Su-57 Stealth Fighter: News #6

GarryB wrote:

But lmfs I think said something counts as supercruise only if its 1.8m+ like the F-22. Su-57 allegedly will only be able to achieve 1.6m with izd.30, and currently its below that.

That is called moving the goalposts...

Being able to cover more airspace than other aircraft without needing to use AB and greatly shorten your flight radius is a good thing.

For a bomber it is amazing because the only aircraft that can catch you need to use AB which automatically halves their flight radius which means the gaps between airfields gets much bigger...

At high speed air intakes are closed and narrowed because the air coming in is supersonic and would choke a turbofan or turbojet engine... The only time it would need big wide open intakes is for takeoff for volume of air at low speeds... the intake suction relief doors on the Tu-22M3 and Tu-160 are for the same purpose... to increase airflow to the engines when the aircraft is not moving fast acting like a big air scoop.

It gives your missiles more range, but you can't hide from anything... S-400s and S-500s will be looking for F-22s on top of the hill...

You mean they might have developed a hypersonic scramjet engine... man that would just blow the Russians away... I hope they can steal the technology and make something useful with it....  

a completely different way compared to a tactical fighter, even the MiG-31 uses it very differently despite not being as big as the Tupolevs. Not saying that all those planes would not benefit from supercruising engines... wrote:

. I think the design point of the Su-57 is significantly higher and faster than any other fighter with the exception of the MiG-31, if I have the time I will try to prove this. In fact I think this holds the key to know the performance of izd. 30 and the real concept of operation of the Su-57... wrote:

Arrow wrote:What is this different use of afterburners on bombers and MiG-31?

The speed of the Mig-41 is expected to reach over 4M. It will be a revolution. The question is whether it will need completely new engines?

LMFS wrote:

We discussed a bit about it, I think it will use a new engine indeed, of the type ABVCE (After-Burning VCE). That is a variable bypass engine that works first as a turbofan, then as a turbojet and then as a ramjet, as the airspeed increases. The SR-71 already used a similar principle, but it was very complicated. Recently the YF120 has been developed in this direction and has potential for speeds similar to those claimed for the PAK-DP

nded for operation at high Mach numbers. I think the design point of the Su-57 is significantly higher and faster than any other fighter with the exception of the MiG-31, if I have the time I will try to prove this. In fact I think this holds the key to know the performance of izd. 30 and the real concept of operation of the Su-57... wrote:

magnumcromagnon wrote:Playing devils-advocate and say the YF120 is as capable as you say, they need to prove that they could have the same flight parameters with a useful weapons load. The SR-71 lacked a useful weapons payload (just sensors), which definitively made the MiG-25 the superior high-speed aircraft especially when you consider the MiG-25 was seriously mass produced while the SR-71 production number's were not even comparable. I mean a version of the MiG-25 without a useful weapons payload (Ye-266M) managed to nearly fly at 40km altitude with 1970's technology. FPI is working on a spin detonation ramjet (not to be confused with PDE) that detonates fuel as opposed to deflagrating like standard engines (significant fuel efficiency increase). That's my bet for PAK-DP.

Arrow wrote:And does Izd 30 have the potential to power PAK-DP? It has a greater thrust than the D30-F6. Development of a completely new engine for PAK-DP will take them another 15 years, if not more. PAK DP will probably be a greater technological challenge than PAK FA. Sometimes it is mentioned that it will already be the 6th generation of the combat aircraft.

What maximum speed do you think the Su-57 can reach? The American new fighter is said to fly around 3.5M. So they already have a prototype. It is not known when PAK-DP will fly

GarryB wrote:But then the US would fail them because they haven't made stealth the absolute tippy top priority that it is on US aircraft, which makes them so expensive and so hard to make well and of course so fussy when it comes to use to keep their stealth levels...

No big deal... running the AB for 10 full minutes to cross the speed of sound and accelerate to a speed where dry power can maintain speed is nothing compared with having to run the AB for the rest of the flight to stay at supersonic speeds...

They don't need it for what they do now... for the MiG-31 flying at mach 2.4 all the way to the target will get them there faster than being able to supercruise 3 times that distance maybe 5 times that amount of time, but fuel efficiency and range are not as important for the MiG as getting to a launch position and launching AAMs at the target... super cruise would not help most of the time because getting there faster is more useful than moving bigger distances.

Supercruise means they could cover that first and last 4,000km in half the time and their top speed might be mach 2.3.

