By: Starfish Prime
- 19th September 2016 at 16:27Permalink- Edited 1st January 1970 at 01:00
The evaluation was not a "turn contest". The performance was based on DCA/OCA missions. For instance, the Gripen scored poorly on a interception mission profile. Climb rate, cruise speed/distance, acceleration at altitude, etc. All figured into scores.
That is because the EJ2000 is rated at 20,250 lbs of thrust, that is slightly greater than 90kN.
Effective wing area at increased g and angle of attack is not as simple as comparing nominal wing area. Lift coefficient at increased bank angle and aoa cannot be predicted by simply comparing wing area. Vortex generation, flow separation characteristics are not easy to predict.
Oversimplification, the F-104 was a tube with wings, again blended wing and body designs with significant (and increasing proportion of body lift as bank angle increases). As you point out LERX vs. non- LERX wings do not perform the same. The LERX will give high Cl and higher Cl max.
Up to what altitude? what model of F-16 were they comparing, MLU? That would not be surprising. You're making a large number of generalizations that don't even answer what andraxxus was pointing out.
A/C Performance covered everything, including those things and turn performance. And the Typhoon came out 30% ahead of a Rafale.
Nah, that's just approximated based on dry thrust + 50%. If you look about most fighters on reheat increase by more than 50%. E.g. F414, lower dry thrust, higher wet thrust. And that's before WEP.;)
And if the two figures were anything like close I would agree but they ain't and the canards tend to help in that respect anyway. They're not remotely close. 63 vs 85lb/ft^2 even with the Ef at 32% fuel fraction and the Su-35 at 25%. Put them on the same fuel fraction and it's 63 vs 90lb/ft^2 and 1.2 vs 1.07 TWR.
So compare the F-104 to other fighters of that era like the MiG-21. That was also a tube with wings but massively superior in turn performance.
And high Cl will increase drag, so it's damned on two fronts.
What he's pointing out is a mile wide of the mark and rough calculations really are all that's required here given the size of the differences AND crucially all we're able to do with the figures available. There is simply no way an Su-35 can beat a Typhoon in STR unless it has about 1.5 times the Cl but somehow 20% less drag at that Cl even though the drag increases with the square of that Cl. And using a comparison of a 10 year newer design (1985) against an older design (1976) to prove something about a 18 year older design (1985) against a newer design (2003) is just silly.
By: FBW
- 19th September 2016 at 19:13Permalink- Edited 1st January 1970 at 01:00
A/C Performance covered everything, including those things and turn performance. And the Typhoon came out 30% ahead of a Rafale.
I've read the report multiple times. There is NOTHING about specific performance numbers. The performance based on the OCA/DCA mission performance. It does not mean that the Typhoon has superior turn performance, nor does it mean inferior. Simply put, there is nothing to support either in the Swiss Eval, except that the overall aircraft performance on the missions was superior.
Nah, that's just approximated based on dry thrust + 50%. If you look about most fighters on reheat increase by more than 50%. E.g. F414, lower dry thrust, higher wet thrust. And that's before WEP.;)
What numbers are you using? Wiki? The F414 produces 14,770 lbs in intermediate and 21,890 in wet thrust. The EJ2000 is very similar at 13,500 and 20,250. These are the manufacturers numbers. There is no credible report that he EJ2000 has a war emergency power setting the pilot can activate similar to some Migs. What the typhoon starstreak site stated was:
An interesting point to note is that the baseline production engine is also capable of generating a further 15% dry thrust (69kN or 15525lbf) and 5% reheat output (95kN or 21263lbf) in a so called war setting.
Like any engine, that means simply, that engine can produce more thrust at higher operating temps at the cost of engine life. There is nothing to suggest that the pilot can control this or that any air force would allow it.
Note also, add 5% to the stated 20,250 lbs of thrust. What do you get? Simply put, the Ej2000's thrust is known.
And if the two figures were anything like close I would agree but they ain't and the canards tend to help in that respect anyway. They're not remotely close. 63 vs 85lb/ft^2 even with the Ef at 32% fuel fraction and the Su-35 at 25%. Put them on the same fuel fraction and it's 63 vs 90lb/ft^2 and 1.2 vs 1.07 TWR.
BTW, I'm not arguing that the Su-35 has a higher sustained turn performance than the Typhoon. I'm saying your reasoning is flawed. Your trying to compare wing loading of canard/delta wing to that of cropped delta/tail planform. I shouldn't have to explain why using simple wing loading numbers do not support that the Typhoon would have superior sustained turn performance
So compare the F-104 to other fighters of that era like the MiG-21. That was also a tube with wings but massively superior in turn performance
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That is the point, they were both designed without high lift devices, and neither likely have significant body lift. So, obviously the Mig-21 with it's larger wing will have superior turn performance as most speeds/alt. ( I see that andraxxus beat me to the comparison below) The F-106 is a good comparison, significantly lower wing loading than the F-4. It could out turn the early F-4 variants at high altitude. The situation was reversed once the slatted F-4E was introduced, it had significantly better sustained turn performance at all but the highest speeds.
And high Cl will increase drag, so it's damned on two fronts.
What? what are you comparing? I was talking about to similar wings one with leading edge root extensions and one without. Which one is going to generate more lift as AoA increases? What are you arguing? That the lift generated by leading edge root extensions on a cropped delta like the Su-27 (or strakes on the F-16) are dragger than a pure delta at high AoA? Sorry, that is one of the major penalties of a delta wing.
By: Andraxxus
- 19th September 2016 at 19:56Permalink- Edited 1st January 1970 at 01:00
Well let me reply to that with this assessment done by the Swiss. The Typhoon scored a maximum in A/C performance against a Rafale and a Gripen C which are very well known for their massive STR and ITR.
