LMFS

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I would find it truly refreshing if someone, for a change, could illustrate those claims with actual budgetary figures that prove that Russian military can't handle basic arithmetic...
 

trose213

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I would find it truly refreshing if someone, for a change, could illustrate those claims with actual budgetary figures that prove that Russian military can't handle basic arithmetic...
So Sukhoi better hope the UAE doesn't buy the F35s after all.

 

haavarla

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I would find it truly refreshing if someone, for a change, could illustrate those claims with actual budgetary figures that prove that Russian military can't handle basic arithmetic...

I don't have any spreadsheet.

But here is a great insight into how the Russian State allocate its defence spending.

View: https://www.youtube.com/watch?v=ts9OG2Zo1_k
 

LMFS

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I don't have any spreadsheet.

But here is a great insight into how the Russian State allocate its defence spending.
Well, that is 1:26:11 too much reflection for many. Much better to keep pumping proud ignorance as if wishful thinking matters in any way in the real world.

Fact is that with the equivalent of $1B, Russia buys all their fighters for one year and probably enough remains to buy a good amount of other things. And that is just like 1/50th of the MoD budget. So yes, they do have "Rubles" for many more toys
 

helmutkohl

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I would find it truly refreshing if someone, for a change, could illustrate those claims with actual budgetary figures that prove that Russian military can't handle basic arithmetic...
So Sukhoi better hope the UAE doesn't buy the F35s after all.

I've also read Turkey and Egypt being touted as potential markets.
not sure how that would work as Turkey and Egypt are on opposing sides in their Libya and Mediterranean disputes.
I could potentially see Egypt eventually acquiring some if the Saudis help finance it. Turkey likely will just stick with their TFX.
 

TSARb

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Here are my estimations for "75" with "izdelie 30" engine:

Wingspan 11.7 ... 11.82 m (38,8 ft)
Wing area 60.2 m² (648 ft²)

Internal fuel < 5700 kg (12566 lb)
Empty weight < 11340 kg (25 000 lb)
Normal takeoff 17888 kg (39 450 lb)
MTOW 24550 kg (54 100 lb)
 
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LMFS

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Here are my estimations for "75" with "izdelie 30" engine:

Wingspan 11.7 ... 11.82 m (38,8 ft)
Wing area 60.2 m² (648 ft²)

Internal fuel < 5700 kg (12566 lb)
Empty weight < 11340 kg (25 000 lb)
Normal takeoff 17888 kg (39 450 lb)
MTOW 24550 kg (54 100 lb)
Question, if I may: is the engine type relevant in this estimation, is it changing weight for instance? In my view, the plane equipped with izd. 30 may have a stronger structure and keep or even improve TWR, but I don't know if you are making such considerations here.

I would say that the fuel estimate is a bit low, but the other numbers look rather ok, apart from the precision which I think is a bit premature, given the uncertainty. To me ca. 11 t empty + 7 t fuel would match the 18 t TOW provided previously, and that would be possible while maintaining the same TWR empty of the F-35A, which is a necessary reference as the main current market competitor, with a 16 tf evolution of the izd. 117. The plane with the izd. 30 would further improve in that regard.
 

Avimimus

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Here are my estimations for "75" with "izdelie 30" engine:

Wingspan 11.7 ... 11.82 m (38,8 ft)
Wing area 60.2 m² (648 ft²)

Internal fuel < 5700 kg (12566 lb)
Empty weight < 11340 kg (25 000 lb)
Normal takeoff 17888 kg (39 450 lb)
MTOW 24550 kg (54 100 lb)
Question, if I may: is the engine type relevant in this estimation, is it changing weight for instance? In my view, the plane equipped with izd. 30 may have a stronger structure and keep or even improve TWR, but I don't know if you are making such considerations here.

I would say that the fuel estimate is a bit low, but the other numbers look rather ok, apart from the precision which I think is a bit premature, given the uncertainty. To me ca. 11 t empty + 7 t fuel would match the 18 t TOW provided previously, and that would be possible while maintaining the same TWR empty of the F-35A, which is a necessary reference as the main current market competitor, with a 16 tf evolution of the izd. 117. The plane with the izd. 30 would further improve in that regard.

