Mikoyan-Gurevich MiG-29/35 Fulcrum - History, Design, Performance & Dissection (Part 2)

Machinery of War Discussion Aircraft
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The main thing is the aerodynamic difference between the 9.15 and 9.41 airframes, and especially why the MiG-35S 9.41SR has more drag than the MiG-29KR 9.41R in the FM.

What I am more interested in is the airframe itself, mainly the fuselage polar and the Mach dependent drag.

Fuselage FM diff values

Parameter MiG-35S 9.41SR MiG-29KR 9.41R MiG-29M 9.15
FuselagePlane.Areas.Main 45 45 38
FuselagePlane.Polar.CdMin 0.0084 0.0082 0.0076
MultMachMax1-7 3.10 / 1.15 / 0.80 / 0.80 / 1.20 / -0.20 / 1.00 3.10 / 1.15 / 0.80 / 0.80 / 1.20 / -0.20 / 1.00 2.80 / 1.15 / 0.80 / 0.80 / 1.20 / -0.20 / 1.00

For those who don’t know.

Areas.Main changes the aerodynamic reference area used for the fuselage. Higher area = the fuselage drag has a larger overall effect.

CdMin changes the base drag of the fuselage. Higher value = more drag even before the Mach effects kick in.

MultMachMax1 changes how strong the drag increase is around the transonic region. Higher value = stronger transonic drag rise. Change: 2.80 to 3.10: It makes the peak of the aerodynamic correction around Mach 1 higher, so the 9.41 gets a stronger transonic drag penalty.

So the 9.41 has more base drag, a larger effective fuselage area and a stronger transonic drag curve than the 9.15.
So it is not just one value. There are several changes in the FM that are increasing the fuselage drag contribution of the 9.41 compared with the MiG-29M 9.15 .
Obviously the 9.41 is a much better airframe at low speed and high AoA, and in game you can clearly feel that in a dogfight. But I do not think that automatically means it should also receive such a large high speed and medium to high altitude drag penalty.

Those are two different things.

The only real difference here is the base fuselage drag:
MiG-29KR 9.41R: CdMin = 0.0082
MiG-35S 9.41SR: CdMin = 0.0084
Even if it doesn’t look like much, changing this value even slightly has quite a noticeable effect because we’re dealing with very small values to begin with.

So what I would really like to know is what aerodynamic evidence supports the MiG-35 having more base fuselage drag than the MiG-29KR.
The MiG-35 does have external sensors and other installations which can obviously add some parasitic drag, but the MiG-29KR is also a naval aircraft with its own aerodynamic compromises.
Without actual aerodynamic data or performance data showing that the complete MiG-35 configuration has more drag, I do not think we should automatically assume that 0.0084 is correct just because the aircraft has additional external equipment.

There is also the engine difference between the MiG-29KR and MiG-35 for those who don’t know.
The KR receives the additional Mode 7 on its RD-33MK while the MiG-35 does not, giving the KR roughly 9% more available thrust .
The engine is therefore not the root of the investigation, but it amplifies the airframe difference.
Since the MiG-35 also uses the RD-33MK , this is particularly questionable because both aircraft use the RD-33MK . There is clear evidence that the MiG-35 uses this engine, while I have not seen public documentation demonstrating that the MiG-35 installation is specifically prevented from using the additional high power regime represented by Mode 7 in the KR FM.

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6572

Basically, all of this comes down to the differences between the MiG-29M 9.15 and the 9.41 airframe. Since there is very little documentation showing exactly how the 9.41 should perform aerodynamically, some things are obviously being assumed.

The main issue is how large the performance penalty currently is, and whether it should really be that severe.

A lower VNE or lower maximum speed does not automatically mean that an aircraft should also take much longer to accelerate toward that speed. Those are not the same thing.

That is basically what I am trying to explain here from an aerodynamic point of view: why the 9.41 can reasonably have a lower top speed or different limits without necessarily needing such a large penalty in acceleration and high speed performance compared with the 9.15

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But yeah, in the end this is almost impossible to prove in a way Gaijin will actually accept, because there just is not declassified documentation that also fits their source requirements.