Well, Grippen C is not exactly known for its massive STR only half official statement is "30deg ITR 20 deg STR", puts its sustained turn performance inferior to all 4 principle 4th gen aircraft I've mentioned. Rafale is a mistery in here as well, so I don't see what that chart exactly proves? Indians liked Rafale over its competitors, Turkey preferred A-129 over AH-64D or Ka-50. This doesn't prove anything.
wing loading than the Typhoon
Again you are missing the point. All, delta wings inherently have large wings. As a result, they are inefficient at sustained turns in general. You are taking a single multiplier in a formula (wing area), but ignoring the others.
In mathematical terms, you are saying x1*y1 = 30; and since x2 > x1, x2*y2 will always be greater than 30. This is clearly not the case.
According to your logic F-106, a delta with just 255 kg/m2 wing loading has higher maneuverability than its generational counterpart F-104, it even has greater maneuverability than Typhoon F-15 or Su-27?
Cd = Cd0 + kCl^2
Now Cd0 dominates in cruise but at higher g loads the latter term dominates and Cl is inversely proportional to wing area for a given lift requirement.
Hell no, small wing area is not desirable for STR.
Ok, for the record, I hate using empyrical formulae for proving anything, but lets have it your way.
We have two aircraft, both have equal weight at 10000kg, and airfoils correspond to Cd0 = 0,02 and k = 0,12 Only difference is, Aircraft #1 50m2 wing area, greater than the wing area of aircraft #2 which is 40. I want to pull 9Gs at M0,9@sea level.
As you see, its quite easy to prove HOW an aircraft with higher wing loading does not necessarily translate to inferior STR. When maneuvering at 9Gs sea level, 25% reduction in wing area actually resulted in 4% decrease in drag, even if we ignore the fact that aircraft with smaller wings would be lighter in reality.
And before you start questioning it, none of my numbers are arbitrary; Cd0 = 0,02 is MiG-29s Cd0, k=0,12 corresponds to MiG-29's airfoil at 0 LE flap deflection. Likewise, 10000kg and 40m2 wing area is ballpark similar to what MiG-29 has, and 50m2 and 10000kg is also the middle point of Eurocanards, namely Rafale and Typhoon.
So I ask two questions; #1, had MiG-29 had larger wings like Typhoon or Rafale, would it sustain turns better or not? #2, do you think MiG-29's wing area is "just" 38m2 and not 50m2 just because inability of Mikoyan Gurevich engineers or is this a result of a thorough optimization that some performance points would degrade (as simple shown above) with increased wing area?
Apples to oranges. F-16 was designed with a CoP ahead of the CoG, F-15 was not. You've also got LERX vs non-LERX.
Ah, apples to oranges, you mention relatively insignificant differneces like relaxed stability or LERX in two conventional layouts, but you have no problem comparing wing areas of two entirely different aerodynamic layouts?
Aside from this, the Typhoon doesn't have to out-manoeuvre an Su-35, the pilot just needs to look at it. This performance analysis is only even relevant in a fictitious training scenario.
Same could be said for even 30 year old Su-27S with its R-73 and HMS combination.
Yeah, judging turn rates from air shows, extremely accurate.
If you have anything more solid and accurate, I am all ears.
Wow, love to see you prove an F-16 can out-climb a Typhoon, this will be funny.
A forum search will help you in this, one I am not inclined to re-do what I've already done by writing a wall of text and posting some 10 pages of the manual.
Result - fail.
Only failure here is your inability to prove any word I've said wrong.
Look, I am not saying I am 100% correct, I openly say I am guesstimating the maneuverability of Typhoon, but some nonsense examples like F-104, or some charts provided by the buyers of the product who may twist the truth in both ways, or some pilot quotes contradicting a numeric comparison of what is published by Typhoon's manufacturer and what is written on F-16 flight manual is just not enough.
The Typhoon came after the Flanker and was purpose-built to beat it.
By the same analogy, Su-35 came after Typhoon, and was purpose built to defeat it. Again, I don't follow the logic here.
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By: Starfish Prime
- 19th September 2016 at 20:14Permalink- Edited 1st January 1970 at 01:00
I've read the report multiple times. There is NOTHING about specific performance numbers. The performance based on the OCA/DCA mission performance. It does not mean that the Typhoon has superior turn performance, nor does it mean inferior. Simply put, there is nothing to support either in the Swiss Eval, except that the overall aircraft performance on the missions was superior.
What numbers are you using? Wiki? The F414 produces 14,770 lbs in intermediate and 21,890 in wet thrust. The EJ2000 is very similar at 13,500 and 20,250. These are the manufacturers numbers. There is no credible report that he EJ2000 has a war emergency power setting the pilot can activate similar to some Migs. What the typhoon starstreak site stated was:
Like any engine, that means simply, that engine can produce more thrust at higher operating temps at the cost of engine life. There is nothing to suggest that the pilot can control this or that any air force would allow it.
Note also, add 5% to the stated 20,250 lbs of thrust. What do you get? Simply put, the Ej2000's thrust is known.
BTW, I'm not arguing that the Su-35 has a higher sustained turn performance than the Typhoon. I'm saying your reasoning is flawed. Your trying to compare wing loading of canard/delta wing to that of cropped delta/tail planform. I shouldn't have to explain why using simple wing loading numbers do not support that the Typhoon would have superior sustained turn performance
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That is the point, they were both designed without high lift devices, and neither likely have significant body lift. So, obviously the Mig-21 with it's larger wing will have superior turn performance as most speeds/alt.
What? what are you comparing? I was talking about to similar wings one with leading edge root extensions and one without. Which one is going to generate more lift as AoA increases?
Right, so how did the Typhoon get 30% ahead of the Rafale if it was just down to a slight speed or climb advantage say? Clearly it must have been better over a range of parameters.
Says 13,000lbf on wiki and 14,000lbf here. Either way, the wet/dry ratio is >1.5. As it is for most Flankers and the like too.
