AndraxxusThen why no one says F-119 is an 36k pound class engine?? No, I believe your method is contradicting in itself;
-You are claiming original YF-119 had exact 30000 lbs thrust, because its called 30k pound class.
-At the same time, you are ignoring F-119 is also called 35000lbs weight class. Why this claim has less weight than the other? Why should we not take this as exact value so other numbers would derive from it?
In your methodology, to be realistic, YF-119 can have 29500 lbs thrust, it would rightly be called 30k pound class. Exact 20% increase would make new F-119 engine have 35400 lbs thrust; rightly called 35k pound class.
Then, words like “nearly” are also problematic, 18% can rightly be called “nearly” 20%. Going from pessimistic numbers, 18% increase from 29500 lbs gives us 34810 lbs thrust in definitive engine; both engines’ thrusts would perfectly match their thrust classes.
As such, both assumtions would not contradict with ANY official information we have including “F-119 = 35k pound class” part.
AndraxxusOnly if one believes that 35k lbs class means 35k exactly. I happen to think it is significantly more powerful than that.
Although the thrust of the F119 is officially quoted as `in the 155kN class’, information obtained by IDR suggests that the actual thrust may be more than 170kN with full augmenter
-F-15E is quoted as having 2×29000 pound class engines. Actual thrust 29160 lbf for F-100-PW-229 and 29400 for F-110-GE-132. +160/+400 lbs difference.
-F-404-GE-402 is quoted as 18000 pound class engine. Its actual full AB thrust is 17700 lbs, or 18100lbs on RM12. -300/+100 lbs difference.
-CF-34-10E is quoted as 20000 pound class engine. Its max thrust is 20360 lbs. +360 difference.
-CF-34-8B is quoted as 14000 pound class engine. Its max thrust is 13790 lbs. -210 difference.
-TF-30-P100 on F-111F is quoted as 25000 pound class engine. Its actual max thrust is 25100 lbs. +100 difference
-F-414 is quoted as 22000 pound class engine. Its actual full AB thrust is exactly that; 22000 lbs.
But somehow, 35000 pound class F-119 engine now produces 38400 lbs? Then why not call it 38000 or 39000 lbs class?
Again, when F-22 is concerned science die, logic is lost, and nonsense propaganda comes into play. 35000 pound class means its ballpark around 35000 lbs. Actual thrust can be 35500, or maybe 34500, but definately NOT 38000+.
AndraxxusWell no official information, following claims are mostly the observations of journalists located at airforce bases, military experts and sources from military but;
-Appearantly, GBU-12 is the most commonly used munition, followed by GBU-10s. However there are several reports claiming the use of NEB, so some of these GBU-10s are quite possibly NEBs with same guidance packages.
-There were also reports of Mk-82 equipped aircraft in 25th and 29th July.
-Newspaper “vatan” cites military sources, confirming usage of bunker busters and continues; “they were particularly effective in hidden armories. In following days, recently developed, even more advanced guided bunker buster bombs, soon added to the inventory of TuAF, will start to be used.”
AndraxxusAn interesting side info about NEB penetrator bomb; its exterior dimensions, CG, inertia are deliberately designed to be similar to Mk-84, so that it is fully compatible with GBU-10B/E or domestic HGK guidance kits, and can be used on any aircraft capable of using Mk-84/GBU-10.
Unfortunately, this also makes it impossible to prove their usage by looking at photos/videos.
AndraxxusDo we know the relative proportion of sorties b/w PKK and ISIS targets ?
Sortie number is unknown, but we can talk about aircraft number to sent to estimate relative proportion:
As of 29 June 2015,
3+11+9 = 23 againist ISIS
9+70+70+25+4+40+30 = 248 againist PKK
AndraxxusIsnt such huge Anti-Ship missile a good target for LR SAM 🙂
If you detonate a fragmentation/continous rod warhead at equal distance lets say 10 meters, a harpoon wouldn’t be more survivable than a P-700 just because its small. However getting a warhead within 10 meters of a M2.5 target is exponentially more difficult than a target flies at M0.8.
Then there is inertia, even if you hit a M2.5 target but not completely destroy it, it will continue its flight for quite a distance.