The aircraft could have a lower TWR than the F-35A and still try to undercut it in cost or through providing additional capabilities (e.g. high diametre missiles).
 

TSARb

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The aircraft could have a lower TWR than the F-35A
I think it's better to calculate TWR after the portion of fuel is spent, and the remaining amount gives eqv. range.

Question, if I may: is the engine type relevant in this estimation, is it changing weight for instance?
Yes. "Izdelie 30" expected to have much higher thrust-to-weight ratio itself. Given almost the same thrust, engine should be lighter compared to AL-41F1-driven planes.

I would say that the fuel estimate is a bit low
5700 kg already the upper bound: it's the necessary amount to reach 2900 km range, assuming lift-to-drag ratio on par with the Su-27. There are two reasons I think the amount of fuel could be lower:
- specific fuel consumption of "izdelie 30" could be better because of higher turbine's temperature and newer afterburner, which gives less drag in the cruise. But officials say the typical fuel consumption will be the same.
- range was calculated under the condition of five rockets in the bay being launched after halfway.
The lower bound for the fuel amount is ~4900 kg (given 7,7% better lift-to-drag ratio than Su-27 and no payload in the bays).

the precision
Pay no attention on this :) I decided to get almost raw numbers because of convertions to imperial values, so everybody could round them as he wants. I'm not be surprised if the difference between my and the real values is more than 10%.


P.s. Reference planes were Su-57, F-32 CTOL, F-35A, KAI F-21 and Eurofighter Typhoon.
 

LMFS

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The aircraft could have a lower TWR than the F-35A and still try to undercut it in cost or through providing additional capabilities (e.g. high diametre missiles).
Sure, but it is always better not having to fight back one argument of your competitors at all. So if a design compromise has to be taken (like reduce weight with a weaker structure or have worse TWR), it seems the ultimate overload capability of the plane was not rated as the top priority. But I agree even with worse TWR the plane has many arguments and that politics will play a bigger role in many ways than pure specs.

Yes. "Izdelie 30" expected to have much higher thrust-to-weight ratio itself. Given almost the same thrust, engine should be lighter compared to AL-41F1-driven planes.
We have collected most of the "official" statements about izd. 30 recently in the thread of the Su-57. One third lower specific weight has been stated, based on that a max thrust of 18 tf @1400 kg seems a reasonable estimate, there is solid evidence supporting this instead of the engine having the same thrust and much lower weight.

5700 kg already the upper bound: it's the necessary amount to reach 2900 km range, assuming lift-to-drag ratio on par with the Su-27. There are two reasons I think the amount of fuel could be lower:
- specific fuel consumption of "izdelie 30" could be better because of higher turbine's temperature and newer afterburner, which gives less drag in the cruise. But officials say the typical fuel consumption will be the same.
- range was calculated under the condition of five rockets in the bay being launched after halfway.
The lower bound for the fuel amount is ~4900 kg (given 7,7% better lift-to-drag ratio than Su-27 and no payload in the bays).
I assume you have applied the Breguet range equation right? Did you try it with the F-35A (2800 km with 8.3 t internal fuel) or MiG-35 (2000 km with ca. 5 t)? Since it has been said the izd. will preserve the SFC, we more or less have that value already. But in any case, by now the izd. 117 and 117S are the engines available for the plane, not the izd. 30.
 

overscan (PaulMM)

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Here are my estimations for "75" with "izdelie 30" engine:

Wingspan 11.7 ... 11.82 m (38,8 ft)
Wing area 60.2 m² (648 ft²)

Internal fuel < 5700 kg (12566 lb)
Empty weight < 11340 kg (25 000 lb)
Normal takeoff 17888 kg (39 450 lb)
MTOW 24550 kg (54 100 lb)
Question, if I may: is the engine type relevant in this estimation, is it changing weight for instance? In my view, the plane equipped with izd. 30 may have a stronger structure and keep or even improve TWR, but I don't know if you are making such considerations here.

