Sukhoi LTS (CheckMate)

[Acatomic]

Never mind, I found it :

https://www.eritreadaily.net/News2021/STEALTH.pdf

Thanks to -> http://paralay.iboards.ru/viewtopic.php?p=664016#p664016

There's also a patent application for a two seater version:
RU2021503628
STEALTH SUPERSONIC SINGLE - ENGINE, TWO SEAT AIRCRAFT

But for some reason Google search can't show it....

 

[flateric]

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[flateric]

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[Trident]

Interesting... the UCAV has only one pair of underwing actuator fairings and DSI compression bumps even in the air scoops at the base of the fins. Neither the UCAV nor the twin-seater have the central strut in the main intake.

 

[Acatomic]

@Trident

Nice catch. Maybe they're still trying out different configurations.
Missing central strut on UCAV and twin seater could be due to lower G-loads?

 

[LMFS]

Quite interesting how Sukhoi criticises their own Su-57 to justify the patent of the LTS (RU 2770885):

The disadvantages of aircraft known from the prior art include a large geometric and weight dimension that occurs in connection with the use of two engines. The presence of two main cargo compartments makes it impossible to place bulky cargo in the side compartments. In addition, placing the main and side cargo compartments, air intake channels and wheel niches of the main landing gear supports at the same distance increases the area of the mid-section of the aircraft, which, together with a large number of aerodynamic control surfaces, increases the area of the washed surface of the aircraft, leads to an increase in weight and aerodynamic drag of the aircraft. The presence of an all-rotating horizontal tail, which forms an acute angle with an all-rotating vertical tail, leads to an increase in the ESR in the lateral hemisphere, which requires special coatings to reduce. The direct channels of the power plant's air intakes make it necessary to install special devices in them that reduce the effective dispersion area (ESR) of engines in the front hemisphere, which also leads to an increase in the weight of the aircraft. The location of the air intakes for purging heat exchangers of aircraft systems and motor compartments on the front part of the pylons of the all-rotating vertical tail unit leads to an increase in the ESR in the front hemisphere and side hemisphere, which requires the use of special measures to reduce the ESR, which causes an increase in the weight of the aircraft.

The technical task to achieve which the invention is aimed is to eliminate the disadvantages of aircraft known from the prior art and create a light tactical aircraft with a smaller geometric and weight dimension, low radar visibility, and the ability to accommodate large-sized cargo.

Also the capacity to carry "bulky" (A2G?) ordnance is confirmed for the side bays:

The location of the niches of the main landing gear supports behind the side cargo compartments allows you to reduce the area of the midsection, while at the same time allowing you to get a significant volume of side cargo compartments, ensuring the placement of bulky cargo in them.

 

[icyplanetnhc (Steve)]

What's interesting is that in Sukhoi's T-50/Su-57 patent, the F-22 is cited as the baseline design for a "supermaneuverable stealth fighter" but one of the biggest criticisms was the F-22's inability to have weapon bays between the engines, resulting in insufficient payload (particularly in large air-to-ground ordnance) to be a multirole fighter. This was repeated by Mikhail Strelets in a fairly recent TV interview as well.

It's a bit ironic that the LTS is likely very similar in size and gross weight to the E-721 that Mikoyan had submitted to the PAK FA competition in 2002 and lost to the T-50. At the time, the T-50 was likely the largest aircraft that the Russian Defense Ministry is willing to spend, as it sought for something smaller and less expensive than the MiG MFI and replace both the MiG-29 and Su-27, rather than having a "heavy" and "light" mix. Of course, the LTS has the advantage of being a much more contemporaneous design and having substantial parts commonality with the Su-57. I guess we'll see if this plays out.