"The Raptor will be the fighter that
regains the high ground", this is how Lockheed Martin F-22 Chief Test
Pilot, Paul Metz, describes a fundamental change in fighter tactics to
be employed with the F-22: coming out of the 'weeds' on ingress to the
target and 'taking the high ground' at medium to high altitude using
stealthy supercruise technology and tactics.
In this world exclusive interview, Air
Power International's Carlo Kopp asks Paul Metz about the great
innovations being incorporated into the 'Raptor', innovations that will
fundamentally change the way fighter pilots fly combat missions, and
survive those missions. He describes how sensor fusion will allow the
pilot to concentrate on fighting the opposing aircraft or attacking the
target - confident that multi-sensor inputs have produced a complete
target picture. The concept of software that synthesizes the
traditional
radar, ILS and communications 'black boxes', and can continuously
evolve
through the life of the aircraft, has far-reaching implications for a
fighter which is expected to remain in service for three decades, and
for future fighter designs.
In the following interview, Paul Metz
comments on many of the fundamental questions which are today being
asked about the future direction of fighter aircraft evolution.
Kopp:
Paul, as a former Northrop TP on the YF-23, and now the
chief TP for the Lockheed-Martin/Boeing F-22A, you have had a long
association with the USAF's Advanced Tactical Fighter Program. Could
you
elaborate on some of the thinking behind the program, and the decisions
to integrate revolutionary technology such as stealth, sustained
supercruise and sensor fusion into the program?
Metz:
The decision to integrate the technologies of stealth,
supercruise, super-maneuverability and sensor fusion was the result of
significant advances in each of these areas in the 1970s and 80s. In
particular, stealth technology had advanced to the point that high
lift,
high angle of attack aerodynamic shapes could co-exist with stealth
requirements. This was a significant evolution from the first
generation
stealth aircraft represented by the SR-71 and A-12. Second generation
stealth as evidenced by the F-117 had yet to allow aerodynamic
efficiency to co-exist with stealth. Only with the third generation of
stealth inherent in the B-2 bomber were we able to achieve efficient
aerodynamic shapes with a low radar signature.
Supercruise became a practical reality with innovative
engine cycles which produced high thrust to weights in the
non-afterburning range of engine operation. These engine technologies
were demonstrated during the Demonstration and Validation of the
Advanced Tactical Fighter concept in 1990 by both General Electric and
Pratt and Whitney. Supermaneuverability (the use of vectored engine
thrust to point the nose of the aircraft at virtually zero airspeed)
was
explored in the 1980s with the F-18 HARV and X-31 research programs and
demonstrated during the ATF prototype phase. This technology was
important for the slow speed dog fight where point-and-shoot missiles
were still employed, but it had performance payoffs in supersonic
flight
as well. The concept of sensor fusion was driven solely by the
explosive
gains made in computer size and power requirements, which are still
proceeding rapidly today. For the first time, it was possible to put
massive computing power into a fighter-size airframe and provide the
pilot with simple, intuitive pictures of the tactical world surrounding
his aircraft. The ability to gather information, compare and analyze it
at the computer level and present it simply at the operator level meant
the pilot would not have to be a part-time data analyst and systems
operator but could devote his total mental capacity to being a
tactician
- the job the human operator does best.
