Donnerstag, 26. Januar 2012

Eurofighter Typhoon - Demon or Lemon?

Dear Mr. Kopp,

I just read your article Eurofighter Typhoon - Demon or Lemon? Initially, it sounded quite convincing, however after a second and third reading a few questions came to my mind. Now, I am not an expert in aircraft design. I am merely a physicist with common sense and a basic technical understanding.

Let me jump to your overall conclusion:

"In terms of where to position the Typhoon in the current menagerie of fighter aircraft, it can be best described as an F/A-18C sized fighter with BVR systems and agility performance better than older F-15 models, similar to growth F-15 models with same generation systems and engines, but inferior to the F-15 in useful operating radius. The Typhoon is not a stealth aircraft, despite various assertions to this effect, nor is it a genuine supercruiser like the F-22."

I don't understand why the size of a fighter matters in terms of overall performance? The smaller a fighter, the less visible it is, so this is a stealth advantage in visual range combat. But, it is really of no concern in terms of the overall conclusion. So basically you're saying that the Typhoon is not much better than legacy fighters like the F-15.

1. Typhoon vs. F-15

The gist of the article appears to be a comparism with the F-15. Interestingly, you compare the fighter to "older" F-15 models and "growth" (future?) F-15 models. What about current F-15 models? You claim that the Typhoon is inferior to future F-15 models in "useful operating radius". I don't know a common definition of "useful operating radius". As far as I know the operating radius of any aircraft can be extended by refuling them in flight and/or adding external fuel tanks. But, I shall come back to this issue.

I would like to make a general remark about this type of comparism. I think it is unfair to compare a possible future F-15 aircraft with a current Typhoon. You should compare a current Typhoon with a current F-15 model and a possible future typhoon with a possible future F-15 model.

The article compares the Typhoon and F-15 on the basis of two criteria. First, the result of comparitive studies and the presumed performance in BVR combat. The performance within visual range is not an issue. Why not?

1.1 Validity of simulations

Two studies are cited: 1.
A DERA simulation against a postulated Su-35 threat and the USAF assessment of the F-22 effectiveness against the F-15. Your conclusion is that "the DERA study roughly agrees with USAF assessments of F-22A vs F-15C combat effectiveness." If two independent studies agree with each other, then one should conclude that their results are very reliable. But you reject this conclusion because of these reasons:

"The validity of this study in today's environment must be questioned. Since its compilation the Russians have developed the NIIP-011M and Phazotron Zhuk-Ph phased arrays for the Su-27/30, the R-77M ramjet Adder, the extended range R-74 digital Archer, 2D and 3D thrust vectoring nozzles, higher thrust AL-31 engine derivatives, and active radar seekers for the R-27 Alamo, as well as fielding an anti-radiation variant of the Alamo...."

However, the improvements to the SU-27 flanker should equally affect the relative combat performance of the Typhoon and F-15
vs. the flanker. Unless you provide any sound reasoning as to why this is more detrimental to the Typhoon in terms of relative combat performance, these arguments must be rejected as non sequiturs. They have no sound basis.

Your next argument is this:
"The F-22A is likely to be shooting the ERAAM, and some USAF F-15Cs are being fitted with active phased arrays, with the likely prospect of getting ERAAMs as well, or even a ramjet AMRAAM variant."

But, here you are changing the topic. This does not change the validity of the DERA simulation, because it's topic was not the relative effectiveness of future F-15 variants vs. current typhoons, it's topic was the relative effectiveness of current F-15 fighters and current Typhoons in relation to current Russian flankers.