I would think if the plane is supercruising towards the SAMs it would increase the distance at which they were effective... a bit like the 140km range of AMRAAM against a closing target...

S-300 and S-400 and S-500 and R-37M were designed to deal with Air dominance aircraft... JSTARS, AWACS, Stealth fighters, and Inflight refuelling tankers... three of which should be quite easy to find and take on, which renders all other fighters including stealth fighters in a much worse position... could even say on the defensive...

To fly at mach 2.83 in a MiG-31 you have to wear an air conditioned space suit.... in case you have to eject at high altitude but also to protect you from the heat of the cockpit canopy which gets to over 70 degrees C at that flight speed

Su-57 should be able to fly about mach 2.4-2.6 at the very most.

Pressurised suits are needed to protect from ejections at high altitude (>20 km IIRC) due to the low ambient pressure.

GarryB wrote:Only if they have children that serve in the Air Force....

Fuel burn rate is easy to calculate, but most engine specs include most efficient fuel burn rate.

Fortunately the D-30F6 in the MiG-31 is intended to be operated in full AB for its entire flight, so efficient and full power fuel burn rates are listed and would probably reflect normal AB fuel burns for other similar turbofans...

The Max AB fuel burn rate for the D-30F6 is 1.9 kg/kgf per hour, while its fuel efficient rating is 0.72 kg/kgf per hour. Full power is 15.5 tons of thrust but we don't know what fuel efficient thrust settings are.

At full AB the fuel burn would be 29.4 tons of fuel, but at Mach 2.83 that would equate to a flight range of about 3,200km... we know it has a flight radius of about 720km, so flying at about 3,200km/h flying 720km would mean full AB for about 26 minutes... about 13 minutes going out and 13 minutes coming back...

The full AB range of the Backfire is about 2,000km radius at mach 2 or so. That means at about 2,300km/h it can therefore fly at full AB for approximately two hours.

A supercruising aircraft will be moving at roughly twice as fast as the same plane operating at subsonic speed, but it will be burning fuel faster than if it was efficiently cruising at a subsonic speed of perhaps 700-800km/h, so if its flight range at subsonic is say 3,000km which would take about 4.2 hours, when it supercruises at say mach 1.5 to mach 1.6 then its flight range might be 2,800km but it will take 2.1 hours to fly that far.

It is not more fuel efficient, but it is faster and is certainly more fuel efficient than flying in Full AB because you also get there faster but your fuel range would be 500-600km at the very most. (most planes are not as efficient in full AB like the MiG-31 and MiG-25 are).

It would but its missiles are even faster so flying to 700km at mach 2.83 and launching four mach 6+ missiles gets the missiles to a 900km range target faster than flying 800km at mach 1.6 taking more than 13 minutes to get there... you can see how getting to the launch position in 13 and a half minutes is a good thing even though you are burning through fuel so rapidly.  The key is time not range or fuel...

In the case of a MiG-31 there is the manouver issue but a big bomber will be limited to 2 maybe 3 g at the very most so flying at mach 2 that is not manouvering... that would be terribly minor course corrections that likely would not effect interception calculations at all.

Very long range missile systems rarely are used as barrier defence, and would most often be located near a target...

I know, but most of the time they don't fly that high but flying at mach 2.6+ will result in an unbearably hot cockpit canopy, which requires protective gear to operate under.

At top speed the MiG-31s cockpit is heated to 70 degrees C, so an entire protective suit is required. AFAIK the cockpit is pressurised, so as long as you don't need to leave the aircraft breathing shouldn't be the biggest problem...

GarryB wrote:The numbers I have given seem consistent...

Bullshit. The gun on the MiG-31 is for chasing down and shooting subsonic cruise missiles... for which it does not need to be manouverable at all.

I believe when the EU consortium that designed the Typhoon realised that its manouver performance was less than both the Flanker and the Rafale they emphasised that climb rate and top speed are important for missile energy...

The Su-57 is a fighter, not an interceptor, but most of the time altitude and speed for missile launches will be the most important thing...

Do they?  How many fighter radars look up that high for such small targets?

It is why they wear them. They fly fast more often than they fly very high...

He flys fast more often than he ejects...

GarryB wrote:Neither the MiG-25 nor MiG-31 can do more than 5g manouvers, and the LERX on the 31 are nothing to do with manouver performance, and everything to do with the shift in cg as it accelerates to max speeds. It is more about trim balancing the aircraft...

And dodging missiles?

It will likely be going on all the time, but if they do notice it happening 300km away I would be impressed, and considering those missiles launched have a range of 400km then those missiles could be headed to intercept a target anywhere within a circle 800km across.