Overall the EJ200 employs a very low By-Pass Ratio (the ratio of air which bypasses the core engine or compressor stages) of 0.4:1 which gives it a near turbo-jet cycle. Such a low BPR has the benefit of producing a cycle where the maximum attainable non-afterburning thrust makes up a greater percentage of total achievable output. At its maximum dry thrust of 60kN (or 13,500lbf) the EJ200's SFC is in the order of 23g/kN.s. With reheat the engine delivers around 90-100kN (or 20,250-22,500lbf) of thrust with an SFC of some 49g/kN.s.
Well that's just as well, because you haven't explained it. I was the original one who made the comparison either. Whilst wing loading and TWR isn't everything, it certainly isn't nothing either and when the differences are this huge, one really has to question exactly how they can be undone by other aspects.
Whilst the F-16 could achieve higher STR than a Mirage 2000 due to the M2000's poor TWR, ITR was not higher. Even with the 25% advantage in TWR, the F-16 only manages marginally better STR of around 10% at 0 PS and 5% at -800PS. The lower wing loading did give an advantage of some 4deg/s peak. Now if the Mirage 2000 had 29,000lbf of thrust instead of 21,400lbf, no doubt it would have won on STR too. Now factor in inherent instability margin and canards on top of a 1.2:1 TWR and that kind of wing loading and you get the picture.
Wing area generally tends to include the part of the body that adds lift and we're again comparing two planes built in the modern era, well actually the Typhoon is much newer in design to boot.
They will both generate more lift as AoA increases and canards area help keep airflow attached at high AoA. Can the Typhoon pull the same AoA as an Su-35? Nope, but that kind of AoA frankly isn't useful for ITR and certainly not for STR. The Typhoon can easily make sufficient AoA that makes AoA a moot point in any turn rate comparison (see 1:30).
By: garryA
- 19th September 2016 at 20:29Permalink- Edited 1st January 1970 at 01:00
Now, typhoon has 312 kg/m2, while it has unknown lift coefficent, Clmax has to be greater than 1,5 to match Su-27's instantenious turn performance. You can bet your house and a million dollars no delta (with todays engine tech) can be made to even approach that number; for comparison similarly configured Mirage-2000's Clmax value is ~0,9.
how about effect of canard ? shouldnt canard improve CL by 10-15% ?
As for TWR; Yes, when both are @ 50% fuel + 2AAMs, Su-27's T/W is inferior to Typhoon at by ~12%. But that is an unfair comparison, as Su-27 would reach nearly twice the range with that fuel. Su-27 @50% fuel has exact same T/W of Eurofigher @88% internal fuel, and probably will have similar range with that fuel as well. That being said, T/W alone is also irrelevant without L/D ratio.
Personally , i think it hard to compare T/W between Su-27 and Typhoon without knowing the dynamic thrust of AL-31F and EJ-2000, with lower bypass ratio , i would expect the EJ-2000 to perform better at high altitude though.On the other hand, the variable intake of su-27 is better at high speed
By: garryA
- 19th September 2016 at 20:34Permalink- Edited 1st January 1970 at 01:00
Whilst the F-16 could achieve higher STR than a Mirage 2000 due to the M2000's poor TWR, ITR was not higher. Even with the 25% advantage in TWR, the F-16 only manages marginally better STR of around 10% at 0 PS and 5% at -800PS.
If SEP is -800 then that isnt a sustain turn , it is instantaneous turn.
Oh, btw, the Su-35S has even higher wingloading vs Vanila Su-27S. I've seen figure over 440kg/m2
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From Su-27 to Su-35 the shape remain the same so i would expect that CL doesnt change, in this case the instantaneous turn performance of Su-35 should be worse than vanilla Su-27
The F414 has a lower bypass ratio than the EJ2000 .314 to .4
Whilst the F-16 could achieve higher STR than a Mirage 2000 due to the M2000's poor TWR, ITR was not higher. Even with the 25% advantage in TWR, the F-16 only manages marginally better STR of around 10% at 0 PS and 5% at -800PS. The lower wing loading did give an advantage of some 4deg/s peak. Now if the Mirage 2000 had 29,000lbf of thrust instead of 21,400lbf, no doubt it would have won on STR too. Now factor in inherent instability margin and canards on top of a 1.2:1 TWR and that kind of wing loading and you get the picture.
How do you figure 25% advantage? The F-16 has 8.5% greater thrust to weight ratio, and a nearly 2.4 degree sustained turn rate advantage at mach .8 15,000 is a HUGE difference. They only approach parity around mach 1.
Wing area generally tends to include the part of the body that adds lift and we're again comparing two planes built in the modern era, well actually the Typhoon is much newer in design to boot.
While that is true, that does not mean that two totally different planforms perform the same as bank angle and AoA increase (we are not talking high AoA , 20 degrees or less).
By: Andraxxus
- 19th September 2016 at 20:47Permalink- Edited 1st January 1970 at 01:00
how about effect of canard ? shouldnt canard improve CL by 10-15% ?
Well, its possible, but very debatable. I would be willing to accept a close couple canard would add to Clmax automatically, but on Typhoon, canards are just too far away to provide a meaningful vortex at high AOA.
In fact, Typhoon has two additional vortex generators to mitigate that.
Such canards would work better when aircraft is supersonic, making maneuvers that require little AOA, but I may be wrong, and there can be improvements on subsonic regime as well, I don't know. In any case, airfoil itself is thin, you can improve it only to a degree, its not logical to expect Cl to go anywhere above ~1,2.
Personally , i think it hard to compare T/W between Su-27 and Typhoon without knowing the dynamic thrust of AL-31F and EJ-2000, with lower bypass ratio , i would expect the EJ-2000 to perform better at high altitude though.
Agreed, then Su-27 has triple shock variable inlet ramps, so it can also give an edge when high and supersonic; nothing is exactly clear on this one.
