maneuvers prevented fuel from flowing into the engine, thereby causing
it to shut down in flight. This increased the risk of tank implosions, a
problem inherited from the MiG-15/MiG-17 and MiG-19.
The short endurance and low fuel capacity of the MiG-21F, PF, PFM, S/SM
and M/MF variants—though each had a somewhat greater fuel capacity than
its predecessor—led to the development of the MT and SMT variants.
These had an increased range of 250 km (155 mi) compared to the
MiG-21SM, but at the cost of worsening all other performance figures,
such as a lower service ceiling and slower time to altitude.
The delta wing, while excellent for a fast-climbing interceptor,
meant any form of turning combat led to a rapid loss of speed. However,
the light loading of the aircraft could mean that a climb rate of 235 m/s (46,250 ft/min) was possible with a combat-loaded MiG-21bis, not far short of the performance of the later F-16A.
Given a skilled pilot and capable missiles, it could give a good
account of itself against contemporary fighters. Its G-limits were
increased from +7Gs in initial variants to +8.5Gs in the latest
variants. It was replaced by the newer variable-geometry MiG-23 and MiG-27 for ground support duties. However, not until the MiG-29 would the Soviet Union ultimately replace the MiG-21 as a maneuvering dogfighter to counter new American air superiority types.
The MiG-21 was exported widely and continues to be used. The
aircraft's simple controls, engine, weapons, and avionics were typical
of Soviet-era military designs. The use of a tail with the delta wing
aids stability and control at the extremes of the flight envelope,
enhancing safety for lower-skilled pilots; this in turn enhanced its
marketability in exports to developing countries with limited training
programs and restricted pilot pools. While technologically inferior to
the more advanced fighters it often faced, low production and
maintenance costs made it a favorite of nations buying Eastern Bloc
military hardware. Several Russian, Israeli and Romanian firms have
begun to offer upgrade packages to MiG-21 operators, designed to bring
the aircraft up to a modern standard, with greatly upgraded avionics and
armaments.
A total of 10,645 aircraft were built in the USSR. They were produced in three factories: AZ 30[N 1] (3,203 aircraft) in Moscow (also known as MMZ Znamya Truda), GAZ 21 (5,765 aircraft) in Gorky [N 2] and at TAZ 31 (1,678 aircraft) in Tbilisi.
Generally, Gorky built single-seaters for the Soviet forces. Moscow
constructed single-seaters for export, and Tbilisi manufactured the
twin-seaters both for export and for the USSR, though there were
exceptions. The MiG-21R and MiG-21bis for export and for the USSR were
built in Gorky, 17 single-seaters were helmed in Tbilisi (MiG-21 and
MiG-21F), the MiG-21MF was first constructed in Moscow and then Gorky,
and the MiG-21U was built in Moscow as well as in Tbilisi
No comments:
Post a Comment