Comparison and Development Analysis of F119-PW-100 &
F135-PW-100
Khalid Mehrab, Md. Zamiul Alam, Shadman Tahmid Haque
Department of Aeronautical Engineering
Military Institute of Science and Technology
khalidmehrab201922030@gmail.com, rafatridoy24@gmail.com,
shadmantahmid1234@gmail.com
Abstract
This comparison contains the performance analysis
between Pratt & Whitney F119 & the F135 while
showing the developments it has achieved. The
main quest for this article is to show the potential
of these engines to develop a new generation of
turbofan engines. While the F119 was built for
supercruise flight, the F135 is more of a stealthy
type as the successor of F119 to achieve the goals
of Joint Strike Fighter (JSF) program. Even for a
discontinued engine the F119’s design held
potential capabilities for further improvement
which has mostly been explored to bring the F135
and more upgrades are in the works. A few
adjustments and further development on these
designs may bring the engine for the sixth
generation fighter aircrafts.
Keywords- Pratt & Whitney F119, F135, Engine
performance, F119-PW-100, F135-PW-400, F135PW-600, F135-PW-100.
Introduction
The F119 engine was created for the F-22 Raptor,
however development was halted when the F-35
arrived with a developed engine (F135) from the
F119. Thanks to thrust vector technology, the F119 gave the F-22 remarkable maneuverability.
The F-135 is a development of the F119, resulting
in a significantly more advanced F-35. The F119PW-100 was first tested on the ground in February
1993. During September 7, 1997, the engines flew
for the first time on the F-22's maiden flight. There
were 507 engines made in total[30]. Pratt aided the
F119 Heavy Maintenance Center (HMC) at Tinker
Air Force Base, Oklahoma, in performing the first
Electronic copy available at: https://ssrn.com/abstract=4454666
depot overhaul of an F119 engine in 2013[1]. The
F119 was available in four different configurations,
three of which were prototypes.
F119-PW-100: Production engine for the F-22A
with larger fan and increased bypass ratio rated for
35,000 lbf thrust class.
YF119-PW-100N: Prototype engine for the YF23.
Fig- F-35[5]
YF119-PW-611: Prototype engine for the X-35.
Analysis
YF119-PW-614: Prototype engine for the X-32.
The F135 is an afterburning turbofan designed by
Pratt & Whitney for the Lockheed Martin F-35
Lightning II single-engine strike fighter. In 2009,
the first manufacturing engines were delivered [2].
The F135 was pitted against the GE/Rolls-Royce
F136 for powering the F-35. The first operational
production propulsion system was intended to be
delivered in 2007 to the United States, the United
Kingdom, and other international customers. The
F135 is still being manufactured to power the F-35.
For the three F-35 variants, the F-135 has three
different engines.
F135-PW-100: For the F-35A. Conventional
Take-Off and Landing (CTOL) variant [3].
F135-PW-400: For the F-35C naval variant built
with salt-corrosion resistant materials [3].
F135-PW-600: Used in the F-35B Short Take-Off
Vertical Landing variant [3].
Fig- F-22 Raptor [4]
Fig- F119 PW-100[6]
The F119 is a twin-spool axial-flow low-bypass
turbofan. It has a three-stage fan driven by a singlestage low pressure turbine and six-stage high
pressure compressor driven by single-stage high
pressure turbine. The F119 produces about 116kN
thrust and 156 kN with afterburner. The two spools
are counter-rotating, which results in weight
savings due to the elimination of a row of stators.
The requirement for the ATF to supercruise or fly
supersonic without afterburners, results in a very
low bypass ratio of 0.3 for the F119-PW-100 in
order to achieve high specific thrust. The F119 has
dual-redundant full authority digital engine control
(FADEC) [7]. The three-zone afterburner or
augmentor, contributes to the stealth of the aircraft
by having fuel injectors integrated into thick
curved vanes coated with ceramic radar-absorbent
materials (RAM). These vanes replace the
traditional fuel spray bars and flame holders and
block line-of-sight of the turbines. The nozzle can
vector ±20° in the pitch axis to improve aircraft
maneuverability and consists two wedge-shaped
flaps for stealth. The nozzles also contribute to
lower infrared signature by flattening the exhaust
plume and facilitating its mixing with ambient air
through shed vortices [8]. The engine has a design
life of 8,650 total accumulated cycles [9].
