investigating Thrust to weight ratio: confused

[Kefa]

@Top JockeyIt NAVAIR F-14AAA-1.1

 

Mig-29 I used this one

 

 Don't have Fulcrum or Flanker specific excess power lines though.  While sustained rate turns matter too, so do turns above the PS-0 line.  I mean, turning while at the expense of airspeed.  And that is important.

Edited December 7, 2021 by Kefa

[Top Jockey]

12 minutes ago, Kefa said:

@Top JockeyIt NAVAIR F-14AAA-1.1

 

Mig-29 I used this one

[image]

 Don't have Fulcrum or Flanker specific excess power lines though.  While sustained rate turns matter too, so do turns above the PS-0 line.  I mean, turning while at the expense of airspeed.  And that is important.

 

 

Thank you @Kefa !

[Ironhand]

55 minutes ago, Top Jockey said:

... but then studying that chart, some doubts appear on my mind :

- i guess in a 2 circle fight,  the MiG flying at 850 kph doing 20,5 deg/sec, would eventually prevail over the Su-27 at 640 kph doing 19,3 deg/sec ;

- but then, the Su-27 pilot could force a 1 circle fight and use its smaller turn radius ;

- also, the Su-27 flying at 970 kph doing 21,7 deg/sec, would be of little use, because of the big turn radius factor ?

Generally speaking, in a 2-circle, rate kills because with every passing second you are x degrees closer to putting your weapons on him than he is on you. OTOH, in a 1-circle, radius wins.

 

Edited December 7, 2021 by Ironhand

[Top Jockey]

17 minutes ago, Ironhand said:

Generally speaking, in a 2-circle, rate kills because with every passing second you are x degrees closer to putting your weapons on him than he is on you. OTOH, in a 1-circle, radius wins.

 

 

 

Completely agree.

So in the end, (keeping pilot skill and other factors like specific avionics, systems, etc. out of the equation), just based on each airframe's ACM performance would you say that :

Can the Su-27S be qualified as a better dogfighting airframe than the MiG-29A, or not at all in your opinion ?

Edited December 7, 2021 by Top Jockey

[Ironhand]

51 minutes ago, Top Jockey said:

 

Completely agree.

So in the end, (keeping pilot skill and other factors like specific avionics, systems, etc. out of the equation), just based on each airframe's ACM performance would you say that :

Can the Su-27S be qualified as a better dogfighting airframe than the MiG-29A, or not at all in your opinion ?

 

Depends on the situation. If the Su-27 is dictating the flight, it'll win every time. If the MiG-29 is dictating the fight, it'll win. The Flanker has strength in some areas, the MiG in others. So I'd say it's a draw.

[Top Jockey]

14 minutes ago, Ironhand said:

Depends on the situation. If the Su-27 is dictating the flight, it'll win every time. If the MiG-29 is dictating the fight, it'll win. The Flanker has strength in some areas, the MiG in others. So I'd say it's a draw.

 

I'm clarified !

Thank you for your time, and the chart from previous page.

[draconus]

6 hours ago, Top Jockey said:

I'm looking at some F-14A EM's I have although they all provide data for 5000 ft altitude and above...

I think @Hummingbird would gladly help

[Max1mus]

51 minutes ago, Ironhand said:

Depends on the situation. If the Su-27 is dictating the flight, it'll win every time. If the MiG-29 is dictating the fight, it'll win. The Flanker has strength in some areas, the MiG in others. So I'd say it's a draw.

Thats a non-answer, you could say the same about the MiG-21 vs F-18.

If there is even a single missile on board said planes in a 1v1 between the two, like an R-73, the Su-27 will win nearly 100% of the time. It gets the first shot off since it gets the nose around much more quickly, and maneuvers much better at slow speeds.

In the DCS guns only community, the Su-27 is much more popular than the MiG-29. The 29 rarely makes one of the competitions. This could be because it is too difficult to fly, lacking an FCS (Modernized MiG-29 when?).

That said, even the Su-27 performs absolutely horrendously compared to the almightly F-18 overlord, which apparently outsustains F-15, F-16, Su-27, Su-33, MiG-29 and the F-14 easily. Even though in real life, it is considered an angles fighter.

