Su-27 vs F-15 performance (in game)

[Cmptohocah]

First of all I wouldn't like this thread to become red vs blue arena, but rather help me understand the Su-27 performance as it is modeled.

 

What first got me thinking about this subject was that I find the Flanker quite sluggish as compared to Mig-29 and, as I was to find out latter, F-15 too. Now, I understand that it's quite a large airplane but then it also has power-to-weight ratio more than 1. This means that the airplane has more thrust than it's weight, so the size kind of doesn't matter-there is influence of air resistance, but I guess that people at Sukhoi took this into account when designing it.

 

Now, I shall describe one of the situations that happened to me while flying online: I was chasing an F-15 who went defensive, and had dropped some 3km in order to defeat my incoming (good for nothing :) ) R-27ER. I went in full after burner, even though I knew there was no chance of catching up but had to stay on him in case he decided to turn back 'hot' again. What happens next blows my mind away: from some 2km alt and running away, this F-15 climbs to over 12km and not only that, it accelerates from some 1200km/h (TAS) to well over 18000km/h (TAS), while doing it. Now, I can barely achieve 1200km/h indicated in level flight at some 7km altitude.

 

My question is: is it possible that Su-27, air supremacy, best that Russian air force has to offer, world record climb performance, fighter is so much lagging behind the F-15? Or am I missing something here?

 

I am not talking about different loads and weights, but rather general performance between two airplanes. It seems to me that F-15 is a class better than Su-27 in flight performance, and I was just wondering is this the real picture and if it is, how can Su-27 be called 'the best fighter in the world' when it basically doesn't stand a chance against the eagle?

 

Hope some of you can bring me to better understanding on what is going on.

 

Kind regards,

[Fri13]

Lot of things are questions about the pilot skills to get the speed and handle the aircraft.

But sure, a 2km > 12km altitude and increase speed from 1200kph to 1800kph sounds odd.

 

But the fairly common thing is that someone finds other aircraft better than a another and then swaps to that one, to find it isn't.

[WinterH]

Su-27 isn't the best fighter in the world. I say that as a Su-27 fan too.

 

Compared to F-15, it's turning ability and low speed handling are better. But F-15 is both faster and climbs better. Of course these all depend pretty significantly on weight of both airframes at that time, but overall and general picture is like that.

 

If your Sukhoi is loaded to the teeth with missiles and fuel, g limit, turning ability, climb rate and acceleration will all suffer.

[Darkbrotherhood7]

Now, I understand that it's quite a large airplane but then it also has power-to-weight ratio more than 1. This means that the airplane has more thrust than it's weight, so the size kind of doesn't matter-there is influence of air resistance, but I guess that people at Sukhoi took this into account when designing it.

 

Sorry but I don't think this is correct, bud. :)

 

 

 

I am not talking about different loads and weights, but rather general performance between two airplanes. It seems to me that F-15 is a class better than Su-27 in flight performance, and I was just wondering is this the real picture and if it is, how can Su-27 be called 'the best fighter in the world' when it basically doesn't stand a chance against the eagle?

 

Who called the Su-27 "the best fighter in the world"?

 

Anyways, would be nice if you could provide a track, it would help to understand what happened.:)

[DarkFire]

First of all I wouldn't like this thread to become red vs blue arena, but rather help me understand the Su-27 performance as it is modeled.

 

What first got me thinking about this subject was that I find the Flanker quite sluggish as compared to Mig-29 and, as I was to find out latter, F-15 too. Now, I understand that it's quite a large airplane but then it also has power-to-weight ratio more than 1. This means that the airplane has more thrust than it's weight, so the size kind of doesn't matter-there is influence of air resistance, but I guess that people at Sukhoi took this into account when designing it.

 

Now, I shall describe one of the situations that happened to me while flying online: I was chasing an F-15 who went defensive, and had dropped some 3km in order to defeat my incoming (good for nothing :) ) R-27ER. I went in full after burner, even though I knew there was no chance of catching up but had to stay on him in case he decided to turn back 'hot' again. What happens next blows my mind away: from some 2km alt and running away, this F-15 climbs to over 12km and not only that, it accelerates from some 1200km/h (TAS) to well over 18000km/h (TAS), while doing it. Now, I can barely achieve 1200km/h indicated in level flight at some 7km altitude.