AndraxxusThe pressure does not rise to increase the thrust. If it did it would move forwards and rearwards. The air moving forwards in the engine would stagnate the gas-flow causing stall and eventually surge. The nozzle expands or contracts the nozzle area, and it does so to meet pressure and velocity conditions. That is normally modulated by turbine pressure.
Excuse me but, if you are so confident about your knowledge about internal workings of the engine, why are you asking in the first place?
A convergent nozzle accelerating the gas-flow to Mn 1.0 still propels the aircraft to Mn 2.27.
No it doesn’t.
That might be an old fashioned Lightning, but the physics remains the same.
If you are talking about english lightning and its rolls royce avro engine, it does have a variable nozzle with divergent section to allow M1.0++ exhaust velocities.
A simple mk1 eyeball inspection can easily prove exhaust velocity is quite supersonic at full AB.
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If you are up there are emprical formulae that gives exhaust pressure by measuring first mach diamond and comparing it to engine outlet diameter. Then use the formula TomcatVIP provided, and 68kg/s mass flow of avon engine, to find the actual exhaust velocity.
So, how does reheat increase the thrust?
Talking about real life engine? In all simplicity, reheat occurs after turbine exit, in exact same fasion as brayton cycle, with two differences. Massflow stays same as dry thrust and max speed at throat is limited to M1.0, heated gas cannot expand inside the engine (unlike the combustion chamber where combustion increase V and T at constant P), so heating is different from combustion chaber that it occurs within same V, but with increasing T and P.
Choked flow = In simplest terms, air cannot be pushed to move faster than M1.0. If nozzle area is reduced further, air will compress inside the nozzle, pressure will increase but speed wont go above M1.0. At exit, this will produce omnidirectional Prandtl-Meyer expansion fans, and wont contribute to the thrust.
On most real life engines, entire afterburner is designed to be inside the choked flow it causes, so that increasing combustion pressure will increase the afterburner efficiency. When this high pressure air enters into divergent nozzle, ideally pressure should equalise with ambient, and all excess pressure would be converted to increasing exhaust velocity.
Andraxxuspilot won’t have to worry abut stall within the selected limit,
Well, technically aircraft is stalled the second it passes its Clmax AOA. First thing pilot -or software- does should do is to bring aircraft back to stall AOA.
and getting the missile aligned with flight path,
This is true, but an F-4E needs much more AOA to match the turn of an F-15. Think about it…
what the pilot complained about was it didnt pitch fast enough to make a flip-up snap-shot,
and lost to much energy for actual maneuvering
That is more related to software IMHO. Technically software is the only thing that can prevent a relaxed stable aircraft from pitch too fast. Eventually these controls will be relaxed, but IMHO its better to be safe than sorry. Turn off such control for a second today, try to pull 2Gs, increased AOA causes negative feedback to increase AOA further, pull 30Gs, die, and break airframe to pieces in the process. It won’t help the program as a whole.
isn’t the F-18 able to turn some where like 30 degree/sec instantaneous at slow speed? or i read the graph wrong?
That chart (chapter 10) is from mission planning section. It is completely unrelated to aircraft performance (in fact it would apply to every aircraft not only F-18E), its a conversion chart which converts bank angle (or G load) and airspeed to rate of turn. Surely F-18 won’t pull 45 deg/s at 120 knots.
In fact, there is nothing concrete about the maneuverability in NFM-200 booklet of F-18E. F-18AC’s manuals are similar: NFM-000 gives basic info, NFM-200 flight performance and NFM-210 gave combat performance data.
We need NFM-210 -or whatever its equivalent is called for F-18E- to get solid maneuverability information, which I don’t have. NFM-200 gives, however, some critical information to validly estimate performance. If you are looking for ITR, its can be simply derived from stall speed graphs, with the assumption that Clmax will stay same with increasing speed.
Weight*G limit*9,8184 = 1/2 * density * Wing area * Clmax * speed^2
F-18E g limit = 7,6;
Weight at 50% fuel = 17868 kg
density at S/L (where its highest, gives highest possible ITR) = 1,225
Wing area = 46,45m2
Clmax = 1,69 (as calculated from stall graph)
gives 166,6 m/s aircraft speed (323,9 knots, ~M0,49). At 7,6Gs this corresponds to 25,43 deg/s max available ITR, for F-18E (You can do THIS conversion with the graph you provided too, this is its purpose).