Then, I question the likelyhood of F-22A being equipped with ERAAM missiles in the future. Currently, the F-22, F-15 as well as the typhoon are equipped with american
AIM-120 AMRAAM, i.e. medium range missiles. No American long range air-to-air missile has been developed or is planned to be deployed with US fighters. However, the MBDA meteor is actively being developed and shall be deployed with British, German and Italian Typhoon in 2015. Therefore, in terms of future BVR capabilities, it is more likely that the Typhoon is going to improve its relative performance in relation to both the F-15 and F-22 than the other way around. The same must be said in terms of the radar performance. The captor-E ASEA radar is actively being developed. This radar will most likely be superior in terms of range and field of view to the American ASEA radars. Germany has decided to retrofit all of its Typhoons with captor-E. Therefore, in terms of radar performance, future Typhoons are going to improve their relative performance in relation to future F-15 and F-22 fighters.

"Clearly the Typhoon is robustly in the BVR lethality class of the F-15C/E, and the principal driver of relative effectiveness between these types will the radar and missile capabilities. Until the USAF field phased arrays and ERAAM or ramjet AAMs on the whole F-15 fleet (some aircraft are currently being retrofitted with APG-63(V)3 active phased arrays), the Typhoon will hold a decisive advantage".

So "robustly in the same class" means the same as "hold a decisive advantage"? Clearly the current Typhoon is superior to the current F-15C/E fighters in terms of BVR combat effectiveness. This is not due to missile capabilities, because they all use the same American BVR missiles. This is due to the sensor and stealth features of the Typhoon. Yes, it is does not have a "very low radar cross section" like the F-22, but with a frontal radar cross section between 0.05 to 0.1 m it is far better than legacy fighters such as the F-15. In terms of radar performance, the captor-E should even widen the gap in relation to future F-15 fighters. Once, the MBDA meteor is included, an additional improvement in terms of relative performance shall be realized. The BVR missiles shall outperform the current American missiles.

"US longwave IRS&T technology is available off-the-shelf and would much reduce any advantage conferred by the PIRATE to the Typhoon."

I find it interesting that this feature is only mentioned in this passing way. We are talking about a long range passive infrared sensor. This gives the Typhoon the capability of identifying enemy aircraft without turning on its radar! Why is this important? Because you may give away your position and identity to an enemy aircraft by turning on your active radar. The signal intensity of the radar is at the very least 4-times stronger at the enemy aircraft than the reflected signal used for reconnaissance. This is not the case when using passive infrared technology. So the standard "stealth mode" of combat for a typhoon is with the active radar turned off. Enemy aircraft is identified using passive infrared and passive radar sensors. IRST technology has been dropped for the F-22 and there are no plans to retrofit the F-15 and F-22 fighters with this technology. Consequently, the probability that this performance gap is going to be reduced in the future is next to nill.

1.2 Performance Considerations BVR

"The other important considerations in BVR combat are transonic and supersonic acceleration, persistence and sustained turn performance. While the latter are difficult to estimate, the former can be directly compared by looking at thrust/weight ratios. "

1.2.1 Acceleration

I largely agree. The main tactic is to shoot first and run away bravely in BVR combat, so as not to be hit by counter missiles. In order to win in this manner, you must be able to run away fast for a considerable amount of time. So Thrust/weight ratios do matter and indicate this performance. However the drag of the airplane does also matter. But why don't you just publish the thrust/weight ratios? I looked and looked but couldn't find them. So here they are:

Thrust/weight of F-15C
: maximum (empty fuel tank): 1,62; nominal (full fuel tank): 1,07; minimal (maximum weight): 0,70
Thrust/weight of Typhoon: maximum: 1,67; nominal: 1,18; minimum: 0,78

Well, if you ask me, the Typhoon has a clear performance advantage here no matter where you look. But, these figures could not be so good if the Eurofighter ran out of fuel very fast. So what is the operating range of these aircraft?

Ferry range (without external fuel tanks) Typhoon: 3.790 km; F-15C: 2.540 km.

3790 km Ferry range is no useful operating radius? Well, it depends on your use. I would say, that's a hell of a lot!

If you add that the typhoon can supercruis at 1.2 Mach, whereas the F-15C can't supercruise at all, then you must concede that the F-15C is outclassed by the typhoon. What is your conclusion? "firmly in the same class"?

