MiG-29's BFM characteristics / doubts

[Pavlin_33]

8 hours ago, Top Jockey said:

...

Thank you @Pavlin_33.

For max. sustained turn rate, I thougth that parameteres like CL max and Wing Loading also played a role... but I'm still learning.

 

Well, technically you are correct: C_L Max does play a role, but only if the airplane in question has enough thrust to overcome the drag in that flight regime. Most of them don't, I believe.

[Top Jockey]

18 hours ago, AeriaGloria said:

https://drive.google.com/file/d/1QKrcvIW949R5Iuz6qEcn1nZDneARkHUe/view?usp=drivesdk

 

Here is PDF with EM charts made only using DCS data. It’s very well written, explained, and the diagrams are both complex and very easy to read. Nothing can beat the I-16 when it comes to turn radius of 200m

 

 

Thank you !

Outstanding info on those charts.

[F-2]

https://www.nasa.gov/centers/dryden/pdf/87983main_H-1243.pdf
 

F-15 CL max is 1.6

 

whats the Mig-29 for comparison?

[Top Jockey]

11 hours ago, F-2 said:

https://www.nasa.gov/centers/dryden/pdf/87983main_H-1243.pdf
 

F-15 CL max is 1.6

 

whats the Mig-29 for comparison?

 

From some website the MiG-29A CL max is supposedly 1.50.

 

edit

CL max for other types, I've gathered from around the web:

F-14A : 2.20 (with unsweept wings)

F-15C : 1.60 (as you mentioned also)

F/A-18C : 2.40 ??

Su-27S : 1.85

 

Can't find the CL max for the Mirage 2000C.

And I'm tryin to know if it's "wing area" (41 square meters) already include the controling surfaces.

Edited April 23, 2023 by Top Jockey

[Mateo]

Regarding MiG-29 there is all data available in "Practical Aerodynamic of MiG-29". Russian engineers published such books for many airplanes, and such books were a great base for all the pilots that were elite and want to know the airplane like test pilot do. For example: lift coefficient changed with Mach speed as below:

 

 

[F-2]

On 4/23/2023 at 7:40 AM, Top Jockey said:

 

From some website the MiG-29A CL max is supposedly 1.50.

 

edit

CL max for other types, I've gathered from around the web:

F-14A : 2.20 (with unsweept wings)

F-15C : 1.60 (as you mentioned also)

F/A-18C : 2.40 ??

Su-27S : 1.85

 

Can't find the CL max for the Mirage 2000C.

And I'm tryin to know if it's "wing area" (41 square meters) already include the controling surfaces.

 

Su-27 is 1.85 isn’t representative of high G maneuvering.

a comparison of T10 and production Su-27

the Tsagi report also uses the 1.6 figure for performance. The manual show the 1.85 is only in limited conditions.

The 2.40 number, I’m not sure if that’s for the hornet or super hornet. I know the super hornet is crazy high and over 2, but maybe the legacy bug is too?

[captain_dalan]

On 4/23/2023 at 1:40 PM, Top Jockey said:

 

From some website the MiG-29A CL max is supposedly 1.50.

 

edit

CL max for other types, I've gathered from around the web:

F-14A : 2.20 (with unsweept wings)

F-15C : 1.60 (as you mentioned also)

F/A-18C : 2.40 ??

Su-27S : 1.85

 

Can't find the CL max for the Mirage 2000C.

And I'm tryin to know if it's "wing area" (41 square meters) already include the controling surfaces.

 

Lift quotients are usually calculated to work with reference wing areas for that plane, so you should be fine with most vanilla data.

[Top Jockey]

On 4/25/2023 at 2:19 AM, F-2 said:

Su-27 is 1.85 isn’t representative of high G maneuvering.

a comparison of T10 and production Su-27

the Tsagi report also uses the 1.6 figure for performance. The manual show the 1.85 is only in limited conditions.

The 2.40 number, I’m not sure if that’s for the hornet or super hornet. I know the super hornet is crazy high and over 2, but maybe the legacy bug is too?

 

Hello,

Sure I understand.

On the Hornet vs Super Hornet, I believe the 2.40 value I've read is for the first; and I believe the values might be different for each, as they are different airframes afterall...

 

 

13 hours ago, captain_dalan said:

Lift quotients are usually calculated to work with reference wing areas for that plane, so you should be fine with most vanilla data.

 

I see.

