The Shadow Phoenixs
22-01-2005, 00:07
Although the genesis of the S-37 remains unclear, some sources suggested that original layout was much closer to X-29A tailless scheme and that aerodynamic of early S-37 directly benefited from Central Aerohydrodynamics Institute (TsAGI) wind-tunnel tests with X-29A scale models. It is possible that S-32 may be a technology demonstrator, built to examine FSW aerodynamics and composite wing structures or may have started its life as one, but realities of 90's urged Simonov to take this project one step further in attempt to present the S-32 as a genuine contender for a fifth-generation fighter seeked by the Russian air force. This might explain the fact that the S-32 seems to be much too heavy for a research testbed, being a considerably larger aircraft than Northrop F-5 sized X-29A.
In fact, the S-37 is in the class of Su-27 as seen from comparison of its scale model to the advanced Su-27 Flanker model presented at the same meeting. Moscow Aerospace (MAKS 97) provided additional data on S-37 and confirmed that dimensions, performance and tandem triplane layout of the S-37 are similar to that of Su-37. First public photographs of the S-37 suggested that the front part of the fuselage including the 'hooded cobra' LERX could have come from the original S-37 canard-delta. If true, this could possibly clear up the origins of the S-37 index.
Forward Swept Wing
The early Soviet designs to feature moderately forward swept wing were Belyaev's DB-LK and Babochka aircraft and Mikoyan Gurevitch PBSh-2 (MiG-6) biplane. Captured at the end of WWII, German FSW Junkers Ju-287 was test flown by German and Russian crews. A six engined EF-131 was build and underwent extensive structural and flight testing until 1947, when theme was closed. At about the same time Pavel Tsybin build several testbeds LL (Letauchaya Laboratoriya) -1, -2 and -3 with stright, swept back and forward swept wings respectively (40 degrees). The LL-1 and LL-3 rocket powered gliders performed number of powered flights and provided TsAGI with much needed FSW data. In one of the flights LL-3 reached Mach 0.97 in dive.
Sukhoi Fifth-generation Fighter Philosophy
The FSW is a better performer at high angles of attack in post-stall manoeuvring much needed in close-in dogfight. The fact that Simonov had chosen FSW for his fifth-generation fighter once again confirms Sukhoi's commitment to the superagility as a crucial requirement for the next generation air-superiority fighter. This approach, so much different from western concepts of stealth, supercruise and BVR engagements, was taken to the limits in Su-37. The FSW S-32 fitted with TVC expected to outperform its stalemate in close-in dogfight involving post-stall flight regimes. Having the edge in manoeuvring, the S-32 is clearly catching up in stealth with US and European new-generation fighters. However even with its internal weapon bay and RAM coating, the new Sukhoi is a very different concept than F-22. The heavy accent on RAM rather than radar absorbing structures (RAS) is obvious. The reason for such attitude is not clear, although a combination of the technology limitations and operational doctrine is most likely candidate. The major components of radar stealth - RAM coatings and surface quality - are subject to the production and maintenance tolerance as it was shown by USAF F-117 and B-2 operational experience. Untightened screws, scratches or unfastened access panels were known to greatly deteriorate the RCS of the aircraft, reducing the engineering efforts put into aircraft design. It remains to be seen how Sukhoi will overcome the looser production standards of the Russian aircraft plans.
The Afghanistan experience where Sukhoi's encountered a thread of the shoulder launched infrared homing surface-to-air missiles such as Redeye, Stinger and SA-7, forced Sukhoi team to work on the reduction of the infrared signature of the Su-25. The results materialized in the Su-25T development - Su-25TM (Su-39 in Sukhoi's nomenclature). The installation of the intake cones hiding the turbine blades and efficient mixing of the exhaust with cold air reduced the IR signature of the Frogfoot from front and rear aspects. This fourfold reduction at expense of 2% lower SFC is indeed an impressive achievement. Further experiments with low visibility involved the advanced Flanker development prototypes, aircraft of 700 (Su-35,-37) and 600 (Su-30) series. These fighters wear eye catchy new camouflage schemes designed to reduce the visual signature of the aircraft on the ground and in the sky. One of the most interesting examples of Sukhoi experiments was a scheme applied to 701, designed to deceive space based optical systems. Some effort was directed in reduction of the radar cross sections of advanced Flankers as well. The Su-34,-32FN have optimized radar random shape, lack variable geometry intakes and were reported to have partial RAM coating. Recently Sukhoi stated that basic export models of Su-30MK can be treated with RAM to fulfill customer requirement for a lower RCS aircraft. Clearly benefitting from previous research, the S-37 prototype relies heavily on the Sukhoi's state of the art low observable technology. The forward swept wing, a conformal underfuselage weapon station(s), use of RAM and the inward-canted tailfins, suggest a further reduction of the aircraft radar signature down from similarly sized Flanker's 3-5 sq m. The extend of the reduction of the IR signature of the S-37 exhausts will depend on the choice of the trust vectoring nozzle. The F-22 type flat 2D nozzle can give a better results while 2D nozzle might contradict to Simonov's superagility ideas favouring 3D exhaust. The Saturn-Lulka was reported to work on reduction of the IR signature of the axi-symmetric trust vector controlled (TVC) Al-37FU power plant on non-afterburning regimes.