 

My question is: is it possible that Su-27, air supremacy, best that Russian air force has to offer, world record climb performance, fighter is so much lagging behind the F-15? Or am I missing something here?

 

I am not talking about different loads and weights, but rather general performance between two airplanes. It seems to me that F-15 is a class better than Su-27 in flight performance, and I was just wondering is this the real picture and if it is, how can Su-27 be called 'the best fighter in the world' when it basically doesn't stand a chance against the eagle?

 

Hope some of you can bring me to better understanding on what is going on.

 

Kind regards,

 

The engines on the Su-27 each have 12,500Kg of thrust (at max afterburner, under optimum conditions) so your T:W ratio will only be above 1:1 if your all-up weight is at or below 25,000Kg. That essentially means less than 50% fuel with ~4 missiles.

 

The F-15C will accelerate and climb faster than the Su-27, but climbing that high while accelerating is a bit suspect. Are you sure he didn't alt-tab? Alt-tabbing used to (not sure if it still does) produce a massive lag spike which causes aircraft to nearly instantly warp miles upwards.

 

Your maximum speed at 7,000m should be in the region of 2,230 Km/h TAS, which in a standard DCS day will be about 1,530 Km/h IAS, which roughly equates to Mach 1.99. It's worth noting that at 95% RPM in a clean configuration the Su-27 will actually supercruise at that altitude.

 

If you're driving a Flanker, you want to entice the Eagle driver in to a turning fight at under 6,000m altitude. Your instantaneous and sustained turn rates will be better as will your nose authority. This combined with your R-73 and HMS gives a powerful advantage. Most disciplined F-15 drivers will however do everything they can to avoid this situation and will try to stick to a high-speed BVR engagement in which their better situational awareness and massively superior BVR missile gives them the advantage.

 

The key in the Flanker is surviving to the merge. Learn how to gauge distance using your SPO-15 RWR. Learn to love the EOS and use the radar sparingly. The Su-27 can be successful at BVR but it really helps if you have a numerical advantage against an enemy and can co-ordinate team work against them.

[Bushmanni]

Flanker is not a bad plane, it can give a good challenge to the Eagle when flown properly, although Eagle is better in most respects when flown by a pro. While Flanker has advantages over the Eagle that the Flanker fanboys (or propagandists) like to make noise of, the advantages the Eagle has over the Flanker actually matter more. Performance at high speed and high altitude and high max G load are all good for BVR. While Flanker has good numbers on paper they come with caveats that make the real story much less impressive. Eagle and Flanker are both nominally 9G platforms but Eagle can actually withstand it on a relatively much higher weight limit. Both can fly stupid fast but Eagle can reach high speed faster and uses less fuel in doing so which makes this capability more useful tactically (same goes for altitude). In BFM Flanker seems to be the better turning plane but Eagle actually turns pretty well also but it can also accelerate, climb, pull G and decelerate much better than Flanker. Smart pilot can use these advantages to overcome the turning disadvantage.

 

Some of your problems are probably due to not understanding how to squeeze max performance out of the Flanker. Or the Eagle was flying low on fuel and without external stores which really gives it a performance boost. I suspect 18000km/h (not possible in DCS) is a typo and was meant to be actually 1800km/h (easy to do in DCS). None of the planes you give as example has T/W ratio over 1 at max T/O weight. The combat payload where the stated T/W ratios occur are also not necessarily comparable between planes. Flanker especially can carry lots of internal fuel that will handicap it severely if there's too much of it.

 

The records set by both planes were flown by modified planes and the Flanker had more modifications done compared to an operational plane. So an operational Eagle should beat an operational Flanker in climbing contest.

[Cmptohocah]

I will try and dig out the track. It shouldn't be a problem since it was my last flight online.

