FBW: you have repeatedly claim F-35 out-perform an F-16 with a belly tank,
now we have the underpowered F-16D block 40 with not one but two external tanks,
from Andraxuss :
an F-16 with 50% fuel and 2 empty fuel tank can defeat a clean Su-27 with 100% fuel.
For F-16 drag index of each 370Gal without any other stores in nearby pylons is 27; 2×27+7(Basic F-16C drag index), so total drag index = 61.
-At DI=50 at 25000lbs, F-16 could still sustain ~18,6deg/s STR, have ~23,2 deg/s ITR, and have 800+fps climb rate.
-At DI=100 at 25000lbs, F-16 could still sustain ~18,4 deg/s STR, have ~23,1 deg/s ITR, and have 800+fps climb rate.
. A Su-27S at full fuel load is limited to 6,65Gs, so turn rate at 500 KTAS will be around 14,7 deg/s, limited by G load
in every last one of the 17 engagements, and i quote:
“the F-3SA remained at a distinct energy disadvantage for every engagement.”
here is what the pilot said
First of all way too much is being made of this test and some players are taking things seriously out of context to grind axes. So, what is of primary importance is to understand what the test objectives were. The FLTS’s out at Edwards don’t fly unless they have a clear objective to gather technical data, that’s what Developmental Test is all about. So, what were the objectives? From the report
OBJECTIVE
The test was designed to stress the high AoA control laws during operationally representative
maneuvers utilizing elevated AoAs and aggressive stick/pedal inputs The evaluation focused on the
overall effectiveness of the aircraft in performing various specified maneuvers in a dynamic
environment. This consisted of traditional Basic Fighter Maneuvers in offensive, defensive, and neutral
setups at altitudes ranging from 10,000 to 30,000 feet MSL. The Flying Qualities criteria were that the
aircraft response would be positive and predictable and that there should be no undesired, unexpected,
or unpredictable aircraft responses. Qualitative observations were made regarding the high AoA
capability, cues that the aircraft was entering a low energy state, as well as various human factors
considerations.Please note that the object wasn’t to see how the F-35 stacked up to the Viper as a dogfight, rather it was to press the limits of the high AoA control laws and then report out the flying qualities in that regime, using various specified maneuvers. The Viper was there to make things dynamic and unscripted. Also, please note “elevated AoAs and aggressive stick/pedal inputs” are also preludes to departing an aircraft, so the evaluation of the effectiveness was how does the anti-spin logic effect high AoA BFM. Of course that’s exactly what the JPO statement said.
The tests cited in the article were done earlier this year to test the flying qualities of the F-35 using visual combat maneuvers to stress the system, and the F-16 involved was used as a visual reference to maneuver against
Next take a look at the setups
MISSION EXECUTION
The sortie consisted of standard administration to the Sea Test Range. Ranging exercises were
conducted to familiarize the target aircraft with F-35 visual cues. An offensive capture/tracking task was
completed by the F-35 from 6,000 feet slant range with a 3,000 foot vertical offset at 22,000′ MSl and
400 kts. All other testing consisted of traditional BFM setups starting at 22,000′ MSL and 440 kts for 6K
and 9K fights and 20,000′ MSl at 380 kts for 3K fights. The neutral fights began at approximately
18,000′ to 20,000′ with no limitations on airspeed or altitude following the check away. The floor was
10,000′ MSL. In all, there were seventeen engagements. No loads or other aircraft limits were
exceeded with unrestricted throttle, stick, and rudder inputs.All I have handy right now are the Block 50/52 performance charts, but they’re close enough to the 40 to show that the 3K, 6K and 9K setups are right at the sweet spots of the Viper’s performance.
Two 370’s Drag Index 70
22,000′ MSL 440 KCAS is 0.96M
20,000′ MSL 380 KCAS is 0.81M
Note assuming KCAS not KTAS since that’s what displays in the HUD and the EM chart below
Puts things in perspective here. So, the Viper was flying right around it’s corner and max instantaneous, while the F-35 was supposed to go elevated AoA and see if the control laws would prevent the plane from departing when performing elevated AoA BFM. The Viper was at a clear advantage all along, but it wasn’t there to win, it was there as a visual reference to maneuver against. The whole point was to put the F-35 in a bad position and see what the control laws did. Which is exactly what the JPO said.While the dogfighting scenario was successful in showing the ability of the F-35 to maneuver to the edge of its limits without exceeding them, and handle in a positive and predictable manner, the interpretation of the scenario results could be misleading.