In fact its not bad, F-16 can’t pull better ITR even at 9Gs, and a MiG-29 can only pull slightly higher 7,86Gs (=26,3 deg/s) at the same speed F-18E reaches 7,6G limit.
BTW the new F-414-GE-400 EPE will increased thrust from 22000 lbs to 26400 lbs, 2 engine will give total 52800 lbs of thurst, a loaded F-18E weight 47000 lbs, so with new engine, it will have T/W of 1.123 at loaded weight
there is no F-18E known or projected to use the “EPE” engine, despite its been offered since 2009, IIRC. I took current F-18E at 39400 lbs which corresponds to 50% fuel and 1,11 T/W. At 50% fuel, F-16 blk 50 has 1,23 and MiG-29A has 1,32 T/W.
AndraxxusAnd if you have only a convergent nozzle, how do you increase the thrust with reheat?
I wrote a more complex answer to these in the past, but to simplify; Whole propulsion system has inlet, engine and nozzle.
-Inlet is simple diffuser for subsonic aircraft.
-supersonic aircraft adds further inlet mechanisms to control shockwaves that ensure air is always subsonic (and preferably at design point) at compressor face.
-Nozzle is convergent if exhaust velocity is below M1.0 when pressure is at 1 atmosphere (at whatever altitude aircraft is). You cannot increase velocity above M1.0 with convergent nozzle.
-As convergent nozzle cannot accelerate air velocity above M1.0, air exits at 1+ atm pressure. So a divergent section is necessary to use this extra pressure to accelerate exhaust veloicty above M1.0+.
As for your question. Reheat is related to “engine” part and has no direct relation to nozzle. Its just another method of increasing air pressure at the engine outlet.
When you see nozzles “expand” or “contract” on modern aircraft. They don’t simply get bigger or smaller. They also change their internal geometry and nozzles switch between Convergent-divergent and convergent-only geometries to meet pressure and velocity conditions of engine, and the environment.
Even with the same engine on same aircraft, what defines “choked flow” at the nozzle throat is also dependent on external pressure, and inlet pressure is dependent on aircraft speed (especially at very low or above transonic speeds). So exact same same dry/wet thrust setting will use different nozzle settings and/or geometries at different speed+altitude combinations.
As for the ongoing AOA discussion? What is the real significance of high AOA capability in dogfight?
And my thoughts about the topic.
-Ability to pull an AOA, Safety at AOA Controllability at AOA and max AOA are all very different things. And assumption of max AOA has to be greater than others may seem logical, but very wrong.
Going from good old Su-27 example.
-Su-27 has the ability to pull 90+ AOA; its negative stability combined with large control surfaces easily allows it.
-Its SAFE to push Su-27 to 90+ deg AOA; as the wings stall, lift vector from wings decrease and aircraft automatically corrects itself to pre-stall conditon. Su-27 is NOT controllable at this AOA however.
-Su-27 is controllable up to 28 deg AOA, which is the stall AOA of wings (including ailerons obviously)
-Su-27’s MAX AOA is 24 degrees, which is the CLmax of the entire aircraft. Above this point lift coefficent starts to decrease.
So when pilot pulls Su-27 to 27 degrees, aircraft is perfectly controllable, but its maneuverability is degraded in both criteria (lift decrease, drag increase). In other words, of the two exact same Su-27Ss, one pulling 24 degrees AOA can turn tighter than one the other pulling 27 degrees, and waste less energy in the process. So unless discussion is about nose pointing to turn weapons axis (which I’ve missed), AOA ability, safety, controllability, limit has zero relationship to actual turning and dogfighting ability of the aircraft.
Su-35’s 35 deg AOA claim is baseless. Su-27’s max AOA is 24, without any changes to its aerodynamics, Su-35 cannot increase this limit. No doubt Su-35 can stay controllable at 0 to 180 AOA due to its TVC engines, and no doubt it will actually have less turn rate than it has at 24 deg AOA.
As for F-18E.