[Stuge]

I'll try to keep it as simple as I can, please correct if you feel any info is wrong:

 

Acceleration (this depends on thrust-to-weight!!): Eagle > Flanker in most weight situations. Eagle can jettison fuel in drop tanks, Flanker can't since all is internal, this also affects the equation.

 

Top speed: close enough to each other that I find the difference insignificant

 

Sustained turn rate: highly dependent on weight!! Half fueled fighter > fully fueled fighter, regardless of type. Interestingly, as Eagle and Flanker both become lighter as fuel is consumed, running on fumes, the Eagle gains a significant performance boost compared to the Flanker, exceeding 20 degrees per second at sea level while the Flanker stays below this number (according to my last test) However there's a big BUT: Eagle is much more speed sensitive than Flanker when it comes to maintaining sustained turn. Eagle needs to fly near perfect corner speed, which depends on its weight, while Flanker merely has to stay in the 600-800 km/h speed range. Also, Flanker's turn rate suffers less from slow speeds.

 

Turn radius at slow speed(smaller turn radius is better): Flanker > Eagle. However, Flanker driver needs to focus to compensate for the slower input reaction time of the Flanker and absolutely must use the S button to gain the minimum turn radius possible if such a maneuver is necessary!

 

Ease of handling and reaction to control inputs: Eagle > Flanker

 

Nose authority at slow speeds: Flanker > Eagle (don't forget the S button to get full nose authority, including the Cobra maneuver if necessary!)

 

G tolerance: Eagle > Flanker (the latter breaks apart if not careful)

 

BVR missile performance: Eagle > Flanker

 

Dogfight missile performance and off-boresight capability: Flanker > Eagle

 

Avionics and situational awareness in a multi-threat environment: Eagle > Flanker

 

BVR sensors: Eagle > Flanker

 

WVR/close range sensors: Flanker > Eagle

 

Stealth: Flanker > Eagle

 

Conclusions:

 

BVR capability: Eagle > Flanker.

 

Dogfighting capability: Flanker > Eagle

 

Regardless, both fighters have a good chance of victory in both BVR and dogfights, and the end result depends more on pilot skill than anything else. A master pilot pretty much always beats a beginner or even regular DCS pilot when a 1 vs 1 situation develops.

 

As a side note, I consider the Mig-29S in its current state inferior to both F-15C and Su-27 in most ways.

Edited August 15, 2016 by Stuge

[GGTharos]

The F-15C will accelerate and climb faster than the Su-27, but climbing that high while accelerating is a bit suspect.

 

It isn't suspect at all; all you need is to have few or no stores, less than full fuel (maybe) and you need to fly the acceleration profile correctly, which can happen just by sheer luck.

Once you hit 20000' and above in an eagle and you're already past M1.1-1.2, it'll take off like a scorched dog. Fly the profile right and you'll me doing M1.5 so fast that anyone chasing you will be calling your flight performance suspect ;)

 

Most disciplined F-15 drivers will however do everything they can to avoid this situation

 

A merge with a flanker isn't the best idea in the world, but it's really not the end of world.

[GGTharos]

I am not talking about different loads and weights, but rather general performance between two airplanes.

 

And yet loads and weights are extremely important in a given situation. If you're hauling 4 ERs and a bunch of 73's and jamming pods, and the other guy's clean, you might find that the amount of drag you've saddled yourself with isn't very helpful for you.

 

That aside, different engines may have different acceleration/power curves, even if on the surface they might appear to have similar performance when installed in a given aircraft.

 

It seems to me that F-15 is a class better than Su-27 in flight performance, and I was just wondering is this the real picture and if it is, how can Su-27 be called 'the best fighter in the world' when it basically doesn't stand a chance against the eagle?

 

Hope some of you can bring me to better understanding on what is going on.

 

Kind regards,

I'll try to give you a very simple answer:

 

The F-15 is tuned to its real performance documentation, and it's done so quite well, verified by people on the English forums here, as well as in the Russian section of the forums.

 

The Su-27 is tuned to data that we're not going to see in public, but frankly I have zero doubts as to Yo-Yo's work on this aircraft; it actually performs better than originally expected.