Last but not least, let's just look at the maximum climb rate of these aircraft as an indicator of agility/acceleration:

Maximum climb rate: Typhoon = 315 m/s; F-15C = 254 m/s

I would say: Firmly outclassed!

Well as it turns out you suddenly compare the current Typhoon with a non-existant airplane, namely an F-15F. This is a supposed future variant of the F-15E strike eagle. Let me quote you:

"If we take a Typhoon with 3 x 1000L external tanks, and an F-15F with 2 x 600 USG external tanks, we have configurations which deliver very similar endurance and operating radius for a point intercept." This is probably true.

"In the latter situation, approaching the target, the Typhoon is around 12% behind the F-15F in critical reheated thrust/weight ratio. If we compare a Typhoon with CFTs, 3 x 1000L external tanks against an F-15F with only CFTs, we get a shortfall of about 20% in thrust/weight ratio in addition to the drag penalty of the external tanks."

How does the thrust/weight ratio with external fuel tanks matter in air-to-air  combat, when it is standard practice to drop the fuel tanks once air-to-air combat commences in order to improve the agility of the plane? It doesn't matter!

Again, you are comparing a non-existent future plane with a current typhoon. If you wanted to, you could easily add conformal fuel tanks to the Typhoon. The British have already developed them, and the 20% drag penalty would suddenly be gone. By the way, 20% sounds like a wild guess to me.

Any way you turn it, the Typhoon is superior to the F-15, it is superior to current F-15s and future Typhoons are superior to future F-15s.

Let me go on in your article: "
The argument that the smaller fighter can fly out in a less encumbered configuration, and rely upon a tanker, disregards the need for enough internal gas to safely if an AAR fails over water."

What a lame argument. Air-to-Air refuling is a common practice today. If your pilots don't know how to do this properly, then they should get more training.

Let's go on:
"By the same token, the use of higher thrust growth EJ200 engines in the Typhoon alleviates the problem, but it would still remain behind an F-15F fitted with the growth 32 klb F100-PW-232 or its GE equivalent F110 variant."

That's interesting, so here we are comparing future Typhoons to possible future F-15Fs with improved engines. An improved version of the EJ200 has already been developed, it's called EJ230. This engine has about 20% more thrust than the EJ200 and is equipped with thrust vectoring!. In this configuration the Typhoon is being offered to India. So how does that improve the Thrust/weight ratio of the Typhoons?

Thrust/weight Typhoon with EJ230:
maximum: 2.00; nominal: 1,41; minimum: 0,93

Now those are stunning figures to say the least. No plane, no Mig, no Sukoi, no F-15, no F-16 and no F-22, nothing would come close to this airplane in terms of agility.

1.2.2 Turn Rates

Although it is difficult to estimate the turn rates of an airplane, there is one parameter, which is widely considered to be highly relevant in this regard. Given the fact that the Eurofighter is highly inherently unstable whereas the F-15 isn't, we are applying a large penalty on the Typhoon if we are judging the turn rates of the F-15 and Typhoon solely on the basis of the respective wing load. So how do they compare?

Wing load Typhoon:
minimal = 220 kg/m²; nominal = 310 kg/m²; maximum = 470 kg/m²
Wing load F-15C:     minimal = 236 kg/m²;nominal = 368 kg/m²;maximum = 546 kg/m²

The lower the wing load, the faster the turn rates. Oh well, that doesn't look good at all for the F-15. Add to that the F-15Cs penalty in terms of thrust/weight ratio, then the gap becomes even wider. Please also consider that the Typhoon has a very unstable airframe, which was the main technical obstical in its development. So we can safely assume that the Typhoon is going to out turn the F-15c easily.

How do future models of the Typhoon and F-15c compare in this manner? Well, the thrust/weight ratio penalty gap is going to widen with the EJ230 engine. Adding thrust vectoring to the Typhoon is also foreseen. Result? The F-15C is thoroughly outclassed.