Besides CL max, and other values I'm gathering, I'm looking at wing area and also total / overall lift area / surfaces.

 

Hence my questions here, as in:

- for the F-14 its wing area is 52,5 square meters, but its total lift area is stated as 94 square meters - which is quite significant;

- therefore my curiosity to know total lift area for other aircraft also;

- in the Mirage 2000C I suppose its total lift area value wouldn't change much from the wing area ?

But I'm curious about that value for the F-15C.

Edited April 28, 2023 by Top Jockey

[captain_dalan]

On 4/28/2023 at 2:35 PM, Top Jockey said:

 

I see.

Besides CL max, and other values I'm gathering, I'm looking at wing area and also total / overall lift area / surfaces.

 

Hence my questions here, as in:

- for the F-14 its wing area is 52,5 square meters, but its total lift area is stated as 94 square meters - which is quite significant;

- therefore my curiosity to know total lift area for other aircraft also;

- in the Mirage 2000C I suppose its total lift area value wouldn't change much from the wing area ?

But I'm curious about that value for the F-15C.

 

Do note that that total surface area isn't available or really useful at all possible Angles of Attack. It only comes into play at very high values. 

[Mateo]

Wings area is defined by engineer just as reference area in order to calculate things not with raw force but with coefficients 

It doesn't mean at all that F-18 which got CL nearly 2 can produce more lift than MiG-29 with it's CL 1.5, they use different references. Usually wing areas are 'extended' inside the fuselage - leading edge extended to root with straight line, and the same with trailing edge line. In case the aircraft have LERX... things complicate a bit. During low angle of attack LERX is aerodynamicaly invisible (if well designed  ), and during high AoA the LERX induced vortex engergy is essential to produce the high lift. Moreover, lifting body issue is also important. Discussion take into account aircraft CL which is superposition of wing CL, fuselage CL, ale horizontal stabilizer CL. Regarding fuselage CL, engineers can define it for many different ways, but reference stays the same as for previously defined wing. Regarding the horizontal stabilizer CL, aerodynamic stability have big influence on the result. If aircraft is not aerodynamicaly stable, it will generate more lift (less negative lift), and if the aircraft is aerodynamicaly stable, we can expect that horizontal stabilizer will generate less lift (more negative lift). Reference here is also wing area.

Very interesting thing is the dynamic lift behavior. During dynamic increase of AoA, lift measured at one value is different than during dynamic decrease of AoA, even the measurement was done at the same value of AoA. Here enters the hysteresis of lift...

Edited April 30, 2023 by Mateo
Little correction of words

[Top Jockey]

Hello again everyone,

I've been comparing Sustained Turn Performance between several DCS jet fighters, (and I've been writing the values in Excel sheet).

And, lo and behold, again I came surprised when for similar test conditions:

- the Mirage 2000 C showed better (higher) Sustained Turn rates than the MiG-29 A ... which according the interview at the link below, in reality the contrary should actually be true.


I'm not on the PC where I have the Excel with the G's load data, but the test conditions (in DCS) were :

- 2 x IR missile and gun ammo

- fuel for 2 mins. full afterburner - using unlimited fuel option - so I could establish what each airframe could do in those conditions.

( internal fuel quantity for 2 mins. full AB : 23 % for Mirage and 35 % for MiG-29  )

- ambient temperature: 18º C

- altitude: 200 - 400 ft above sea level

- speeds tested (in kts IAS at the F2 view bottom infobar) : 310 kts, 330 kts, 370 kts, 410 kts, 440 kts.

 

Obviously this was in no way a "scientific" test, as it is very difficut to keep the aircraft's speeds and altitude constantly stable while turning.

But clearly, on all of those speeds the Mirage 2000C was able to pull more Sustained G load than the MiG-29A - so what's wrong here ?

https://hushkit.net/2019/08/12/mig-29-versus-mirage-2000-personal-account-from-by-air-marshal-harish-masand/

Edited July 26, 2023 by Top Jockey

[Top Jockey]

Here is a print of the G loading comparison table, with the G forces attained while experimenting on DCS.

As in the previous post, what leaves me surprised is that for roughly the same speeds, the Mirage can pull more Gs than the MiG... which in real life isn't supposed to be.

Any opinions on why, or what I might be doing wrong ?

Thank you.

 

 

[Ironhand]

Kind of hard to tell if something is amiss without the STRs. Your G numbers for the Mirage 310-370 kt range seem reasonable.

