Operational Performance Comparison: Viper, Beagle and Stubby

[sprstdlyscottsmn]

The APG-83 has over 30 % more Range compere to the APG-66v3 (90km range). So we talk about over 120km vs 5m3 target.

https://airforcesmonthly.keypublishing. ... ight-test/

The AN/APG-83 can simultaneously perform search, tracking and lock-on functions. For multiple targets, the detection range is increased by more than 30% compared with the original APG-66(V)3 radar.

This is a significant step backwards from what I had. I had 215km v 5m^2 detection, 167km lock.

Man, this tanks the APG-83 to the ballpark of 47nm detect and 37nm track for 1m^2 targets. Air cooling is seriously robbing the SABR of it's inherent capability.

[zero-one]

There is a reason that noting in 2.1 is counted for a score, because it is mostly meaningless even though it is a group of specifications often used for comparison.

Thats actually what I mean't to ask about 2.1, in clean configuration the F-15SA has most of the turn rate advantages over the Su-35. But once we get to A-A config, there is a sharp drop in the Eagle's turn performance. NATO missiles are lighter than their Russian counterparts, so are they so much draggier or is there something else at play here.

With the Minimum time to get the nose on target
The goal is to literally get the target on your HUD not necessarily to get within HOBS weapons parameters right?
If so, the F-15SA is 0.02 seconds behind the Su-35, is this correct? Or is it 0.02 seconds behind the 60 second mark,

I think I'm confused on why they still have 10 points each despite having different results.

[garrya]

Those numbers sound way off for the APG-83 (which is a more advanced set than the APG-80.)

The main reason seems to be the cooling system for the APG-83.

https://www.ainonline.com/aviation-news ... velopments

Specialists at other radar design houses question how effective the APG-83 can be since the set depends on using the airflow that cools the other avionics in the F-16 and then using an internal liquid-cooling module and heat exchanger that is on-board the radar set itself.

“This has the advantage of not having to plumb a liquid-cooling system into the aircraft, as Lockheed Martin did with the F-16E/F Block 60 for the UAE,” said a U.S. airborne radar firm’s representative. “But the question is whether or not that cooling solution allows you to run the radar’s T/R modules at their maximum capacity because of the heat that they generate. Plus there are other questions about whether the modules could be software limited in order to be in compliance with U.S. government policy” on the export of sensitive technology.

Thank you Swiss
Feel so great to have an official source confirm what i said in the past
viewtopic.php?f=55&t=11311&start=1245

[sprstdlyscottsmn]

Thats actually what I mean't to ask about 2.1, in clean configuration the F-15SA has most of the turn rate advantages over the Su-35. But once we get to A-A config, there is a sharp drop in the Eagle's turn performance. NATO missiles are lighter than their Russian counterparts, so are they so much draggier or is there something else at play here.

Look at the configuration weight. Air to Air has CFTs and dropped EFTs (historically speaking Strike Eagles on Air-Air missions carried the wing tanks and targeting pods). This is why it has a fuel fraction of .3 even at 60% of take-off fuel.

With the Minimum time to get the nose on target
The goal is to literally get the target on your HUD not necessarily to get within HOBS weapons parameters right?
If so, the F-15SA is 0.02 seconds behind the Su-35, is this correct? Or is it 0.02 seconds behind the 60 second mark,

I think I'm confused on why they still have 10 points each despite having different results.

It's about the missile shot, so HOBS matters, otherwise the F-15 would get creamed here. It was .2s behind the Su-35, but since I stated the F-15 was going to be the baseline it gets 10pts by default so I specified that each second (rounded) better or worse is a point. As An Su-35S is going to have a 0s advantage against an Su-35S, and 0s is less than 1s different than the F-15s -0.2s it gets the same score.

[basher54321]

Specialists at other radar design houses question how effective the APG-83 can be since the set depends on using the airflow that cools the other avionics in the F-16 and then using an internal liquid-cooling module and heat exchanger that is on-board the radar set itself.