Turns out the early law are biased towards departure prevention(not a bad thing early in a program), not exactly an Earth shattering discovery, and that there’s plenty of margin available to improve performance, again not exactly Earth shattering. At least a sizable subset of these critics aren’t old enough to remember that the first wave of FBW A/C went through similar cycle or didn’t pay attention/forgot that Super Bug and Raptor did also.
Now with the critic’s original argument discredited they take something else out of context…Wash, lather, repeat, the cycle continues. They’re always certain their right but curiously avoid making a stand in the face of a rigorous technical argument.
Either you count the sensitivity based on thermal noise threshold in which case both radar receivers and RWR will exhibit the same limit at ~-120 dB (ok, small advantage to the radar receiver LNA as it can be tuned to a smaller band but we’re talking a couple of dB max).
Or you count the sensitivity including the processing gain in which case the radar will get a 30-40dB advantage depending on the amount of spectrum spreading done (typically from 10kHz to 1 MHz or more, giving 30+dB). But then you can’t count any gain due to the signal coding ’cause it’s already included!
Radar have advantage that it is directional while RWR have to cover 360 degree around, radar know what frequency it send out and what frequency to listen to and in general most radar work in very narrow frequency range while RWR have to cover wide range of frequency thus will be alot less sensitive, that can give radar 30-40 dB gain advantage depending on radar type
Radar can code or modulate the signal so that it achieves significant processing gain over RWR. Either phase or frequency modulation/coding can be used. As radar knows the coding, it can filter out the signal from noise using matched filters. The RWR can’t know the coding and this gives the radar another big advantage in total gain ( could be around 70 dB)
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Actually scan time is a function of the beam width, AESA makes it possible to achieve much narrower beams if needed but this results in longer scan times…
FYI, 3s is the time if takes an APG-68 to perform a 120°x4.9° field. Scanning the whole FoV will take upward of a minute. Reposition of the dish takes 17% of the time so moving to an AESA reduces scan time by 17% at most
Reposition the dish take more than 17% of the time, Normally radar divided it’s FoV in to several horizontal bar, then start scan bar left to right, after finishing the 1 bar the antenna shifts down to the secondary bar and scans from right to left… etc and so on, depending on the beam width and the steering rate of the dish the time scanning each bar is different, but saying repositioning the dish only took 17% of total scan time is wrong, since the dish have to steer to scan each bar, and it also have to shift down/up for the next bar
Scan time is the function of [ ( total FoV) / beam width ] / steering rate of the beam. And unlike mechanical radar, AESA can steer it’s beam at much faster rate
active electronic beam scanning — which allows the radar beam to be steered at nearly the speed of light
http://www.raytheon.com/capabilities/products/apg79aesa/
another advantage of AESA/PESA over mechanical radar is that they have instantaneous target revisiting mode for tracking
To sum up, modern RWR are about improving the pilot situation awareness, giving him the information needed to avoid the threat or to engage it and cueing other sensors (passive or not) to get positive ID and a firing solution if needed.
yes RWR improve situation awareness, cue other sensors like radar or IRST, geolocate ground SAM.. etc but many people have the wrong idea that as long as an aircraft have a modern RWR then it’s RCS and radar power doesn’t matter anymore
Unless the two aircraft are literally on a head on collision, range will become obvious with one slight turn
it already determined in the research paper what is the turn you would need to measure range, range willnot be obvious with one slight turn because the change in bearing over time will be affected by both the velocity, heading and distance to enemy, a closer enemy moving at slow speed will have similar change in bearing if he was far aways and move at high speed , and since you are trying to determined range to a moving object at unknow range, the slighter turn you take, the longer it will take to measure range, and the more error you will have since the range is only guesstimate from the change in bearing, and that haven’t take into account that enemy may change heading, speed or altitude either and if the enemy turn their radar on and off while the data are being taken for the measurements then everything will be messed up
a couple of “paints” by the target aircraft radar.