[Top Jockey]

12 hours ago, Ironhand said:

Kind of hard to tell if something is amiss without the STRs. Your G numbers for the Mirage 310-370 kt range seem reasonable.

 

Hello Ironhand,

Yeah I'll compare with the NATOPS F.M. charts and try to find conclusions ...

Edited July 27, 2023 by Top Jockey

[Top Jockey]

So, anyone else ?

[draconus]

On 7/26/2023 at 2:52 PM, Top Jockey said:

so what's wrong here ?

You did your tests. Do you have their tests results? No. You don't know their config, their training rules/limitations, their weather conditions. Where they even the same M-2000C versions we have? Afaik simulated dogfights IRL take place higher and with more fuel than your test.

DCS aircraft performance are based off charts, specifications and SME feedback - then we have simulated computations of thrust, mass, drag, AoA and all that to match the charts as accurate as possible. RL aircraft differ a bit between each other even within the same factory series and so do the testing aircraft. Also the charts are not that precise as we would like them to be.

So you still want to challenge the DCS FMs because of some interview?

btw: NATOPS is for USN aircraft only.

Edited August 2, 2023 by draconus

[Top Jockey]

7 hours ago, draconus said:

You did your tests. Do you have their tests results? No. You don't know their config, their training rules/limitations, their weather conditions. Where they even the same M-2000C versions we have? Afaik simulated dogfights IRL take place higher and with more fuel than your test.

DCS aircraft performance are based off charts, specifications and then we have simulated computations of thrust, mass, drag, AoA and all that. RL aircraft differ a bit between each one (even within the same factory series) and so do the testing aircraft. Also the charts are not that precise as we would like them to be.

So you still want to challenge the DCS FMs because of some interview?

btw: NATOPS is for USN aircraft only.

 

Hello draconus, thank you for your time.

No, I'm not knowledgeable enough to challenge the DCS FMs, just a jet fighter enthusiast who wants to know which airframes are superior in some regards.

And I trust the developers work and capabilities.

 

The thing is, merely the MiG-29's ACM performance seems so 'weak' and subpar from what is worldwide known for, particularly when compared with the majority of the jets on that table in DCS, that one can't help to notice and feel that something kind of is missing there.

About the interview:

- sure the Air Marshal clearly admited that, specific data wouldn't be disclosed

- but at the same time, he specifically said the the MiG-29 was superior in STR, ITR and climb

( which leaves us with the scenario he mentioned being only true, with more fuel weight and at higher altitudes ? )

- the Mirage's lower T/W ratio and delta wing, also raise questions for me regarding its Sustained Turn rate when comparing with the MiG-29

- also, the Mirage 2000 C we have in DCS, is a mid-80's version, correct ?

 

About attaining more Gs in the Mirage in my tests than the real life FMs, sure i suppose the conditions on known real life FM diagrams are not so 'favorable' as in my DCS experiments.

Regarding the NATOPS FM diagrams, yep it's from another sim, and I don't know where they compiled them from.

 

Edited August 1, 2023 by Top Jockey

[Ironhand]

7 hours ago, Top Jockey said:

 

Hello draconus, thank you for your time.

No, I'm not knowledgeable enough to challenge the DCS FMs, just a jet fighter enthusiast who wants to know which airframes are superior in some regards.

And I trust the developers work and capabilities.

 

The thing is, merely the MiG-29's ACM performance seems so 'weak' and subpar from what is worldwide known for, particularly when compared with the majority of the jets on that table in DCS, that one can't help to notice and feel that something kind of is missing there.

About the interview:

- sure the Air Marshal clearly admited that, specific data wouldn't be disclosed

- but at the same time, he specifically said the the MiG-29 was superior in STR, ITR and climb

( which leaves us with the scenario he mentioned being only true, with more fuel weight and at higher altitudes ? )

- the Mirage's lower T/W ratio and delta wing, also raise questions for me regarding its Sustained Turn rate when comparing with the MiG-29

- also, the Mirage 2000 C we have in DCS, is a mid-80's version, correct ?

 

About attaining more Gs in the Mirage in my tests than the real life FMs, sure i suppose the conditions on known real life FM diagrams are not so 'favorable' as in my DCS experiments.

Regarding the NATOPS FM diagrams, yep it's from another sim, and I don't know where they compiled them from.