“This has the advantage of not having to plumb a liquid-cooling system into the aircraft, as Lockheed Martin did with the F-16E/F Block 60 for the UAE,” said a U.S. airborne radar firm’s representative. “But the question is whether or not that cooling solution allows you to run the radar’s T/R modules at their maximum capacity because of the heat that they generate.

Well they still don't really know, but it should be running much more CPU power at a much lower voltage than something from 15 years back that is for certain and a lot of liquid cooling systems still depend on air anyway to some extent.

[swiss]

Those numbers sound way off for the APG-83 (which is a more advanced set than the APG-80.)

The main reason seems to be the cooling system for the APG-83.

https://www.ainonline.com/aviation-news ... velopments

Specialists at other radar design houses question how effective the APG-83 can be since the set depends on using the airflow that cools the other avionics in the F-16 and then using an internal liquid-cooling module and heat exchanger that is on-board the radar set itself.

“This has the advantage of not having to plumb a liquid-cooling system into the aircraft, as Lockheed Martin did with the F-16E/F Block 60 for the UAE,” said a U.S. airborne radar firm’s representative. “But the question is whether or not that cooling solution allows you to run the radar’s T/R modules at their maximum capacity because of the heat that they generate. Plus there are other questions about whether the modules could be software limited in order to be in compliance with U.S. government policy” on the export of sensitive technology.

Thank you Swiss
Feel so great to have an official source confirm what i said in the past
viewtopic.php?f=55&t=11311&start=1245

You're welcome.

Specialists at other radar design houses question how effective the APG-83 can be since the set depends on using the airflow that cools the other avionics in the F-16 and then using an internal liquid-cooling module and heat exchanger that is on-board the radar set itself.

“This has the advantage of not having to plumb a liquid-cooling system into the aircraft, as Lockheed Martin did with the F-16E/F Block 60 for the UAE,” said a U.S. airborne radar firm’s representative. “But the question is whether or not that cooling solution allows you to run the radar’s T/R modules at their maximum capacity because of the heat that they generate.

Well they still don't really know, but it should be running much more CPU power at a much lower voltage than something from 15 years back that is for certain and a lot of liquid cooling systems still depend on air anyway to some extent.

At least the figures of the APG-80 seems to confirm this. Not only range. Resolution in SAR is on the same Level like the MSA Radar Captor-D ( 1 foot). And it can track 20 targets simultaneously. The roughly 20 years old RBE2 pesa can do 40.

[viper12]

Man, this tanks the APG-83 to the ballpark of 47nm detect and 37nm track for 1m^2 targets. Air cooling is seriously robbing the SABR of it's inherent capability.

Smells they gotta review a chunk of thermal compounds and water cooling solutions. Or maybe even chiller solutions if they got the power and they comply with the flight conditions.

[madrat]

What a great excuse to add DSI inlet to gain some extra volume in that quadrant.

[sprstdlyscottsmn]

Dude, you are the man
I think you should add these charts for each missile if possible

Or one chart with all missiles at the same altitude and start velocity

So, I am looking hard at this. I think some interesting information may be actual speed/altitude and turn rate/radius measurements. I realized also that the missile guidance I was using in the CAP scenario had varied somewhat from what was in the Missile section. I have some things to update. I already need to re-run the CAP mission due to a change in the Irbis-E so re-doing the missile shots is already going to happen. I will first change the missile section to ensure the listed ratings are consistent with what will be used in CAP.

Thank you all for your comments. You help make this the best analysis I can produce. These updates in total should only be 10-20 hrs of work and then I can get back to the F-16V. I'm also realizing the F-16E is the most capable Viper, but it is not in production.

[gta4]

When you have time, can you please do a simulation on the "rear hemisphere engagement envelope (180 shot)" of short range aams?

[southerncross]

I do not have, nor do I currently plan on having, a list in the analysis of the 50+ physical characteristics that go into the model.

