PAK FA vs F-22A

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Corsair1963

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Unread post08 Feb 2018, 07:14

wrightwing wrote:
Corsair1963 wrote:




Do you have a source to support that???

A clean Flanker has an RCS in the 15 to 20m^2 range. As soon as you start hanging ordnance, it just gets worse. A clean Super Hornet has an RCS in the .5 to .1m^2 range. In an A2A configuration, a Super Hornet could easily stay in the 5 to 10m^2 range (and likely smaller.)



.....and you have a source to support that???
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gta4

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Unread post08 Feb 2018, 12:31

mixelflick wrote:So if they're similar performing machines at low speed and the Flanker holds the edge in acceleration/straight line speed....


This may surprise you, but F/A-18E is at least on par with, or slightly better than Flanker in subsonic acceleration.

A Su-27 single seater at 18920 kg flying weight (very little fuel on board) accelerates from 600km/h to 1100km/h in 15 seconds. Average acceleration is 9.26m/s^2.

A super hornet at 17241kg flying weight (definitely carries more fuel than a 18920 kg Su-27) accelerates from 360 kts to 550kts in 10 seconds, average acceleration is 9.77m/s^2.

During the operation test and evaluation, the F/A-18E demonstrated subsonic acceleration comparable to Mig-29A, which was designated as the "primary threat".
Last edited by gta4 on 09 Feb 2018, 02:11, edited 1 time in total.
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gta4

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Unread post08 Feb 2018, 12:39

ricnunes wrote:However TVC is not an "end all - win all" solution (or else every modern fighter aircraft would be equipped with TVC which is clearly not the case). TVC also has it's own drawbacks such as making the aircraft losing more energy when performing those high alpha maneuvers compared with a SH performing those same high alpha maneuvers (since the SH doesn't have TVC engines and as such the energy loss would be less). TVC engines also increase the aircraft's weight (in the case of the Su-35 not by much but by something, that's for sure).
So and as I said above, it's quite possible that the Su-35 ends up loosing more energy when performing high alpha maneuvers compared to the Super Hornet which means that the SH could still have the advantage here.


The reason why Super hornet loses less altitude in high alpha is in fact quite interesting. It is all about aerodynamics.
This figure is from a book published by Sukhoi, the flanker designer:
18 27 lex design.jpg


Flanker picked the LERX that loses lift at high alpha. Super Hornet picked the LERX that maintains lift even at very high alpha, which was discarded by Sukhoi because this LERX generates strong and non-linear pitch moment which was hard to control at 1980s (when Flanker was designed).
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hornetfinn

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Unread post08 Feb 2018, 15:21

Corsair1963 wrote:
wrightwing wrote:
Corsair1963 wrote:

Do you have a source to support that???

A clean Flanker has an RCS in the 15 to 20m^2 range. As soon as you start hanging ordnance, it just gets worse. A clean Super Hornet has an RCS in the .5 to .1m^2 range. In an A2A configuration, a Super Hornet could easily stay in the 5 to 10m^2 range (and likely smaller.)


.....and you have a source to support that???


It's pretty clear that SH has significantly lower RCS than Su-27 or even Su-35S. We don't have exact figures for operational aircraft, but there are lot of modeling software available which can give fairly good idea about RCS of these aircraft. Most models I've seen give roughly those figures but of course it also depends on very small details and materials used. The difference might be bigger in real life as SH seemingly has a lot more work put into those small details.

Weapons and EFTs don't necessarily affect RCS that much (for 4th gen fighters) with modern weapons and tanks that are designed for lower RCS. Western weapons definitely have lower RCS than Russian ones. AMRAAM, AIM-9X and ASRAAM have much better design from RCS PoV than R-77, R-27 or R-73/74 in Sukhois. They have a lot less reflecting surfaces and could easily have order of magnitude lower RCS even with equal materials and built quality. There have been studies made about different weapons. Even old weapons have pretty low RCS:
https://nsarchive2.gwu.edu/NSAEBB/NSAEB ... a51_13.PDF (document by Boeing from 1975)

The document says that individual Mk-82 bomb has RCS of about 0.05 to 0.1 square meters from most angles. 2 TERs with 6 Mk-82s has RCS of about 0.5 to 1 square meter according to this. Modern A-G weapons likely have a lower RCS than that.
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mixelflick

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Unread post08 Feb 2018, 15:29

gta4 wrote:
mixelflick wrote:So if they're similar performing machines at low speed and the Flanker holds the edge in acceleration/straight line speed....


This may surprise you, but F/A-18E is at least on par with, or slightly better than Flanker in subsonic acceleration.

A Su-27 single seater at 18920 kg flying weight (very little fuel on board) accelerates from 600km/h to 1100km/h in 15 seconds. Average acceleration is 9.26m/s^2.

A super hornet at 17241kg flying weight (definitely carries more fuel than a 18920 kg Su-27) accelerates from 420 kts to 550kts in 10 seconds, average acceleration is 9.77m/s^2.

During the operation test and evaluation, the F/A-18E demonstrated subsonic acceleration comparable to Mig-29A, which was designated as the "primary threat".


Indeed, I wasn't aware of this. Thank you. I was thinking comparing it moreso to the SU-35 though. I'll do my best to research that.

I always heard the following about the F-18: "Nothing gets slower, faster than a Hornet. And nothing gets faster, slower than a Hornet." So... does that refer only to the legacy Hornet?
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gta4

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Unread post08 Feb 2018, 15:46

mixelflick wrote:
gta4 wrote:
mixelflick wrote:So if they're similar performing machines at low speed and the Flanker holds the edge in acceleration/straight line speed....


This may surprise you, but F/A-18E is at least on par with, or slightly better than Flanker in subsonic acceleration.