1.3. Performance considerations withing visual range.

So now that we have firmly established that the Typhoon is vastly superior to the F-15s in beyond visual range combat, let's look at their performance within visual range.

a) Stealth: A clear advantage for the Typhoon. It is considerably smaller and therefore more difficult to see. It can supercruise at high speeds, whereas the F-15 can't. Therefore, it is less visible both in terms of eye visibility and infrared visibility.

b) Sensors: The Pirate infrared sensor - non-existent for the F-15 - offers a clear advantage in terms of seeing enemy planes. Sensor fusion means that this information is readily available to the pilot. Care-free-handling and head up display in the helmet means that the pilot can keep his eyes on the enemy aircraft while trying to outmaneuver it.

c) Affectors: The Typhoon has the best short range infrared missiles available on the market, the IRIS-T. It is vastly superior to the common AIM-9 sidewinder. The missiles agility is such that it can be shot at targets behind the airplane. The Mauser BK-27 gun of the Typhoon also appears to be superior to the respective gun on the F-15. The Mauser BK-27 gun was originally intended for the F-35 but dropped later on due to its high price.

4) Agility: The Typhoon both accelerates and turns faster than the F-15

So in a dogfight the Typhoon's superiority is formidable. I wonder why you failed to mention this?

So what was your overall conclusion again? "In terms of where to position the Typhoon in the current menagerie of fighter aircraft, it can be best described as an F/A-18C sized fighter with BVR systems and agility performance better than older F-15 models, similar to growth F-15 models with same generation systems and engines, but inferior to the F-15 in useful operating radius."

I think it would be fair to say, that the current Typhoon is in a different class than current F-15s in each and every aspect. This is true for current as well as probable future configurations of both aircraft. This is true for any operating range; it is true for beyond visual range combat as well as within visual range combat.

1. Typhoon vs. F-22

I think that the current F-22 is superior to the Typhoon in BVR combat situations. Why?

a) Stealth: The radar cross section - although classified - is probably at around 0.01
(radar cross section of a bird has been spouted around) from the front, whereas it is around 0.05 to 0.1 for the Typhoon. Furthermore, the F-22 can super cruise at higher speeds than the Typhoon (Mach 1.8 vs. Mach 1.2). So the F-22 is less "visible" both in the infrared as well as in the radar spectrum.

b) Sensors: The F-22 has a superior active Radar (ASEA) than the mechanical scan radar of present Typhoons. However, the F-22 lacks IRST technology. So depending how much you value an active radar over a passive infrared detector and passive radar detector, you will come to one or the other conclusion. Given that the mechanical radar of the Typhoon is no slouch, I'll say it's a draw.

c) Affectors: Both F-22 and Typhoon use the same medium range missiles. So this is most definitely a draw.

d) Agility:
F-22:                minimum = 0,84; maximum = 1.62
Typhoon:         minimum = 0,78; maximum = 1.67

F-22:                 minimum = 252 kg/m²; maximum = 487 kg/m²
Typhoon:          minimum = 220 kg/m²; maximum = 470 kg/m²


Let's again look at the operating range of both aircraft: 

Ferry Range: F-22 = 3,219 km; Typhoon = 3,790 km

So this looks like the typhoon has the edge: This is what the US air force chief of Staff has to say:

""The Eurofighter is certainly, as far as smoothness of controls and the ability to pull (and sustain high G forces), very impressive," he said. "That is what it was designed to do, especially the version I flew, with the avionics, the color moving map displays, etc. -- all absolutely top notch. The maneuverability of the airplane in close-in combat was also very impressive."

The F/A-22 performs in much the same way as the Eurofighter, General Jumper said. But it has additional capabilities that allow it to perform the Air Force's unique missions.

Given that the US air force chief of Staff is most likely biased in favor of American Aircraft, I would assume that the Typhoon is even slightly superior in terms of agility.

Overall the F-22 is superior in terms of beyond visible range combat due to its greater stealth, ability to supercruise at higher speed (mach 1.8 vs. mach 1.2) and better radar. Is the Typhoon outclassed? I don't think so and the US air force chief of Staff agrees with me.

