In my previous article, I covered the origin and the development of the Su-27 in detail. In this article I will track the evolution of the Su-27 and its combat capabilities and we will see how it compared with its American rival, the F-15. The previous article ended with the acceptance of the Su-27 into the Soviet Air Force. It officially was still a secret fighter and now, the Soviets were ready to unveil it to the world. The details for the story and photos are sourced from the ‘Wings of Russia’ documentary which I recommend Su-27 lovers to watch. Here I have interpreted and given an analytical account of the story as well as additional information from my research. Do read the first part for a better understanding of this article.
In 1986, when the Su-27 was still an official secret, it was decided to make a special variant of it which was modified to break the word records set by the F-15 special variant ‘Streak Eagle’ in 1975. This aircraft, for the purpose of secrecy was designated as P-42 as the Soviets still weren’t ready to unveil it to the public. The P-42 was a heavily stripped Su-27 and had all its combat systems and electronics removed in order to reduce its weight to minimum. Its paint was removed as well in order to make it more aerodynamic. The other extremely important factor is the thrust to weight ratio which is directly affected by the weight of the aircraft. The Su-27 had a weight of 23 tons and a thrust of 25 tons, which meant that the thrust to weight ratio exceeded 1. This ensures very good performance.
However, the P-42 was so heavily stripped to make it light that its weight was reduced to almost 12 tons from the initial 23 tons! This meant that the thrust to weight ratio was 2 (because 25/12 is approx =2) which allowed it to attain incredible rates of acceleration. This was demonstrated when the P-42 exceeded the speed of sound in vertical flight! In the next 2 years, the P-42 set more than 30 world records. Test pilot Victor Pugachev broke the F-15 climb record by 2 seconds and Test pilot Nikolai broke the F-15 climb record by 7 seconds by climbing 15 km in 1 minute 16 seconds! This made the Su-27 the winner in the performance parameters round. But it still had a long way to go and was yet to be exposed to the world.
In 1987 the NATO got its first good look at the Su-27 during its operational patrols. The photos taken at that time were the first clear photos possessed by the western intelligence. The first image was taken in 1978 from a spy satellite. At last in 1989, the Soviets decided to display the Su-27 at the Paris air show and unveil its existence to the world formally. It made a spectacular impact by flying nonstop from Zhukovsky, near Moscow to Paris without external fuel tanks and air tanker support. This was done to show to the west that the Su-27 could easily cross over half of Europe and had more range than any other fighter they had. It then vowed the audience and aviation experts with its incredible maneuverability.
It was here that Victor Pugachev performed the famous Pugachev Cobra manoeuver which remains associated like a trademark with the Flanker till date. The Cobra involves the Su-27 going into supercritical angles of attack (>90 degrees) and sharply reducing its speed by about 250 km/hr, to allow the trailing fighter to fly past so that the Su-27 can get on its tail. The illustration below shows how the manoeuver in performed. These excellent characteristics led to the Russian Knights air display team using the Su-27 which is popular all over the world.
Illustration of Su-27 performing cobra manoeuver
It was in this particular air show that Chinese and Indian officials paid attention to the Su-27 and the Soviet Union was going to get large export orders from these 2 nations in the coming years. The Chinese procured the Su-27 and made their own copies. They later on procured the multirole Su-30 as well. India however took a different approach. They wanted a Su-30 which was fitted with their choice of avionics sourced from western nations. This resulted in the Su-30Mki which remained the best variant of Su-30 in service until Russia started producing the S-30SM. It is interesting to note that these Su-30s are twin seaters. India became the largest Su-30 customer when their order for the Su-30Mki touched 272 aircraft.
In 1992, a long awaited dream came true for both sides when after negotiations, the Su-27s made a friendly visit to the USAF base in Virginia for mock combat with their nemesis F-15s. It was decided that there would be 2 rounds of dogfights in which the Su-27 would be the tail for one round and vice versa for the other round. First, the Su-27 tailed the F-15 in a mock dogfight, but the Eagle failed to break the tail and disengage the Flanker. In the second round, the F-15 tailed the Su-27. The flanker pilot managed to rapidly reduce speed and did a one and half turn which made the F-15 to shoot past and put the flanker on the tail of the eagle. This meant that the Su-27 clearly won both the mock dogfighting rounds and showed its worth. The America general flew in a 2 seat Su-27 and later on indicated that its maneuverability was better than that of the F-15. It was a sweet victory for the Su-27 of the now Russian Air Force.
