Sukhoi T-75 LTS (CheckMate)

[flateric]

https://tass.ru/ekonomika/22437017

 

[Geo]

After reading the book on the anniversary of Sukhoi, it is now more obvious that the Izd. 177S engine is intended for the T-75 platform.

 

[Anduriel]

After reading the book on the anniversary of Sukhoi, it is now more obvious that the Izd. 177S engine is intended for the T-75 platform.

With that specs I don't see how it's better than 117. For Su-75 at least, where you don't have to concern yourself with diameter.

 

[F-14ATomcat]

View: https://www.youtube.com/watch?v=sIh9qnZDdXo

 

[Airborne2001]

I feel like the Su-75 being good or bad (focusing on performance specs only) is a toss up.

One one hand:
I can imagine that Sukhoi has some nerves over the Su-57 issues. The amount of criticism and negative publicity on an almost global scale hopefully pushed them and the Russian Air Force to try and get this right. The delay for a redesign (yes, I am aware this is mostly because of sanctions, but still) makes me believe that they really want this to work.

On the other hand:
The Su-57 still appears to have underperformed from its expectations even though it was designed before the mass sanctions instituted in 2022. Considering that the Su-75 is being designed and built mostly during the heavy sanctions, things don't look very good. Of course, when we factor in domestic Russian issues, it is no longer a toss up, and it might be checkmate for the Checkmate.

I don't like to blame Sukhoi for their development problems because they are mostly a decent company at the mercy of the Russian economy, the Russian industry, and sanctions. It is a complex issue...

 

[Scar]

Su-57 still appears to have underperformed from its expectations

what performance and what expectations you are talking about?

 

[Airborne2001]

what performance and what expectations you are talking about?

Mainly the stealth due the lack of s-ducts.

 

[Avimimus]

Mainly the stealth do the lack of s-ducts.

They use radar blockers for that (similar to the X-32 solution).

 

[Airborne2001]

They use radar blockers for that (similar to the X-32 solution).

Ah I see. I may have judged the Su-57 a little too harshly then.

 

[Cjc]

Ah I see. I may have judged the Su-57 a little too harshly then.

Radar blockers have never and will never be as good as s-ducts. Better then nothing but it's still very bizarre that russia decided to go in that direction, it's not like the su-57 didn't have the room for an s-duct.

 

[AGS-1787]

you must know something Sukhoi doesn’t know!

 

[Ainen]

Radar blockers have never and will never be as good as s-ducts.

Deep enough radar blocker is a sort of s-duct. As for how big the penalty is, we just don't know.
They played with digital and full-scale RCS models, not us.

As for reasons, there may be many.
Ultimately, not the first or second LO aircraft to implement them only partially(YF-23/F-23A) or skip them entirely(XF-32/F-32).

But on the other hand, S-70 and T-75 went for proper s-ducts.

 

[Avimimus]

It might also be worth quickly noting that the Su-57 has a partial s-duct in addition to the radar blocker.

 

[Joint Soviet Fighter]

Radar blockers have never and will never be as good as s-ducts. Better then nothing but it's still very bizarre that russia decided to go in that direction, it's not like the su-57 didn't have the room for an s-duct.

So how did The F-117 ever manage to survive, then, with its straight intakes & fiber glass "screens"/radar blockers?

 

[Joint Soviet Fighter]

It might also be worth quickly noting that the Su-57 has a partial s-duct in addition to the radar blocker.

You say that like it's a good thing...

 

[Avimimus]

You say that like it's a good thing...

Both probably contribute to reducing frontal RCS from certain angles. Whether that's a good thing - well, I suppose it'd depend a lot on whether you are flying the Su-57 or whether the Su-57 is flying at you.

 

[Cjc]

So how did The F-117 ever manage to survive, then, with its straight intakes & fiber glass "screens"/radar blockers?

It's called being the first stealth aircraft (and retired to boot) lockheed had a hard enough time getting the thing to fly to mess with s-ducting (wich as russia has show is hard to do) something lockheed fixed on there next stealth aircraft (the f-22).

 

[Avimimus]

It's called being the first stealth aircraft (and retired to boot) lockheed had a hard enough time getting the thing to fly to mess with s-ducting (wich as russia has show is hard to do) something lockheed fixed on there next stealth aircraft (the f-22).