if you want to paint enemy’s with your radar to determine range then obviously Stealth aircraft have significant advantage here
Hence why any modern RWR has to have resolution of ~1deg.
the experiment in the research paper used an IRST to passive measures range, IRST are known to have much better angular resolution compared to radar, ( and radar are known to have better angular resolution compared to RWR) , and it still take significant time to measuring range and the measurements still have significant error in term of range
You make it out as if the pilot is sitting there with a pen, paper and calculator.
no, measurement could be done by software
, but given how much earlier RWR detects radar relative to radar detecting passive aircraft, in itself this is not an issue.
.
in theory RWR only have to listen to signal that travel one way, thus giving them 80 dB advantage compared to radar that have to detect reflected signal that travelling 2 ways, because of that in theory aircraft carry RWR should be able to detect Radar twice the range the radar can detect them if 2 side have equal sensitivity . In real life radar could be alot more sensitive than RWR because they have better gain . Here are reason why radar antenna have better gain :
1. RWR antenna typically has a gain of about 0 dB due to wide angular coverage. Fighter AESA radar has a gain of roughly 40 dB. This means instant 40 dB advantage to the radar.
2. Radar can operate at much narrower bandwidth as it knows the frequencies it uses and RWR does not and has to operate at much wider bandwidth. RWR receivers have a sensitivity in the region of -40 to -60 dB while radar receivers have a sensitivity is roughly about -100 dB with digital receivers achieving even better sensitivity like -120 dB.
This can give additional 50 to 80 dB advantage to radar depending on exact design of the systems involved. As AESA has a very wide total bandwidth, RWR must cover that very wide bandwidth leading to much less sensitivity. As the radar signal has a quite narrow bandwidth and radar can process only very narrow bandwidth giving large advantage in sensitivity. For AESA the advantage can be for example in the 60 to 80 dB range.
3. Radar can code or modulate the signal so that it achieves significant processing gain over RWR. Either phase or frequency modulation/coding can be used. As radar knows the coding, it can filter out the signal from noise using matched filters. The RWR can’t know the coding and this gives the radar another big advantage in total gain. This is called Processing gain and it can be tens of decibels. The more complex the coding the larger the processing gain of radar is. Modern AESA radar using Digital Beamforming can use very complex coding schemes and basically only processing power and software is the limit here. A simple calculation about processing gain is dividing the spreading bandwidth (bandwidth where the signal is spread) with actual signal bandwidth.
4. When the radar main beam is not directly pointing towards the RWR, then it will only be seen through sidelobes. Given that sidelobe level can be lower than -50 dB in AESA radars (about -20 to -30 dB in fighter MSA/PESA radars), this gives the radar a healthy advantage against RWR/ESM systems which it’s not painting. This means RWR will only see very short flashes of main beam and makes it more difficult for the RWR to work effectively.
Calculated together, radar can suddenly have well over 100 dB advantage over RWR system through mainlobe and over 150 dB advantage otherwise. There are ways for RWR/ESM systems to get some of that back and of course the race is never ending. RWR/ESM system can use more directional antenna, more sensitive receivers and higher processing power.
Another problem is side aspect RCS of any aircraft are alot higher than head on RCS , especially the non stealthy one, the moment they try to turn to measure range passively they will shine bright on the radar
Before this discussion goes further, I need to reinforce 1 point:
LPI radar is not magic. It won’t always work against modern digital RWR.
http://www.artechhouse.co.uk/International/books.aspx?iid=978-1-59693-234-0
http://www.ijetae.com/files/Volume2Issue9/IJETAE_0912_76.pdf
These are all public domain. BAe, Thales etc are all 5-10 years ahead of this. i.e.
https://www.rusi.org/downloads/assets/WHR_1-15_Maximising_European_Combat_Air_Power.pdf
whether RWR can detect AESA radar or not depending alot on software, sensitivity of that particular RWR and AESA radar, another problem is the range that a RWR can detect an AESA radar, that is very important, one can claim Mig-21’s radar can detect B-2, F-22 or F-35 and that would still be true, however quite irrelevant since the distance is too short to give any tactical advantage.
I would also want to stress that in multi ship engagement, you can data links several aircraft together, fusing their information, in that case RWR can measure range to an air target ( by triangulate between multiple aircraft ) and allow a missiles launch, however in multi ship engagement enemy can also datalink their aircraft and letting only 1 aircraft transmitting ( that aircraft could be an AWACs) thus using RWR only in that case will put you in serious trouble
in single ship engagement ( 1 vs 1) even if your RWR, ESM system managed to detect enemy fighter’s AESA radar, the only thing you know is bearing, it very hard to measure range for a missiles launch solution . Geolocated enemy aircraft by ESM, RWR is alot harder than geolocated ground target
First let see how a modern RWR, ELINT can geolocate a ground radar to generate fire solution for anti radar missiles :
there are 6 ways:
however you cant really use most of them to geolocated an aircraft
here is why :
1- single ship triangulation method required target to be stationary , and take very long time
2- Azimuth / Elevation method will not work because you dont know enemy fighter altitude ( for a ground target you know the altitude is 0 ) thus cant use the Sine and Cosine function to work out the distance to target
3 – Time different arrival method required at least 3 aircraft stay at significant distance from the other ,but doesnt work well again AESA radar due to it very small side lobe , and thin beam, it also required many aircraft working together
4- determine distance by signal strength : required to threat radar characteristic to be known , and still doesnt work again modern AESA radar because they can managed transmitting power at short range to reduce probably of detection
there are some 2 additional methods to determine distance by RWR included :
5- phase rate change
6- RF doppler processing
they can be used again enemy’s aircraft, using quite similar principles, will be discussed in the paper bellow :
http://subs.emis.de/LNI/Proceedings/Proceedings154/gi-proc-154-222.pdf
http://users.isy.liu.se/en/rt/fredrik/reports/05bearingsonly.pdf
As you can see the method have many requirements such as
1) enemy’s fighter fly at constant speed the whole time
2) enemy’s fighter doesn’t change heading the whole time ( the method measures range by calculate the changing of bearing between enemy fighter and ELINT aircraft when ELINT aircraft fly side to side ” zic zack pattern” , thus it wouldn’t be possible to apply the method if enemy fighter change heading and point their nose to ELINT aircraft direction all the time)
3)enemy’s fighter will constantly emitting for the whole time needed for ELINT aircraft to measure range :
4) ELINT aircraft have to perform specific maneuver for a period of times to measure range
5) Accuracy is terrible , 20-40% error in range is very significant, at 100 km distance that is 20 – 40 km error, at 50 km distance that still 10-20 km error, that is even worse than long wave VHF radar thus not very useful for long range BVR engagement again enemy’s fighter
How to counter RWR passive ranging :
let call the aircraft carry RWR sensor : ELINT aircraft
Method 1:
To collect data for range measurement the ELINT aircraft must fly zigzag side to side to measure change in bearing , thus showing it’s side aspect RCS to enemy’s radar. And the S maneuver will only work if the enemy fighter fly straight and doesn’t change their heading, fly at constant speed.
remember that side aspect RCS of any aircraft is very high (often in the range 20-30 dBsm or 100-1000 m2) , so the ELINT aircraft if wasn’t detected by enemy radar earlier will be detected the moment it perform the S shape maneuver. Since most aircraft radar nowadays have no trouble tracking airborne target with RCS =100-1000 m2 from 300-400 km
So after detecting the ELINT aircraft, all enemy pilot have to do is changing their heading according to the heading of ELINT aircraft ( if the ELINT aircraft turn left, you turn left, if the ELINT aircraft turn right, you turn right, accelerate or decelerate to make your speed not constant)
that action will neutralise ELINT aircraft passive ranging ability
Method 2 :
alot more simple, since the ELINT aircraft take at least 15 seconds of constant receiving enemy’s radar signal to measure range with error about 25-40%, if enemy’s pilot turn their radar on and off constantly, the ELINT aircraft wont be able to measure range in that case
modern AESA take 2-3 sec to scan it’s whole FoV so you can turn radar on for 2 seconds and then off for 10 seconds then on again
and still have good tracking of target
=> to sum up, RWR cannot replace Radar in air to air BVR engagement ( whether it is multi ship or single ship engagement) because they are alot more time consuming, less accurate, easily be neutralise by enemy tactics
That has never come out in anything but rumour.