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By: Starfish Prime
- 19th September 2016 at 20:58Permalink- Edited 1st January 1970 at 01:00
Well, Grippen C is not exactly known for its massive STR only half official statement is "30deg ITR 20 deg STR", puts its sustained turn performance inferior to all 4 principle 4th gen aircraft I've mentioned. Rafale is a mistery in here as well, so I don't see what that chart exactly proves? Indians liked Rafale over its competitors, Turkey preferred A-129 over AH-64D or Ka-50. This doesn't prove anything.
Again you are missing the point. All, delta wings inherently have large wings. As a result, they are inefficient at sustained turns in general. You are taking a single multiplier in a formula (wing area), but ignoring the others.
In mathematical terms, you are saying x1*y1 = 30; and since x2 > x1, x2*y2 will always be greater than 30. This is clearly not the case.
According to your logic F-106, a delta with just 255 kg/m2 wing loading has higher maneuverability than its generational counterpart F-104, it even has greater maneuverability than Typhoon F-15 or Su-27?
Ok, for the record, I hate using empyrical formulae for proving anything, but lets have it your way.
We have two aircraft, both have equal weight at 10000kg, and airfoils correspond to Cd0 = 0,02 and k = 0,12 Only difference is, Aircraft #1 50m2 wing area, greater than the wing area of aircraft #2 which is 40. I want to pull 9Gs at M0,9@sea level.
As you see, its quite easy to prove HOW an aircraft with higher wing loading does not necessarily translate to inferior STR. When maneuvering at 9Gs sea level, 25% reduction in wing area actually resulted in 4% decrease in drag, even if we ignore the fact that aircraft with smaller wings would be lighter in reality.
And before you start questioning it, none of my numbers are arbitrary; Cd0 = 0,02 is MiG-29s Cd0, k=0,12 corresponds to MiG-29's airfoil at 0 LE flap deflection. Likewise, 10000kg and 40m2 wing area is ballpark similar to what MiG-29 has, and 50m2 and 10000kg is also the middle point of Eurocanards, namely Rafale and Typhoon.
So I ask two questions; #1, had MiG-29 had larger wings like Typhoon or Rafale, would it sustain turns better or not? #2, do you think MiG-29's wing area is "just" 38m2 and not 50m2 just because inability of Mikoyan Gurevich engineers or is this a result of a thorough optimization that some performance points would degrade (as simple shown above) with increased wing area?
Ah, apples to oranges, you mention relatively insignificant differneces like relaxed stability or LERX in two conventional layouts, but you have no problem comparing wing areas of two entirely different aerodynamic layouts?
Same could be said for even 30 year old Su-27S with its R-73 and HMS combination.
If you have anything more solid and accurate, I am all ears.
A forum search will help you in this, one I am not inclined to re-do what I've already done by writing a wall of text and posting some 10 pages of the manual.
Only failure here is your inability to prove any word I've said wrong.
Look, I am not saying I am 100% correct, I openly say I am guesstimating the maneuverability of Typhoon, but some nonsense examples like F-104, or some charts provided by the buyers of the product who may twist the truth in both ways, or some pilot quotes contradicting a numeric comparison of what is published by Typhoon's manufacturer and what is written on F-16 flight manual is just not enough.
By the same analogy, Su-35 came after Typhoon, and was purpose built to defeat it. Again, I don't follow the logic here.
It is known for good ITR though. Rafale is known for good STR and ITR and we see the Swiss rank the Typhoon well ahead of both by some margin.
Oh really, care to prove the assertion that Canard-deltas are inefficient? Hmmm.... wonder why so many European manufactuers have specifically gone with them? Only those manufacturers aiming for stealth haven't in the Western sphere.
It is if y1 ~ y2, which it likely will be to within less than 34% in this case.
Well do we know what the STR of an F-106 is? For a start you're comparing older tech again though. No canard, stable configuration, CoP after of CoG.
Nope. All you've proved there is that with that specific Cd0 and k value, a plane with 25% higher wing loading has greater drag in the turn at that speed but they are both pulling 9g anyway. The plane with the larger wing area will continue to be able to pull 9g at lower speeds than the other, and hence higher turn rates. I could also use the Cd0 and k value in Jet Propulsion by Nicholas Cumpsty on Page 183, which are 0.01 and 0.2 respectively and get a different result. 0.0282 for Cd1 and 0.128 for Cd2, giving Cd1.A1 as 1.41 and Cd2.A2 as 5.12 and I have reason to believe they're based on a Eurofighter's Cd0 and k value. Cd0 is generally higher for aircraft with smaller wings too.
Probably
a) because Cd0 would likely reduce for larger wings.
b) the larger wing would be able to maintain 9g at lower speeds.
c) subsonic sea level turns where peak rates are achieved are not drag limited, making the entire premise of your argument invalid.
Repeat the calculation at higher altitude, e.g. half the air density, or at lower speed, e.g. 0.707 times and the value of Cl1 and Cl2 increases two-fold and Drag1.A1 becomes less than Drag2.A2 - 3.19 vs 3.53.
Everyone knows relaxed stability makes a huge difference and the Typhoon was designed for a relatively large margin of instability. That's why comparing the F-16 to the F-15 is a bad comparison. The M2000 on the other hand doesn't have relaxed stability and still beats the F-16 in ITR, proving that wing area is indeed important.
Yes it could against an early F-15 but the R-73 does not have LOAL yet and HOBS is still <90deg, so it still ain't the same.
There's nothing to say whether either aircraft is even maxing out a manoeuvre at an airshow, or whether SEP is maintained.
Actually it didn't the Su-27M came out in 1988. The Su-35 is literally an overhauled Su-27, which came out in 1985. So what you're actually arguing is that the Soviets designed a plane which could out-turn a Typhoon 20 years earlier. That's quite a stretch considering it was never able to match the US year for year from 1955-1976, after which their focus moved to stealth.
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By: Starfish Prime
- 19th September 2016 at 21:00Permalink- Edited 1st January 1970 at 01:00
If SEP is -800 then that isnt a sustain turn , it is instantaneous turn.
