It might “miss” chart because of constant oswald
BTW, gaijin doesnt care about stuff like that. “close match to any altitude and speed is not key target for WT FM.”
https://community.gaijin.net/issues/p/warthunder/i/9LFJm1a6EfsD
Sukhoi Su-27/30/33/35/37 Flanker series & Su-34 Fullback - History, Design, Performance & Dissection
At 1000m and 460kph IAS it is underperforming by a lot, about 0.5G (3.0G instead of 3.5G) which is way more than with afterburner on since it is both 0.2G more and the total Gs are lower.
Looks like the plane has too much drag and a little bit too much thrust
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I don’t wanna be offensive, but looking at how you are writing I don’t think you know what the Oswald coefficient is and how it works.
Guy there used WTRTI and complained about 0.5deg/sec, which is pretty much like complaining for less than 0.1G…
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In case of WT it mostly about speed loss by AOA
CBR stated that in case of Su-27 constant isnt right, which leads to a lot of stuff and sustained turn rate included. It will overperform at high speeds, but underperform on low speeds. Theres nothing to do, only wait for non constant oswald coef to match chart fully
Report link only for refference, where quote was taken.
first of all the oswald efficiency number in the WT files is not the Oswald coefficient that is there in real life or that you would actually measure in a test in war thunder.
The Oswald coefficient of an aircraft is never constant (that is right), but it always decreases as AoA increases. If the Su-27 in war thunder had a constant oswald coefficient it would actually over perform at low speed since at high speed the performance is right.
The only aircraft in war thunder where the oswald coefficient was constant was the gripen before may, when it still had a wild flight model (you can check my thread about it if you are interested).
To make myself clear again, right now the Su-27 in war thunder does not have a constant oswald coefficient.
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Here it is, give it some “I have the same issue” :D
https://community.gaijin.net/issues/p/warthunder/i/pMIS9A3vdNzU
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I love how you tested all of the stuff regarding the su-27 and made a report all in 1 day lol, absolute epic.
Gaijin owes you a lot for correcting their shit.
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I am betting they will say you are using 4×R-73, instead of 2xR-73 and 2x-27.
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At least in the second video (the one at 100% throttle no AB) they can’t :D.
Also luckily the flanker is quite stable in a sustained turn, so it doesn’t take too long to get an acceptable run if I need to do it again.
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thanks for quality report good job mate
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The weight is is still weird to me.
The devs say that the referense weight is with 4 missiles and 5200 kg fuel totaling at 22800, and that at 50% of that fuel load it should be 20200.
But the manual gives the reference weight at 23250 with fuel weight at 5090, so half of that should be 20705.
What total weight did you do the test with?
@BBCRF, do you know if “расчётная взлётная масса” refers to the same fuel load as “нормальная заправка?”
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20200kg, just to be safe without going against the devs.
This whole weight thing seems strange to me as well, especially considering that the 0.3G I reported, while very much noticeable, would bring the Su-27 to about the level of MiG-29As in low speed STR (which is still a huge jump considering the flanker current state), and the Su-27 doesn’t have the massive increase in rate that the MiG-29s have at higher speeds.
Considering that the flanker, being aerodynamically unstable, should outperform the 29As in low speed STR there might still be something left on the table
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I’m wondering, what’s the best sustain turn rate of the Su-27 right now ?
If I remember correctly in Ride2R sustain turn rate tests with 30 min of fuel the Su-27 could out rate the 29 by a small margin, and from the tests at 200knts it already outrate the 29 at low speed. Here is the doc just in case Sustained turn rate tests - War Thunder - Google Spreadsheets
I hope your bug report work, Su-27 would be amazing tbf !
Thanks for your work ;)
The sustained rate of the Su-27 isn’t relevant because every foe it faces forces it to “tighten down” continuously or they simply climb in the rate. Trying to rate fight in the aircraft is only possible with full real and careful control / maintaining a higher airspeed.
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I know rating at low speed is a bit of an imaginary thing an may happens really only with full controls like in SIM, but if I’m not mistaken the fact it doesn’t rate as well as it should be means it has less energy retention ? And from what giovanex said it may have too much energy generation if I understood it correctly
It says there. That this is the estimated take-off weight. This is a normal refueling of 5090 kg and 4 rockets 2 R-27 and 2 R-73
Yeah, the aircraft doesn’t perform that well with max fuel at sea level, it’s pretty bad at rate fighting when you have fuel overall…
As long as it’s accurate to its IRL counterparts I’m fine with it.
Such indicators are at an altitude of 1500m, but not at sea level
Moreover, the MiG-29 at a speed of 800 + km / h is already impossible to keep from accelerating
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The issue with the Su-27 is not necessarily the sustained turn rate but rather it’s energy retention while turning harder than the sustained rate speeds. Basically the drag increases much too quickly which causes the plane to slow down faster than its real life counterpart.
This can be seen by comparing real life HUD footage and trying to replicate it in game. It can also be seen by comparing CD/CL diagrams that are generated from in-game files and comparing them to wind tunnel tests.
Energy retention is something that WarThunder does a pretty lackluster job of modeling. For instance, if you use WTRTI and compare the Ps (specific excess power) values in-game to publicly available diagrams and you’ll see some huge discrepancies.
For instance the way the Mirage 2000 retains energy at high speeds and sheds it at low speeds has very significant deviations from its diagram. It retains 20-30 percent too much speed Mach .7 - Mach.8, matches the Ps values at Mach .6 - Mach .5, and then loses around 40 percent more speed than it should around Mach .4.
Basically it means the whole “curve” you could imagine how the plane bleeds speed is wrong. It retains too much speed when you start the turn at high speeds and then bleeds too much when you get to slow speeds. In reality it should bleed a lot of speed at higher speeds and then retain more at lower speeds.
The F-16s also end up having similar issues when compared to their EM diagram but kind of reversed. It’s accurate at higher speeds, retains too much at medium-high speeds by a large margin, and then is accurate at low speeds until it starts to exceed its IRL AoA limits.
The Su-27 on the other hand just seems to be under performing its IRL counterpart at all speeds. So it’s not only inaccurate to the IRL version…but also skewed in the opposite direction of “war thunder-isms”.
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