Future Of Su-57 Next-Generation Engine Uncertain
Piotr Butowski January 06, 2020
GDANSK, Poland—As new details about a next-generation engine for Russia’s premier Su-57 fighter emerge, new concerns are apparent as well.
On Dec. 6, the head of Rostec Corp.’s aviation cluster, Anatoly Serdyukov, provided an update on the state of work on the new-generation Lyulka “izdeliye 30” (product 30) turbofan engine intended for the final modification of the Su-57 fighter, the so-called “second-stage” aircraft. Su-57 fighters currently fly with Lyulka AL-41F-1 (izdeliye 117) engines.
Izdeliye 30 is the first all-new engine for tactical combat aircraft developed in Russia for several decades. The previous Lyulka AL-31F engine entered production together with the Su-27 Flanker fighter in 1981. All subsequent engines, including the AL-41F-1 for the first Su-57s, are upgrades of the base AL-31F.
The clean-sheet design offers a thrust increase, lighter weight, a smaller number of elements and lower operating costs. In December 2014, Russia’s United Engine Corp. CEO Vladislav Masalov said the new engine will be “17-18% more effective” than the current one. If this refers to full thrust, the new izdeliye 30 should provide 17 tons compared to 14.5 tons for AL-41F-1. The engine’s thrust-to-weight ratio is to be more than 10:1. Thanks to glass-fiber plastic inlet guide vanes, the new engine fan would reduce the radar cross section in a front view.
“Bench tests of the future engine are being continued. The engine optimization on a flying testbed is being conducted,” Serdyukov said. “In October, another flight was executed aimed at checking the engine characteristics at various flight modes. Operation of the thrust-vectoring nozzle was checked, as well as operation of the oil system at negative G loads. In total, the flying testbed executed 16 flights.”
The flying engine testbed, the Su-57’s second prototype T-50-2LL, replaced the port engine with a prototype of the izdeliye 30. It performed the first flight on Dec. 5, 2017.
But 16 test flights in two years is not an impressive test pace, especially considering how important this engine is for the Russians.
Serdyukov concluded his remarks with the following: “The issue of the use of this engine on airplanes is currently under consideration.” This statement suggests that it is not yet assured that the Su-57 will receive the new engines in the foreseeable future.
Though there is no official information on the topic, the next-generation engine program faces serious obstacles. The main one is the lack of modern materials that would enable the planned engine characteristics. Replacing planned materials with those that are available is likely to adversely affect the engine’s weight and performance.
The first series-production Su-57 fighter was to be handed over to the Russian Defense Ministry in December 2019, but it crashed Dec. 24 during a handover flight in Komsomolsk-on-Amur. In total, the ministry ordered 74 Su-57s—the first two aircraft for testing and then six operational squadrons of 12 fighters each—with delivery by the end of 2027.
During the Army 2018 exhibition, Deputy Defense Minister Alexey Krivoruchko claimed that from 2023 the Su-57s will be delivered in a “second-stage” configuration, with the new engines. But in a statement to the Russian Defense Ministry newspaper Krasnaya Zvezda in December 2019, Krivoruchko corrected this deadline: Deliveries of the first-stage aircraft will last until the “mid-2020s.”
Future Of Su-57 Next-Generation Engine Uncertain | Aviation Week Network