Flight models have been reworked all the time in DCS. I would say that most of them perform severely differently from the original while maintaining the general characteristics associated with them, with exception of some extreme outliers (F-18 not being an angles fighter). I would say that older modules from before 2.5 (like the pre-buff A-10) tend to underperform, while new ones generally tend to overperform. I dont know if its something about the way ED develops flight models now, but these old planes did not have questionable characteristics like being able to go mach 1.7+ on the deck without structural damage.

PS @bkthunderDid you manage to find some data on Su-27? Could you compare its T/W to that of the "full fi" modules?

Edited December 7, 2021 by Max1mus

[Top Jockey]

22 minutes ago, Max1mus said:

Thats a non-answer, you could say the same about the MiG-21 vs F-18.

If there is even a single missile on board said planes, in a 1v1 between the two, like an R-73, the Su-27 will win nearly 100% of the time. It gets the first shot off since it gets the nose around much more quickly, and maneuvers much better at slow speeds.

In the DCS guns only community, the Su-27 is much more popular than the MiG-29. The 29 rarely makes one of the competitions. This could be because it is too difficult to fly, lacking an FCS (Modernized MiG-29 when?).

That said, even the Su-27 performs absolutely horrendously compared to the almightly F-18 overlord, which apparently outsustains F-15, F-16, Su-27, Su-33, MiG-29 and the F-14 easily. Even though in real life, it is considered an angles fighter.

Flight models have been reworked all the time in DCS. I would say that most of them perform severely differently from the original while maintaining the general characteristics associated with them, with exception of some extreme outliers (F-18 not being an angles fighter). I would say that older modules from before 2.5 (like the pre-buff A-10) tend to underperform, while new ones generally tend to overperform. I dont know if its something about the way ED develops flight models now, but these old planes did not have questionable characteristics like being able to go mach 1.7+ on the deck without structural damage.

 

 

Why would the Su-27 win 100 % of the time ?

Because of the "direct link control" ?

Undoubtedly, the Su-27's flight control system is more modern and effective than the MiG-29A's one, no doubts here.

 

The only way I manage to get the Su-27's nose around quicker than the MiG-29 is only when using the "direct link control" ("S" key in-game)... and in that case I believe the Flanker is the airframe with the highest pitch rate currently in DCS.

Edited December 7, 2021 by Top Jockey

[Ironhand]

1 hour ago, Max1mus said:

Thats a non-answer, you could say the same about the MiG-21 vs F-18.

Within the confines of the parameters under discussion, I stand by my answer. Taking rate at corner into consideration as well, I’d lean toward the Su-27.

As far as the online community is concerned, the Flanker is a much easier airframe to fly than the MiG-29 and their rates, etc, are sufficiently similar that the easier aircraft to fly will be the one you experience the most success in. So it kind of self selects. Very few people fly online to lose.

1 hour ago, Top Jockey said:

The only way I manage to get the Su-27's nose around quicker than the MiG-29 is only when using the "direct link control" ("S" key in-game)...

Ouch! In that case, something is very wrong. Or are you not using the G-limiter override?

[bies]

9 hours ago, Top Jockey said:

Regarding less afterburner usage, I believe in that case the F-15C should also benefit from it, as its Thrust / Weight ratio is even higher than the MiG-29A's one.

F-15C had great T/W ratio, but original 1980s Soviet MiG-29A (9-12) had even slightly better T/W (comparable to F-15A with VMAX switch) at cost of smaller fuel fraction. Later MiG-29 variants obviously had lower and lower T/W due to gradual mass increase.

Quote

Mass taken directly from the DCS, Fully fueled + gun ammo + pylons T/W ratios:

MiG-29A  2x81,6kN (163,2kN) / 14445 kg = T/W 1,13   (fuel fraction 23%)

F-15C  2x 105,7kN (211,4kN) / 19727 kg = T/W 1,07     (fuel fraction 31%)

F-16C Block 50  1x 131kN/ 13119 kg = T/W =1              (fuel fraction 25%)

F/A-18C  2x 79kN (158kN) / 17058 kg = T/W 0,93       (fuel fraction 29%)

Su-27  2x 122,6kN (245,2kN) / 26797 kg = T/W 0,91   (fuel fraction 35%)

F-14B  2x 125kN (250kN) / 27560 kg = T/W 0,91         (fuel fraction 27%)

Another thing is uninstalled thrust doesnt equal real thrust at certain conditions, speed, altitude, air intake operation etc.