I would say that the fuel estimate is a bit low, but the other numbers look rather ok, apart from the precision which I think is a bit premature, given the uncertainty. To me ca. 11 t empty + 7 t fuel would match the 18 t TOW provided previously, and that would be possible while maintaining the same TWR empty of the F-35A, which is a necessary reference as the main current market competitor, with a 16 tf evolution of the izd. 117. The plane with the izd. 30 would further improve in that regard.
12000kg empty equipped (F-35 is 13,290 kg)
5250kg fuel
750kg missiles (3 x RVV-MD, 2 x RVV-SD)

= 18,000kg.

TWR at 50% internal fuel = 0.97 (Izdeliye 117) or 1.04 (Developed Izdeliye 117) or 1.1+ (Ideliyie 30)
 

LMFS

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12000kg empty equipped (F-35 is 13,290 kg)
5250kg fuel
750kg missiles (3 x RVV-MD, 2 x RVV-SD)

= 18,000kg.

TWR at 50% internal fuel = 0.97 (Izdeliye 117) or 1.04 (Developed Izdeliye 117) or 1.1+ (Ideliyie 30)
With that empty weight estimate for the LTS putting it clearly in the same size ballpark of the F-35, why would the later need 60% more fuel for roughly the same (or even less) range?
 

overscan (PaulMM)

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Su-27SK fuel load - 5240kg (normal) 9400kg (max)
Normal TOW 23,400kg (Fuel fraction: 0.22)
Max Fuel TOW (normal TOW + full fuel) 27560kg (Fuel fraction: 0.34)
Max TOW 33,000kg (Fuel fraction: 0.28)
Max range (from manual) : 3680km.

Su-27UB has exactly the same fuel load and engines but due to increased drag gets only 3000km range.

I assume Sukhoi are using broadly the same range calculation methodology for Checkmate as Su-27SK, so 2900km compares to 3680km for Su-27SK = 78% of the range. Range is related to fuel fraction. If the Checkmate had 7000kg fuel for 18000kg TOW = fuel fraction of 0.38, which would mean if range is only 2900km then it must be notably draggier or higher cruise sfc compared to Su-27.

When comparing to F-35 - we don't know the exact flight profile, or any other details, for Checkmate range figure. We can guess that is a ferry flight, clean, i.e. no external weapons, at optimum speed and altitude. Is it 2900km and the plane is empty and crashes, out of fuel? 10% fuel reserve on landing?

Therefore its difficult to compare with F-35 figures which also don't give details.

Regarding weight, if dimension calculated by e.g. Paralay are reasonably accurate its hard to see how Checkmate would be 2,290kg lighter (e.g. 11t) than F-35.

All speculation of course. We don't have any real weight figures.
 

Avimimus

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The aircraft could have a lower TWR than the F-35A and still try to undercut it in cost or through providing additional capabilities (e.g. high diametre missiles).
Sure, but it is always better not having to fight back one argument of your competitors at all. So if a design compromise has to be taken (like reduce weight with a weaker structure or have worse TWR), it seems the ultimate overload capability of the plane was not rated as the top priority. But I agree even with worse TWR the plane has many arguments and that politics will play a bigger role in many ways than pure specs.

I'm not disagreeing in principle.

But we're talking about delivering 800kg of internally stored ordinance at twice the range of the Mig-29, while being faster than the F-35 and being capable of super cruise - and doing all of that with ~93 kN instead of ~99 kN (Mig-29) or ~128 kN (F-35) of thrust.

I wouldn't be surprised if it is relatively heavy at take-offs in order to achieve that range (i.e. low loaded power-to-weight ratio), and has worse overall sustained manoeuvrability have to be sacrificed in order to reduce drag during cruise.

That said the STOLL requirement would go against this. But I wouldn't be surprised if the STOLL performance can only be achieved with reduced fuel or if it has to burn off a significant amount of fuel on the outboard leg before it can super cruise.
 