Powerplant
The scarce availability of trust vectoring Saturn-Lulka Al-41F engineered for the Mikoyan's article 1.42 forced Sukhoi to seek a replacement for the originally planned powerplant. According to MAPO MIG sources, the limited number of Al-41F are involved in Mikoyan's Article 1.42 tests and not available to Sukhoi's competitor. Reluctance of MAPO MIG made a trust-vectoring control (TVC) Al-37FU (sometime referred as Al-31FU where FU stands for Forsazh, Upravlaemoye soplo - afterburning, articulated nozzle) powerplant used in Sukhoi's Su-37 a natural choice for fifth-generation fighter, but would have been premature for the first S-32 airframe. Additionally, the availability of the Al-37FU could be a problem since all prototypes are involved in flight tests on the Su-37 and in the bench endurance tests. At the time of the Su-37 first flight only three Al-37FU were built.
The ultimate S-32 powerplant - Al-37FU - operates in automatic and manual modes. In manual mode the nozzle deflection angle is set by the pilot, and in automatic mode the axi-symmetric nozzles are controlled by the MNPK Avionika full-authority, digital fly-by-wire flight control system (FCS). The movable in pitch axis nozzle deflects ±15 degree at 30 deg/s by a pair of hydraulic jacks. The production Al-37FU will use jet fuel instead of hydraulic liquid to drive the nozzles. Surprisingly, as a temporal solution, instead of similar and widely available Su-27 Flanker's Al-31F powerplants, the S-32 prototype received a pair of Perm Aviadvigatel D-30F6 engines used on MiG-31 Foxhound interceptors. Designed by the 1980, this full authority digital engine control (FADEC) engine comprises six interchangeable modules and a core module.
Although powerplant accumulated several thousand flight hours and experienced no operational drawbacks, it has estimated 300 hrs life between overhauls (Russian engine maintenance is very different from western philosophy and term 'overhauls' has a different meaning). There were no reports on TVC versions of D-30F6.
The photographs of S-37 Berkut, show two details: the starboard tail sting is slightly longer than the port one and the two auxiliary intakes on the top of the fuselage. There are three reasonable explanations to the sting asymmetry: a) it houses a breaking or a spin recovery shute b) it is due to the asymmetric engine installation typical for prototypes. The port engine will be used to test a 3D TVC nozzle which will require adequate space for the yaw vectoring c) Sukhoi used two 2D nozzles oriented perpendicular to each other to control pitch and yaw separately. Combined action give a pseudo 3D effect. This last explanation is least likely since Lulka reported to have 3D TVC nozzle 'in the pocket' at the time of Farnborough 96. Auxiliary intakes could be used during take offs for increased air flow to the engines. These could have been repositioned from the underside of the aircraft due to the reduces radar cross section considerations or/and lack of the space taken by internal missile bay(s).
Avionics
In early September, defence-ministry acquisition chief Col Gen Anatoly Sitnov noted: 'What is the use of developing the Sukhoi fifth-generation fighter, if the aircraft's cockpit dates back to a second- or third-generation design?' While Sitnov statement clearly implying the state of the art of the S-32, one can hardly expect that a first test airframe will incorporate all innovations planned for the series production. Similarly, the sole Su-37 demonstrator flies with a counterweight instead of the advanced radar hence the aircraft is intended to explore among other things the trust vectoring modes of the new powerplant. However, the Su-37 fighter will have the top notch avionics suit which is tested on other 700 series airframes - Sukhoi Su-35s. It is expected that the sophistication of S-32 cockpit and avionics suit should at least match that of forth-and-a-half generation Su-35 and Su-37 aircraft. The cockpit of the S-32 does most certainly feature the color liquid crystal MFDs and wide angle HUD. The test proven in Su-37 demonstrator inclined pilot seat, a fixed pressure sensitive throttle and side-stick controller will also find its way to the cockpit of new fighter expected to impose even greater G-loads on pilot than superagile Su-37.