There is an article USAF pilot Lt. Col. Fred "Spanky" Clifton, one of the most experienced aggressor pilots ever, having flown the F-15, F-5, F-16 and the MiG-29, compares directly F-15C and MiG-29 9-12 right after the fall of the USSR, flying both next to each other and testing acceleration and climb. MiG-29A was slightly better, but again, similar fuel fraction (F-15C without full fuel) could equalize that to some extend. Plus F-15 engines were tuned to higher speeds. Both F-15 and first MiG-29 were nearly uncompromised A-A hotrods with fantastic performance.

[bies]

9 hours ago, Seaeagle said:

No it wasn't bies. Its refered to as "internal external fuel" because thats what it is - compare the amount to any other comparable fighter design. It was a design decision in connection with its intended role to take advantage of internal space for extra fuel instead of carrying it externally(no external tanks available for the Su-27) - less drag penalty, while freeing up external pylons for more weapons.

 

Su-27 with 59% fuel ("design weight") had significanly lower luel fraction than F-15C.

Su-27 has fuel fraction of the F-15C when Su-27 has 88% fuel, but this is significantly above "design weight", especially if having additionally 8 AAM like the F-15C, and this makes Su-27 even more G limited than shown above.

Just saying.

[captain_dalan]

On 12/6/2021 at 10:49 AM, Top Jockey said:

 

Hello @captain_dalan,

1. It would be time till fuel out, as I would prefer to have an idea of performance in very light airframes;

2. Sure - DCS data would be enough for me, as RL data on those very specific conditions might not always be at hand;

(But, if you have RL data on similar conditions, that would be very good also.)

3. It's just a personal curiosity, as the max. degrees per second a given airframe can sustain always caught my attention.

Well, here are my findings, specific to DCS. But first the initial conditions:
Standard atmosphere, altitude between 0-1000ft. Time in burner at FULL power, about 3 minutes and 15 seconds. There are alternatives to calculating the fuel flow for different regimes, but i don't think we need to be THAT pedantic. All sorties were flown with the scripted mission, so the room of errors and deviations were minimized. Each plane was evaluated at 300, 350, 400 and 450 knots of TAS. I thought these airspeeds to be most viable and relevant for BFM.

F-14A, internal fuel 7776lbs - clean
301KTAS -5g => 18.3 deg/s
353KTAS -6.2g => 19.1 deg/s
404KTAS -6.9g => 18.8 deg/s
453KTAS -7.1g => 17.2 deg/s

MiG-29A, internal fuel 6100lbs - clean
295KTAS - 4.7g => 17.7 deg/s
353KTAS - 5.9g => 18.7 deg/s
401KTAS - 6.8g => 18.8 deg/s
446KTAS - 7.8g => 18.9 deg/s

The planes are rathe close in terms of STR, with the F-14A having a slight advantage at lower speeds, as expected. Around 400 knots they become rather equal. Above 400 knots, the MiG has the obvious advantage. The runs aren't that pedantic again, as you can see, there is a delta between the airspeeds at which the measures were taken, but i don't think it really matters in the grand scale of things. What the STR data doesn't show though, is the ability of the MiG to accelerate, even with some g's on it, or alternatively to climb. Especially above 400 knots. In fact, it has so much power, that maintaining a coordinated steady turn in level flight is (for me) very hard. The plane just wants to climb.  I hope this answers your question.

Cheers!

P.S. The time in burner was chosen purely arbitrary as it was the first value i got when i was fine tuning the fuel states. My original goal was to have both planes between 3 to 4 minutes in burner and this was the first value during the iterations at which their timings roughly matched. I think i got 3:16 for the MiG and 3:24 for the F-14. 

EDIT: edited for the MiG's fuel state, i forgot to include it in the original post.

Edited December 8, 2021 by captain_dalan

[captain_dalan]

7 hours ago, Max1mus said:

In the DCS guns only community, the Su-27 is much more popular than the MiG-29. The 29 rarely makes one of the competitions. 

 

I think this has most to do with the DCS flying habits in ACM, that due to spotting and maintaining tally difficulties tends almost always result in :
1. Very closely knit, tight fights with sub optimal range (hugging the bandit);
2. Avoiding of vertical maneuvers.
 

[Dell_Murrey-RUS]

19 часов назад, Top Jockey сказал:

... but then studying that chart, some doubts appear on my mind :

- i guess in a 2 circle fight,  the MiG flying at 850 kph doing 20,5 deg/sec, would eventually prevail over the Su-27 at 640 kph doing 19,3 deg/sec ;

- but then, the Su-27 pilot could force a 1 circle fight and use its smaller turn radius ;

- also, the Su-27 flying at 970 kph doing 21,7 deg/sec, would be of little use, because of the big turn radius factor ?

