By Gaston Dubois
A series of patents filed by United Aircraft Corporation (UAC) with the Russian Federal Intellectual Property Service show interesting changes from the first Su-75 Checkmate design, as well as the development of a two-seat tandem version and a unmanned version.
Presented to the public for the first time during the first day of the MAKS-2021 International Aviation and Space Exhibition in Russia, the Su-75 Checkmate is Sukhoi’s (part of the UAC conglomerate) proposal for a new-generation light multi-role combat aircraft, incorporating advanced technical solutions (low radar signature, Artificial Intelligence, advanced materials, etc), but adapted from technologies already developed for aircraft such as the Su-57 or the MiG-35 Fulcrum. It is the first single-engine fighter developed in decades by the Russian aerospace industry, after the MiG-23 Flogger (NATO code).
Denis Manturov, Russian Minister of Industry and Trade, during an interview given to the local press in the framework of the Army-2022 military and technical forum, had informed that the first flight of the Su-75, originally scheduled for 2023, would be delayed by one year. According to Manturov, delays are to be expected when developing a new fighter jet, and surely the economic sanctions imposed on Russia since February 2022 must also have played a role. Since then, no news on the Checkmate status has emerged, and it seemed that its progress had come to a complete halt… but there is a new development!
Design modifications
United Aircraft Corporation’s design office filed a patent for a “single-engine single-seat stealth aircraft,” which features some significant changes to the Su-75 Checkmate design.
The most noticeable change is the modification to the wing, with respect to the model presented at MAKS-2021 and the Dubai Air Show 2021 (the only time the mockup was exhibited outside Russia), which features an extension and inclination of the trailing edge, increasing the wing area and, perhaps, slightly reducing the aircraft’s rear radar signature.
On the other hand, the engine installation appears to have been slightly advanced. There is also a modification to the fuselage that seems to increase the internal volume of the aircraft. This could mean that either the side armament bays (where short-range air-to-air missiles would normally be housed) have been enlarged or that the amount of internal fuel that the Checkmate can carry has been increased… or both.
Two-seater version
Based on this latest redesign, UAC presented the design of a “single-engine two-seater stealth aircraft”. Similar to other two-seater models of the Sukhoi company, the modifications feature a tandem two-seater cockpit, with the rear seat raised to provide some forward vision.
In addition to training future Su-75 crews, the two-seat version could take on “command center” duties for drones and Loyal Wingman-type unmanned combat aircraft.
Unmanned version
An unmanned Checkmate variant, which otherwise looks the same as the piloted aircraft design, was also unveiled. This is a feature being developed for the sixth-generation air dominance systems, which were touted several times as “optionally manned.”
While there is still a long way to go to see these designs materialize into an actual combat aircraft (or family of aircraft), and there are reasonable doubts that Russia can carry this project forward when all its resources and energies are focused on the war in Ukraine, it is evidence that the development of the Su-75 Checkmate is still alive.
