F-16.net

hornetfinn wrote: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.

marsavian 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".

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.

citanon wrote: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.

element1loop wrote:
Alternatively, it's a product of post-Soviet collapse and extremely limited austerity budget, and desperation, in the face of US 5th-gens, plus Eurocanards.

Which likewise explains the Su35 and late build MiG29s.

In 2005, as F-22A was becoming a thing, RuAF were scarcely able to afford fuell to train pilots and maintain corroding parked aircraft.

popcorn wrote:

hornetfinn wrote: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.

What would your educated guess be for the RCS of an AIM-9X mounted on a F-35 stealth pylon?

hornetfinn wrote:

popcorn wrote:

hornetfinn wrote: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.

What would your educated guess be for the RCS of an AIM-9X mounted on a F-35 stealth pylon?

That's really tough to say without simulating that with some software. However Brazilians measured their MAA-1 Piranha (basically AIM-9L/M in shape and size) to have RCS of about 0.01 to 0.1 square meters from most angles (except directly perpendicular and directly from behind where there were spikes). AIM-9X and ASRAAM have a lot smaller fins and wings and their shape is better for low RCS. Their IIR seekers are also I'm sure the materials have improved a lot, but the RCS effects are impossible to know from public info.

That Brazilian study:
http://www.jatm.com.br/papers/vol3_n1/J ... 10_GHz.pdf

My guess is that AIM-9X/ASRAAM have RCS of something like 0.001 to 0.01 square meters or better depening on materials used. Being mounted on pylons probably increases RCS somewhat, but pylon could have quite a lot of RAM to help the situation. I think two AIM-9X or ASRAAMs on F-35 will not have that huge impact on RCS. It will increase for sure and there will likely be bigger RCS spikes from some directions. IMO, F-35 will still be a lot stealthier than any other fighter aircraft (besides F-22 of course). I'd guess they will be used when tasked for air to air missions but likely omitted when on air to ground missions against fully operational defenses.

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

Fig. 3. The "facet" model of the Su-27 (above) and the effective scattering surface diagram of the aircraft
as a function of the viewing angle in the horizontal plane (bottom)
The solid line corresponds to the diagram of the scattering of a real aircraft, the dashed line corresponds to an aircraft with a reduced radar visibility; 1 and 2 - averaged over the range of angles ± 30 ° EPR values

marsavian wrote:

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

It is. 1 and 2 refer to the average RCS of Su-27/stealthy Su-27 which according to the right horizontal scale is just over 20 m^2 and just under 10 m^2 respectively.

hornetfinn wrote:My guess is that AIM-9X/ASRAAM have RCS of something like 0.001 to 0.01 square meters or better depening on materials used. Being mounted on pylons probably increases RCS somewhat, but pylon could have quite a lot of RAM to help the situation. I think two AIM-9X or ASRAAMs on F-35 will not have that huge impact on RCS. It will increase for sure and there will likely be bigger RCS spikes from some directions. IMO, F-35 will still be a lot stealthier than any other fighter aircraft (besides F-22 of course). I'd guess they will be used when tasked for air to air missions but likely omitted when on air to ground missions against fully operational defenses.

hornetfinn wrote:
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.

marsavian wrote:the last few decades has been for combat to become more BVR

zero-one wrote:

marsavian wrote:the last few decades has been for combat to become more BVR

Though I firmly believe that the majority of air combat would be BVR, I don't think saying that BVR accounted for the majority of kills during the past decades is a good way to prove this. Because people can counter by saying, the most recent air to air kills the past few years have been WVR.

Just like how a certain set of conditions were met to allow BVR kills in past wars, certain circumstances can also lead to the recent influx of WVR kills as of late.