True but it is taking a measurement at the same energy bleed rate, I mentioned the 0 PS figure too.
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By: Basher54321
- 19th September 2016 at 21:01Permalink- Edited 1st January 1970 at 01:00
Such canards would work better when aircraft is supersonic, making maneuvers that require little AOA, but I may be wrong, and there can be improvements on subsonic regime as well, I don't know. In any case, airfoil itself is thin, you can improve it only to a degree, its not logical to expect Cl to go anywhere above ~1,2.
Eurofighter were pushing this mod that might have brought it upto F-16 class :p
Adding leading edge root extensions and extended trailing edge flaps, and reshaping the side-of-cockpit ILS antennae covers as 70° delta strakes should improve the aircraft’s agility for close-quarters combat.
Laurie Hilditch, head of future capabilities at Eurofighter, says the modification kit should give the aircraft the sort of “knife-fight in a phone box” turning capability enjoyed by rivals such as Boeing’s F/A-18E/F or the Lockheed Martin F-16, without sacrificing the transonic and supersonic high-energy agility inherent to its delta wing-canard configuration.
The F414 has a lower bypass ratio than the EJ2000 .314 to .4
How do you figure 25% advantage? The F-16 has 8.5% greater thrust to weight ratio, and a nearly 2.4 degree sustained turn rate advantage at mach .8 15,000 is a HUGE difference. They only approach parity around mach 1.
While that is true, that does not mean that two totally different planforms perform the same as bank angle and AoA increase (we are not talking high AoA , 20 degrees or less).
Ah okay, well most aircraft are above a 1.5:1 wet/dry ratio.
I would expect higher BPR engines to benefit from afterburning more, because the core gas is already very hot anyway.
Umm no, F-16C is 1.1, M2000 is 0.88, 1.14 is a mis-calc, it's 1.37 at that weight - 28,600lbf. The thrust figure they state is not for a -200, it's for a -100. That's a 25% advantage. And bear in mind that the M2000 is canard-less and doesn't run relaxed stability and despite that, only a 1.75deg/s advantage for the F-16 and a 4deg/s ITR advantage for the M2000.
Exactly, which is why the Typhoon is likely to win on turn rate.
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By: Starfish Prime
- 19th September 2016 at 21:14Permalink- Edited 1st January 1970 at 01:00
Eurofighter were pushing this mod that might have brought it upto F-16 class :p
Adding leading edge root extensions and extended trailing edge flaps, and reshaping the side-of-cockpit ILS antennae covers as 70° delta strakes should improve the aircraft’s agility for close-quarters combat.
Laurie Hilditch, head of future capabilities at Eurofighter, says the modification kit should give the aircraft the sort of “knife-fight in a phone box” turning capability enjoyed by rivals such as Boeing’s F/A-18E/F or the Lockheed Martin F-16, without sacrificing the transonic and supersonic high-energy agility inherent to its delta wing-canard configuration.
That's probably more for Storm Shadow carriage than dog-fighting. AoA would benefit too though. Swiss thought the a/c performance was more than fine as is.
By: garryA
- 19th September 2016 at 21:16Permalink- Edited 1st January 1970 at 01:00
In any case, airfoil itself is thin, you can improve it only to a degree, its not logical to expect Cl to go anywhere above ~1,2.
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how thicks the airfoil of Su-27" is compare to Typhoon?
i know f-15 use NACA 64A203 but have no idea about the Su-27 or Typhoon
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By: Starfish Prime
- 19th September 2016 at 21:21Permalink- Edited 1st January 1970 at 01:00
Agreed, then Su-27 has triple shock variable inlet ramps, so it can also give an edge when high and supersonic; nothing is exactly clear on this one.
A fixed ramp works fine until you exceed M2.0. Even pitot works fine up to M1.6 (-5% loss for F-16 intake vs F-15 intake at M1.6).
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By: Basher54321
- 19th September 2016 at 21:22Permalink- Edited 1st January 1970 at 01:00
That's probably more for Storm Shadow carriage than dog-fighting. AoA would benefit too though. Swiss thought the a/c performance was more than fine as is.
By: Starfish Prime
- 19th September 2016 at 21:25Permalink- Edited 1st January 1970 at 01:00
Well, its possible, but very debatable. I would be willing to accept a close couple canard would add to Clmax automatically, but on Typhoon, canards are just too far away to provide a meaningful vortex at high AOA.
In fact, Typhoon has two additional vortex generators to mitigate that.
Such canards would work better when aircraft is supersonic, making maneuvers that require little AOA, but I may be wrong, and there can be improvements on subsonic regime as well, I don't know. In any case, airfoil itself is thin, you can improve it only to a degree, its not logical to expect Cl to go anywhere above ~1,2.
Agreed, then Su-27 has triple shock variable inlet ramps, so it can also give an edge when high and supersonic; nothing is exactly clear on this one.
They examined canard position thoroughly and moving it forward would only have improved lift for a less unstable aircraft.
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By: Rii - 19th September 2016 at 16:10 Permalink - Edited 1st January 1970 at 01:00
Good to hear you acknowledge the primacy of T-50, coming after the F-22 and having been designed to beat it. :cool:
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By: Starfish Prime - 19th September 2016 at 16:12 Permalink - Edited 1st January 1970 at 01:00
I'll refer you to this.
http://forum.keypublishing.com/showthread.php?139991-Historical-evaluation-of-Russian-hardware-in-combat-breakout-thread
Posts: 949
By: Starfish Prime - 19th September 2016 at 16:27 Permalink - Edited 1st January 1970 at 01:00
A/C Performance covered everything, including those things and turn performance. And the Typhoon came out 30% ahead of a Rafale.