 

It all comes down to this: All these aircraft are different, and are 'better' at some specific things compared to other aircraft.

 

But if the differences in aircraft weren't enough, there are circumstantial differences, as well as pilot knowledge, skill, and situational awareness required to recognize what the opponent is doing and countering it in time.

 

Basic BFM is a huge and difficult subject. It isn't uncommon to see people surprised that a given aircraft doesn't live up to its propaganda (we've gotten more than one complaint that the F-15 won't accelerate straight up, for example :) ).

Focus on your own knowledge of the aircraft, and on your flying knowledge. These aircraft's FMs are correctly tuned and checked multiple times by various people.

[MiG21bisFishbedL]

Performance also needs to be qualified with altitudes.

 

I wouldn't want to try and turn with an Eagle above 40,000, for example.

[SinusoidDelta]

Performance also needs to be qualified with altitudes.

 

I wouldn't want to try and turn with an Eagle above 40,000, for example.

 

I think the OP is mostly speaking about climb rate. A clean F-15 with less than 5k lbs of fuel will climb like a bat out of hell. OP hasn't provided a track so we don't really know the specifics of his concern. It would be much appreciated if he would post the track, in order to keep this thread from devolving like they typically do.

[Fri13]

Most disciplined F-15 drivers will however do everything they can to avoid this situation and will try to stick to a high-speed BVR engagement in which their better situational awareness and massively superior BVR missile gives them the advantage.

 

That needs to be added that is when it is 1 vs 1 situation without any other help and in extreme hazardous SAM area with experienced SAM NEZ triggery and because DCS doesn't model radar missiles capabilities correctly.

[Cmptohocah]

First of all I have to apologize: I was not on afterburner at all, but I will try out how fast Su27 can go with 6xR-27ER and 4xR73 and 5t of fuel at 7-8k altitude with full burner.

 

Here is the video of the incident:

[ame]

[/ame] Edited August 15, 2016 by Cmptohocah

[GGTharos]

He dove for speed, got over the mach hump and ran away.

 

Zero strangeness. :)

 

Also, the speed you see for him is TAS, not IAS/CAS. IAS will pretty much always be lower than TAS at altitude.

Edited August 15, 2016 by GGTharos

[DarkFire]

It isn't suspect at all; all you need is to have few or no stores, less than full fuel (maybe) and you need to fly the acceleration profile correctly, which can happen just by sheer luck.

Once you hit 20000' and above in an eagle and you're already past M1.1-1.2, it'll take off like a scorched dog. Fly the profile right and you'll me doing M1.5 so fast that anyone chasing you will be calling your flight performance suspect ;)

 

A merge with a flanker isn't the best idea in the world, but it's really not the end of world.

 

Having watched the video, what happened was actually completely believable. It appears that the Eagle driver realised the situation, hit zone 5 and descended to gain air speed before turning away and zoom climbing. For some reason when I read the original post I envisages some sort of Saturn-V level of climb-to-orbit from a low and slow starting condition. Duh, my bad. :doh: I also later remembered "test" flying the ED F-15C myself a few times and being incredibly impressed with both the acceleration and climb performance.

 

I'm actually amazed that the Eagle driver didn't push and force the engagement as the point of closest approach was just under 35Km at only about 3,000m altitude difference. Plus ~8,000m isn't a particularly good altitude for conducting BFM in a Flanker. Maybe they were out of AIM-120's or something. I guess without full knowledge of the tactical situation we'll never know.

 

That needs to be added that is when it is 1 vs 1 situation without any other help and in extreme hazardous SAM area with experienced SAM NEZ triggery and because DCS doesn't model radar missiles capabilities correctly.

 

True. Being in a friendly SAM WEZ and / or having AWACS or EWR support makes a big difference for the Flanker driver. In fact I'd go so far as to say that having a fully populated HDD in the Su-27 gives you equal SA to the F-15.

[SinusoidDelta]

"...For some reason when I read the original post I envisages some sort of Saturn-V level of climb-to-orbit from a low and slow starting condition. Duh, my bad. :doh: I also later remembered "test" flying the ED F-15C myself a few times and being incredibly impressed with both the acceleration and climb performance...."