"One advantage of having flown the Eurofighter, General Jumper said, is that it allows him to get first-hand knowledge of technology U.S. allies use and to see how America's handiwork stacks up. He said he believes the two aircraft are running neck-and-neck, but America must always be vigilant to ensure it stays on the cutting edge of aviation technology."

So how do future versions of the F-22 and Typhoon compare ? At the moment, no future versions of the F-22 are predictable. The maintenance costs and technical problems of the F-22 are still outrageous, wherefore the US airforce has stopped ordering more F-22 fighters. Until these technical problems have been solved, we won't see any additional improvements to the F-22. But, we do know of several improvements that are going to be available for the Typhoon.

Future F-22 vs. Future Typhoon

a) Stealth: The advantage of the F-22 will stay largely the same. The new EJ230 will mean that the Typhoon is going to narrow the gap in terms of supercruising speed.

b) Sensors: The introduction of the captor-E ASEA radar will mean that the Typhoon is going to have a better active radar than the F-22. The addition of the infrared sensor PIRATE with no equivalence on the F-22 means that the Typhoon is going to have clear advantage in terms of sensor performance.

c) Effectors: The MBDA Meteor is going to be added to the Typhoon, the Typhoons long range rockets are going to outclass the medium range air-to-air missiles of the F-22.

d) Agility: By adding the EJ230 engine including thrust vectoring, the Typhoon is going to enjoy a considerable advantage over the F-22 in terms of agility.

So b), c) and d) shall speak for the Typhoon, compared to a) in favour of the raptor. Now, you can still believe that the Raptor is still going to be superior to the Typhoon in BVR, but only if you think stealth is the be all and end all of fighter plane design. You probably don't think so and will have to accept opinions that hold the future Typhoons will be superior to future F-22s, if the F-22s have any future at all.

Last but not least, how do the weapon systems compare in visual range performance? The Typhoon has a clear stealth advantage due to its much smaller size. The infrared sensor and sensor fusion means that the sensor suite of the Typhoon is superior in this situation. Finally, the short range rockets IRIS-T and Gun
Mauser BK-27 of the Typhoon are superior to the Aim-9 sidewinder and gun of the F-22. There are no signs that this is going to change in the foreseeable future. Apparently, the agility of the Typhoon is currently slightly superior to the F-22, but both fighter are neck-to-neck in this field. With the inclusion of the EJ230 including thrust vectoring, the typhoon is going to have a considerable edge in this area. So in any possible measure, the Typhoon beats the F-22 in a dogfight, although the F-22 is still a top contender in this area.

What is my personal conclusion? Future versions of the Typhoon are going to beat the F-22 in any possible performance measure except for the radar cross section. Consequently, the Typhoon is going to be better than the F-22 performance wise. It depends on how much you value this stealth feature compared to all other performance measures of a fighter. Oh, and we haven't even talked about the price! The F-22 is almost twice as expensive as the Typhoon in acquisition costs and far more expensive in terms of maintenance costs.

I understand that you are a huge fan of the F-22 and want the Australian Airforce to acquire these planes. But, if you can't get them, not even for 200 million $ per F-22, why not get the best plane on the market? The Typhoon for half the price? The F-35 is not a fighter, it merely has low visibility from the front in terms of radar cross section and is inferior to the Typhoon in any other possible way. So we agree that Australia should scrap the F-35, which should really be called A-35.

Finally, I would like to comment your recommendation to the UK to scrap the Eurofighter Typhoon and buy plenty of F-16 instead:
"As can be seen, in Figure 11 even at an average exchange rate of 1.5 USD to 1 GBP the Royal Air Force F-16 Air Force of 594 aircraft would be expected to be able to defeat decisively the planned 232 Royal Air Force EFA Typhoon Air force with no surviving deployed EFAs after 312 sortie cycles, 7,545 targets destroyed and 86 deployed F-16s surviving...."