You can calculate the distance traveled for each radius. (Ты можешь посчитать пройденный путь по каждому радиусу.)

In general, when fighting on sustaned turns, it is better if the effective sustaned turn rate speed was a slightly smaller radius than that of your opponent. (В целом, при боях на виражах лучше что бы эффективная скорость установившегося виража была с чуть меньшим радиусом, чем у твоего оппонента.)

17 часов назад, Ironhand сказал:

Depends on the situation. If the Su-27 is dictating the flight, it'll win every time. If the MiG-29 is dictating the fight, it'll win. The Flanker has strength in some areas, the MiG in others. So I'd say it's a draw.

So, I think... Air combat dictates an aircraft with faster capabilities (fast acceleration and high speed). The MiG-29 may dictate flight, but not for long, how the Su-27 will be able to continue flying for a long time.

And all this is only for air combat on guns.
The presence of close combat missiles radically changes the strategy, and therefore the requirements for specific capabilities of the aircraft.

 

16 часов назад, Top Jockey сказал:

Because of the "direct link control" ?

Undoubtedly, the Su-27's flight control system is more modern and effective than the MiG-29A's one, no doubts here.

 

The only way I manage to get the Su-27's nose around quicker than the MiG-29 is only when using the "direct link control" ("S" key in-game)... and in that case I believe the Flanker is the airframe with the highest pitch rate currently in DCS.

This is a big misconception. The control systems were made for specific gliders with specific parameters. (Это большое заблуждение. Системы управления были сделаны под конкретные планеры с конкретными параметрами.)

The Su-27 is a statically unstable aircraft in the longitudinal channel, so a special control system was made for it. (Су-27 это статически неустойчивый самолет в продольном канале, поэтому ему сделали специальную систему управления.)

In addition, the Su-27 does not need use direct control (S). He has the ability to pull the control stick, thereby increasing overload capabilities (W).
For example, if I have a speed in the turn of 850 km/h and I need to reduce it (changing potencial energy to higher turn rate speed), I just need to start pulling the control stick on myself outside the limiter. The overload will briefly increase from 8 G to 9,5 G with a short-term increase in the angular speed of the turn and at the same time without the risk of falling into emergency modes. The amount of additional overload will depend on how much you drag the control stick.

The MiG-29 has a classic design. It does not require a special control system. At the same time, you can also turn off the damper in the longitudinal channel "(this is also implemented in DCS). And get the appropriate capabilities (if necessary). (МиГ-29 выполнен по классическому дизайну. Для него не требуется специальная система управления. Она у него прямая. При этом у него так же можно отключить демпфер в продольном канале" (в DCS это тоже реализовано). И получить соответствующие возможности (если это необходимо)).

The MiG-29 is a fairly maneuverable fighter. He has only one serious flaw - insufficient fuel for a long air battle.
This is his main problem, from which they do not like to choose him as a fighter in duels or long air battles. The enemy can exhaust the MiG-29 by the remainder of the fuel and win the battle.

 

Good luck!

[Top Jockey]

15 hours ago, Ironhand said:

Within the confines of the parameters under discussion, I stand by my answer. Taking rate at corner into consideration as well, I’d lean toward the Su-27.

As far as the online community is concerned, the Flanker is a much easier airframe to fly than the MiG-29 and their rates, etc, are sufficiently similar that the easier aircraft to fly will be the one you experience the most success in. So it kind of self selects. Very few people fly online to lose.

Ouch! In that case, something is very wrong. Or are you not using the G-limiter override?

 

Although I do not fly online, I fully agree with the bold also.

In the MiG-29 there's the slightly abrupt uncommanded pitch-up moment after the 11 degrees AoA, and also the loss of roll authority after a given AoA.

 

Not sure right now, but if you mean the "y" key in-game (which I also assigned to my joystick), yes I do.

But even using it, the Su-27's nose doesn't seem to pitch around with the same freedom / quickness of the MiG-29... 

 

I mean: it sure isn't anywhere as quick as when using the "direct link control" - which in the MiG-29 doesn't exist; but using the MiG's G-limiter override it can sling its nose around pretty quick.