A Su-27 single seater at 18920 kg flying weight (very little fuel on board) accelerates from 600km/h to 1100km/h in 15 seconds. Average acceleration is 9.26m/s^2.

A super hornet at 17241kg flying weight (definitely carries more fuel than a 18920 kg Su-27) accelerates from 360 kts to 550kts in 10 seconds, average acceleration is 9.77m/s^2.

During the operation test and evaluation, the F/A-18E demonstrated subsonic acceleration comparable to Mig-29A, which was designated as the "primary threat".


Indeed, I wasn't aware of this. Thank you. I was thinking comparing it moreso to the SU-35 though. I'll do my best to research that.

I always heard the following about the F-18: "Nothing gets slower, faster than a Hornet. And nothing gets faster, slower than a Hornet." So... does that refer only to the legacy Hornet?


That Only refers To transonic acceleration rather than subsonic acceleration.
Last edited by gta4 on 09 Feb 2018, 02:41, edited 1 time in total.
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citanon

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Unread post08 Feb 2018, 19:32

The su57 is a defendor, not a penetrator.

So, I'm wondering if the su57 is meant to be a mainly defensive fighter in Russian service.

In the years since its debut one thing= that's never made sense to me is the apparent neglect of stealth treatment on the bottom of the aircraft.

Today I saw a Russian state media video boasting of the extremely short takeoffs for the su57 and it all started to make sense.

These characteristics:

Stealthy top side, short takeoffs, extreme maneuverability, would make sense for a plane designed from the ground up to work over friendly territory with friendly air defenses to defend against enemy air incursions.

In this scenario, the situation would operate close to the ground, below the altitude of enemy aircraft, as a mobile, stealthy air defense element. This is why most of the stealth treatment is on top.

It will use its speed and the support of friendly iads to close in undetected on enemy aircraft or suspected positions of said aircraft, and engage them in close range fights.

The offensive fight will mostly be left to the army and long range precision fires. The job of the su57 is to buttress aa/ad over friendly territory to allow sustainment of such fires.
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mixelflick

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Unread post08 Feb 2018, 20:15

Interesting hypothesis..

If true, does that mean it won't be participating in something like Syria??
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Unread post08 Feb 2018, 23:07

hornetfinn wrote:
Corsair1963 wrote:.....and you have a source to support that???


It's pretty clear that SH has significantly lower RCS than Su-27 or even Su-35S. We don't have exact figures for operational aircraft, but there are lot of modeling software available which can give fairly good idea about RCS of these aircraft. Most models I've seen give roughly those figures but of course it also depends on very small details and materials used. The difference might be bigger in real life as SH seemingly has a lot more work put into those small details.

Weapons and EFTs don't necessarily affect RCS that much (for 4th gen fighters) with modern weapons and tanks that are designed for lower RCS. Western weapons definitely have lower RCS than Russian ones. AMRAAM, AIM-9X and ASRAAM have much better design from RCS PoV than R-77, R-27 or R-73/74 in Sukhois. They have a lot less reflecting surfaces and could easily have order of magnitude lower RCS even with equal materials and built quality. There have been studies made about different weapons. Even old weapons have pretty low RCS:
https://nsarchive2.gwu.edu/NSAEBB/NSAEB ... a51_13.PDF (document by Boeing from 1975)

The document says that individual Mk-82 bomb has RCS of about 0.05 to 0.1 square meters from most angles. 2 TERs with 6 Mk-82s has RCS of about 0.5 to 1 square meter according to this. Modern A-G weapons likely have a lower RCS than that.


Thanks Hornetfinn. Again very interesting. What means TERs?

@Corsair1963

This Pic will help you. Left the Su-27, right the Su with RAM. Like the Su-35s. The Picture was posted from eloise.

viewtopic.php?f=55&t=16457&start=450

Image
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SpudmanWP

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Unread post08 Feb 2018, 23:28

TER = Triple Ejector Rack (bomb rack with 3 locations)

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Unread post08 Feb 2018, 23:39

Not going to lie, I thought that would be higher than 1m^2
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swiss

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Unread post08 Feb 2018, 23:40

SpudmanWP wrote:TER = Triple Ejector Rack (bomb rack with 3 locations)

Image


Ah ok. Thanks for enlighten me Spudman.
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Unread post08 Feb 2018, 23:53

mixelflick wrote:Interesting hypothesis..

If true, does that mean it won't be participating in something like Syria??


I don't know what other roles it might also play. The Russians could send it there to show the flag, conduct some trivial strikes, or reinforce their control over AD zones. I think the plane will be much more important to Russian operations in Europe.
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Unread post08 Feb 2018, 23:55

The USMC just qualified a "Smart" TER that can mount smart weapons (JDAMs, Paveways, etc) on all three stations and the French have a TER also.

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marsavian

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Unread post09 Feb 2018, 01:18

gta4 wrote:
mixelflick wrote:So if they're similar performing machines at low speed and the Flanker holds the edge in acceleration/straight line speed....


This may surprise you, but F/A-18E is at least on par with, or slightly better than Flanker in subsonic acceleration.

A Su-27 single seater at 18920 kg flying weight (very little fuel on board) accelerates from 600km/h to 1100km/h in 15 seconds. Average acceleration is 9.26m/s^2.

A super hornet at 17241kg flying weight (definitely carries more fuel than a 18920 kg Su-27) accelerates from 420 kts to 550kts in 10 seconds, average acceleration is 9.77m/s^2.

During the operation test and evaluation, the F/A-18E demonstrated subsonic acceleration comparable to Mig-29A, which was designated as the "primary threat".


From your figures I make the Hornet's average acceleration to be 6.69 m/s^2. In 10s the Hornet has increased its speed by 31% whereas the Su-27 has increased its speed by 83% in 15s.
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