Rumours to the opposite have come out too, but they are dubious aswell.
not heard of rumours that Rafale, Eurofighter beat F-22 in BVR
, all kill claim again F-22 has been WVR
According to SAAB ( fighter producer that isn’t related to USAF or LM at all) , F-22, F-35 are much better than Typhoon, Rafale
According to USAF simulation
September 20, 2008 U.S. Air Force analyses show the Lockheed Martin F-35 Lightning II is at least 400 percent more effective in air-to-air combat capability than the best fighters currently available in the international market.
.
According to LM simulation :
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re. the upgrades, no not really. USAF -16s and -15s are by and by large vintage stuff.
No, they get upgraded alot, arguably lots more than other air force
Antiquated RWR,
i dont know about F-15 but F-16CJ use ASQ-213 ( r7) , which is highly accurate digital RWR that can support both HARM and GPS weapons
ancient radar
APG-63v3 is arguably the most powerful AESA radar on fighter nowadays
what does F-22 dominance over F-16 got to do with F-35 anyway ?
F-22 dominance over F-15, F-16 is mainly from stealth and SA
by the looks of it F-22>F-16>F-35,
well now that i wrote it i got the point, F-22 is going to defend F-35
iam gonna re quote Andraxxus for you :
As a numbers guy, I am really curious about WHY F-35 is called bad, F-15/16 good, and F-22 phenomenal.. All F-22 lovers may trash my post all they want but;
Comparing F-15E vs F-22 and F-16C vs F-35A;
F-35 has 146,2% empty weight of F-16C.
F-22 has 138,1% empty weight of F-15E.Wing area linearly contributes to drag, and Thrust directly counters the drag.
F-22 has 138% wing area of F-15E. It also has 121% Thrust.
F-35 has 153% wing area of F-16C. It also has 146% Thrust.In thrust/drag department, all else being the equal (I am not saying it is, just making a point), F-35 is 4% inferior to F-16, and F-22 is 12% inferior to F-15E.
At their empty weights;
F-35 has 99,8% T/W of F-16C.
F-22 has 87,8% T/W of F-15E.F-35 has 95,4% Wing Loading of F-16C
F-22 has 99,7% Wing Loading of F-15E.Now I generated a term equalised fuel, based on aircraft’s SFC and Cd are all the same, wing area alone will dictate thrust is required to move the aircraft, and this thrust will be directly proportional to range. ie, if F-16C carries 27,87*X amount of fuel, F-35 will need 42,7*X, because its more draggy. Taking X=50, at this equalised weight;
F-35 has 99,1% T/W of F-16C
F-22 has 87,7% T/W of F-15E.F-35 has 96% Wing Loading of F-16C.
F-22 has 99,8 Wing Loading of F-15E.*I assumed F-22’s engine thrust to be 156kN. If anyone has better value I can input that, but I must say, F-22 needs 177,8 kN thrust from each engine to match F-15E’s T/W.
Heres the table;
Now according to these values, F-35 is much more closer to F-16 than F-22 is to F-15. Any assumption due to advances in technology (improved aerodynamics, improved SFC) that may benefit F-22 would F-35 even more.
Its true that F-35 looks ugly as sh!t, and F-22 is cool and looks more aerodynamic, but on numbers alone, it doesn’t give one reason WHY F-35 is underpowered, (it fares just as well as F-16, far better than F-22), or unmaneuverable (Very similar wingloadings and general layout and features).
On the contrary, F-22 looks clearly underpowered when compared to F-15E. Though addition of several aerodynamic features (negative stability, LE flaps etc) would offset this disadvantage, its important to remember F-35 has them too.
My point? Every claim about F-35 cannot dogfight (based on its heavy, or underpowered or have small wings) must also apply to F-22; either that or this claim is wrong.