The synthesis of these four technologies meant that a
new generation of fighter aircraft was practical, which could leap frog
us over our future adversaries. There is another subtlety of the
decision to build a new fighter aircraft that is not readily apparent
when talking only about the four new technologies above: overriding the
decision to build this next generation Advanced Tactical Fighter was
the
realization that national budget pressures would not allow the purchase
of large numbers of aircraft, and that this new aircraft would be in
service for well over 30 years. While the ATF would have ascendancy
over
other fighters when it was built, how could that ascendancy be retained
after 30+ years? With fighter aircraft being defined more and more by
their sensor or avionics capability, and computers being exponentially
more powerful, how could the F-22 expect to remain viable in 10, 20 or
30 years from now? New aircraft every 10 years was not politically or
fiscally viable so how could we maintain ascendant air superiority for
30+ years? The answer was to turn the F-22 into a 'changeling', a
fighter that could alter its sensor 'shape' at will. To do this, the
F-22 was designed so that it has no dedicated 'black boxes'. For
example, the F-22 does not have a radio, an Instrument Landing System
(ILS) or a radar - at least in the sense that we have come to know
these
devices. You cannot, for example, remove the UHF radio box from the
F-22 and inspect it. What we have learned to do is emulate the radio
(and radar and ILS and many other functions) in software rather than
hardware. Like booting up a Microsoft Word application on your PC, the
F-22 boots up the UHF RADIO application on a micro processor. These
common integrated processors or CIPs are composed of identical modules,
any one of which can boot up the UHF RADIO application program. The
power of this approach is obvious. If battle damage should take out the
processor handling your UHF radio, one of the spare modules re-boots
the
UHF RADIO application and you are back in business. But the real power
of this use of the computer is to project the F-22 30+ years into the
future. As we develop new and now-unknown weapons and sensors of the
future we will simply reboot the F-22's computers with the new
applications rather than build new and expensive black boxes. The
exciting thing is that computers continue to get smaller and use less
power. That means that the computer 'hole' in the F-22 structure where
the existing CIPs reside today will hold much greater computer power 30
years from now. The aircraft will not have to go through expensive and
time consuming structural changes to add blisters, bumps and cavities
to
house new hardware. New capabilities will become the software
application of the future. 'Boot me up, Scotty.'
Kopp:
It is understood that both the YF-22 and the YF-23 met
the USAF's performance and capability criteria for the ATF contest.
Since you have flown both aircraft, could you comment on your
observations of relative handling and performance between the two
prototypes?
Metz:
I do not make direct comparisons between the two
prototypes. In fact, no pilot ever flew both prototypes so a comparison
between a prototype and a production-representative fighter may not be
of value. The USAF position was that both the YF-22 and YF-23 met the
requirements set forth by the Air Combat Command for an Advanced
Tactical Fighter. Both the Pratt and Whitney YF119 and the General
Electric YF120 engines were superb and provided eye-watering
supercruise
capability. I will say that the handling qualities of the F-22 have
been
superb to this point in the test program. The match of the aircraft to
the wind tunnel and simulator predictions is very close and I would
expect it to remain so as we expand the flight envelope.
Kopp:
Sustained supercruise is a vital aspect of the ATF
package, could you comment on the implications of this, and how the
F-119 differs in performance from current generation conventional
turbofans, some of which nominally achieve similar static thrust
ratings?
Metz:
Supercruise is vital to the entire concept of a
stealthy
fighter. Stealth alone does not make you 'invisible' , only very small.
Speed confounds the enemy's problem by reducing the time allowed to
detect, lock on, launch and have the missile or gun rounds reach your
aircraft. Taken to its extreme, a fighter that could travel at the
speed
of light could probably survive on its speed alone. By the time you saw
your speed-of-light fighter, it would be long gone. The F-22 has yet to
conquer warp speeds but the high sustained supercruise speeds are a
distinct advantage in evading the enemies weapons.
The F119 is the 'push' for supercruise, and it differs
from conventional turbojets and turbo fans in several ways. Firstly, it
is a low bypass turbofan. Turbojets are most efficient at supersonic
speeds and turbofans are most efficient subsonically. The low bypass
design of the F119 is optimized for sustained supersonic speeds. In
addition, the use of digital engine controls, advanced turbine
materials
and cooling concepts allow the turbines to be controlled precisely near
their maximum temperatures. High turbine temperatures allow high thrust
at supersonic speeds where conventional engines must reduce airflow
and,
consequently thrust, to preserve the turbine blades.
Kopp:
What are your observations of in-flight engine handling
with the F-119 powerplants, especially in the transonic and supercruise
air combat regimes? How does the much higher sustained turbine inlet
temperature rating impact the pilot? Does he still have to fly with one
eye on the TIT gauges?
Metz:
The F-119 is, like most modern digital-controlled
engines, a 'set-it-and-forget-it' power plant. Amazingly, the engine is
able to self-diagnose its own health and performance and adjust its
operation accordingly to keep thrust at a maximum. For example, the
engine's own internal computers and sensors allow it to run a model of
what the optimum engine should be doing at a particular flight
condition. This theoretical engine model is then compared to the
engine's actual performance using on-engine and on-aircraft sensors.
The
engine can then re-adjust itself to match the 'perfect' engine as
represented by the engine model it computes. The real power of this
technology is applied in combat. When the engine has failures of
sensors or components that would fail a conventional engine, the
computers can synthesize values for the failed parameters and the
engine
will continue to run. Pretty astounding technology which gives new
meaning to the phase, "Doctor (or Engine in this case), heal thyself".