Nah, that's just approximated based on dry thrust + 50%. If you look about most fighters on reheat increase by more than 50%. E.g. F414, lower dry thrust, higher wet thrust. And that's before WEP.;)
And if the two figures were anything like close I would agree but they ain't and the canards tend to help in that respect anyway. They're not remotely close. 63 vs 85lb/ft^2 even with the Ef at 32% fuel fraction and the Su-35 at 25%. Put them on the same fuel fraction and it's 63 vs 90lb/ft^2 and 1.2 vs 1.07 TWR.
So compare the F-104 to other fighters of that era like the MiG-21. That was also a tube with wings but massively superior in turn performance.
And high Cl will increase drag, so it's damned on two fronts.
What he's pointing out is a mile wide of the mark and rough calculations really are all that's required here given the size of the differences AND crucially all we're able to do with the figures available. There is simply no way an Su-35 can beat a Typhoon in STR unless it has about 1.5 times the Cl but somehow 20% less drag at that Cl even though the drag increases with the square of that Cl. And using a comparison of a 10 year newer design (1985) against an older design (1976) to prove something about a 18 year older design (1985) against a newer design (2003) is just silly.
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By: FBW - 19th September 2016 at 19:13 Permalink - Edited 1st January 1970 at 01:00
I've read the report multiple times. There is NOTHING about specific performance numbers. The performance based on the OCA/DCA mission performance. It does not mean that the Typhoon has superior turn performance, nor does it mean inferior. Simply put, there is nothing to support either in the Swiss Eval, except that the overall aircraft performance on the missions was superior.
What numbers are you using? Wiki? The F414 produces 14,770 lbs in intermediate and 21,890 in wet thrust. The EJ2000 is very similar at 13,500 and 20,250. These are the manufacturers numbers. There is no credible report that he EJ2000 has a war emergency power setting the pilot can activate similar to some Migs. What the typhoon starstreak site stated was: Like any engine, that means simply, that engine can produce more thrust at higher operating temps at the cost of engine life. There is nothing to suggest that the pilot can control this or that any air force would allow it.
Note also, add 5% to the stated 20,250 lbs of thrust. What do you get? Simply put, the Ej2000's thrust is known.
BTW, I'm not arguing that the Su-35 has a higher sustained turn performance than the Typhoon. I'm saying your reasoning is flawed. Your trying to compare wing loading of canard/delta wing to that of cropped delta/tail planform. I shouldn't have to explain why using simple wing loading numbers do not support that the Typhoon would have superior sustained turn performance .
That is the point, they were both designed without high lift devices, and neither likely have significant body lift. So, obviously the Mig-21 with it's larger wing will have superior turn performance as most speeds/alt. ( I see that andraxxus beat me to the comparison below) The F-106 is a good comparison, significantly lower wing loading than the F-4. It could out turn the early F-4 variants at high altitude. The situation was reversed once the slatted F-4E was introduced, it had significantly better sustained turn performance at all but the highest speeds.
What? what are you comparing? I was talking about to similar wings one with leading edge root extensions and one without. Which one is going to generate more lift as AoA increases? What are you arguing? That the lift generated by leading edge root extensions on a cropped delta like the Su-27 (or strakes on the F-16) are dragger than a pure delta at high AoA? Sorry, that is one of the major penalties of a delta wing.
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By: Andraxxus - 19th September 2016 at 19:56 Permalink - Edited 1st January 1970 at 01:00
Well, Grippen C is not exactly known for its massive STR only half official statement is "30deg ITR 20 deg STR", puts its sustained turn performance inferior to all 4 principle 4th gen aircraft I've mentioned. Rafale is a mistery in here as well, so I don't see what that chart exactly proves? Indians liked Rafale over its competitors, Turkey preferred A-129 over AH-64D or Ka-50. This doesn't prove anything.
Again you are missing the point. All, delta wings inherently have large wings. As a result, they are inefficient at sustained turns in general. You are taking a single multiplier in a formula (wing area), but ignoring the others.In mathematical terms, you are saying x1*y1 = 30; and since x2 > x1, x2*y2 will always be greater than 30. This is clearly not the case.
According to your logic F-106, a delta with just 255 kg/m2 wing loading has higher maneuverability than its generational counterpart F-104, it even has greater maneuverability than Typhoon F-15 or Su-27?
Ok, for the record, I hate using empyrical formulae for proving anything, but lets have it your way.
We have two aircraft, both have equal weight at 10000kg, and airfoils correspond to Cd0 = 0,02 and k = 0,12 Only difference is, Aircraft #1 50m2 wing area, greater than the wing area of aircraft #2 which is 40. I want to pull 9Gs at M0,9@sea level.
Aircraft#1 -> 9*10000*9,8184 = 0,5 * 1,225 * 50 * Cl1 * 309^2 , Cl1 = 0,302; Cd1 = 0,02+0,12*0,302^2 = 0,0309. Cd1*Wing Area1 = 1,547.
Aircraft#2 -> 9*10000*9,8184 = 0,5 * 1,225 * 40 * Cl2 * 309^2 , Cl1 = 0,377; Cd2 = 0,02+0,12*0,377^2 = 0,0370. Cd2*Wing Area2 = 1,48.
As you see, its quite easy to prove HOW an aircraft with higher wing loading does not necessarily translate to inferior STR. When maneuvering at 9Gs sea level, 25% reduction in wing area actually resulted in 4% decrease in drag, even if we ignore the fact that aircraft with smaller wings would be lighter in reality.
And before you start questioning it, none of my numbers are arbitrary; Cd0 = 0,02 is MiG-29s Cd0, k=0,12 corresponds to MiG-29's airfoil at 0 LE flap deflection. Likewise, 10000kg and 40m2 wing area is ballpark similar to what MiG-29 has, and 50m2 and 10000kg is also the middle point of Eurocanards, namely Rafale and Typhoon.
So I ask two questions; #1, had MiG-29 had larger wings like Typhoon or Rafale, would it sustain turns better or not? #2, do you think MiG-29's wing area is "just" 38m2 and not 50m2 just because inability of Mikoyan Gurevich engineers or is this a result of a thorough optimization that some performance points would degrade (as simple shown above) with increased wing area?