 

 

Regardless of what was said in the interview, the only way you will know, if anything is amiss, is to get the G and turn rate graphs for each aircraft and see how closely the DCS versions hew to it. You’d need to match each aircraft’s graph in terms of fuel, missiles (if any) gross weight and altitude. Anything other comparison just leads to confusion.

[draconus]

15 hours ago, Top Jockey said:

The thing is, merely the MiG-29's ACM performance seems so 'weak' and subpar from what is worldwide known for, particularly when compared with the majority of the jets on that table in DCS, that one can't help to notice and feel that something kind of is missing there.

I thought you already got the conclusion back in 2020

[Snappy]

On 7/27/2023 at 6:00 PM, Top Jockey said:

 

Hello Ironhand,

Yeah I'll compare with the NATOPS F.M. charts and try to find conclusions ...

 

You cannot do that. The Mirage is a french aircraft. NATOPS  (Naval Air Training and Operating Procedures Standardization) and are available for aircraft used by the U.S. Navy.

As far as I'm aware , there is no official Mirage 2000 flight manual with performance data available in the public domain. There are some performance charts with turn rates floating around, yes.  But they are not official/from Dassault and as far as I know they were produced by a competiting aircraft manufacturer that was trying to promote its own aircraft, so you better take the data with a grain of salt.

 

 

Edited August 2, 2023 by Snappy

[Pavlin_33]

On 7/26/2023 at 11:38 PM, Top Jockey said:

Here is a print of the G loading comparison table, with the G forces attained while experimenting on DCS.

As in the previous post, what leaves me surprised is that for roughly the same speeds, the Mirage can pull more Gs than the MiG... which in real life isn't supposed to be.

Any opinions on why, or what I might be doing wrong ?

Thank you.

 

 

Your results mean that M-200C has higher thrust-to-drag ratio than the MiG-29A.
Aircraft settle into certain sustained turn rate once the drag from high Angle-of-Attack equals the thrust produced.
I was under the impression that the delta-wing of the Mirage should be very draggy under high AoA, but what do I know? I am no expert.

[Top Jockey]

21 minutes ago, Pavlin_33 said:

Your results mean that M-200C has higher thrust-to-drag ratio than the MiG-29A.
Aircraft settle into certain sustained turn rate once the drag from high Angle-of-Attack equals the thrust produced.
I was under the impression that the delta-wing of the Mirage should be very draggy under high AoA, but what do I know? I am no expert.

 

Precisely - hence its tendency to loose speed quickly and such, it has been mentioned over and over.

Besides, the aicraft which the MiG-29 was mentioned by pilots (earlier times) to somewhat 'compete' against in STR was the F-16 ... not so much the Mirage 2000 I believe ?

[draconus]

4 minutes ago, Top Jockey said:

Precisely - hence its tendency to loose speed quickly and such, it has been mentioned over and over.

MiG-29 is draggy too. Look at @bies explanation:

[Top Jockey]

3 hours ago, draconus said:

I thought you already got the conclusion back in 2020

 

Yes, it is correct, and back there I was comparing the MiG-29 against other types.

However, this time I've took the time to look at things with a little more attention (experimenting several stuf), and comparing against the Mirage 2000 C ... and voila: even the delta winged can surpass it in STR.

[Top Jockey]

4 minutes ago, draconus said:

MiG-29 is draggy too. Look at @bies explanation:

 

Yes, that might be an important part of the reason it performs below my expectations ... believe it or not I do have a print screen of that explanation from @bies !

While the Mirage 2000 C does have 'relaxed stability', the MiG-29 A does have 'stable design', with the consequent known effects in their respective maneuvering capabilities.

 

The thing is, before begining experimenting so much with the different types in DCS (and reading much, much more), I was expecting the MiG-29 to be on pair, (and probably even slightly above) the following airframes in some aspects :

- F-16 A/C

- F/A-18 C

- Mirage 2000 C

Even some time ago, on my mind it was also: yeah forget airframes like F-14 or F-15 against the MiG-29 ... "too heavy, not so 'refined' airframe, etc." I thought.

Then one starts looking at data comparing the F-15C with the MiG-29A, and there comes a reality check ... T/W ratio ... wing loading ... lift coefficients ... not to mention stuf I don't yet know so well - lift to drag ratio and such.

 

Even the F-15C nose pointing ability is much more hassle free than the MiG-29's.