Let us now examine the exact combat capabilities and features of the Su-27. The initial Su-27 production models had a completely analog cockpit with a tiny display for the radar. The pilot used a helmet mounted sight to aim his weapons. The radar was a mechanically scanning radar which could detect fighter sized targets at 100+ km. It also featured an optical detection system which consisted of an infrared Search & Track system and a laser rangefinder. This allowed to the Su-27 to detect targets at around 50 km passively, without using its radar and exposing itself. This feature would be very crucial in close combat scenarios. The radar, optical sensors and the helmet mounted display were completely integrated and used in conjunction to ensure optimal combat performance. Systems like helmet mounted display and the IRST were missing from its rival, the F-15. It is also interesting to note that the twin seater Su-27UB had the same capabilities of the single seater with no reduction in capabilities whatsoever.
The basic Su-27 was an air superiority fighter and lacked air to ground capabilities. However the following batch was upgraded to Su-27M standard and was fitted with a new radar which enables it to detect air and surface targets and carry air to air and air to ground weapons. This made it a true multirole fighter but it didn’t enter service due to economic troubles and instability in the early 1990s. But there was another variant of the Su-27 which was lucky. The Su-27K was chosen to be the main fighter of the Soviet Navy and was redesigned to operate from their fleet of new carriers which were being built. The main role of the Su-27K ( renamed as Su-33) was to provide protection to a Soviet Naval battle group from air attacks launched by the US Navy’s extremely powerful carriers. Only small numbers of the Su-33 were built before their production was stopped and with the collapse of the Soviet Union, the carrier fleet dream also ended. Only one carrier was in service with around a dozen Su-33 fighters based on it. This was how the Soviet dream of a powerful carrier based fleet of fighters was cut short.
The missile load of the Su-27 is highly enviable. It has 10 hardpoints which can accommodate 10 air to air missiles in air superiority mode which was increased to 12 on later models. This is twice the usual load of lightweight fighter and definitely more the the F-15 as the Su-27 never had to waste hardpoints for carrying external fuel tanks due to the massive range provided by the internal fuel tanks itself. This meant that the Su-27 could stay in the fight, long after its rivals had exhausted their missiles. The missiles carried include the R-73, R-77 and R-27 Air to Air missiles. Nearly every type of bomb and missile in the Soviet inventory could be carried by the Su-27 although its abilities as a multi role fighter were limited. The need for a tactical bomber with the performance of the Su-27 led to the development of the Su-34 fighter-bomber which is currently unparalleled in its capabilities.
The Su-27 didn’t stop at the Su-30 evolution. The Sukhoi design bureau further improved upon the Su-27 and developed the Su-35/37. These aircraft featured large multifunction LCD displays in their cockpit and the revolutionary new 3D thrust vectoring control (TVC) nozzles for their engines which gave them what we call as supermanoeuverability which enables it to out turn its rivals in a dogfight. These aircraft are unequaled in range, payload and maneuverability by any other fighter. The thrust vectoring nozzles was also adopted on some of the Su-30 series. The Su-37 was basically a technology demonstrator and the Su-35 design was adopted for serial production. The Su-35 is essentially a Su-37 without the canards in front of the main wings. The Su-35S is the latest variant which is a single seat multirole fighter. It was put into full scale production and the Russian Air Force has ordered around 100 aircraft.
The major difference in the Su-30/35 when compared to the Su-27 is the presence of a Passive Electronically Scanning Radar (PESA) and 12 missile carrying hardpoints which can be increased to 14 in an Air to Air load where 4 R-77 (RVV-AE) missiles can be fitted under the fuselage, 2 R-77 under engine air intakes, 4 R-77 and 4 R-73 under wings. The even shocking fact is that the number of hardpoints can be increased to 16! This is done using multiple ejector racks to carry lightweight AAMs or Rocket pods. Can you name any other aircraft in the world has a similar weapon load and yet retains a 1000+ km combat radius? These aircraft are fully multirole are now scheduled to get X-band AESA radars. The Su-35S has a wing mounted L-band radar which is said to be capable of detecting stealth aircraft and long ranges. The Indian Su-30Mki is rumoured to get this capability after its upgrade as well. They also feature an advanced optical detection system and IRST to passively detect aircraft. These features and abilities, theoretically put the upgraded Su-30Mki, Su-30SM and the Su-35S beyond the capabilities of the F-15 and only the F-22 can be considered as a rival for these deadly Russian fighters.
I have highlighted the incidents and performance parameters of the aircraft and it should not be assumed the Su-27 will defeat the F-15 in combat. It depends entirely on the skill of the pilots on both sides, the support assets and the number of aircraft available. The F-15 has proven to be extremely successful in all the wars it has participated in till now and none have been lost in air to air combat. Whereas the Su-27 is largely unproven in combat. Until a Flanker and Eagle of major air forces face off in actual combat, we won’t know what will happen if these legends clash.