Ah, apples to oranges, you mention relatively insignificant differneces like relaxed stability or LERX in two conventional layouts, but you have no problem comparing wing areas of two entirely different aerodynamic layouts?
Same could be said for even 30 year old Su-27S with its R-73 and HMS combination.
If you have anything more solid and accurate, I am all ears.
A forum search will help you in this, one I am not inclined to re-do what I've already done by writing a wall of text and posting some 10 pages of the manual.
Only failure here is your inability to prove any word I've said wrong.
Look, I am not saying I am 100% correct, I openly say I am guesstimating the maneuverability of Typhoon, but some nonsense examples like F-104, or some charts provided by the buyers of the product who may twist the truth in both ways, or some pilot quotes contradicting a numeric comparison of what is published by Typhoon's manufacturer and what is written on F-16 flight manual is just not enough.
By the same analogy, Su-35 came after Typhoon, and was purpose built to defeat it. Again, I don't follow the logic here.
Posts: 949
By: Starfish Prime - 19th September 2016 at 20:14 Permalink - Edited 1st January 1970 at 01:00
Right, so how did the Typhoon get 30% ahead of the Rafale if it was just down to a slight speed or climb advantage say? Clearly it must have been better over a range of parameters.
Says 13,000lbf on wiki and 14,000lbf here. Either way, the wet/dry ratio is >1.5. As it is for most Flankers and the like too.
http://www.sps-aviation.com/story_issue.asp?Article=731
That seems to be exactly what it suggests.
https://web.archive.org/web/20081231141150/http://typhoon.starstreak.net/Eurofighter/engines.html
Well that's just as well, because you haven't explained it. I was the original one who made the comparison either. Whilst wing loading and TWR isn't everything, it certainly isn't nothing either and when the differences are this huge, one really has to question exactly how they can be undone by other aspects.
Whilst the F-16 could achieve higher STR than a Mirage 2000 due to the M2000's poor TWR, ITR was not higher. Even with the 25% advantage in TWR, the F-16 only manages marginally better STR of around 10% at 0 PS and 5% at -800PS. The lower wing loading did give an advantage of some 4deg/s peak. Now if the Mirage 2000 had 29,000lbf of thrust instead of 21,400lbf, no doubt it would have won on STR too. Now factor in inherent instability margin and canards on top of a 1.2:1 TWR and that kind of wing loading and you get the picture.
Wing area generally tends to include the part of the body that adds lift and we're again comparing two planes built in the modern era, well actually the Typhoon is much newer in design to boot.
They will both generate more lift as AoA increases and canards area help keep airflow attached at high AoA. Can the Typhoon pull the same AoA as an Su-35? Nope, but that kind of AoA frankly isn't useful for ITR and certainly not for STR. The Typhoon can easily make sufficient AoA that makes AoA a moot point in any turn rate comparison (see 1:30).
Posts: 1,081
By: garryA - 19th September 2016 at 20:29 Permalink - Edited 1st January 1970 at 01:00
how about effect of canard ? shouldnt canard improve CL by 10-15% ?
Personally , i think it hard to compare T/W between Su-27 and Typhoon without knowing the dynamic thrust of AL-31F and EJ-2000, with lower bypass ratio , i would expect the EJ-2000 to perform better at high altitude though.On the other hand, the variable intake of su-27 is better at high speed
Posts: 1,081
By: garryA - 19th September 2016 at 20:34 Permalink - Edited 1st January 1970 at 01:00
If SEP is -800 then that isnt a sustain turn , it is instantaneous turn.
From Su-27 to Su-35 the shape remain the same so i would expect that CL doesnt change, in this case the instantaneous turn performance of Su-35 should be worse than vanilla Su-27
Posts: 3,106
By: FBW - 19th September 2016 at 20:44 Permalink - Edited 1st January 1970 at 01:00
The wikipedia numbers are wrong for the F414, I took the actual intermediate and wet thrust from: http://www.dtic.mil/dtic/tr/fulltext/u2/a493918.pdf
The F414 has a lower bypass ratio than the EJ2000 .314 to .4
How do you figure 25% advantage? The F-16 has 8.5% greater thrust to weight ratio, and a nearly 2.4 degree sustained turn rate advantage at mach .8 15,000 is a HUGE difference. They only approach parity around mach 1.
While that is true, that does not mean that two totally different planforms perform the same as bank angle and AoA increase (we are not talking high AoA , 20 degrees or less).
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By: Andraxxus - 19th September 2016 at 20:47 Permalink - Edited 1st January 1970 at 01:00
Well, its possible, but very debatable. I would be willing to accept a close couple canard would add to Clmax automatically, but on Typhoon, canards are just too far away to provide a meaningful vortex at high AOA.
In fact, Typhoon has two additional vortex generators to mitigate that.
Such canards would work better when aircraft is supersonic, making maneuvers that require little AOA, but I may be wrong, and there can be improvements on subsonic regime as well, I don't know. In any case, airfoil itself is thin, you can improve it only to a degree, its not logical to expect Cl to go anywhere above ~1,2.
Agreed, then Su-27 has triple shock variable inlet ramps, so it can also give an edge when high and supersonic; nothing is exactly clear on this one.
Posts: 949
By: Starfish Prime - 19th September 2016 at 20:58 Permalink - Edited 1st January 1970 at 01:00
It is known for good ITR though. Rafale is known for good STR and ITR and we see the Swiss rank the Typhoon well ahead of both by some margin.
Oh really, care to prove the assertion that Canard-deltas are inefficient? Hmmm.... wonder why so many European manufactuers have specifically gone with them? Only those manufacturers aiming for stealth haven't in the Western sphere.
It is if y1 ~ y2, which it likely will be to within less than 34% in this case.