To make F-22’s T/D equal with F-15E, either Cd curve or dynamic thrust must be improved by 15%. That is where all “simplifications” come in, so lets count them all;
Thrust:
1- a fixed inlet can never exceed a variable inlet. It may -at best- closely match it for a very limited part of the envelope.
2- Boilerplate exhausts have far greater losses, compared to round exhaust.
3- F-100 has lower bypass ratio than F-119, so higher % of thrust retained at high altitude.
Drag:
4-F-22 is newer design, so advancements like CFD should improve Cd0
5-F-22 has VLO considerations whereas F-15E is solely designed to be aerodynamic.
6-F-22 is negative stable F-15E is not.
7-Thrust vectoring may assist in trim, but may also have little or no effect at all.
8-F-22 has LE flaps so drag while maneuvering would decrease, and lift at hard turns increase.That is 4 vs 4, with most important ones being 1,2,6,8 its 2 vs 2. So speaking of features doesn’t look very bright for F-22 is it?
Speaking of features like my F-15/F-22 post.
-Both F-35 and F-16 blk50 have same wing loading
-Both F-35 and F-16 blk50 have same T/D assuming Cd0 and inlet performance is the same.
-Both F-35 and F-16 blk50 have same T/W assuming inlet performance is same.
-F-35 has DSI F-16 has fixed pitot inlet. By all reports, there was slight performance increse when DSI is tested on F-16.
-GE-132 has lower bypass so it should work better than F-135 at high altitude.
-Both aircraft have negative stability.
-Both aircraft have LE flaps, but F-35’s TE flaperons are way larger and Flybywire algorithms improved.
-F-35 is 25+ years newer so cd diagram should improve.
-F-35 has VLO concerns, F-16 is pure aerodynamic.All in all, there is nothing to indicate F-35 should perform any worse than F-16 but people are clearly convinced it is *significantly* worse. (while on the contrary F-22 has IMO clear indications that makes it worse than F-15E, people have no problem believing F-22 is much better).
Well my 0.02; There is just too much propoganda and assumptions with all the new aircraft. I don’t believe there is significant kinematic difference between 4th 4.5th and 5th gen aircraft. The problem is in the internet, one writes a report from his rear end. Another copies it, and another, and as a result it becomes the truth. And whats worse, if something is repeated too much by too many people, any indication to contrary is also rejected. Only undeniable hard proof will convince most (and even then, not all).
The consensus about F-22 is that its very good. All the indications to contrary (that its repeatedly defeated in BFM, its airshow turn/climb rates suck, and numeric guestimates) is merely ignored, or “disproven” by another copy of a copied report.
The consensus about F-35 is that its very bad. All the indications to contrary (numeric guesses and aerodynamic feature list) and the lack of evidence (F-35 is not tested, not in service, and not seen maneuvering in airshows) is ignored or disproven by “hot air”.And worse, F-22’s alleged performance is now used as a benchmark to trash talk F-35 further. All logic fails there.
You know not long ago (10 years), every USAF guy and their devoted forum people were claiming Su-27 can only maneuver in airshows, and its maneuverability was real bad when armed. Even 3-4 years ago people, including some in this forum, were claiming Su-27 can only make sharp turns not sustain them. Half were only to be convinced by airshow videos and flight manual data, other half just quietly disappeared. And now, all the talk about F-22 or F-35? They are all to be proven wrong like these.
Both F-15A and F-16A demonstrated 24 deg/s turn in airshows, MiG-29A demonstrated 23deg/s and Su-27S demonstrated 26deg/s; all sustained for full 360 degree circle and within a few years into service. Note that those are ABOVE their 50% fuel STR rates (as they carry minimal fuel). If they are SO good, where are Typhoon, F-22 or Rafale videos? 10-14 years into service, and not one exceeded 18-19 deg/s. Technically an F-4E with minimal airshow fuel loadout can do 18 deg/s too. My point? If we are questioning manufacturer claims, and looking proof of high maneuverability, there are WAY more questionable aircraft around than F-35.
Depends on what engine goes into it, but shape wise J-20 is second only to F-106 as a supercruiser
http://history.nasa.gov/SP-367/fig91.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/3/33/Sears-Haack.png/220px-Sears-Haack.png
shape wise Mirage look like a better Supercruiser than mig-31
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