 

Well as a matter of fact....;)

Edited August 15, 2016 by SinusoidDelta

[Fri13]

 

True. Being in a friendly SAM WEZ and / or having AWACS or EWR support makes a big difference for the Flanker driver. In fact I'd go so far as to say that having a fully populated HDD in the Su-27 gives you equal SA to the F-15.

 

I don't think (but I don't have the info anyway so...) that the Su-27S HDD is exactly correctly modeled, like it might miss some other information shown on it (like compare the HDD before Su-27S got the AFM/PFM and then today, like how we can duplicate HUD on HDD etc) like it might even miss a RWR memory and visuals on it.

 

And as we don't have the informations how the datalinks work exactly between Su-27S and GCI/EWR etc. At least I know from the books like "Red Eagles: America's Secret MiGs"

 

They were a fantastic asset. These guys flew with us, briefed with us, were part of the post-flight debriefing, and made it possible for us to do our mission. During our air-to-air engagements they were in there with us and we felt that they were as valuable as another wingman. I remember flying against a flight of two F-4s. During the debrief, I was playing my tape recording of the engagements and you could hear my GCI controller talking to me as if he were another fighter pilot participating in the fight.

 

At one point in the fight I was engaged with one of the F-4s and “Stump”, my GCI guy, was talking almost non-stop. “Kobe, you can press your fight … the other F-4 is across the circle from you … Kobe, you’ve got 40 seconds left before he’s a threat … Kobe, come off hard right. The other F-4 is your 5 o’clock and 9,000ft, closing.” I did break right, picked up the other F-4 and continued the fight. During the debrief when the F-4 guys heard my tape they were convinced that I had brought another wingman into the engagement.

They said, “There is no way any GCI controller could have that much awareness of what’s going on by looking at a radar screen. And he is not talking like a GCI controller, he’s talking like the fighter pilot that he is!” They were really upset and I’m not sure to this day that I convinced them that I was the only T-38 in the fight. Our GCI controllers were absolutely fantastic.

 

The soviet air doctrine was so heavily build around information of air situation by all kind radars, that the pilots had very good situational awareness. And as here has been as well said, when Su-27S is missing a capabilities guide others missiles (like allowing front fighters to accelerate to optimal launch speeds, launch missiles and then turn away and escape the enemy missiles while other flights further guided missiles in) that heavily affects to BVR combat.

 

And what all kind things F-15C is missing, is as well unknown by all others than those who fly those.

 

We just can't make clear defining "this is better than that" in DCS as we are missing so many features and there are so many elements that just ain't counted in 1 vs 1 or 2 vs 2 situations when those situations would be like... never happening.

 

It is already nice to fly in DCS when you have a friend as a GCI, talking to you through TS and telling what is likely going to happen.

[Cmptohocah]

Thank you very much for the answers. I do appreciate the input. Had no idea that F-15 could climb and accelerate like that. Thanx once again.

[JunMcKill]

I'll try to keep it as simple as I can, please correct if you feel any info is wrong:

 

 

 

Avionics and situational awareness in a multi-threat environment: Eagle > Flanker

 

 

There is another situation, SA with AWACS: Flanker > Eagle

 

Thats why most of the public servers have the AWACS off! and sorry if someone is ofended, it's my intention! :)

[*Rage*]

SA in multiship engagements if the Su27 had a properly modelled datalink (peer to peer)

 

Flanker>>Eagle

 

Come on ED. Pull your finger out:)

[Stuge]

True true AWACS shifts the balance in favor of Flanker :)

[metzger]

Does Mig-29 has the latest flight model ?

[DarkFire]

Well as a matter of fact....;)

 

:shocking:

 

Wow, I'd never seen that graph before. I'm surprised they didn't use F-15's as chase planes for the later Apollo missions... Unless they did?

[DarkFire]

Does Mig-29 has the latest flight model ?

 

Not yet. I think the Su-33 is slated to get the professional flight model first, followed by the MiG-29.