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Taking values in favour of F-18E will yield Clmax = 1,69, which is 5% better than F-16’s slow speed clmax, and 12% improvement over MiG-29A.
Compared to F-16 blk50 and MiG-29A when all are clean at 50% fuel, F-18E has 1% higher wing loading than F-16, and 17% higher wing loading than MiG-29A.
So net result is as this: F-18E has only 4,8% higher ITR than F-16C blk50 at slower speeds. In fact, as speed increases and CAT-1 limits F-16, F-18E will start to have increasingly better ITR (not at slow speeds but at medium speeds, before 7,33G limits hold F-18E back)
F-18E has 4% inferior low speed turn rates than MiG-29A. I don’t doubt F-18E has better controllability at slow speeds, but it definately doesn’t turn better than a good old MiG-29A.
In MiG-29A vs F-18E, the choice is obvious; MiG-29 turns better, has ballpark same T/D and 20% higher T/W. Let F-18E pilot play at high AOAs, I would simply turn inside him at relatively conservative 24 deg AOA and kill him.
Personally I would pick still F-16 over F-18E in any slow dogfight; I wouldn’t care if F-18E could turn 9 deg/s instead of my F-16’s 8,6 deg/s at same airspeed, and would use F-16C 10% better T/W and quite possibly better T/D to make vertical maneuvers he can’t follow.
AndraxxusThis forum has degenerated into an adolescent/comical discussion of kinematics, especially d!ck-waving with respect to kinematics of air-to-air.
Threads title is [test pilot: “F-35 can’t dogfight”]. Really, what else were you expecting other than kinematics?
In fact, kinematics are the SOLE discussion topic of this thread, and all the horsesh!t about some techno-magical equipment claimed to be all seeing all hearing, is both nonsense, and irrelevant.
F-22 provides better combat effectiveness by staying on station using SA and stealth to ambush opponents than dash to-and-fro in supercruise. But one thing remains true: if you merge, you are doing it wrong because everybody dies in a furball. Helmet mounted sights and dogfight missiles assure mutual destruction.
Talk about adolescent/comical.. AWACS backed F-15s couldn’t prevent dogfighting with MiG-29s, nor MiG-25s couldn’t avoid dogfight with F-15s. These aircraft can see each other from 150+ km away. Two VLO aircraft cannot see each other from half that distance. How on earth one can really believe a VLO vs VLO engagement will occur at even longer ranges, and end long before WVR…
AndraxxusProbably with kinematics he means not just speed but the sum of it, climb rate and acceleration.
He means mk1 eyeball inspection, and guestimates of the aircraft which supposedly prioritize and improve “kinematics”. Which obviously include mixture of ITR, STR, climb rate, range, acceleration, top speed. I’ve made my T/W T/D guestimates regarding F-22 and F-15 a few pages ago, I am open to explainations to contrary.
As for climb… Historically, every generation of fighter had numerous record breakers. On US side, 1st gen F-86, 2nd gen F-106, 3rd gen F-4 and 4th gen F-15; all broke records of previous aircraft by a great margin, until F-22. Doesn’t it look REAL odd? F-15 and Su-27 are still the most recent record breakers in climb rate. Where is F-22?
a)Is it so secret that, despite the unquestionable capability of taking the records back from Russians, they are not revealing it?? -BS, I don’t buy it. SR-71 was way more secret than F-22, it has its own share of speed records.
b)Is it too new to be declassified? -No, F-4A made its climb records 2 years into service. F-15 broke several time-to-climb records 1 year prior to active service. Were they not just as “classified” back then?
c)F-22 has too few airframes for participating such events? -No, all F-4, F-15, Su-27, MiG-25 etc etc record breakers were derived from prototypes. Not one airframe wasted from operational service. In fact, F-22 had 8 prototypes in total, more than what MiG-25 had when it started record braking flights.
If F-22 was half the people claimed, it would have at least tried to break some of these world records, we would have seen something in these 10 long years in service.
Andraxxusi dont know exactly how powerful the transmitting power of data link is
what i know is aircraft can guide their missiles by datalinks all the way to target, if the data link is powerful enough for the receiver antenna on missiles to received and use the information, the RWR should be able to detect it too ( of course background noise could be a problem, but i guess they can get around that with better software to find some characteristics of data link that background noise doesn’t have)
Well numbers are everything, only difference between magnetron in microwave oven and a transmitter of over-the-horizon radar is just 3 numbers.