Edited December 8, 2021 by Top Jockey

[Top Jockey]

15 hours ago, bies said:

F-15C had great T/W ratio, but original 1980s Soviet MiG-29A (9-12) had even slightly better T/W (comparable to F-15A with VMAX switch) at cost of smaller fuel fraction. Later MiG-29 variants obviously had lower and lower T/W due to gradual mass increase.

Another thing is uninstalled thrust doesnt equal real thrust at certain conditions, speed, altitude, air intake operation etc.

There is an article USAF pilot Lt. Col. Fred "Spanky" Clifton, one of the most experienced aggressor pilots ever, having flown the F-15, F-5, F-16 and the MiG-29, compares directly F-15C and MiG-29 9-12 right after the fall of the USSR, flying both next to each other and testing acceleration and climb. MiG-29A was slightly better, but again, similar fuel fraction (F-15C without full fuel) could equalize that to some extend. Plus F-15 engines were tuned to higher speeds. Both F-15 and first MiG-29 were nearly uncompromised A-A hotrods with fantastic performance.

 

I see, didn't know that about the F-15A's VMAX switch - interesting.

To have a just an aproximate notion of each airframe's capability, I tipically use absolute empty weights and maximum thrust (full AfterBurner) data i can gather from the web.

Let's say I go at Wikipedia (for the sake of quickness), for example:

 

MiG-29A :

Max. Thrust - 16.637 kgf

Empty weight - 10.900 kg

T/W ratio - 1.52

 

Su-27S :

Max. Thrust - 25.038 kgf

Empty weight - 16.380 kg

T/W ratio - 1.52

 

F-15C :

Max. Thrust - 21.563 kgf

Empty weight - 12.700 kg

T/W ratio - 1.69

 

Obviously, many will question the usefullness of calculating for an absolutelly empty airframe - but its purpose is just i can have an idea of a given airframe's "crude" capabilities, and start from there.

What i might do after is, doing those calculations not with the same fuel fraction, but with the fuel quantity for 3 - 4 minutes full Afterburner (in DCS) and compare 2 different airframes... naturally they will have different internal fuel quantities.

Edited December 8, 2021 by Top Jockey

[Dell_Murrey-RUS]

The only thing that is more clear from these characteristics is that one fighter has slightly better speed characteristics. It will not be possible to draw other conclusions from this.

[Seaeagle]

16 hours ago, bies said:

Su-27 with 59% fuel ("design weight") had significanly lower luel fraction than F-15C.

Su-27 has fuel fraction of the F-15C when Su-27 has 88% fuel, but this is significantly above "design weight", especially if having additionally 8 AAM like the F-15C, and this makes Su-27 even more G limited than shown above.

Just saying.

F-15C internal fuel capacity is 13860 lbs ~ 6286 kg.

Su-27 internal fuel capacity is some 9300-9400 kg(!)

So 59% ~ 5546 kg and has the same load as the F-15C at around 67 %. Its perhaps also a little unfair to include missile loads(design weight) for agility comparison since 8 AAMs for the F-15C would involve AMRAAMs, which are considerably lighter than R-27s.

Anyway, I am not arguing with your points about agility - only the bit about the "normal fuel load" of the Su-27 being some sort of artificial figure to make it look better.

Besides, it would probably be more appropriate to compare it to the MiG-29(more similar design philosophies), for which just about everything(overall size, dry weight, engine thrust etc) is a case of + 50% and the "normal fuel load" of the Su-27 is perfectly in line with that:

MiG-29 at 100%: ~3500 kg

Su-27 at 59%: ~ 5500 kg

....i.e. around 57% more.

Edited December 8, 2021 by Seaeagle

[Top Jockey]

11 hours ago, captain_dalan said:

Well, here are my findings, specific to DCS. But first the initial conditions:
Standard atmosphere, altitude between 0-1000ft. Time in burner at FULL power, about 3 minutes and 15 seconds. There are alternatives to calculating the fuel flow for different regimes, but i don't think we need to be THAT pedantic. All sorties were flown with the scripted mission, so the room of errors and deviations were minimized. Each plane was evaluated at 300, 350, 400 and 450 knots of TAS. I thought these airspeeds to be most viable and relevant for BFM.