I can't say I have ever seen a MiG-31 pilot in anything but a space suit or an immersion suit which performs a similar function...

Not considering that SAM batteries do have radars and may switch them on, the launch of a big missile has a huge IR footprint, plus other airborne radars in theater are easily going to see it from 500 km away, more as the missile climbs. That is some reaction time (ca. 4 minutes), even if your missile flies very fast.

Isos wrote:Not realistic.

Awacs will be kept away from S-400 and will never go above front line... Their radar detection ranges are not great at all. Some 300 km against a 4th gen fighter so against a missile of 30cm diametre it will be 50 or so km.

Against an su-57 it should be around 150-200km so with a r-77M it will be able to sneak in and shoot it down. No need for r-37M.

Tracking a mach 5 missile is also unlikely by an airborne radar. In front of those S400 you will have a buk battery and 3 or 4 pantsir protecting the S-400. So the plane being attacked by s-400 will go down and change course and probably fall in range of anther AD system.

The real advantage of S400 is that its radars can spot and give away position of enemy fighters at great distance and coordinate smaller systems to destroy them which waiting in ambushes. That's why they need to buy thousands of shorads and cover all the area with them. S400 will oblige enemy fighter to fly low and then even a zsu-23-4 will be very good at shooting them down.

LMFS wrote:

Where are you taking all those conclusions from?

> AWACS have a radar horizon of >500 km. That is more than S-400 range so they have an observation line to see them and still be safe from their missiles.
> I am talking about airborne radars, that does not necessarily mean AWACS
> How is detection range of an AWACS vs a S-400 missile 50 km? And how do you know the different ISR means don't detect the emissions of the radars, the lock on the target, or the different data links being used during the engagement? How do you know no space based asset is going to detect the flare, or any other IR/EO detector present in the battlefield?
> Where do you get the AWACS detection range vs. the Su-57?
> How is it that no airborne radar can track a 5 M missile?

GarryB wrote:For which high g turns are less important than high speed escape after all the missiles have been launched.

In a 400km radius on a battlefield there will likely be hundreds or thousands of radars operating, and tens of thousands of missiles being launched... why would a fighter notice one in particular?

Reaction time to do what?  Most long range S-400 SAMs probably fly above 30km altitude on their way to the target so what exactly could any fighter do as they blow past on their way to your AWACS platform first I would suspect...

That is an immersion suit... the valves on the arms are for improved buoyancy. Used when operating over water... It would inflate in the water to improve floatation and also insulation from the cold water...

Isos wrote:At 500km it won't see anything smaller than a civilian aircraft.

Radar horizon works in both ways. If s-400 can't see the awacs then the awaxs can't see him too.

Awacs have radar similar to ground search L band radars. Their only advantage is that they are not affected by ground and have no radar horizon.

In use awacs have ranges of around 300-400km against 4th generation jets. With its shapes su57 bounces away a part of the energy and its coating absorbs also a part, less effective than against X band radar but still somehow effective. So I assume they have a 200km range against it.

S-400 missiles have a tiny diameter and won't be detected at 500km. They may be lucky if they deect it at 50km. Those radar are not meant to compute a target flying at mach 5. It's not magical, if it wasn't designed to do it don't expect it do it. Even detecting such target may not be possible.

Other fighter based radars are far less effective and their search field of view is much smaller.

S-400 are not egyptian sa-6. They are not SARH missiles but Track via missile. Not an expert about it but the tracking can happen only at the last moment and uses the missile's radar with processing made buy the ground radar and the missile cruise unoticed with no signal until that mement. An awaxs to be effective needs to operate at 10km altitude. And we are not taking into account r37M.

Russia uses an IADS. Elint plateform will detect mai ly emmissions in L and S bands from radars far away. S-400 engaging radars will work for few second to allow a hit. They won't know where they are.

A nabo U can detect your awacs from 400km on your left but a s-400 may be 50km away from you and destroys you with you RWR noticing it only 10 seconds before impact.

Source?

Sure, but at 500 km the S-400 cannot hit the AWACS

In which case you would use a 9M96 missile and not a 40N6, as I keep saying.

I am aware they would not activate the active radar seeker until the last moments, that does not mean a 7.5x0.5 m missile, almost 2000 kg flying 7 M is a stealthy target or can be launched without nobody noticing.

Between this guess of yours and Russian officials' statements that "no AWACS can detect it" I guess we have quite a window of uncertainty...