2
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Fig- F135[10]
On the other hand, the F135 brought the target of
the JSF program closer as it became the successor
of F119. The F135 is a mixed-flow afterburning
turbofan with a new fan and LP turbine [11]. It
produces 128 kN thrust and 191 kN with
afterburner. The lift for the STOVL version in the
hover is obtained from a 2-stage lift fan (about
46%[12]) in front of the engine, a vectoring
exhaust nozzle (about 46%[12]), and a nozzle in
each wing using fan air from the bypass duct (about
8%[12]). These relative contributions to the total
lift are based on thrust values of 18,680 lb. 18,680
lb and 3,290 lb. respectively [12]. In this
configuration most of the bypass flow is ducted to
the wing nozzles, known as roll posts. Some is used
for cooling the rear exhaust nozzle, known as the
3-bearing swivel duct nozzle (3BSD) [13]. At the
same time an auxiliary inlet is opened on top of the
aircraft to provide additional air to the engine with
low distortion during the hover[11]. A higher
bypass ratio increases the thrust for the same
engine power as a fundamental consequence of
transferring power from a small diameter
propelling jet to a larger diameter one [14]. When
the F135 is in the hover using the significantly
increased bypass ratio from the lift-fan, the thrust
augmentation is 50% [12] with no increase in fuel
flow. Thrust augmentation is 52% [12] in
conventional flight when using the afterburner, but
with a large increase in fuel flow. The transfer of
approximately 1⁄3 [15] of the power available for
hot nozzle thrust to the lift fan reduces the
temperature and velocity of the rear lift jet
impinging on the ground [15]. The F-35 can
achieve a limited 100% throttle cruise without
afterburners of Mach 1.2 for 150 miles [16]. Like
the F119, the F135 has a stealthy augmentor where
traditional spray bars and flame holders are
replaced by thick curved vanes coated with ceramic
RAM. Afterburner fuel injectors are integrated into
these vanes, which block line-of-sight of the
turbines, contributing to aft-sector stealth. The
axisymmetric nozzle consists of fifteen partially
overlapping flaps creating a sawtooth pattern at the
trailing edge. This creates shed vortices and
reduces the infrared signature of the exhaust
plume. The effectiveness is reportedly comparable
to that of the F119’s wedge nozzles, while being
substantially more cost effective and lower
maintenance [17]. The engine uses thermoelectricpowered sensors to monitor turbine bearing
health[18]. Engine reliability and ease of
maintenance have been achieved for the F135. The
engine has fewer parts than similar engines, which
improves
reliability.
All
line-replaceable
components (LRCs) can be removed and replaced
with a set of six common hand tools [19]. The
F135’s health management system is designed to
provide real time data to maintainers on the ground.
This allows them to troubleshoot problems and
prepare replacement parts before the aircraft
returns to base. According to Pratt & Whitney, this
data may help drastically reduce troubleshooting
and replacement time, as much as 94% over legacy
engines [20]. The first stage fan from the F119
engine for the lift fan. The engine fan and core from
the F100-220 were used for the core of the
demonstrator engine and the larger low-pressure
turbine from the F100-229 was used for the lowpressure turbine of the demonstrator engine. The
larger turbine was used to provide the additional
power required to operate the lift fan. variable
thrust deflecting nozzle was added to complete the
lift-fan technology and led to the development of
the current F135 engine [21].