Theory around ducts and duct losses was well established decades ago. Many aircraft had s-ducts prior to that era (just look elsewhere on the forum). The B-1B (a contemporary of the F-117) even had s-ducts to reduce its forward RCS.

I'm very much inclined to believe that the F-117 doesn't have s-ducts because it wasn't considered the optimal solution for the requirements they were trying to achieve (rather than Skunk Works being unable to figure out a duct design that had already been used successfully for decades).

 

[Hydroman]

The 117 did not use s-ducts, inlets were a straight shot with the grid inlets, anti-ice was a wiper blade since the aircraft was being developed at a very rapid pace. S-ducts could have changed the airframe shaping quite a bit. Plus the aircraft had the simple, spring-loaded aux air inlet suck-in doors, KISS. The 117 inlets were definitely trade offs for sure. Since the SU-75 seems to be in it's early stages, they may try for an s-duct or semi-s-duct possibly if LO is a priority over propulsion performance?

 

[FighterJock]

Looks like Sukhoi have learnt their lessons from the Su-57 design. Stealth is finally going to be the key feature of the Su-75.

 

[Ainen]

Looks like Sukhoi have learnt their lessons from the Su-57 design. Stealth is finally going to be the key feature of the Su-75.

More like t-75, as a commercial proposal, was designed to match market expectations.
Su-57 was designed to meet requirements of PAK-FA program.

Otherwise, i wouldn't link those two aircraft too closely together. JSF contenders took first flight within a few years from F-22.
T-75 program was even begun when Su-57 was nearing service, and it hasn't flown yet. They're at least half a generation apart.

 

[EmoBirb]

I feel like the Su-75 being good or bad (focusing on performance specs only) is a toss up.

One one hand:
I can imagine that Sukhoi has some nerves over the Su-57 issues. The amount of criticism and negative publicity on an almost global scale hopefully pushed them and the Russian Air Force to try and get this right. The delay for a redesign (yes, I am aware this is mostly because of sanctions, but still) makes me believe that they really want this to work.

On the other hand:
The Su-57 still appears to have underperformed from its expectations even though it was designed before the mass sanctions instituted in 2022. Considering that the Su-75 is being designed and built mostly during the heavy sanctions, things don't look very good. Of course, when we factor in domestic Russian issues, it is no longer a toss up, and it might be checkmate for the Checkmate.

I don't like to blame Sukhoi for their development problems because they are mostly a decent company at the mercy of the Russian economy, the Russian industry, and sanctions. It is a complex issue...

> hopefully pushed them and the Russian Air Force to try and get this right.

??? There was never anything wrong with the Su-57. So the only pressure is for them to deliver yet another functional design. Something they've done for decades.

 

[EmoBirb]

it wasn't considered the optimal solution for the requirements they were trying to achieve

And the same applies to the Su-57. Increasing the volume of the internal weapons bays was deemed far more important than implementing S-ducts like tested on previous projects like the Su-47. This in turn gives the Su-57 the ability to launch ALCMs from it's internal weapons bays, something unique among all 5th generation fighters.

The LTS however clearly has an S-duct though. The nay sayers will find other things to latch onto though. Thinking they're smarter than a literal team of engineers with years of experience, lol.

 

[Ainen]

And the same applies to the Su-57. Increasing the volume of the internal weapons bays was deemed far more important than implementing S-ducts like tested on previous projects like the Su-47. This in turn gives the Su-57 the ability to launch ALCMs from it's internal weapons bays, something unique among all 5th generation fighters.

The LTS however clearly has an S-duct though. The nay sayers will find other things to latch onto though. Thinking they're smarter than a literal team of engineers with years of experience, lol.

T-75 design has the same bay, though.
Just one instead of two.

ALCM part is benefitting from a long, deeper bay, but I don't think we should make it a deal breaker - there are different ways to get deep bays, and the reason of Su-57 primacy in this aspect was simply that plane and the weapon were designed for each other.
As with any other plane(and su-57 began from proper fuselage and s-ducts, check the scans of the new book), final configuration is not the only way to get the work done, but the most optimal one.

Otherwise, F-35 was meant to get SOM-J, and only political prevented it from doing so(and Kaan will likely get it).
JSM is scrambling as a replacement, too.

 

[Joint Soviet Fighter]

Theory around ducts and duct losses was well established decades ago. Many aircraft had s-ducts prior to that era (just look elsewhere on the forum). The B-1B (a contemporary of the F-117) even had s-ducts to reduce its forward RCS.

I'm very much inclined to believe that the F-117 doesn't have s-ducts because it wasn't considered the optimal solution for the requirements they were trying to achieve (rather than Skunk Works being unable to figure out a duct design that had already been used successfully for decades).

Yeah, my post wasn't actually a criticism, as, speed notwithstanding, the combination of a straight inlet with a radar blocker/screen on The F-117 is on the level of The F-35 from an rcs standpoint, if various estimates & statements are to be believed, which is really interesting, imo.

 

[Joint Soviet Fighter]

Looks like Sukhoi have learnt their lessons from the Su-57 design. Stealth is finally going to be the key feature of the Su-75.

Almost. They need to get rid of the irst bulb for that to happen, but it's still a much better overall design than The Su-57 from the standpoint of stealth. I think.

 

[Joint Soviet Fighter]

> hopefully pushed them and the Russian Air Force to try and get this right.

??? There was never anything wrong with the Su-57. So the only pressure is for them to deliver yet another functional design. Something they've done for decades.

Oh come on, lol. There are problems with every plane, hence invariable design modifications at some stage of the process.

 

[FighterJock]

Quite right Joint Soviet Fighter, getting rid of the bulb that contains the IRIST would help improve the stealth qualities greatly. A stealthy successor designed to look similar to the EOTS on the F-35 and J-20 would improve things greatly.

 

[Ainen]

A stealthy successor designed to look similar to the EOTS on the F-35 and J-20 would improve things greatly.

T-75 has it; look underneath the plane.

Upd: in fact there's a model in the configuration you describe - the updated unmanned one. No IRST ball, only "EOTS".

 

[Joint Soviet Fighter]

T-75 has it; look underneath the plane.

Upd: in fact there's a model in the configuration you describe - the updated unmanned one. No IRST ball, only "EOTS".

It reminds me of a dark chocolate (boo) Reese's Miniature Cup that has been turned upside down.



Arguably the funniest one, though, is that The Su-57's radar blocker...bears a striking resemblance to this image on the back of the box of Honey Nut Cheerios.

 

[Joint Soviet Fighter]

Deep enough radar blocker is a sort of s-duct. As for how big the penalty is, we just don't know.
They played with digital and full-scale RCS models, not us.

As for reasons, there may be many.
Ultimately, not the first or second LO aircraft to implement them only partially(YF-23/F-23A) or skip them entirely(XF-32/F-32).

But on the other hand, S-70 and T-75 went for proper s-ducts.

Not sure about a radar blocker being "a sort of s-duct", but in regards to the potential effectiveness/penalty to using one as opposed to another intake configuration, I think that the issue, there, is that the blocker only guards the front of the jet engine, & the "partial s-duct" doesn't provide enough bounces to reduce the radar return to the same extent as that of a true s-duct, but then again, we also don't know the capabilities of the kind of ram that is being used, so...yeah.

 

[Airborne2001]

> hopefully pushed them and the Russian Air Force to try and get this right.

??? There was never anything wrong with the Su-57. So the only pressure is for them to deliver yet another functional design. Something they've done for decades.

Since posting that I think more of the issue is the Russian industry itself and less of the Su-57 being a problem. The real issue lies in the numbers of aircraft the company can make. The issues with the Russian industry, now amplified by the sanctions, are proving to be difficult. The Su-57E and M are moving slower than anticipated, the Su-75 has been delayed numerous times (though may be ready by the end of the year?), and the PAK DA is very behind schedule. I think the Su-75 probably will be a great design, but it likely will lack in needed numbers.

 

[paralay]

The issues with the Russian industry, now amplified by the sanctions, are proving to be difficult. The Su-57E and M are moving slower than anticipated

Really?

 

[Acatomic]

One more patent from 2023 that wasn’t posted here.

Now usually they compare patents with Russian/Soviet ones, but I think this is the first time that they are actually comparing it to a western one, in this case F-35 style intake:

LOW-OBSERVABLE AIR INTAKE OF SUPERSONIC AIRCRAFT

The state of the art also includes a supersonic non-adjustable air intake (US 5749542 A, 12.05.1998), located on the side of the fuselage or under the wing of the aircraft, consisting of a shell, the edges of which form an entrance to the channel and have a sweep, a throat and a subsonic diffuser. The entrance is made non-rectangular in the front view and is located directly on the surface of the aircraft. The air intake in front of the entrance has a braking body of complex shape, which allows to deflect the boundary layer and prevent it from entering the air intake channel.

This air intake was taken as the closest analogue to the claimed invention.

The disadvantage of the closest analogue is the placement of the air intake inlet on a flat surface, which limits the possibilities of the aircraft layout and does not allow for the optimal placement of the aircraft's structural elements and systems in the "shadow" of the air intake inlet.

The objective of the claimed invention is to eliminate the shortcomings of the known prior art.

The technical results that the invention aims to achieve are:

- ensuring stable operation of the power plant up to Mach number = 2.1 with a total pressure recovery coefficient at the engine inlet not lower than the typical one for non-adjustable air intakes and a total flow non-uniformity below the maximum permissible value;

- reduction of aircraft radar visibility;

- ensuring the possibility of placing as many different aircraft elements as possible in the “shadow” of the air intake entrance to ensure a minimum area of its midsection.

Reducing the radar visibility of an aircraft implies that the shape of all its elements contributes to reducing the aircraft's effective scattering area. This also applies to the shape of the air intakes for supplying air to the aircraft's power plants.

In the declared air intake, all edges of the shell are swept and can be parallel to any elements of the aircraft (wing edges, empennage, etc.), while there is no gap between the air intake entrance and the surface on which it is located for draining the boundary layer.

The declared technical results are achieved by a set of features declared in an independent claim of the invention formula.

A supersonic non-adjustable air intake contains an inlet section with a braking body and a shell, a throat (the section of the channel with the smallest area) and a subsonic diffuser. In the front view, the air intake inlet has a U-shape and is located symmetrically on both sides and below (above) the aircraft fuselage, enveloping it from three sides. When changing the shape of the channel section behind the throat in the subsonic diffuser from U-shaped to rectangular, oval or close to them, the linear dimensions of the channel section (height and width) are reduced, which allows the necessary structural elements and aircraft systems to be placed in the "shadow" of the air intake inlet in the most optimal way, ensuring a minimum area of the aircraft midsection

The inlet edges in the side view and the edges adjacent to the fuselage have a reverse sweep, which improves the air intake characteristics while reducing the air flow from the maximum value at all Mach numbers within the operating range. In addition, the lower (upper) edge of the inlet in the plan view is wedge-shaped or has a wedge-shaped cutout, or has wedge-shaped teeth (i.e., the lower (upper) edge of the air intake is not perpendicular to the aircraft axis), which reduces the radar visibility of the aircraft.

Source: https://new.fips.ru/registers-doc-view/fips_servlet?DB=RUPAT&DocNumber=2801718&TypeFile=html

 

[Acatomic]

Also i hope one day Sukhoi implement EORD-31 style OLS window on all of their aircraft, not with the purpose to meaningfully reduce RCS - but to stop endless OLS RCS discussions on forums all around the world



Source:
Post in thread 'MAKS: Chinese firm unveils new sensors for J-20, J-31'
https://www.secretprojects.co.uk/th...s-new-sensors-for-j-20-j-31.25279/post-257993

 

[Hydroman]

It reminds me of a dark chocolate (boo) Reese's Miniature Cup that has been turned upside down.

View attachment 757355

Arguably the funniest one, though, is that The Su-57's radar blocker...bears a striking resemblance to this image on the back of the box of Honey Nut Cheerios.

View attachment 757356

Honey Nuts, a venereal disease of Bee Keepers just like Donuts is a venereal disease of Bakers. These are are not half-baked comments either.

 

[Airborne2001]

Really?

I mean, I feel like by now the Su-57E and M should be further along. (Unless that was sarcasm on your part.)

 

[paralay]

Where do you get these fantasies about some kind of problems from everyone except you? The production of the Su-57 is progressing at a faster pace, accept it, you have lost

 

[GTX]

Where do you get these fantasies about some kind of problems from everyone except you? The production of the Su-57 is progressing at a faster pace, accept it, you have lost

So how many have been produced/delivered?

 

[TheBoss]

So how many have been produced/delivered?

The Russian Ministry of Defence doesn't usually disclose the numbers especially during the times of war( both real and informational). But based on OSINT: 32 built + 10 prototypes