The Su-31 differed from its predecessor in its more extensive use of composite materials, which form up to 65% of its total structure and allow for a drastic reduction in weight, while simultaneously maintaining the same rigidity and structural durability. The pilot also has a more comfortable and pleasant cockpit. Powered by the M-14PF engine, the Su-31 reaches a power-to-weight ratio of 1. This means that the Su-31 gives the pilot the option of being able to fly rotating maneuvers completely suspended from the propeller.
At the 1992 World Championship, held in France, pilot Yurgis Kairys won the bronze medal. In fall, at the Franborough airshow, he flew the Su-31 and left the attendees breathless with the maneuvers he performed, never-before-seen by any other aerobatics pilot of that time.
The export version, the Su-31Kh, differs from the Su-31 in that it has added fuel tanks in the wings to increase the range of the ferries. The 16 Su-31Kh models produced were delivered to clients in the United States, England, Australia, Spain, and Italy. To improve the safety of the sport, the Sukhoi Design Office worked diligently to create a simple system that would save the pilot in an emergency, and that could be used in aerobatic planes. The system, initially called Zvezda, and now known as SCS-94, consisted of an ejectable seat and allowed the pilot to exit the plane safely at altitudes between 15 and 4,000m at speeds of 70 to 350km/h, and at an altitude of 45m when flying upside down.
The flight trials of the SKS-94 system were performed in 1995 using specially prepared Su-29 aircrafts. During the tests, the pilots performed more than 20 ejections at heights from 50 to 2,000m and flight speeds of 180 to 350km/h, including upside-down flight at a height of 50m.
The operating version of the SKS-94 was installed for the first time in a Su-31M. During the 1995 Paris Air Show, the prototype Su-31M-1 was on exhibit both statically and in flight. It became the first aerobatic plane in the world to have an ejection system installed. Other modifications, like a new arsenal of instruments and an improved cabin interior, were made to the Su-31M. The first flight of the Su-31M was made in 1996, and its debut was at the United States championship.
Serial production of the Su-31M was ready by the end of 1996. The first Su-31M aircrafts were delivered under contract with Switzerland, Italy, Czechoslovakia, and the Russian Defense Sports-Technical Organization (ROSTO).
|Flight test of the SKS-94|
At the 1996 World Championship that took place in Oklahoma City (USA), more than half of the participants flew Sukhoi planes. The national Russian team had the Su-26, Su-31, and Su-31M aircrafts at their disposal. The results surpassed everyone's expectations. The Russian team took first place in the teams category and won the P. Nesterov Cup. Victor Chmal became Top World Champion. Russia got the Aresti Cup, the most prestigious trophy in aerobatic sport, which it had wanted since 1984. Svetlana Kapanina became Female World Champion. Between 1986 and 2003, Russian pilots won 330 medals at the World competitions, the European competitions, and the World Air Games. They got a total of 156 gold medals, 105 silver metals, and 69 bronze medals.
To become the leaders and first worldwide brand in the production and innovation of aerobatic planes, it was necessary to incorporate new improvements to the planes on a regular basis, improve their performance and reliability, offer superior service, and reduce costs. To meet these objectives, the Design Office developed improvements for the Su-26. In 1993, Sukhoi built a plane that incorporated all these improvements, the Su-26M2. To improve the range of the ferries, they incorporated an extra fuel tank in the fuselage. 13 Su-26M were sold and delivered to clients in Russia, the United States, Australia, and other countries.
Other improvements, like refining the aerodynamic configuration, weight reduction, and improving the power-to-weight ratio were incorporated little by little in all models, while the Design Office found new and better ways to improve the already-incredible performance of the Sukhoi planes.
It was later in 2003 that they offered a recommended configuration for all their models in order to significantly improve their clients' planes' performance:
Power-To-Weight Ratio Improvement:
M-9F Engine (420 cv)
-Increasing the Wingspan
Completely Designed New Ailerons
New More Refined Rudder
Improved Leading Edge Profile
Flight Security Improvement:
SKS-94 ejectable seat
New Installed dome
For the 2003 World Championship, Sukhoi prepared a modified plane, the Su-26M3, and on March 25, 2003, pilot Yury Vashchuk flew it for the first time. That same year, at the World Championship held in the United States, pilot Svetlana Kapanina and Victor Chmal flew it. Svetlana Kapanina won the World Champion title.
The Sukhoi planes - specifically the 26, 29, and 31 series - displayed great acceleration, substantial rate of climb, excellent controllability, significant permissive G-load, great ergonomics, and unparalleled structural integrity (23 Gs destructive load). This allowed the pilots, with their seats reclined at 35 degrees, to sustain between +12/-10 Gs, giving the advantage of being able to manage a fast plane in a reduced flight program, such as in the 1000 m2 aerobatic box.
There is no doubt that the Sukhoi planes have gained the place and recognition of being some of the best aerobatic planes in the world, for training and formation, as well as for more demanding use at competitions and aerobatic airshows. Since 1996, the Sukhoi planes have had an important presence at all international competitions, and will conceivably continue to do so in upcoming years. With the emergence of new planes with similar features to the Sukhois, many pilots choose these new models (Sbach or Extra) as their mounts to compete at the highest level, due largely to the high cost of the Sukhoi, both in maintenance and in consumption. Even so, what the workers of the Sukhoi Design Office did in its beginnings in 1983 is admirable, creating impressive and unique machines that have transformed the history of aerobatics worldwide, forever. It's possible that in the near future, the Sukhoi boys will return to impress us again.