LMFS

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Su-27SK fuel load - 5240kg (normal) 9400kg (max)
Normal TOW 23,400kg (Fuel fraction: 0.22)
Max Fuel TOW (normal TOW + full fuel) 27560kg (Fuel fraction: 0.34)
Max TOW 33,000kg (Fuel fraction: 0.28)
Max range (from manual) : 3680km.

Su-27UB has exactly the same fuel load and engines but due to increased drag gets only 3000km range.

I assume Sukhoi are using broadly the same range calculation methodology for Checkmate as Su-27SK, so 2900km compares to 3680km for Su-27SK = 78% of the range. Range is related to fuel fraction. If the Checkmate had 7000kg fuel for 18000kg TOW = fuel fraction of 0.38, which would mean if range is only 2900km then it must be notably draggier or higher cruise sfc compared to Su-27.

When comparing to F-35 - we don't know the exact flight profile, or any other details, for Checkmate range figure. We can guess that is a ferry flight, clean, i.e. no external weapons, at optimum speed and altitude. Is it 2900km and the plane is empty and crashes, out of fuel? 10% fuel reserve on landing?

Therefore its difficult to compare with F-35 figures which also don't give details.

Regarding weight, if dimension calculated by e.g. Paralay are reasonably accurate its hard to see how Checkmate would be 2,290kg lighter (e.g. 11t) than F-35.

All speculation of course. We don't have any real weight figures.
Su-35 has 3600 km range with 11.5 t internal fuel, so that value for the SK is interesting indeed.

The range given for the F-35A is a max range in hi-hi-hi conditions, optimal cruising with internal AAM load, so as close as possible to the max range on internal fuel of Russian manufacturers. A 60% difference is not justified because of fuel reserve issues.

Determining range based on the fuel fraction is not an appropriate method BTW.

I agree we don't know the weight difference of the LTS vs de F-35, I am assuming it must be lighter by a decent margin because of the inferior thrust of the export engines and the 8 g airframe, if not I find it difficult to understand them talking about the superior TWR of the plane, as was said in the presentation by people in the know.

Again, I don't see that a plane with the basic dimensions of the MiG-35 as the LTS has 50% more range with the same fuel load, that does not make any sense to me. But we will see.

I'm not disagreeing in principle.

But we're talking about delivering 800kg of internally stored ordinance at twice the range of the Mig-29,
The MiG-29 has 3.5 t internal fuel, that is the reason for me saying that the LTS may have roughly twice the fuel for ca. twice the range.

while being faster than the F-35 and being capable of super cruise - and doing all of that with ~93 kN instead of ~99 kN (Mig-29) or ~128 kN (F-35) of thrust.
Being faster is pretty easy given the design of the F-35 is not optimized for the supersonic flight. The LTS has a totally different bay layout that results in a longer, more slender fuselage which should quite naturally lead to lower supersonic drag.

As to the claim about supercruising, that is new to me. They talked about sustained supersonic flight, but I have not seen any clear, reliable mention to supersonic cruising.

I wouldn't be surprised if it is relatively heavy at take-offs in order to achieve that range (i.e. low loaded power-to-weight ratio),
That is what I assume too. 5G fighters have big fuselages with big internal volume due to the internal bays, it is just logical to use that for increased range, the same way F-35 does. And that translates in low TWR of course. For instance a F-35A at MTOW will be roughly 0.63, almost exactly the same as a LTS would, with 11 t empty weight, 7.4 payload and 7 t fuel, for a 16 tf engine. Coincidence?

and has worse overall sustained manoeuvrability have to be sacrificed in order to reduce drag during cruise.
Don't quite get that sentence. But sustained turn has two different relevant aspects in the LTS:
> The overload capability is lower than the standard with 8 g, that would restrict the manoeuvring at low to medium altitude compared to 9 g aircraft
> The wing loading, on the other hand, seems quite good in fact, much more in the class of the Eurofigter and Rafale (ca. 220 kg/sqm empty) than in that of the F-35 (310 kg/sqm), and that, even if we assume an empty weight as high as that of the F-35. So, at medium to high altitudes where the lift is the actual limitation for turning, the LTS should be substantially better than the F-35 and possibly, if the empty weight is contained, even better than the Eurocanards.

