Su-27 Flight Performance

[GGTharos]

And there is definitely something wrong with one off these planes FM's, or both.

 

Comparison to each aircraft's RL performance figures please, rather than against each other?

 

Can you show/prove that something is wrong?

 

Right around 720kph IAS was the best I could sustain in a Flanker without going into GLOC. At that speed, and with the Eagle at 350knots IAS, we were equal. We went round and round and round without gaining any purchase. If I tried to turn faster than that, I pull too much G. If I went slower, the Eagle out turned me. If we both went slower, the Flanker won. But, why would the eagle choose to do that? He wouldnt.

 

What gross weight and altitude?

 

So GGtharos, what gives?

 

So ArkRoyal, what gives with questions without actual data? :)

 

At 350KIAS the flanker should out-turn the eagle at low altitudes. It's something along the lines of a 2deg/s advantage IIRC, which means you should see a change of 20deg over 10 seconds.

But this also assumes that the comparison is made at the 'nominal combat weights'.

 

You won't find much data to compare flanker performance against because it isn't out there and AFAIK ED isn't going to hand it out. But it's much better data than what's available to you.

 

On the other hand, there's -1's sitting around that you can check the eagle against, as long as you use the correct charts - for the -220 engines, not the -100's.

 

So you tell me ... what gives?

[=4c=Nikola]

^Well, you said this:

 

No, it doesn't. The F-15 isn't capable of keeping up with a flanker in a straight-up turning fight, and there's almost no way to get a flanker out of your TC as long as the flanker pilot has a reasonable clue with respect to conducting BFM. Right now the flanker behaves better throughout the entire envelope compared to the eagle.

[GGTharos]

Yep, I also flew it against some pretty good BFMers.

 

Let's take a couple extremes here: You get an F-15 with 4000lbs fuel and a flanker with 9000kg of fuel.

 

Who's going to turn better? (Ever here though, the answer is - it depends :) )

 

There is a published chart out there from a RuAF manual that shows performance of Su-27 vs. F-15 and I imagine you probably have it. It also lists the specific configuration of each aircraft. You can use this to compare the Su-27 performance (but not the F-15 one).

 

It should give you a basic idea of what it means to be 'better behaved', but it is by no means the full picture.

[ArkRoyal]

Comparison to each aircraft's RL performance figures please, rather than against each other?

 

Can you show/prove that something is wrong?

 

 

 

What gross weight and altitude?

 

 

 

So ArkRoyal, what gives with questions without actual data? :)

 

At 350KIAS the flanker should out-turn the eagle at low altitudes. It's something along the lines of a 2deg/s advantage IIRC, which means you should see a change of 20deg over 10 seconds.

But this also assumes that the comparison is made at the 'nominal combat weights'.

 

You won't find much data to compare flanker performance against because it isn't out there and AFAIK ED isn't going to hand it out. But it's much better data than what's available to you.

 

On the other hand, there's -1's sitting around that you can check the eagle against, as long as you use the correct charts - for the -220 engines, not the -100's.

 

So you tell me ... what gives?

 

What gives is that we are comparing in game performance predominantly against statements that you have made. Others have already pointed that out for me.

 

I agree completely that the Flanker should be about 2 deg/sec better at the speed you stated. This is not news, as is already implied that I think something is wrong with what essentially everyone except for you is seeing in game.

 

As for weight, I had the Eagle at 50%, and the Flanker a 47%. This is close to being equivalent in fuel in terms of time. Actually less, since I ran out of fuel in the 27 before the Eagle. So I stand only to get heaver. Altitude was about 6000ft, and remained basically constant.

 

 

I dont need 10 pages of flight manuals to point out that the plane is not performing as you say it is. As to whether or not the game is currently consistent with real life, well you stated your self the 2 deg/sec figure, and have on numerous occasions stated the Flanker should without a doubt win a nose to tail turning fight at low altitude. So, while I have seen some Flanker data and Eagle data on my own, lets not obfuscate things by pretending I have to prove something with data that you already agree with.:smilewink:

[GGTharos]

I agree completely that the Flanker should be about 2 deg/sec better at the speed you stated.