Well do we know what the STR of an F-106 is? For a start you're comparing older tech again though. No canard, stable configuration, CoP after of CoG.
Nope. All you've proved there is that with that specific Cd0 and k value, a plane with 25% higher wing loading has greater drag in the turn at that speed but they are both pulling 9g anyway. The plane with the larger wing area will continue to be able to pull 9g at lower speeds than the other, and hence higher turn rates. I could also use the Cd0 and k value in Jet Propulsion by Nicholas Cumpsty on Page 183, which are 0.01 and 0.2 respectively and get a different result. 0.0282 for Cd1 and 0.128 for Cd2, giving Cd1.A1 as 1.41 and Cd2.A2 as 5.12 and I have reason to believe they're based on a Eurofighter's Cd0 and k value. Cd0 is generally higher for aircraft with smaller wings too.
Probably
a) because Cd0 would likely reduce for larger wings.
b) the larger wing would be able to maintain 9g at lower speeds.
c) subsonic sea level turns where peak rates are achieved are not drag limited, making the entire premise of your argument invalid.
Repeat the calculation at higher altitude, e.g. half the air density, or at lower speed, e.g. 0.707 times and the value of Cl1 and Cl2 increases two-fold and Drag1.A1 becomes less than Drag2.A2 - 3.19 vs 3.53.
Everyone knows relaxed stability makes a huge difference and the Typhoon was designed for a relatively large margin of instability. That's why comparing the F-16 to the F-15 is a bad comparison. The M2000 on the other hand doesn't have relaxed stability and still beats the F-16 in ITR, proving that wing area is indeed important.
Yes it could against an early F-15 but the R-73 does not have LOAL yet and HOBS is still <90deg, so it still ain't the same.
There's nothing to say whether either aircraft is even maxing out a manoeuvre at an airshow, or whether SEP is maintained.
Well you started with the assumptions, at least appeared to.
http://forum.keypublishing.com/showthread.php?140171-What-s-the-difference-between-energy%96maneuverability-theory-amp-Supermaneuverability&p=2340023#post2340023
What pilot quotes are you referring too?
Actually it didn't the Su-27M came out in 1988. The Su-35 is literally an overhauled Su-27, which came out in 1985. So what you're actually arguing is that the Soviets designed a plane which could out-turn a Typhoon 20 years earlier. That's quite a stretch considering it was never able to match the US year for year from 1955-1976, after which their focus moved to stealth.
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By: Starfish Prime - 19th September 2016 at 21:00 Permalink - Edited 1st January 1970 at 01:00
True but it is taking a measurement at the same energy bleed rate, I mentioned the 0 PS figure too.
Posts: 87
By: Basher54321 - 19th September 2016 at 21:01 Permalink - Edited 1st January 1970 at 01:00
Eurofighter were pushing this mod that might have brought it upto F-16 class :p
Adding leading edge root extensions and extended trailing edge flaps, and reshaping the side-of-cockpit ILS antennae covers as 70° delta strakes should improve the aircraft’s agility for close-quarters combat.
Laurie Hilditch, head of future capabilities at Eurofighter, says the modification kit should give the aircraft the sort of “knife-fight in a phone box” turning capability enjoyed by rivals such as Boeing’s F/A-18E/F or the Lockheed Martin F-16, without sacrificing the transonic and supersonic high-energy agility inherent to its delta wing-canard configuration.
https://www.flightglobal.com/news/articles/eurofighter-new-aerodynamics-set-for-2014-test-flight-400762/
Posts: 949
By: Starfish Prime - 19th September 2016 at 21:12 Permalink - Edited 1st January 1970 at 01:00
Ah okay, well most aircraft are above a 1.5:1 wet/dry ratio.
Says 0.25:1 here.
http://www.mtu.de/engines/military-aircraft-engines/fighter-aircraft/f414/
I would expect higher BPR engines to benefit from afterburning more, because the core gas is already very hot anyway.
Umm no, F-16C is 1.1, M2000 is 0.88, 1.14 is a mis-calc, it's 1.37 at that weight - 28,600lbf. The thrust figure they state is not for a -200, it's for a -100. That's a 25% advantage. And bear in mind that the M2000 is canard-less and doesn't run relaxed stability and despite that, only a 1.75deg/s advantage for the F-16 and a 4deg/s ITR advantage for the M2000.
https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting_Falcon
Exactly, which is why the Typhoon is likely to win on turn rate.
Posts: 949
By: Starfish Prime - 19th September 2016 at 21:14 Permalink - Edited 1st January 1970 at 01:00
That's probably more for Storm Shadow carriage than dog-fighting. AoA would benefit too though. Swiss thought the a/c performance was more than fine as is.
F-16? Okay now.
Posts: 1,081
By: garryA - 19th September 2016 at 21:16 Permalink - Edited 1st January 1970 at 01:00
how thicks the airfoil of Su-27" is compare to Typhoon?
i know f-15 use NACA 64A203 but have no idea about the Su-27 or Typhoon
Posts: 949
By: Starfish Prime - 19th September 2016 at 21:21 Permalink - Edited 1st January 1970 at 01:00
A fixed ramp works fine until you exceed M2.0. Even pitot works fine up to M1.6 (-5% loss for F-16 intake vs F-15 intake at M1.6).
Posts: 87
By: Basher54321 - 19th September 2016 at 21:22 Permalink - Edited 1st January 1970 at 01:00
LOL Let me refer you to http://www.thefreedictionary.com/clueless
Posts: 949
By: Starfish Prime - 19th September 2016 at 21:25 Permalink - Edited 1st January 1970 at 01:00
They examined canard position thoroughly and moving it forward would only have improved lift for a less unstable aircraft.
http://www.dtic.mil/dtic/tr/fulltext/u2/p010499.pdf
Posts: 949
By: Starfish Prime - 19th September 2016 at 21:26 Permalink - Edited 1st January 1970 at 01:00
I see you found your way there first.:highly_amused: