Is the Typhoon a
Demon or a Lemon?
Given
the vigorous marketing effort of the Eurofighter consortium both in Europe and
Australia, and the often extremely hostile coverage the aircraft has received
in the international press, and moreso UK press, it is worth exploring the
aircraft's strengths and weaknesses against some established baselines.
The aircraft's counter air performance is cited as its major strength, and it
is frequently cited to be “82% as effective as an F-22”.
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%.
The probability of a successful engagement can be translated into the more
commonly used metric of a kill ratio by making some reasonable statistical
assumptions, and doing this yields about 10.0:1 for the F-22A, 4.6:1 for the
Typhoon, 1.5:1 for the single seat F-15E, 1:1 for the Rafale and 0.75:1 for the
F-15C. So in the most common terms used, the Typhoon is by the DERA simulation
about half as combat effective as the F-22A, about three times as combat
effective as the F-15F, about five times as effective as the Rafale and 6 times
as effective as the F-15C. If we compare this with cited USAF claims rating the
F-22A as 10-15 times as combat effective as the F-15C in BVR engagements, this
means that the DERA study roughly agrees with USAF assessments of F-22A vs
F-15C combat effectiveness. The detailed assumptions applied to this study have
not been disclosed.
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. 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.
Therefore it is likely that most of the supporting assumptions used in the
study are very stale, if not irrelevant. Until Typhoons are equipped with the
AMSAR and Meteor, the projected 4.6:1 BVR kill ratio is by any measure
optimistic, against an evolved Su-30 variant.
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. US longwave IRS&T technology is available off-the-shelf
and would much reduce any advantage conferred by the PIRATE to the Typhoon.
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.
The clean Typhoon, with 50% internal gas and 6-8 AAMs is firmly in the class of
the F100-PW-229 powered F-15F, on dry thrust, and about 15% behind the F-15F on
reheat. Where the Typhoon falls behind the F-15F is when its operating radius
is stretched and additional external gas is being carried. 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. 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. These are very approximate
estimates, not accounting for combat gas, but even doing a very accurate
simulation would yield the inevitable conclusion - an F/A-18 sized fighter, no
matter how agile when clean, cannot compete in thrust/weight ratio with an F-15
sized fighter at extended operating radii.
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. 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.
Clearly in any scenario where unrefuelled operating radius is not a major
issue, the Typhoon is a highly competitive conventional fighter, and exceeds
the capabilities of an F-15 variant without a phased array and extended range
AAMs. However, a new build F-15 with current technology engines, and
AESA/ramjet AAM package will maintain a healthy performance margin even over a
growth variant of the Typhoon, and an operating radius advantage. The relative
effectiveness would then boil down to issues such as tactics, and any relative
advantages of the specific AAMs carried and radars fitted.
The comparative advantages of the Typhoon over the Su-27/30 family exhibit
similar sensitivities to technology upgrades in the Sukhoi fighters. Fitted
with a phased array, longwave IRS&T, carrying ramjet R-77M missiles,
supported by SuAWACS, and using growth engines we must seriously question how
great a lethality margin the Typhoon would hold against such a fighter. The
Sukhoi, inevitably, exhibits the same thrust/weight ratio advantages the F-15
does in extended range combat, which was a design objective for this type as it
was for the F-15.
In comparing the Typhoon against the only other fighter in its weight class,
the F/A-18A/C, the benefits of using later generation technology show very
clearly. The Typhoon outperforms the F/A-18A/C in BVR weapon system capability
as well as aerodynamic performance. While much better than the F/A-18A/C in
operating radius and agility, its optimal operating radius is not in the class
of the F-15 and Su-27/30.
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