You can compare the airframes, compare the FM values test it, prove it, look at the performance difference and the aerodynamic logic can point very clearly toward something being not that clear, but none of that really matters to Gaijin unless you can find one specific acceptable source that directly says it

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Gaijin vs Logic challenge (impossible)

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Rank Aircraft / FM M1→1.2 M1→1.4 M1→1.6 M1→1.8
1 MiG-29M 9.15 Live 15.6 s 33.5 s 52.8 s 76.8 s
2 MiG-29KR modified drag: CdMin 0.0082 (original) / MultMachMax1 2.90 16.7 s 34.8 s 55.1 s 83.8 s
3 MiG-35 + KR Mode 7 16.0 s 34.1 s 55.6 s 89.5 s
4 MiG-29KR 9.41R Live 17.5 s 38.8 s 58.7 s 93.0 s
5 MiG-35 modified drag: CdMin 0.0083 / MultMachMax1 2.90 18.8 s 41.9 s 71.7 s 141.6 s
6 MiG-35 9.41SR Live 20.7 s 46.3 s 81.7 s Does not reach M1.8

I ended up doing my own tests just for fun with different versions of the MiG-35 and MiG-29KR flight models to see how much each change actually affects acceleration.

For all the tests I used the same method, clean conf, 30% fuel, starting at Mach 1.0 at 8,000 m and measuring the time required to reach Mach 1.2, 1.4, 1.6 and 1.8.

REASONING AND CONCLUSIONS:

Spoiler

First I tested the MiG-35 with exactly the same FM as the live server, but with the same emergency thrust / Mode 7 used by the MiG-29KR. I did not modify any of the aerodynamic values in this test.

With this change, the MiG-35 becomes slightly faster than the current MiG-29KR in acceleration. It reaches Mach 1.6 in 55.6 s compared with 58.7 s for the KR, while still remaining noticeably worse than the MiG-29M, which reaches it in 52.8 s. The same pattern continues up to Mach 1.8, where the MiG-35 reaches it in 89.5 s compared with 93.0 s for the MiG-29KR and 76.8 s for the MiG-29M.

This would also be the only modification in these tests that could affect low altitude turn performance, since it actually increases the available engine power. However, during sustained low altitude fighting you would have to reduce the throttle back to around 109% to prevent the engines from overheating, same as the 29KR.

For the second MiG-35 test, I only made relatively small changes to the drag values. I reduced the fuselage CdMin from 0.0084 to 0.0083, meaning it still remains higher than the MiG-29KR at 0.0082 and the MiG-29M at 0.0076. I also reduced MultMachMax1 from 3.10 to 2.90, while still keeping it above the MiG-29M value of 2.80.
With these changes, the MiG-35 becomes closer to the current MiG-29KR during the first part of the acceleration test, but it is still clearly slower overall. The difference becomes especially noticeable above Mach 1.6. The modified MiG-35 requires 141.6 s to reach Mach 1.8, while the current MiG-29KR requires only 93.0 s.

I also tested the MiG-29KR with exactly the same transonic drag change. Its CdMin remained completely unchanged at 0.0082, and the only modification was reducing MultMachMax1 from 3.10 to 2.90. The reason I applied the same MultMachMax1 change to the KR is that the MiG-35 and MiG-29KR are both based on the same 9.41 airframe. So if the transonic drag penalty is adjusted for one of them because of the 9.41 airframe itself, it makes sense to apply the same change to the other one as well.
That single change reduced the MiG-29KR Mach 1.0 to Mach 1.8 acceleration time from 93.0 s to 83.8 s. This shows how significant the transonic drag parameter becomes as the aircraft approaches the higher end of its supersonic acceleration.

Finally, the current live MiG-35 FM gives by far the worst result. It takes 81.7 s just to reach Mach 1.6 and does reach Mach 1.8.

From these tests, both the engine regime and the drag values clearly have a significant effect on the MiG-35 supersonic performance. However, the missing emergency thrust Mode 7 produces a much larger improvement than the relatively small drag changes tested here.

With the KR Mode 7 and otherwise unchanged aerodynamics, the MiG-35 ends up slightly ahead of the MiG-29KR while still remaining behind the MiG-29M, which seems like a much more reasonable progression between the three aircraft

The more mass and external weapons the aircraft carries, and the lower the altitude, the more noticeable and exponential the difference becomes.