Well, recent numbers indicate that a single F-16 costs around 50 million $, whereas a single Typhoon costs around 100 million $. So buying 594 F-16 would be a lot more expensive than getting 232 Typhoons.

India gave no second thought to the upgraded F-16s due to their poor performance compared to the Typhoon. Either the Rafale or the Typhoon are going to win the competition.
Given that the typhoon is "running neck-and-neck" with the F-22 and the F-22 has a kill rate in the order of 10 to 15 in relation to the F-15, it appears safe to assume that the kill rate of the Typhoon in relation to the F-16 is also in the order of 10. Consequently, your recommendation to scrap the 232 Typhoons in favour of 594 F-16 would have been more expensive and resulted in a far inferior air force.

We can actually put this into numbers given the studies you cited agree with the US airforce chief of staff impressions:

"The magic 82% number is derived from a mid nineties DERA simulation against a postulated Su-35 threat. The number is based upon the rather unusual metric of probability of successful engagement in BVR combat, rating the F-22 at 91%, the Typhoon at 82%, the F-15F (single seat E) at 60%, the Rafale at 50% and the F-15C at 43%.

This means that the probability of a successful engagement of the Typhoon is at around 90% of the probability of success of the F-22, namely 82/91*100=90%. If the term "neck-and-neck" makes any sense at all, then it must apply in this case. And this merely relates to beyond visual range combat. The figures should become even closer if you include within visual range combat.

Or did I miss any major argument in favour of the F-22, F-15 or F-16? I really don't think so. So maybe you should reconsider your opinion.


Recent reports about mock combat between the Typhoon and F-15 bear out my opinion. Accordingly, 2 spanish typhoon successfully engaged 8 F-15.

"In an interview on the exercise, Major Juan Balesta, the 41-year old Commander of the 111 Squadron stressed that a two-ship formation of Eurofighters involved in a dogfight simulation "against" the F-15s enjoyed full control of the engagement. The Typhoons managed to smash a formation of eight F-15s which had the role of the attacker with the first Eurofighter jet managing to "shoot down" four F-15 fighter jets. The second Eurofighter managed to disable three F-15 jets. Eventually the pilots were using the Eurofighter Typhoon to full capacity and taking advantage of its enormous capabilities. Trump that."

Furthermore, German typhoon pilots had raptor salad when engaging F-22s in one on one mock battles:

"If you want to shoot down an F-22 in a Eurofigher Typhoon (pictured directly above), here's how:
Step 1: Find the F-22 on infrared. The Raptor is very hard to spot on radar, but it's big, and it's hot. A Typhoon can pick up a Raptor from about 50 kilometers away with infrared sensors.
Step 2: Get close and stay close. F-22s excel at long-range combat, so bring the fight to them.
Step 3: Force an aggressive, turning dogfight. In its slickest configuration (without external fuel tanks), the Typhoon (which is smaller, lighter and more powerful) can outmaneuver, outaccelerate and outclimb the F-22. The Raptor does have those fancy thrust vectoring engines, but using the thrust vectoring takes a lot of energy, meaning that the Raptor can make rapid direction changes but becomes vulnerable immediately afterwards as it "sinks" and has to recover.
Step 4: Use your helmet-mounted sight to engage. Technical problems prevented the Raptor from being designed with an integrated helmet sight, which lets Typhoon pilots simply look at a target to lock onto it."

1 Kommentar:

  1. I'd say that Typhoon can find F-22 even further away at infrared, but anyways.

    Thrust vectoring is also less useful than commonly assumed, F-22 *cannot* make a rapid direction change, it can point the nose rapidly but it continues flying in previous direction for some time. Anyway, TVC = higher AoA = higher drag; couple that with fact that it also causes loss of lift, which has to be compensated for by thrust, and it means that TVC usage results in huge energy loss for no gain in turn rate. Reason F-22 has it is a) it improves supersonic agility, and b) it allows F-22 to reach angle of attack required for maximum lift (which aerodynamically it can't).