These engines simply give the pilot what he asks for when he asks for
it. Concerns over compressor stalls, over temps and similar engine
problems are a thing of the past. Digital control of the engine's fuel
flow and geometry allow the engine designer to extract maximum
performance from the engine by running up to but not beyond stall
margins. Parameters like EGT are monitored and controlled by the FADEC
or full authority digital controls, the 'brains' of the engine. Quite
frankly, modern fighter engines are so reliable in this regard that
pilots tend to not monitor their engine instruments any more than you
monitor your car's engine instruments (if you have instruments at all).
We have achieved that level of sophistication and reliability.
Kopp:
There is some debate in the fighter community about the
relevance of thrust-vectoring in this day and age of Helmet Mounted
Displays and 4th Generation heaters. What advantages do you see in
having thrust vectoring, and how does it influence both instantaneous
and sustained turning performance in the F-22A?
Metz:
Thrust-vectoring is often thought of in terms of the
classic 'dogfight' where one aircraft is trying to out-turn his
opponent
at ever decreasing airspeeds. Whether a pilot should ever engage in
these slow speed fights is a matter that is hotly debated within the
fighter pilot community. Certainly, there is general agreement that it
is best to not get slow - ever. With the advent of the helmet mounted
sight, 4th generation heat seeking, off-boresight missiles the slow
dogfight becomes even more dangerous. 'To slow or not to slow' are
questions of tactics and best left to the expert fighter pilots of the
future. The F-22's thrust-vectoring can provide remarkable nose
pointing
agility should the fighter pilot choose to use it. What is not widely
known is that thrust-vectoring plays a big role in high speed,
supersonic maneuvering. All aircraft experience a loss of control
effectiveness at supersonic speeds. To generate the same maneuver
supersonically as subsonically, the controls must be deflected further.
This, in turn, results in a big increase in supersonic trim drag and a
subsequent loss in acceleration and turn performance. The F-22 offsets
this trim drag, not with the horizontal tails, which is the classic
approach, but with the thrust vectoring. With a negligible change in
forward thrust, the F-22 continues to have relatively low drag at
supersonic maneuvering speed. . But drag is only part of the advantage
gained from thrust vectoring. By using the thrust vector for pitch
control during maneuvers the horizontal tails are free to be used to
roll the airplane during the slow speed fight. This significantly
increases roll performance and, in turn, point-and-shoot capability.
This is one of the areas that really jumps out to us when we fly with
the F-16 and F-15. The turn capability of the F-22 at high altitudes
and
high speeds is markedly superior to these older generation aircraft. I
would hate to face a Raptor in a dogfight under these conditions.
Kopp:
In terms of aircraft handling and manoeuvre
performance,
how does the F-22A compare with established types such as the F-15 and
F-16 in areas such as transonic acceleration, supersonic acceleration,
climb rates, and supersonic sustained turn rates? How does the
supersonic energy bleed in manoeuvres compare to teen series fighters,
optimised for transonic energy bleed?
Metz:
My previous answer touched on the subject of maneuver
performance. It is interesting to fly an airplane like the F-22 which
is
optimized to fly supersonically as a matter of course compared to
current generation fighters designed for momentary or transitory
excursions supersonically. An example may illustrate this. The best
subsonic afterburner climb speed in the Raptor occurs at 600 knots
calibrated airspeed.
The fastest way to get to altitude in a Raptor is to
accelerate to supersonic on the deck and climb all the way
supersonically. Sorry, I can't quote the numbers but suffice is to say
that we are talking high supersonic climb speeds. The F-15, on the
other
hand, has its best climb rate when the climb is made subsonically to
30,000-35,000 feet and the aircraft is then dived to a supersonic speed
before once again pulling up into a supersonic climb. The difference in
time to climb using the Raptor versus the Eagle climb technique is
dramatic but, again, classified.
You also asked about handling qualities, which is a
different subject than raw performance. Handling qualities refers to
how
hard the pilot has to work to accomplish a task. An airplane can be a
great performer but, if the pilot is sweating bullets just to keep it
upright and under control, it isn't a particularly usable machine. We
formalized the desired handling qualities of the F-22 with the
engineers
early in the design process by defining 'carefree abandon' flying
qualities. This meant that the pilot could do anything with the stick
and rudder as well as the throttles with the assurance that he would
never overstress the structure and break it; that he would never lose
control of the airplane, or that he would never have his engines
'backfire'. Many hundreds of simulator and engine wind tunnel tests
resulted in an airplane that today meets those expectations. The
importance of 'carefree abandon' flying qualities is that it makes
flying second nature and frees the pilot to concentrate on being the
wiley tactician that the human being is so adept at.
Kopp:
You are on record as describing the F-22A to be 'as
easy
to fly as a Cessna 150'. Knowing how over-damped the 150 is in all
axes,
the tempting question here is what is the damping like in the various
modes of the F-22A's fly-by-wire control system? Can you comment on FBW
behaviour in different flight regimes, and how this appears to the
pilot?
Metz:
Some days I wish I had never made that comment about
the
Cessna 150 and the ease of flying the F-22. I've had about a million
applications since then so I need to get the word out through your
publication. Here it is: "sorry folks, we're all sold out."
Seriously, the handling qualities are actually better
than a light aircraft since we have an active control system that damps
out unwanted disturbances to the flight path. Where a Cessna bounces in
turbulence the Raptor rides smoothly. The sensation in the cockpit is
of
a more direct connection to the airplane - a very solid link between
man
and machine. Quantitatively, the F-22 is well damped in all axes (the
technical term is 'heavily damped'). Since the Raptor is also an
unstable airplane it requires very little control deflection to start
it
moving in a new direction. The combination of unstable airframe with a
digital, fly-by-wire flight control system gives a cat-like quickness
but very predictable and pleasant flying qualities.
The flight control computers coordinate roll maneuvers
to eliminate adverse yaw so that rolls are executed with lateral stick
inputs with 'feet-on-the-floor'. Fly-by-wire is one of those
technologies that is totally transparent to the pilot. It is only when
you go back to an un-augmented airplane (such as your Cessna 150) or
less sophisticated flight control systems such as the F-15 that you
realize how much improvement you gain from a computer controlled
system.
As an example, the F-15 pilot can overstress or over-G his airplane,
particularly in the transonic region. As a result, the Eagle pilot must
constantly be alert to rapid aft stick inputs as he accelerates in a
fight. One careless input in an air-to-air fight and you can overstress
the Eagle. It has been done and continues to be a problem. As a result,
the Eagle driver cannot be quite as aggressive with his flying at all
times for fear of over-G. The F-16 pilot is a little better off but his
flight control system does not protect him from over-G while rolling so
he must also temper his aggressiveness in a fight. The F-22 pilot has
no
such concerns. Aside from diving the airplane directly into the ground,
the Raptor pilot can 'yank and bank' to his heart's content without
fear of over-G, loss of control or otherwise 'hurting' the jet. This
makes for one aggressive fighter pilot in a fight and makes the F-22 a
lethal opponent.
Kopp:
The F-22A cockpit sets a new benchmark in automation,
with virtually everything under software control, and sensor fusion
employed to reduce the pilot's workload in combat. What are your
observations on the aircraft's cockpit environment, in comparison with
contemporary fighters?
Metz:
Stealth, supercruise and supermaneuverability are the
components of the pilot's 'chariot'. The cockpit of the F-22 is the
design component that allows the chariot become a weapon system and the
pilot to become the charioteer. Several cockpit characteristics make
the
F-22 a departure from existing cockpit designs. The Raptor receives
numerous inputs from its own or 'onboard' sensors as well as data from
sources outside the aircraft (offboard sensors). Current fighters use
the pilot as the sensor systems operator to point or cue various
systems
and sensors to acquire data. The pilot must then become the data
analyst
to sort through these sensor inputs and determine what it all means.
The F-22 pilot is neither a sensor operator nor data analyst.
We looked at the cockpit problem from the outside in
when we sat down with the avionics engineers. For example, we asked
what
did the pilot really want to know and at what time did he need to know
it. We broke the airspace surrounding the Raptor into spheres or
'globes' where the pilot wanted to know specific things about the enemy
and tactics. For example the pilot would like to know when he is flying
undetected by the enemy. This area of 'cloaked' operation or the
'engage-avoid' globe allows him to move with impunity in the battle
arena. I-see-you-but-you-can't-see-me affords the fighter pilot a
certain degree of aggressiveness and tactical positioning prior to
using
his weapons. It allows him to not only position himself to maximum
advantage but he can also vector friendly forces and his own flight
members into positions of advantage: something akin to the perfect
ambush. Five globes were subsequently defined to give the pilot
knowledge about his surroundings, ranging from the engage-avoid globe
where the F-22 is invisible to the defensive zone where the enemy can
see and hit you with his weapons.