 

AND AT SPECIFIC GW

AND AT SPECIFIC ALTITUDE

AND WITH SPECIFIC PAYLOAD

 

But none of that matters because ...

 

I dont need 10 pages of flight manuals to point out that the plane is not performing as you say it is.

In fact you do. ED has long stopped accepting 'omg this is wrong' stuff. The data is out there, show that the eagle's data is wrong, and by how much, and then we've got something to talk about :)

(I'd say the flanker data too, but sadly none of us can get that data. There are a few examples of it, but not as much information as for the eagle)

 

As to whether or not the game is currently consistent with real life, well you stated your self the 2 deg/sec figure

At a specific point in a chart that I barely recall. :)

 

and have on numerous occasions stated the Flanker should without a doubt win a nose to tail turning fight at low altitude.

And it certainly does when I fly it.

 

So, while I have seen some Flanker data and Eagle data on my own, lets not obfuscate things by pretending I have to prove something with data that you already agree with.:smilewink:

Nothing is obfuscated. Want to prove something's wrong?

 

Compare each aircraft to its own data. There's literally nothing else to it.

Relative performance is something we all only 'heard about' or 'read about' somewhere.

 

We all have an idea of what it should be, and there's no guarantee that this is correct.

 

Want the right answers?

 

Compare to relevant data. The rest is garbage, pretty much including anything I say using things I recall off the top of my head :)

[*Rage*]

Thanks to however split this discussion off into its own thread:thumbup:

 

Sorry but no. Way outdated, assuming it even mattered back then. I can point the nose anywhere I want with a flanker in such a way that anyone who wants to actually make it a fight, has to extend so far out as to be subject to missile employment.

 

You're not going to out-turn a flanker with an eagle. If it truly was ever possible back in the day, it's really not at this point.

 

The only time I 'out-turn' a flanker is because the other guy does something silly in front of me, not because the eagle can out-rate it.

 

But you still haven't explained this. Because right now you can still out turn a Su27 with an F15 at low altitude and equivalent (low) fuel states. I haven't formally tested it myself. I'm only talking of experience in a 1v1 guns only dogfight and testing done by someone better qualified than me to test it. With 1.5 around the corner I'm not sure its worth me trying to replicate his results.

[ArkRoyal]

AND AT SPECIFIC GW

AND AT SPECIFIC ALTITUDE

AND WITH SPECIFIC PAYLOAD

 

But none of that matters because ...

 

In fact you do. ED has long stopped accepting 'omg this is wrong' stuff. The data is out there, show that the eagle's data is wrong, and by how much, and then we've got something to talk about :)

(I'd say the flanker data too, but sadly none of us can get that data. There are a few examples of it, but not as much information as for the eagle)

 

At a specific point in a chart that I barely recall. :)

 

And it certainly does when I fly it.

 

Nothing is obfuscated. Want to prove something's wrong?

 

Compare each aircraft to its own data. There's literally nothing else to it.

Relative performance is something we all only 'heard about' or 'read about' somewhere.

 

We all have an idea of what it should be, and there's no guarantee that this is correct.

 

Want the right answers?

 

Compare to relevant data. The rest is garbage, pretty much including anything I say using things I recall off the top of my head :)

 

Point # 1: Not news, I am aware that the performance changes as conditions change.

 

2: You misunderstand. A flight manual for IRL, is not relevant in showing that the game is not performing consistently with things you have said. This is a question of your statements vs the game, not your statements or mine vs IRL.

 

3/4/5: Tell me something. If the community is expected to provide ample evidence that something is incorrect, why should we not expect the same of ED? Your statement implies that you also have never seen this data they are supposedly working with with your own eyes, which means you are taking them at face value. Perhaps they really do have information. But if that data is at odds with everything else available to everyone else, I see no reason why we should all be expected to swallow the blue pill.

 

So while I still stand by that my original argument is about the game vs what you said... not what you said vs IRL or IRL vs anything else.............if ED wants people to stop whinging about supposed performance problems, then it would behoove them to be as forthcoming with proof as you apparently expect myself and everyone else here to.