Based on these tests, the most balanced option would probably be to slightly reduce the transonic drag penalty of the 9.41 airframe and, in the MiG-35, reduce the CdMin by just 0.0001 from 0.0084 to 0.0083. This would slightly improve both aircraft while still keeping them inferior to the other MiG-29s, because the 9.41 airframe still has its own limitations. It would simply allow them to build speed better at medium and high speeds above Mach 1, without affecting dogfight performance

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Required Repost
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Whoop! I see Mode 7(emergency thrust) really help a lot). Iv been waiting it to be fixed for weeks.

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I would be content if we do have the acceleration for 9.41 close to 9.15m. Mode 7 already makes MiG-35 almost the same as 9.15, and it can be inferred that MiG-35 acceleration would be slightly better than 9.15 if your proposed drag reduction is implemented.

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I wouldn’t combine both changes. I don’t think the MiG-35 should end up accelerating better than the 9.15 above Mach 1.
The increase excess power from the emergency thrust test already puts the MiG-35 closer to the MiG-29M, and if we also apply the airframe 9.41 drag reduction on top of that, it would probably become better than the 9.15.
The MiG-29M is documented with a higher maximum speed and a higher VNE. While neither parameter directly defines its acceleration rate, the higher maximum speed indicates that its thrust to drag balance remains more favorable into the supersonic regime.
The point is not to make the MiG-35 the fastest accelerating Fulcrum, just to make it stop being absurdly bad above Mach 1.
That’s why I think the more balanced solution would be the small drag reduction by itself. It improves the 9.41 airframe at medium and high supersonic speeds while still leaving the MiG-29M clearly ahead

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A side effect is that the 9.41KR would probably improve by a slightly higher percentage at medium and high altitude, because it already has the extra thrust to compensate for its higher weight.

That is what makes this difficult to balance, because we do not really know how both aircraft should perform in that exact situation. Since the MiG-35 and MiG-29KR use the same 9.41 airframe, any drag reduction would affect both, but the KR could benefit slightly more from it because of its higher available thrust

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Yep, considering the enlarged air wing of 9.41 airframe and limited improvement from RD-33k to RD-33mk. It’s a pity that Klimov stops improving the RD-33 series to keep it as competitive as ej2000 or F414.

And Idk whether they are going to fix dozens of MiG-35 issues, including the emergency thrust. The mode 7 issue got accepted, but then the issue was closed. Is it because they are considering it as a suggestion? But I see the BRM said ‘forwared to devs’.

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https://community.gaijin.net/issues/p/warthunder/i/KP6lOlTmvNv0

A simple report about the max afterburner thrust poblem of MiG-35 with and without the emergency thrust. It basically follows from the emergency thrust one and thrust-missing reports. Hope it will remind them of those issues.

I also refer to Balta’s previous report about RD-33MK’s thrust and borrow the RD-33MK brochure. Anymore to add?

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image-7
image-72160×2376 63.5 KB

A Mig-29UB i got to see at the pacific air show :D (my friends got most of the pictures so i don’t have many more on me)

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The report about the missing emergency thrust got accepted and has been forwarded to the developers, but yeah… we already know what that usually means

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AC8 MIG35
AC8 MIG352560×1441 322 KB

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ace-combat-8-wings-of-theve

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Never knew that despite having less thrust, MiG-29M still the fastest, guess I abandon MiG-29KR grind then lol.

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Nah, KR is absolutely worth it
You get a top-10 FM for duelling and superior defensive kit

MiG-29M’s fm is a just better than the SMT’s

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Don’t forget loosing 2 missiles on KR (I refuse to acknowledge existence of R-73 at this BR).

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Well, we know the 9.41 airframe is quite different from the older MiGs with some pros and cons, and the MiG-29M naturally has better high speed performance. The MiG-35 and MiG-29KR are much closer, but the MiG-35 is around one and a half tons lighter.

The main difference in game is that only the MiG-29KR gets the RD-33MK emergency thrust mode. There is no proof the MiG-35 used it, but there is also no proof it did not. That extra thrust helps the KR compensate for its weight and drag, while the MiG-35 ends up performing ridiculously badly at medium and high altitude.

Giving the MiG-35 the same emergency thrust mode would make it slightly better than the KR at medium and high altitude while still being worse than the MiG-29M, which would make much more sense. The downside would be the same as the KR at low altitude, where you would have to stay around 99 percent throttle or cook the engines

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