F-14A, internal fuel 7776lbs - clean
301KTAS -5g => 18.3 deg/s
353KTAS -6.2g => 19.1 deg/s
404KTAS -6.9g => 18.8 deg/s
453KTAS -7.1g => 17.2 deg/s

MiG-29A, internal fuel - clean
295KTAS - 4.7g => 17.7 deg/s
353KTAS - 5.9g => 18.7 deg/s
401KTAS - 6.8g => 18.8 deg/s
446KTAS - 7.8g => 18.9 deg/s

The planes are rathe close in terms of STR, with the F-14A having a slight advantage at lower speeds, as expected. Around 400 knots they become rather equal. Above 400 knots, the MiG has the obvious advantage. The runs aren't that pedantic again, as you can see, there is a delta between the airspeeds at which the measures were taken, but i don't think it really matters in the grand scale of things. What the STR data doesn't show though, is the ability of the MiG to accelerate, even with some g's on it, or alternatively to climb. Especially above 400 knots. In fact, it has so much power, that maintaining a coordinated steady turn in level flight is (for me) very hard. The plane just wants to climb.  I hope this answers your question.

Cheers!

P.S. The time in burner was chosen purely arbitrary as it was the first value i got when i was fine tuning the fuel states. My original goal was to have both planes between 3 to 4 minutes in burner and this was the first value during the iterations at which their timings roughly matched. I think i got 3:16 for the MiG and 3:24 for the F-14. 

 

@captain_dalan,

You've done a lot again, thank you.

By the way, which was the internal fuel (in lbs) in the MiG ?

 

Sure, the fuel quantity for (roughly) same time in burner for each of the 2 different aircrafts being compared, is the measure which I find makes more sense.

(Contrary to exactly the same % (percentage) of fuel in both 2 different aircraft, that as we all know very probably would burn fuel at different rates.)

 

Going straight to the point, my issue is:

I have some difficulty bearing my mind around that (the bold), as I always thought that in Real Life the F-14A variant (which is one of my very favorite jets), would be somewhat inferior to the MIG-29 in all of those speed ranges, turn-rate wise.

The F-14B variant, I can fully understand that would be a more than a match for the Fulcrum ACM wise, but the F-14A ?

I mean - even the pilots qualified it as completely under-powered because of its TF30 engines... ?

 

My point being:

- empty weights:  the F-14A is almost twice heavier than the MiG-29A;

- Thrust / Weight ratio:  is better on the MiG-29A;

- Wing loading:  is better on the F-14A;

- Lift coefficients (CL max):  no idea which is better, I've read the MiG-29A's is supposedly 1.5 or something...

 

Several people here have explained to me that I've most likely over-valued the Fulcrum's real life ACM (BFM, dogfighting, whatever) turning capabilities, particulary against the Su-27 for instance, because:

" MiG-29 is a stable design, it's elevators acts opposite to wings decreasing it's overall lift, this increases AoA in turn (plane needs higher AoA for given G, thus bigger drag) and cause MiG to lose it's speed in turn faster than modern unstable designs like F-16 or Su-27. "

 (quoting @bies, from another thread)

 

But the Fulcrum being nothing special, turn-rate wise against the F-14A ?

 

[Cmptohocah]

12 hours ago, captain_dalan said:

F-14A, internal fuel 7776lbs - clean
...
404KTAS -6.9g => 18.8 deg/s
...

MiG-29A, internal fuel - clean
...
401KTAS - 6.8g => 18.8 deg/s
...
 

Perfect example of physics right there. At same airspeed (true) and same load all flying objects will have the same turn rate, regardless of their specific characteristics (engines, air frame...).

[Cmptohocah]

22 hours ago, Kefa said:

...
Don't have Fulcrum or Flanker specific excess power lines though.  While sustained rate turns matter too, so do turns above the PS-0 line.  I mean, turning while at the expense of airspeed.  And that is important.

 

In that case the limiting factor would be the max. AoA, provided that the structural G limit is not lower than the load produced at max. alpha.

Edited December 8, 2021 by Cmptohocah

[Top Jockey]

4 hours ago, Dell_Murrey-RUS said:

You can calculate the distance traveled for each radius.

In general, when fighting on sustaned turns, it is better if the effective sustaned turn rate speed was a slightly smaller radius than that of your opponent.

...

This is a big misconception. The control systems were made for specific gliders with specific parameters.

The Su-27 is a statically unstable aircraft in the longitudinal channel, so a special control system was made for it.

In addition, the Su-27 does not need use direct control (S). He has the ability to pull the control stick, thereby increasing overload capabilities (W).
For example, if I have a speed in the turn of 850 km/h and I need to reduce it (changing potencial energy to higher turn rate speed), I just need to start pulling the control stick on myself outside the limiter. The overload will briefly increase from 8 G to 9,5 G with a short-term increase in the angular speed of the turn and at the same time without the risk of falling into emergency modes. The amount of additional overload will depend on how much you drag the control stick.