While the engage-avoid sphere may sound like a notional
space, we were able to translate this globe into specific physical
boundaries defined by sensor detection capabilities. But the importance
of the globes is this. The pilot is always presented the final,
analyzed
data about the enemy. The pilot does not directly aim, cue or point his
sensors in the F-22. He is not a sensor operator. The sensors are
automatically tasked to constantly search the entire volume of space
above, below, to the front and rear of the F-22 and then present the
information as a single, simple picture of the battle space.
The pilot is also not a data analyst. For example, the
sensors collectively determine that a particular aircraft is an enemy
and presents a red triangle when the enemy is identified as such. That
identification may be the result of inputs from one, two or six sensors
working together to conclude that there is one and only one enemy
fighter in that point in space. The pilot does not care nor does he
need
to know how the avionics conclude that there is a MiG-29 at 330� at
38.2
miles doing 0.85 Mach number at 30,000 feet. The MiG is real. It is
there and he needs to do something about it.
This de-coupling of the pilot from the role of sensor
operator and data analyst is the most profound change in cockpit design
since the advent of fighters. It frees up tremendous human RAM to use
for intuition, insight, innovation and inference - the attributes that
make a human being so dangerous and a fighter pilot so lethal.
Kopp:
The new APG-77 active phased array air intercept radar
embodies many of the technological ideas in fielded systems such as the
Aegis radar. Can you comment on what the implications are, of having
the
equivalent of a miniaturised SPY-1 in the nose of a fighter aircraft?
Metz:
I am not familiar with the Aegis radar system so I
cannot make a direct comparison. The main difference with this radar at
the pilot's station is that the pilot does not think in terms of his
radar or his EW suite or any of his specific sensors. With a
conventional fighter radar, the pilot must direct the radar beam to
search in specific areas and he must command the radar to lock on to a
detected target. In the F-22, the pilot does neither of these tasks.
The
radar is one contributor to a knowledge base of information about the
air and ground space surrounding the Raptor. The radar is self-cueing
and continuously searches all available space within its field of
regard. It can also perform multiple tasks at one time such as
searching
and tracking multiple targets. The radar does this with no pilot
interaction and inputs its findings to the core avionics which, in
turn, sorts and sifts this information along with inputs from the other
sensors to formulate a complete picture of enemy aircraft, friendly
aircraft and ground threats in the vicinity of the Raptor.
Kopp:
With all air-air weapons carried internally, the
aircraft has zero stores drag in comparison with teen series fighters
and their European cousins. Can you comment on the practical
implications, from a pilot's perspective, of carrying a fighter's
missile load internally?
Metz:
Internal weapons carriage has both pluses and minuses
from a design point of view. The obvious advantages are reduced drag
which translates into longer range, higher speed, better
maneuverability
and very small signature. The negatives are the challenges of having
weapons survive inside an acoustically noisy cavity, the changes in
performance and handling qualities when the doors are opened,
especially
at high speeds, and the requirement to lock on some weapons before
launch. Many of these problems were considered and demonstrated by the
Lockheed team during the prototype phase of the ATF program, and we
believe we have design solutions for each. One of the challenges of the
flight test program is to now validate those design solutions.
Kopp:
The F-22A Block 0 is intended to replace the F-15C in
the air superiority role; but also be capable of performing much of the
deep strike role currently performed by the F-117A, and previously the
F-111. The stated intent is to perform these missions dropping
GPS-guided internally-carried JDAMs, with Mk.83, BLU-110 warheads, and
later MMTD derivative 'Small Bombs'. Can you comment on the practical
and operational implications of abandoning the established 'hug the
ground' ingress to target and penetrating high/fast/stealthy to engage
surface targets?
Metz:
Hugging-the-ground tactics were, perhaps more than
anything, the impetus to develop stealthy aircraft. The advent of the
surface-to-air missile drove aircraft 'into the weeds' for
survivability. Unfortunately, this is very disadvantageous for several
reasons. Firstly, it opens you up to small arms and undirected AAA,
traditionally the most lethal of all defensive ground weapons.