Topic
Length
Diameter
F119-PW-100
16 ft 11 in (516 cm)
46 in (120 cm)
Dry weight
Bypass ratio
Maximum
thrust
3,900 lb (1,800 kg)
0.30:1
Military thrust =
26,000 lbf (116 kN)
With afterburner =
35,000 lbf (156 kN)
Thrust to
weight ratio
6.7:1 (dry), 9.0:1
(afterburning)
F-135-PW-100
220 in (559 cm)
46 in (117 cm)
max., 43 in
(109 cm) at the fan
inlet
3,750 lb (1,701 kg)
0.57 : 1
Military thrust
=28,000 lbf (128
kN)
with
afterburner=43,000
lbf (191 kN)
7.47:1 military
thrust
11.47:1 augmented
3
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Compressor
3-stage fan, 6-stage
high-pressure axial
flow compressor
Turbine
1-stage highpressure, 1-stage lowpressure counter rotating turbine
Annular combustor
2D
vectoring convergentdivergent
Combustor
Nozzle
1963 knots
3,635 Km/h
3-stage fan, 6stage highpressure axial flow
compressor
1-stage highpressure turbine, 2stage low-pressure
turbine
Annular
Thrust vectoring
nozzle of the
SVTOL variant,
improved
afterburner
1043 knots
1,932 Km/h
Maximum
cruise speed for
installing in F22 and F-35
respectively
Rear
temperature
Turbine Inlet
Temperature
2000°F
3,600 °F
3,000 °F (1,649 °C;
1,922 K)
Fuel tank
capacity
2400 gallon
9085 litre
3,600 °F
(1,980 °C;
2,260 K)
2760 gallon
10448 litre
engine and reduce maintenance costs. The goal of
Block 2 is to work with the US Air Force’s
Adaptive Engine Transition Program, with the
intention of introducing technology for an engine
rated at 45,000 lb. of thrust, for installation in a
sixth-generation fighter.
References
[1] PRNewswire. "Pratt & Whitney, U.S. Air Force
Complete First Depot Overhaul of an F119 Engine".
providencejournal.com
[2] F135 Engine Exceeds 12,000 Engine Test Hours as
Pratt & Whitney Prepares to Deliver First
Production Engines" (2009). Pratt & Whitney press
release.
[3] DP Staff Writer (October 5, 2019). "Pratt &
Whitney Awarded with $5.7B F135 Production
Contract"
[4] https://en.wikipedia.org/wiki/Lockheed_Martin_F22Raptor#/media/File:F22_Schematics.jpg
Table- Comparison of F119 & F135 [22][23][ 24][25][26]
Conclusion
The sectors which were developed of the F119 to
bring the F135 are weight, maximum thrust with
increased bypass ratio, temperature resistance,
vertical landing and take-off technology, lift-fan
concept, engine reliability and efficiency, stealthy
augmentor, low pressure turbine, fuel tank
capacity. The change in these sectors brought the
F135 closer to the JSF program, showing the
potential of the F119 engine as even further
improvements were done in 2017 to the F135. At
the end of May 2017 Pratt and Whitney announced
the F135 Growth Option 1 had finished testing and
was available for production. The Growth Option
1 offers an improvement of 6-10% thrust across the
F-35 flight envelope while also getting a 5-6% fuel
burn reduction. The upgrade requires the changing
of the power module on older engines. In June
2018, Growth Option 2.0 was announced by United
Technologies, parent company of Pratt &Whitney
to help provide increased power and thermal
management system (PTMS) capacity, providing
options for operators for instance if they are
wishing to upgrade to heavier weapons. A twoblock improvement plan for the F135 engine is in
motion. The goals of Block 1 are a 7–10% increase
in thrust and a 5–7% lower fuel burn. The plans
include better cooling technology for turbine
blades which this will increase the longevity of the
[5] https://media.defense.gov/2014/Mar/11/200078382
6/-1/-1/0/140310-F-NG006-007.JPG
[6] https://www.nationalmuseum.af.mil/shared/media/
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Capability". Pratt & Whitney. 10 September 2010.
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[14] V/STOL by Vertifan" William T. Immenschuh,
Flight International, 1 October 1964
[15] The Shaft Driven Lift Fan Propulsion System for the
Joint Strike Fighter" Paul M. Bevilaqua, American
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4
Electronic copy available at: https://ssrn.com/abstract=4454666
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//www.f135engine.com/docs/B-24_F135_SpecsChart.pdf
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[28] https://www.airforce-technology.com/news/prattwhitney-launches-growth-option-2-0-upgradef135-engine/
[29] Norris, Guy, Power plan, Aviation Week & Space
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5
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