The MiG-29 has a classic design. It does not require a special control system. At the same time, you can also turn off the damper in the longitudinal channel "(this is also implemented in DCS). And get the appropriate capabilities (if necessary).

The MiG-29 is a fairly maneuverable fighter. He has only one serious flaw - insufficient fuel for a long air battle.
This is his main problem, from which they do not like to choose him as a fighter in duels or long air battles. The enemy can exhaust the MiG-29 by the remainder of the fuel and win the battle.

 

Good luck!

 

Thank you @Dell_Murrey-RUS,

 

Sure, but my point was the Su-27's "direct link control" can always allow for a "lightning quick" pitch rate (nose pointing) capability for a gun or missile snap-shot, that other fighters can not equal...

( Obviously to be used in rare situations i imagine, as it would require a lot of skill, reflexes, aim from the pilot, and with the corresponding speed / energy loss. )

 

Regarding the MiG-29A's damper I've tweaked with it some time ago, but does it allow for a pitch rate nearly as quick as the Su-27's "direct link control" ?

 

On the low internal fuel, yes its a reality.

But if there's R-73 Archer missiles involved, many fights will not last much.

 

In the end, I will ask you the same question I asked to Ironhand:

Would you qualify the Su-27S as a better dogfighting airframe than the MiG-29A, or not at all ?

Edited December 8, 2021 by Top Jockey

[Top Jockey]

57 minutes ago, Cmptohocah said:

Perfect example of physics right there. At same airspeed (true) and same load all flying objects will have the same turn rate, regardless of their specific characteristics (engines, air frame...).

 

Very true yes.

But eventough, for me it's like: "always thought in real life the Fulcrum would do better"...

[Spurts]

1 hour ago, Top Jockey said:

My point being:

- empty weights:  the F-14A is almost twice heavier than the MiG-29A;

- Thrust / Weight ratio:  is better on the MiG-29A;

- Wing loading:  is better on the F-14A;

- Lift coefficients (CL max):  no idea which is better, I've read the MiG-29A's is supposedly 1.5 or something...

 

 

 

CL max for the F-14 is ~2.2. 

 

If you run the equation for induced drag it is D_i=C_Di*q*S. (q is dynamic pressure, 0.5*rho*V²)

C_Di=C_L²/pi*e*AR (e is the Oswald's Efficiency Factor and measures how elliptical the lift distribution is across the span, we will largely ignore this for now)

C_L=n*W/q*S

We will ignore stability impacts on n for the moment

C_Di=n²*W²/q²*S²*pi*e*AR

AR=b²/S (b is Wingspan)

C_Di=n²*W²/q²*S*pi*e*b²

If we fold this back into induced drag and simplify we get

Di=n²*W²/q*b²*pi*e

Let's call n²/q*pi*e "K" as this will assume same G, Speed, Altitude, and Oswald's efficiency factor

Di=K*W²/b²  

So we can see that the driving force for drag due to lift is span loading, not wing loading.  Stability plays an equal part but makes the computations much uglier.

F-14A and B have slightly lower Span Loadings when loaded (4AIM-9s and 4-AIM-7s vs 4R-73s and 2R-27s) and at matching fuel fractions (20%).  Assuming they have equal stability this pans out.  Long straight wings tent to have better e than swept trapezoidal wings so the e value in the equation lends itself more to the F-14 advantage as well.

 

In the end though this is about T/W ratios.  Thrust drops ~15-20% on installation, increases with airspeed, and drops with altitude.  Different engines perform differently at different regimes and in different airframes (inlet design and function matters).  A J79-GE-10 installed in an F-4 makes more thrust at 2.0M and 35,000ft than an F110-GE-129 installed in an F-16 at the same flight condition.  A higher T/W on paper does NOT mean better acceleration under a given regime in flight.  

 

You see this in cars too.  I had a truck with 305hp, 380lb-ft of torque, a 5-speed transmission, a 3.55 rear axle, and weighed 5200lb.  I had an SUV with 255hp, 330lb-ft of torque, a 4-speed transmission, a 3.42 rear axle, and weighed 6100lb.  On paper it shouldn't even be close, but the SUV had better straight line performance across the board.