[GGTharos]

2: You misunderstand. A flight manual for IRL, is not relevant in showing that the game is not performing consistently with things you have said. This is a question of your statements vs the game, not your statements or mine vs IRL.

 

It's always someone's statements vs. RL as far as the FMs are concerned in this game. Everything else is a waste of time ... unless the goal is to moan about stuff.

 

I get that people have their favorite in the fight etc., but like this particular discussion, it all gets too long winded and in the end it is meaningless.

 

Your statement implies that you also have never seen this data they are supposedly working with with your own eyes, which means you are taking them at face value. Perhaps they really do have information. But if that data is at odds with everything else available to everyone else, I see no reason why we should all be expected to swallow the blue pill.

 

Correct, I know they have it, I know I won't get to see it. Take from that what you will, I have complete confidence in Yo-Yo's work.

 

To put it in other words ... if you want Yo-Yo to change something, you'll probably be asked why. 'Stuff' you generally read on the internet is not good enough.

 

So while I still stand by that my original argument is about the game vs what you said... not what you said vs IRL or IRL vs anything else.............if ED wants people to stop whinging about supposed performance problems, then it would behoove them to be as forthcoming with proof as you apparently expect myself and everyone else here to.

 

ED has nothing to prove, and again, they have access to things you or I won't get to look at any time soon.

 

People who complain about things do need to present proof, and so far I don't see anyone here doing such a thing (there ARE people who have done good comparisons though, and you might even be able to find those).

 

If you want change, present adequate proof. If you're told your proof isn't good enough, present better proof. If you don't want to do the extra work, you don't have an argument.

 

That's how it is, and it applies to everyone, including myself.

[ArkRoyal]

It's always someone's statements vs. RL as far as the FMs are concerned in this game. Everything else is a waste of time ... unless the goal is to moan about stuff.

 

I get that people have their favorite in the fight etc., but like this particular discussion, it all gets too long winded and in the end it is meaningless.

 

 

 

Correct, I know they have it, I know I won't get to see it. Take from that what you will, I have complete confidence in Yo-Yo's work.

 

To put it in other words ... if you want Yo-Yo to change something, you'll probably be asked why. 'Stuff' you generally read on the internet is not good enough.

 

 

 

ED has nothing to prove, and again, they have access to things you or I won't get to look at any time soon.

 

People who complain about things do need to present proof, and so far I don't see anyone here doing such a thing (there ARE people who have done good comparisons though, and you might even be able to find those).

 

If you want change, present adequate proof. If you're told your proof isn't good enough, present better proof. If you don't want to do the extra work, you don't have an argument.

 

That's how it is, and it applies to everyone, including myself.

 

 

GG, my statement and others was, whether you think it a waste of time or not, about your statements. Not IRL. You do not get to tell me what my intent was in my posts. :)

 

Second let state some facts base on what we both just said.

 

1. You are assuming ED has information you do not.

2. You are assuming that said information is accurate.

3. You are assuming that ED used that data correctly

4. You are assuming that ED made no serious mistakes in then applying that data to the game.

 

 

You are applying a double standard ED vs the rest of us. To be clear: ED can do whatever they want. If they want to sell games and see no reason to prove to any degree that their aircraft are indeed accurate, they can very well go right ahead and do this.

 

However, your idea that we are being silly by asking for more that "trust us, we have secret data you dont" is crazy man. If you want to, go right ahead. But please don't insinuate that the rest of us are being ridiculous when we aren't satisfied with that explanation. It is impossible to for ED to prove itself correct on these matters unless it demonstrates its own data is real and superior to whatever the community possesses. Period. Full stop. ED doesnt have to have a conversation with us at all, but if there is to be one, you cant very well demand proof when not applying that standard to the company itself. I could very well claim I have secret data that I cant share with you. See how convincing that is?:smilewink:

 

Let us just state the obvious so that there isnt a misunderstanding. ED is under no obligation to listen to any criticism or change anything etc. They can do as they darn well please with their game. Roger. But lets not beat around the bush here. Nothing anyone says on here every constitutes proof of anything to ED. ED does what it wants, they aren't even slightly forthcoming with FM data, or inclined whatsoever to explain anything to their player base that isn't a deflection. The missile mod report was shrugged off like nothing if the statements they made in that thread are reflective of actual policy. They can do what they want, and we will probably keep buying their stuff (kinda the idea right?:D) But when someone gets on here and makes a complaint, its rather exasperating when you think were being unreasonable when we down down the Kool-Aid when told do so with no further evidence.

