An interesting video lets you hear the distinctive sound of the Russian Air Force new generation Su-57 Felon jet.
This video, featuring four Russian Air Force Su-57 Felon jets performing a low level flyby (most probably during Russia’s annual Victory Day parade on May 9 at Moscow) as someone films them, has been around for a few months now. However, it’s still pretty interesting as it lets you hear the aircraft’s pretty peculiar jet engine sound.
The engine used for the Su-57 is the NPO Saturn AL-41F-1, derived from the one used by the Su-35. It’s an interim variable-bypass ratio turbofan engine rated at approximately 88.3KN (19,842 lb st) of dry thrust and 142.2kN (31,967 lb st) with afterburning.
According to Russia’s Warplanes Vol. 1 by Piotr Butowski, it’s basically a thorough upgrade of the AL-31F as used in the Su-27/Su-30 family with a larger diameter fan, new high and low-pressure turbines, upgraded combustion chamber and a new FADEC (Full-Authority Digital Engine Control) system. And, based on the video they also generate a cool howling sound!
As reported in detail in a previous article, the current AL-41F-1 engine, considered underpowered for the aircraft, is only an interim power plant until the final engine is ready. The latter, known as Izdeliye 30 (literally Product 30) will be supposedly more efficient than previous designs, giving to the jet a top speed in excess of Mach 2 and a supercruise capability at Mach 1.3, and features 3d thrust vectoring. The Izdeliye 30 begun flight testing in 2017 and is expected to be ready by 2025. This means that serial production of the Su-57 may have to keep using the AL-51F-1 for the first examples and retrofit them when the new engine becomes available. The S-duct air inlet doesn’t cover the entire engine face, as done for the F-22 and F-35; the problem is mitigated by the air intake screen (which then have a double function other than FOD prevention) and a radar blocker in front of the engine fan, similar to the one used by the F/A-18 Super Hornet.
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A new engine was specifically developed for the Su-57, known as Izdeliye 30 (literally Product 30), but, since the engine is not yet ready for production and tested only on an earlier prototype, T-50S-2 is still using the Saturn AL-41F-1. Production of the Product 30 engine should begin in 2022, with the first serial deliveries of the Product 30-equipped Su-57 in 2023. Dealing with the engine, the Felon was recently showcased in a video for the 100th anniversary of the Chkalov State Flight Test Center, where the radar blockers in the engines’ air intakes were allegedly exposed for the first time. The Su-57 uses a S-duct air inlet which does not cover the entire engine faces, as done for the F-22 Raptor and the F-35 Lightning II, leaving it exposed to radar signal reflection. The problem was said to be mitigated by a radar blocker that, however, was never clearly seen on any of the 11 prototypes or the first two serial aircraft.
By the way, another aircraft of the past was very well known for its engine’s howling sound: the F-104 Starfighter. In particular, the General Electric J79-GE-11A axial-flow turbojet engine, that equipped the F-104G (including the TF-104G and RF-104G) had a characteristic, fabulous howling sound that made the aviation lovers crazy. Listen to it in the following cool video. BTW, compared, the Russian Su-57 engine sounds more like a siren than a scream. Still cool to hear.