That said the STOLL requirement would go against this. But I wouldn't be surprised if the STOLL performance can only be achieved with reduced fuel or if it has to burn off a significant amount of fuel on the outboard leg before it can super cruise.
Seeing how the Su-57 takes off on the spot, with the same wings, and without even bothering deploying flaps, leaves me no doubt the lift generating capabilities of the LTS can be really outstanding. As said, the wing load is between low and ridiculously low. I don't know how such big wing surface reflects in skin friction drag, but it is clear that Sukhoi opted for the advantages of having big wings instead of keeping that drag contribution at a minimum like in the F-35.
 
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eagle

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The range given for the F-35A is a max range in hi-hi-hi conditions, optimal cruising with internal AAM load, so as close as possible to the max range on internal fuel of Russian manufacturers. A 60% difference is not justified because of fuel reserve issues.

Is it? What's the source?
We know the combat radius in A/A configuration, which is 760 nm. Some clever people simply assumed range is two times that. No other range info has been given afaik.
 

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Need to know the calculation method for sure.

Like everyone can give different value. Plus in terms of fuel.. how much is spent for what. Like when i do the thing i will make assumptions on fuel usage for takeoff-landing, cruise, combat, RTB (if needed), Trapped fuel which cannot be piped out, and loiter fuel because the runaway can get occupied. One can maybe expect only 85% of the fuel to be usable to fly while other 15% for other stuff particularly avionics cooling.

L/D can be of average value like typical fighters may have L/D of some 10-13 for subsonic cruise while when it goes supersonic L/D can drop to 6 or less, more than 6 implies use of some specialized methods e.g shockwave trap like XB-70. The average can be taken as 86% of that.

Transparency in method being used and how is important if one wish to have any productive day discussing aircraft range and basically everything technicals.
 

AleDucat

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Rough estimation, 8250 liters of fuel. Two seater would lost 1000 liters.
9b3203885aa54bc96f490f7843f54e75.png





ef817f1dab8474726f52c372dde037fb.jpg

38afe84918a8adad58ceb86259d64e3a.png

ca10cbef1c23dcd1f22f9c66d157abed.png





7d92108ae871b6ed1cfdb50f3fda4c92.png

73a810d3dafc3d80b186580565727bd7.png
 

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Artwork is great, but I'm not sure if that model has sufficient space allocated to the internal airframe structures, which at certain sections have to be quite wide and bulky to carry all the loads. For example, I'd think that most of the dorsal fuel tank would not be like as depicted, one uninterrupted long tank, since the structural spine of the plane would take up most of that space.
 

AleDucat

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Artwork is great, but I'm not sure if that model has sufficient space allocated to the internal airframe structures, which at certain sections have to be quite wide and bulky to carry all the loads. For example, I'd think that most of the dorsal fuel tank would not be like as depicted, one uninterrupted long tank, since the structural spine of the plane would take up most of that space.
Artwork, I think, is just more "art" than "work" ;)
But for doing that I first had to model the side bays (the way we know they are) and give them enough internal volume to carry a RVV-SD with the associated launcher and adapter, next the main weapons bay with space for Kh-69 and UVKU-50U launcher, then I had to imagine how the air duct goes from the known intake to the guessed position of the engine inlet, without affecting the weapon bays, and also so the air duct left enough space for fuel and cockpit (and a second seat.. for the two seater).
Then, I use the remaining internal space with a 10% to 15% less for airframe structure to "calculate" the available amount of fuel, measured in liters. The "uninterrupted long tank(s)" are just a visual help.

But then, this is just some fanwork done on my little available time after childs go to sleep.. after 11 pm up to 2 am.