[FSKRipper]

GG, my statement and others was, whether you think it a waste of time or not, about your statements. Not IRL. You do not get to tell me what my intent was in my posts. :)

 

Second let state some facts base on what we both just said.

 

1. You are assuming ED has information you do not.

2. You are assuming that said information is accurate.

3. You are assuming that ED used that data correctly

4. You are assuming that ED made no serious mistakes in then applying that data to the game.

 

 

You are applying a double standard ED vs the rest of us. To be clear: ED can do whatever they want. If they want to sell games and see no reason to prove to any degree that their aircraft are indeed accurate, they can very well go right ahead and do this.

 

However, your idea that we are being silly by asking for more that "trust us, we have secret data you dont" is crazy man. If you want to, go right ahead. But please don't insinuate that the rest of us are being ridiculous when we aren't satisfied with that explanation. It is impossible to for ED to prove itself correct on these matters unless it demonstrates its own data is real and superior to whatever the community possesses. Period. Full stop. ED doesnt have to have a conversation with us at all, but if there is to be one, you cant very well demand proof when not applying that standard to the company itself. I could very well claim I have secret data that I cant share with you. See how convincing that is?:smilewink:

 

Let us just state the obvious so that there isnt a misunderstanding. ED is under no obligation to listen to any criticism or change anything etc. They can do as they darn well please with their game. Roger. But lets not beat around the bush here. Nothing anyone says on here every constitutes proof of anything to ED. ED does what it wants, they aren't even slightly forthcoming with FM data, or inclined whatsoever to explain anything to their player base that isn't a deflection. The missile mod report was shrugged off like nothing if the statements they made in that thread are reflective of actual policy. They can do what they want, and we will probably keep buying their stuff (kinda the idea right?:D) But when someone gets on here and makes a complaint, its rather exasperating when you think were being unreasonable when we down down the Kool-Aid when told do so with no further evidence.

 

Sorry, I followed this the last 4 pages and with every additional post this sounds more like conspiracy theories.

 

If you have any doubts about the current (work in progress) flight model of FC3 aircraft, is there only a single reliable source of hard data other than Wiki, tv documentations or the feelings of some disappointed eagle drivers?

 

I would say when in doubt, for the accused...

 

If you can't bring hard evidence that there is something wrong your feelings and experiences are simply irrelevant...

 

ED is well aware of the missile problems and working on them. But please don't be so stupid to believe everything that was posted in this thread. Even as flight engineer you won't be able to create an exact missile model based on dimensions and guessed performance data.

Edited September 22, 2015 by FSKRipper

[pr1malr8ge]

Sorry, I followed this the last 4 pages and with every additional post this sounds more like conspiracy theories.

 

If you have any doubts about the current (work in progress) flight model of FC3 aircraft, is there only a single reliable source of hard data other than Wiki, tv documentations or the feelings of some disappointed eagle drivers?

 

I would say when in doubt, for the accused...

 

If you can't bring hard evidence that there is something wrong your feelings and experiences are simply irrelevant...

 

ED is well aware of the missile problems and working on them. But please don't be so stupid to believe everything that was posted in this thread. Even as flight engineer you won't be able to create an exact missile model based on dimensions and guessed performance data.

 

This is a game and I know I've been hot headed on certain aspects and have ran my mouth.

 

What needs to be said is this:

 

Its the nature of human ideology to believe what they/we want. A great example of this is spacial disorientation that results in CFIT. The instruments state you are diving but you believe you are climbing and dive further and into the ground.

The same thing holds true with games or anything else we feel is wrong or right for that matter..

