Tuesday, April 15, 2008

Multirole Fighter - Sukhoi Su-33 "Flanker D"

The Sukhoi Su-33 (NATO reporting name 'Flanker-D') is carrier-based multi-role fighter aircraft produced by Russian firm Sukhoi beginning in 1982. It is a derivative of the Su-27 'Flanker' and was initially known as the Su-27K. The main difference from the Su-27 is that the Su-33 can operate from aircraft carriers. Unlike the Su-27, the Su-33 is capable of aerial refueling.

Su-33 on the deck of a Russian aircraft carrier

The Su-33 first flew in May 1985, and entered service in the Russian Navy in 1994. An air regiment comprising 24 fighters of the type was formed upon the Russian Navy's only operating aircraft carrier, Admiral Kuznetsov.

Forward view of an Su-33 with wings folded

The Su-33 is designed to use a ski-jump instead of catapult for carrier takeoff. The ski jump provides many advantages over a catapult launch. The most evident is that a ski jump does not put stress on the airframe and pilot, allowing lower weight because less structural reinforcement is required and prevents G-LOC (G-induced loss of consciousness.) Also, with a ski jump launch, the aircraft can engage full afterburner earlier than a catapult launch, because the aircraft is restrained by pop-up detents rather than a catapult shoe. Once in the air the aircraft has a positive AOA as well as pitch angular speed which increases during acceleration, and assists the climb. This method does require an aircraft that is more stable and maneuverable at low speeds.

An Su-33 on board Admiral Kuznetsov (Russian aircraft carrier)

The Su-33 sports canards that shorten the take-off distance and improve maneuverability, but required reshaping of the leading edge extensions. The canards counter pitch-down force generated by leading and trailing edge flaps reducing approach speed by 1.5 times; They also act as destabilizers in supersonic flight, by reducing pitch trim drag.

Su-33 preparing for takeoff

The wing area was also increased, though the span remained unchanged. The wings were fitted with power-assisted folding, and the vertical tails were shortened to allow the fighter to fit in the typically crowded hangars of an aircraft carrier. The rear radome was shortened and reshaped to allow for the tail hook, as well as to save space inside the hangars. The IRST was moved to provide better downward visibility and an L-shaped retractable refuelling probe was fitted to increase range.

One Su-33 takes off while another prepares to launch

The Su-33 carries guided missiles such as the Kh-25MP, Kh-31 and H-41. The plane can be used in both night and day operations at sea. It can operate under assistance of the command center ship, or in conjunction with a Kamov Ka-31 (a variant of the Ka-27) early-warning helicopter. The R-27EM missiles provide it the capability to intercept antiship missiles.

Su-33 showing its planform in flight

Other than air defence, the duties of the Su-33 include destruction of enemy ASW, AWACS, and transport aircraft, anti-shipping strike, support of amphibious landing, escort, reconnaissance, and laying of minefields.

Su-33 maneuvering in flight

Su-33 in flight

Overhead view of an Su-33 and an Su-25

3 view schematic

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