Best regards
 

totoro

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Artwork is great, but I'm not sure if that model has sufficient space allocated to the internal airframe structures, which at certain sections have to be quite wide and bulky to carry all the loads. For example, I'd think that most of the dorsal fuel tank would not be like as depicted, one uninterrupted long tank, since the structural spine of the plane would take up most of that space.
Artwork, I think, is just more "art" than "work" ;)
But for doing that I first had to model the side bays (the way we know they are) and give them enough internal volume to carry a RVV-SD with the associated launcher and adapter, next the main weapons bay with space for Kh-69 and UVKU-50U launcher, then I had to imagine how the air duct goes from the known intake to the guessed position of the engine inlet, without affecting the weapon bays, and also so the air duct left enough space for fuel and cockpit (and a second seat.. for the two seater).
Then, I use the remaining internal space with a 10% to 15% less for airframe structure to "calculate" the available amount of fuel, measured in liters. The "uninterrupted long tank(s)" are just a visual help.

But then, this is just some fanwork done on my little available time after childs go to sleep.. after 11 pm up to 2 am.

Best regards
Sounds like a lot of work to me. Anyway, keep it up!

RVV-SD (R-77-1) are not carried internally
That's doubtful. RVV-SD should be carried in the central bay under the belly. The presentation at MAKS said 5 missiles altogether can be carried internally. With the 2 RVV-MD carried in the lateral bays, logic suggests the 3 remaining missiles are carried in the central bay. Those are likely to be RVV-SD.
 

stealthflanker

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Well.. the Su-57 arent gonna carry SD inside the internal bay but Izd-180 instead. I guess it's the same for Checkmate too.

Russia may instead offer export version of the Izd-180 for Checkmate.
 

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That's doubtful. RVV-SD should be carried in the central bay under the belly. The presentation at MAKS said 5 missiles altogether can be carried internally. With the 2 RVV-MD carried in the lateral bays, logic suggests the 3 remaining missiles are carried in the central bay. Those are likely to be RVV-SD.
Logic suggests that you want MRAAMs besides your A2G loadout taking all of the main bay, and not only SRAAM. Maybe it is not possible, space wise, but tactically it would make full sense. And the side bays are quite long and deep from what we have seen.

u1TVTVW.jpeg

OTH, structure does not take most of the internal volume of the dorsal tank, which is by far the most important fuel carrying space in any fighter, see Su-57 below.

EvPgHA8XAAM0MLF.jpeg
 

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I really like the look of your two seat mock up. I actually think its one of the few cases where the two seater looks nicer than a single

i also like Paralay's version too, but I wonder if there is not enough space between the cockpit and radome and the associated space needed for the radar and other electronics
 
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FighterJock

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I really like the look of your two seat mock up. I actually think its one of the few cases where the two seater looks nicer than a single

i also like Paralay's version too, but I wonder if there is not enough space between the cockpit and radome and the associated space needed for the radar and other electronics

And not forgetting the space for fuel, that is the main problem with twin-seater fighters over single.
 
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AleDucat

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I think Paralay's version doesn't only lost space for radar, but it seems to lost the refueling probe too. Mine "only" lost 1000 liters of fuel but retains the same functionality and capabilities that are present on the single seater.
 

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It is very important to preserve the cross-sectional area of the air intake channel along its entire length
The side walls of the central compartment are a supporting structure. You can't cut them. Only small windows are allowed, for example, for chassis wheels ;)
 

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F119Doctor

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One obvious limitation of this inlet design is access to the front of the engine for pre/post flight inspection for FOD damage. The shape of the inlet does not appear to be big enough for personnel entry.

For US fighters, the crew chief typically crawls into the intake and visually inspects the engine 1st stage blades for damage. I don’t see any provision for the Russian FOD screen / alternate intake seen on the MiG 29 or SU 27 aircraft. Remote imaging via borescope is a possible low airframe volume solution, but this requires expensive equipment to be readily available for every inspection and is typically not a quick process

Or, they just don’t do the inspection and accept a number of engine failures due to undetected blade damage….
 
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