 

ED could theoretically produce an EXACT perfect replication on all aspects of these aircraft and no matter what every single person will have some debate that something isn't right. Even a real life veteran f15c pilot were to fly he would bitch about the su27 being wrong when it shoots him down since he never flown one. Even to add that not one single air frame acts identical to the next air frame. Case in point. My cousin was telling me that he was doing some maintenance ferry flights of f15s and he said there was one f15c he got in that for what ever reason was SCREAMING. It was just faster and more agile then the rest he flew.

 

In the end we can bitch but unless you make your own game you ultimately have no leg to stand on if the Devs want to not deal with it or just know you're wrong about it.

[SinusoidDelta]

So these are excerpts from, "САМОЛЕТ СУ-27СК РУК В ДСТВ П ЛЕТН Й ЭКСПЛУАТАЦИИ" aka the Su-27SK Flight Manual, dated 2004. Could someone possibly translate the chart titles and axes so we may use them for evaluation of the DCS FM?

 

[=4c=Nikola]

tables designated with 3 and 4 are speed vs load factor in stable (sustained?) turn for different altitudes, with 50% of fuel, 2x r73, and 2x r27, at standard temperature. Table 3 is for max dry power, and table 4 is for max AB. At table 4, hidden line indicates overload area while long red lines indicates area of "volatile instrument readings".

Correction for different aircraft mass is: final load factor= initial load factor * 20000 / mass of aircraft.

 

Tables designated 5 and 6 are predicted altitude lost in recovery from different initial speeds, dive angles and for different load factors during recovery, at idle power, with 2x r73, and 2x r27. Follow red line. Table 5 is for speed brake closed and table 6 is for speed brake open.

 

Just a note, all fuels are given as "50% of normal amount of fuel", which doesn't necessarily mean 50% of fuel tank. Maybe it is, maybe it is not, I don't know.

Edited September 25, 2015 by =4c=Nikola

[Esac_mirmidon]

This is the best internet could provide us for free i think.

 

 

[SinusoidDelta]

This is the best internet could provide us for free i think.

 

 

The charts I posted literally came out of the 2004 flight manual. Are they lacking something? Where did the charts you posted come from?

[SgtPappy]

Make note that the F-15's curves in the scanned pages is not very accurate. Comparing it to the STR values in the -1 manual shows that the Russians slightly overestimated the Eagle's turning capabilities.

[Hummingbird]

Make note that the F-15's curves in the scanned pages is not very accurate. Comparing it to the STR values in the -1 manual shows that the Russians slightly overestimated the Eagle's turning capabilities.

 

Correct.

 

In addition to this remember that the most accurate figures are the measured accelerations, i.e G forces.

 

F-15C's measured sustained turn performance in G's:

[Teknetinium]

Is there a consensus that Su-27S turns to slow compere to F-15C in DCS?

[Pikey]

Not when I've been in WVR, I've seen that thing hook on a dime. :)

[Esac_mirmidon]

G-load vs Speed, 100% dry thrust and Afterburner. Su-27 with 2 R-73 and 2 R-27. F-15 with 4 sidewinders. I think but it´s only an assumption, that the Su-27 is flying at 50% of its max weight 18920 Kg, and the F-15 the same, at 15.800 Kg.

 

 

[SinusoidDelta]

Is there a consensus that Su-27S turns to slow compere to F-15C in DCS?

 

No there is not. In order to have a consensus someone will need to test sustained level turn performance, find a way to log it, and plot the results vs the actual flight manual.

 

Also don't forget the manuals impose structural limits and give no performance figures beyond that point. The F-15 could be stressed to 12G in combat safely but the performance at those loads is not captured in the -1.

[=4c=Nikola]

No there is not. In order to have a consensus someone will need to test sustained level turn performance, find a way to log it, and plot the results vs the actual flight manual.

 

Also don't forget the manuals impose structural limits and give no performance figures beyond that point. The F-15 could be stressed to 12G in combat safely but the performance at those loads is not captured in the -1.

 

He asked for DCS, not RL comparison.

[SinusoidDelta]

He asked for DCS, not RL comparison.

 

The data would need to be extracted from a DCS flight to make that comparison. Tacview can record telemetry which can be exported to a csv. Then we could prove, quantitatively, which bird turns better and where in DCS.