Secondly,
it significantly reduces range. Thirdly, it reduces your own weapons
range. Fourthly, it reduces your ability to see and find the enemy (the
'high ground' is still the desired position). Finally, it is very
fatiguing for the pilot and we still lose a number of pilots and
airplanes when they simply run into the ground flying low altitude
combat. Until the advent of stealth, there was no way for a force to
survive at medium to high altitudes, so our fighter and fighter bomber
effectiveness has been sorely reduced by low altitude tactics. The
Raptor will be the fighter that regains the high ground.
Kopp:
One of the interesting design features on the F-22A is
the provision to jettison the wing pylons to regain both stealth and
performance, should this be required. Could you comment on this
facility, and its practical implications for the pilot?
Metz:
Jettisoning wing pylons is neither new nor unusual for
a
fighter aircraft. To my knowledge, all current fighters have provisions
for jettisoning some or all of their pylons. Certainly, the F-22 will
enter the initial phases of combat as a stealthy platform and will
continue in this mode until air superiority is assured for the
less-stealthy strike aircraft. The F-22 can carry out air-to-air or
air-to-ground missions in a stealthy mode. When air dominance is not in
question, the F-22 can operate in a non-stealthy mode carrying up to
5000 pounds of stores at each of four external hard points. The pilot
can jettison the stores and pylons at any time to 're-cloak' into the
stealthy mode and use his internal weapons.
Kopp:
The JSF is to have provisions to carry weapons
internally during the 'Day One of the War' scenario, to achieve best
stealth performance, and later carry external weapons when observables
are no longer an issue. Do you see any technological or performance
obstacles in doing the same with a Block 20 or 30 'Strike Raptor'? How
does the airframe/propulsion package measure up as a 'load carrier', in
comparison with established types such as the F-15E?
Metz:
The JSF concept of stealthy and non-stealthy weapons
delivery is similar to the one I postulated in the above question. The
Raptor is a larger airplane and hence a larger load carrier than the
JSF
but it can operate in this same dual-mode manner. As I mentioned, the
F-22 can carry a significant external load as well as an internal load
and, while the exact gross weights remain classified, the design of the
F-22A is capable of hauling large loads comparable to the F-15E Strike
Eagle. We will have to certify each new weapon for carriage and release
as they are identified but the basic load carrying capability exists in
the airframe today.
Kopp:
Can you comment on current progress in the flight test
program, and your intended strategy for clearing the aircraft envelope,
as the program progresses?
Metz:
The first three test aircraft are what I call an
'engine
and airframe'. That is, they do not have the sophisticated avionics of
the full up F-22 as their job is to expand the flight envelope. The
first aircraft will push out to maximum speed and maximum altitude
ensuring that the engines, flight controls and subsystems operate under
these extreme conditions. The second aircraft will explore the slow
speed envelope of the Raptor, concentrating on high angle of attack
flight, commonly referred to as 'spin' testing. Tragically, the Raptor
has 'carefree abandon' flying qualities and won't spin so our job will
be to punish the airplane at high angles of attack to prove the
forgiving nature of the design. In addition, this aircraft will perform
weapons separation and jettison tests. The third F-22 will be used to
test the structure to maximum Gs.
The fourth through ninth Raptors will be identical,
full-up rounds. They will contain all of the complex tactical avionics
we have talked about and will be identically configured at any given
time in the test program. The planned testing includes 4337 flight
hours
divided almost equally between the engine and airframe testing with the
first three Raptors and the avionics testing on the remaining six
aircraft.
The flight test program is progressing well with what I
would consider a normal number of problems at this formative stage of
the program. The problems encountered, while aggravating, have not
stopped the program and all have solutions either in work or already
applied to the airplane. That, after all, is why we have an engineering
and development phase in a new aircraft program and why my job exists
in
the first place. There is a lot of good news coming out of the flight
testing to date. Handling qualities, the 'carefree abandon' aspect of
the design, have been very close or right on the money. They match
simulator and wind tunnel predictions closely and are very gratifying
to
see come to life after years of development work in the simulator. The
engines are truly extraordinary and trouble free and performance is
breathtaking.
All in all, I look forward to exploring and proving the
potential of this remarkable fighter in the next three years.
Air Power International
would
like to thank Paul Metz for making his time available and to Ray
Crockett for his assistance.