Sure, that is probably not the priority, given the amount of work involved in your analysis. A reduced set of basic characteristics would probably help though.

My analysis is step by step. Talking about basic things that don't really apply like pure T/W and eventually evolving to "how far can you reach this type of target and how well does your ECM suite allow you to prosecute the target".

Ok I see what you mean, that is a sensible approach.

...In 2.2.1 Afterburner Time Remaining is a scored component.

BTW I still don't understand how the F-15 has 8.2 minutes left and the Su-35 only 3.1 after the Rutowsky push, maybe you could clarify? They should have 18,514 and 15,524 lb fuel at the start of the simulation respectively, if I am understanding correctly. At the end of the push they should have 14,089 and 11,917 lb fuel. The Sukhoi should have fuel for 12.2 minutes at that flow rate, the F-15 for 12.6, disregarding reserves. So the difference is in the reserve fuel considered and not in the actual time remaining, or am I missing something like dynamic calculation of flow rate...?

There is a reason that noting in 2.1 is counted for a score, because it is mostly meaningless even though it is a group of specifications often used for comparison.

You are right, and that is why your analysis is so welcome

Looking at it I do not see an where such analysis exist. I am always on the lookout for useful info however.

They publish their analysis in their issues, you can find them here:

https://www.aviapanorama.ru/catalog/

For instance:

https://www.aviapanorama.ru/2019/02/v-b ... ajut-35-e/
http://www.aviapanorama.ru/2015/12/vero ... ost-tozhe/

They seem to use classified data for Russian fighters so they don't disclose them, but maybe some kind of useful info comes from comparing analysis.

[sprstdlyscottsmn]

So I played with that once and the question became "what scenario?" I guess I can try something, I have an idea.

[gta4]

A basic scenario could be

The ego plane at speed x1 is being chased by a bandit at speed x2 at distance L. Both are flying straight line. What is the interval [Lmin, Lmax] for a 50g missile to land the hit?

The performance constrain for the missile is:

The motor works for 2~3 seconds at maximum thrust;
The usable g for the missile is proportional to the square of its speed, and is maxed out at 50g;

[sprstdlyscottsmn]

A basic scenario could be

The ego plane at speed x1 is being chased by a bandit at speed x2 at distance L. Both are flying straight line. What is the interval [Lmin, Lmax] for a 50g missile to land the hit?

The performance constrain for the missile is:

The motor works for 2~3 seconds at maximum thrust;
The usable g for the missile is proportional to the square of its speed, and is maxed out at 50g;

Not all missiles are 50G and almost no missile has a 2-3s motor (they are longer). My missile simulator calculates an estimated lift and drag profile based on the physical shape of the missile.

[sprstdlyscottsmn]

Sure, that is probably not the priority, given the amount of work involved in your analysis. A reduced set of basic characteristics would probably help though.

I'll see what I can do. I don't like the "Flow" of the aircraft section as is.

BTW I still don't understand how the F-15 has 8.2 minutes left and the Su-35 only 3.1 after the Rutowsky push, maybe you could clarify? They should have 18,514 and 15,524 lb fuel at the start of the simulation respectively, if I am understanding correctly. At the end of the push they should have 14,089 and 11,917 lb fuel. The Sukhoi should have fuel for 12.2 minutes at that flow rate, the F-15 for 12.6, disregarding reserves. So the difference is in the reserve fuel considered and not in the actual time remaining, or am I missing something like dynamic calculation of flow rate...?

This is an excellent question and you are on the right track. The F-15SA has a 7,200lb reserve for this comparison while the Su-35S has a 8,400lb reserve. the Su-35S flying at 1.757M at 40,000ft is burning a LOT more fuel than the F-15SA flying at 1.4M at 50,000ft. The dynamic thrust difference here is remarkable. 18,938 lb of thrust for the Eagle and 37,946 lb of thrust for the Flanker.