 

If we are then saying the Su-27 turns too slow compared to F-15C we would need to correlate with the flight manuals. Opinions need to be left out of FM validation.

 

ps

Thanks for the translation help on those perf. charts.

Edited September 26, 2015 by SinusoidDelta

[ArkRoyal]

Ok everyone buckle you seat belts, were about to go for ride that I think will settle this issue. :)

 

So after some more thinking on this, trying to figure out the statements by GGTharos that appear to be contradictory and the other issue that have come up in this thread, I thought it would make sense to just start over totally. To do that, I went in game and tested the Flanker and F-15 at comparable fuel loads and compared them to the Documents we have on the Flanker and the -1 for the F-15.

 

Let us begin. Please direct your attention to Figure 1. I am sure we are all familiar with this by now.

 

 

Red is in game F-15 Performance at 50% fuel.

 

Blue is the Same for the Flanker.

 

Brown is the Flight tested performance of the Eagle in the -1, at the lowest weight in the -1, which is ^7% fuel, or 2300lbs heavier.

 

Now previously it was assumed that this Russian chart was for both planes at 50%, than that seems likely still. Note that the F-15 at 67% fuel in the -1 performs slightly worse, which corroborates the Russian estimate shown here. Note that while my turn testing in game did not yield the same numbers, this is probably due to my own error (because holding these turns was on the edge of G limit in most cases). More importantly, they are basically proportional to the official figures for both aircraft.

 

So what this shows is that at corner speed, the F-15 CAN out-rate a Flanker, while at lower speeds near its own corner the Flanker out-rates the Eagle. The Flanker has a larger margin for error here, since there is a narrow band in which the eagle can sustain corner without going into G-Loc. But it can out turn the flanker around .7 to .8 mach SL. The reason I suggest for this is a difference in weight and how we are comparing these documents. A flanker consumes fuel hugely faster than an Eagle. I tested both planes a sea level at the same speed at AB and got 2000lbs/min for the Eagle and 3333lbs/min for the flanker, at low speed just around 250knots. Fuel consumption for the Flanker is even higher at higher speed, proportionally. This should not be news to anyone, the Flanker hogs fuel. It has always been that way, even since the SFM. So you need a proportionally heavier Flanker to have the same time on station at any speed. So a Eagle at 50% or 6700lbs of fuel, would would need a Flanker loaded with 11,165lbs, or the 56% we see as the default for the in game Flanker........Also note, that previous testing showed that at supersonic speeds, a Flanker would need even more fuel to remain equivalent. A 16,000lbs fuel Flanker equaling a 13,400lbs Eagle.

 

So in Summary.

 

Your being out turned because at proportional weight, the Eagle actually does turn better, slightly.

 

So it looks to me like the game is accurate, as it appears to have the relative performance, down pat. It may also very well be the exacting performance, due to errors on my part.

Edited October 1, 2015 by ArkRoyal

[GGTharos]

Good work, and nearly correct conclusion (the one being out-turned is the pilot. The flanker has advantages at low/slow that aren't reflected in STR or ITR charts ... I won't be going into it though).

 

The chart you posted actually comes with specific data regarding the GW and payload for both aircraft. Unfortunately, I don't remember what they were - certainly each aircraft was equipped with at least two heaters though.

 

Also we did at some point find out that the F-15 performance in this chart is slightly over-estimated, but IIRC it is also for an F-15A. -100 and -220 are not the same, and the -220 performs very nicely despite it's 'stated on the internet' lower thrust output compared to the -100.

 

Finally, a note or turn rate: If you got your TR from Tacview, it may not be accurate. It's fine for comparing relative performance of two aircraft, but might not reflect what's in the charts. Probably the best way to measure anything in-game when you intend to compare to RL charts is to use your cockpit instruments.

 

So, in this case, your parameters would be in-game GW, in-game sustained G, in-game TAS.

 

You can convert those parameters into TR easily enough, though usually you can just find TASvG charts so you don't have to go that far :)

Edited October 1, 2015 by GGTharos