-A GPS sattelite transmits 25,6 watts on 13dbi antenna. A cell phone can track 3+ satelites 20200+ km distance with a 0,5 watt reciever.
-Longer ranged “walkie-talkie” two-way radios can communicate at 50km distance with 1,5 watt transmitter/reciever.
-Typical fighter radar sets operate between 5000 watts to 600000 watts (MiG-25).
-Each T/R module of APG-77 radar is 10+ watts peak.
In an analogy, you are trying to detect the mentioned “walkie-talkie” with a Radar or RWR. With 15% power of a single T/R module, neither Radar nor RWR will discriminate it from background noise from 50 meters, but a specialized SIGINT/COMINT aircraft can not just detect but can listen-in such walkie-talkie from quite a distance.
I believe datalinks’ power outputs are much more comperable to GPS or radio transmitters than radars.
i dont think they would spend money and time to make stealth datalinks if it doesn’t bring any benefits
I never said it doesn’t bring any benefits. In a theoratical WW3 againist Russia today, it would be quite stupid if a Balzam or Vishniya type ship could triangulate an F-22/35 from 200 km away, just because pilot made a radio call, or he didn’t turn of his continiously transmitting datalink. And it would be equally stupid and suicidal to send a few F-22s into dense ECM environment patrolled by several Su-27s without an external source to improve SA, either. So a passive link-16 is a stopgap, but a proper datalink is still a must in the long run.
That, however, doesn’t matter if your adversary doesn’t have signal intelligence platforms in the area, which is pretty few even in RuAF and USAF. In same analogy, a Slava class won’t detect link-16 like a Balzam class does, despite the numerous and superior ESM and EW equipment and two 3D track/scan radars the cruiser possess.
Andraxxus, it was a demonstration. the 5th to 4th and 5th to 5th program is some time away and is open for all competitors to come in with their solution. The F-22 at the moment, has IFDL for LPI directional data communication, and a receive only Link-16 for receiving data from other platforms. The F-35 has the MADL for communicating with other F-35’s in a discreet fashion and has the L16 (both receive and send) for communicating with the legacy fleet in a non-stealthy fashion.
At one point there was a plan to install MADL on the F-22 and B-2 fleet but it appears to have been dropped. A long term solution for 5th to 4th will be developed in the medium term and I guess a 5th to 5th solution will also follow. MADL and IFDL are what each platform uses as the best way to communicate discreetly.
Ok, I stand corrected about F-22 will not transmit link-16, but my point stands, I think its not well understood:
Running simulation in command lets say 4x F-35 vs 4x good old Su-27S.
-F-35 has super-duper high tech stealthy MADL intra-fighter datalink and link-16 for off-board information.
-Su-27 has good old TKS-2 for intra-fighter and Laszlo/Lazur datalinks for off-board data feed.
-F-35 has NO means to detect TKS-2, Laszlo Lazur datalinks, let alone track/classify/listen-in/decrypt, and use it to pinpoint targets.
-Su-27 has no means to detect MADL; it also has NO means to detect link-16 too.
So what difference does it make for such scenario? A big zero. Then how does T-50 or Su-35 DO fall in disadvantage, because their -yet unknown- datalinks are assumed not stealthy? This translates as nonsense to me.
With current technological development, there wont be a tiny DAS or RWR sized equipment to provide a means to track datalinks in any forseeable future, so it has no relevance in any fighter vs fighter scenario.
BTW, which part of the F-22, PAK-FA or J-20 does not seem to be focused on kinematics, in your books?
Although not directly asked to me, I would ask the opposite; Which part of F-22, PAK-FA or J-20 makes you think that they are focused on kinematics?
F-22? I put the numbers, maybe true maybe not. No single data to indicate it will clearly outperform F-15C in any area sufficent to make a difference.
PAK-FA? A definate no with current engines. It needs the mentioned 170+kN engines to significantly surpass Su-27S’s kinematics.
J-20? Most definately not when compared to J-11. No planned/desired ~150 kN engine will make a difference unless the aircraft actually weigh some 17 tons empty.
AndraxxusThe F-22 has a receive-only Link-16. It receives information, but does not transmit. This has proven to be a headache in some cases because the F-22 pilots will know something that they can only relay via voice transmission.
Dated March 2014:
http://aviationweek.com/awin/lockheed-s-secret-project-missouri-links-f-22-f-35
AndraxxusClearly the Pentagon believes this is a very real risk given the lengths they have gone to to replace Link-16 with less detectable datalinks.
On the contrary, they put link-16 on F-22, because without it, it couldn’t operate in any operation USAF did around the world. So now what, F-22 is no stealth because it transmits link-16?
The F-35 was also designed from the start as a multi-role fighter with an 8k hour airframe life and an incredibly extensive avionics fit. It is essentially already at the F-15E stage of the F-15’s evolution.
Certainly it will gain weight along the way, but I don’t expect it to gain nearly as much as the F-15 and F-16 did when they moved from their initial models to the current versions.
Well, I am sure some one said same thing about F-15A like “Its has incredibly extensive avionics, superb maneuverability which is far better than F-4E’s level and will never need to get any heavier”. Surely F-35 will need many new features which we cannot imagine right now.
AndraxxusDatalink signals for all of those systems are omni-directional (usually L-band) radio signals. While some offer jam resistance by spreading signals over a frequency range, they are all most certainly detectable by ESM equipment capable of detecting in sub 2GHz range.
Stealth data link are datalinks at high frequency, directional precise beam thus they are harder to detect by RWR, by contrast, normal datalinks are omnidirectional, thus they are alot easier to be detected, of course RWR won’t allow pin point geolocation of aircraft, but it still give you general direction of them
Ok, name one RWR system mounted on ANY fighter capable of such? Currently, only few specialized ELINT aircraft can detect and listen such datalinks, and many times you see those aircraft skim the territorial airspace (~21 km) to get closer to signal and still, they are not always succesful. Somehow I don’t think you can shrink such equipment by 200 times in size, make it 20 times more powerful (so that range will extend to 40+ km) and make it several times more reliable, then put several of them on the aircraft to have omni directional coverage (which even dedicated ELINT aircraft or even ships lack).
You are completely ignoring the “transmit power” of the equation and the processing power. Theory is good, but in theory Wifi, microwave ovens or cheap walkie talkies also operate at 2.4 GHz range. Just like these, datalinks have insufficent transmit power to ping a RWR. Even if one makes the RWR capable, it needs supercomputer level processing power to discriminate from other noise sources.
Intraflight comms such as voice comms or datalink transmissions such as position updates, fuel states, SAR images, track data will all produce a signal intermittently which can be tracked by receivers built for the task.
You are talking about dedicated signal intelligance ships, and Boeing 737 sized aircraft.
The issue is significantly worse with most TKS-2 comms as the throughput of TKS-2 is a max of only 4kbps compared to 120+kbps for typical NATO standards. TKS-2 needs to “talk” for a comparatively long period of time to transfer data.
IFDL and MADL use high frequency, short range, very low sidelobe, high gain, directional signals to prevent the enemy from ever receiving the signal sent between members of the flight.
You don’t know power output of TKS-2 vs Link-16, or WHAT they are transmitting. Nor TKS-2’s range, its transmitter positioning and individual power output, reciever’s threshold power, the probability of detection at given range/angle, etc compared to “stealth” datalinks. Just like every assumption your “accurate simulator” makes about F-35, Su-35 and T-50, they are all baseless.
but ADVENT engine also improve fuel consumption of F-35 by 25%, wouldn’t that counter the weight gain of avionics?
F-35 internal fuel capacity is around 18498 pounds, so reduce 25% fuel load needed is around 4624 pounds decrease
As far as I know, ADVENT is neither funded, nor developed for upgrading F-135 engines. Its a new engine, and Pratt Whitney is NOT a contractor. 15% thrust increase was claimed by original engine builder and part of AETD, so I take its much more realistic. Saying goal of ADVENT is to drop fuel consumption by 25%, is talking about expectations of an nonexisting engine; compared to a non-specified engine.
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