The type of the radar intended for S-32 is not known. The size of the random seems to be somewhat smaller than that of Su-27 family, possibly implying the smaller diameter antenna. Since the S-32 lacks the Flanker's sting, the placement of the rearward facing radar will be challenging at best.
Armament
The armament of the S-32 will most likely never get close to the air-to-air arsenal of Mikoyan's article 1.42, enjoying super long range K-37. However the ram jet version of AA-12 Adder, R-77PD (RVV-AE-PD), seems to be the most appropriate long stick for the new fighter. The missile's collapsible lattice stabilizers give R-77 family the compactness well suited for the internal weapon bay(s) of the stealth S-32. However, the aerodynamically superior lattice stabilizers have reportedly a much greater RCS than conventional surfaces, thus potentially revealing the position of the aircraft at the moment of the missile launch. The exact number of weapon bays is not known, although the total number of the hardpoints will be fourteen. The use of the internal/external weapon loads will depend on the mission.
S-37/S-32 vital statistics
Wingspan: 16.7 m
Length overall: 22.6 m
Height overall 6.40 m
Weight empty, equipped : 24,000 kg (52,910 lb)
Max T-O weight : 34,000 kg (74,960 lb)
Max level speed at height : 2,500km/h (1,350 knots)
Max level speed at S/L : 1,400km/h (756 knots)
Service ceiling : 18,000 m (59,050 ft)
Range with max fuel at height : 1,782 nm (3,300 km/2,050 miles)
Number of hardpoints: 14: 2 wingtip, 6-8 underwing, 6-4 conformal underfuselage
Air-to-air : R-77, R-77PD, R-73, K-74
Air-to-surface: X-29T, X-29L, X-59M, X-31P, X-31A, KAB-500, KAB-1500
Name: S37 Berkut
Constructor: Sukhoi
Armament: 14 hardpoints
Length: 22m60
Max Speed: 2500 km/h
Ceiling: 18000 m
height: 6m40
Weight Max: 34000 kg
Range: 3300 km
Span: 16m70
Crew: 1
Engines: 2
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F-22 Raptor
The F-22 program is developing the next-generation air superiority fighter for the Air Force to counter emerging worldwide threats. It is designed to penetrate enemy airspace and achieve a first-look, first-kill capability against multiple targets. The F-22 is characterized by a low-observable, highly maneuverable airframe; advanced integrated avionics; and aerodynamic performance allowing supersonic cruise without afterburner.
Stealth: Greatly increases survivability and lethality by denying the enemy critical information required to successfully attack the F-22
Integrated Avionics: Allows F-22 pilots unprecedented awareness of enemy forces through the fusion of on- and off-board information
Supercruise: Enhances weapons effectiveness; allows rapid transit through the battlespace; reduces the enemy’s time to counter attack
The F-22's engine is expected to be the first to provide the ability to fly faster than the speed of sound for an extended period of time without the high fuel consumption characteristic of aircraft that use afterburners to achieve supersonic speeds. It is expected to provide high performance and high fuel efficiency at slower speeds as well.
For its primary air-to-air role, the F-22 will carry six AIM-120C and two AIM-9 missiles. For its air-to-ground role, the F-22 can internally carry two 1,000 pound-class Joint Direct Attack Munitions (JDAM), two AIM-120C, and two AIM-9 missiles. With the Global Positioning System-guided JDAM, the F-22 will have an adverse weather capability to supplement the F-117 (and later the Joint Strike Fighter) for air-to-ground missions after achieving air dominance.
The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission. There are two basic external configurations for the F-22:
Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks.
Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations.
An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration. Prior to its selection as winner of what was then known as the Advanced Tactical Fighter (ATF) competition, the F-22 team conducted a 54-month demonstration/ validation (dem/val) program. The effort involved the design, construction and flight testing of two YF-22 prototype aircraft. Two prototype engines, the Pratt & Whitney YF119 and General Electric YF120, also were developed and tested during the program. The dem/val program was completed in December 1990. Much of that work was performed at Boeing in Seattle, Lockheed (now known as Lockheed Martin) facilities in Burbank, Calif., and at General Dynamics' Fort Worth, Texas, facilities (now known as Lockheed Martin Tactical Aircraft Systems). The prototypes were assembled in Lockheed's Palmdale, Calif., facility and made their maiden flight from there. Since that time Lockheed's program management and aircraft assembly operations have moved to Marietta, Ga., for the EMD and production phases.
The F-22 passed milestone II in 1991. At that time, the Air Force planned to acquire 648 F-22 operational aircraft at a cost of $86.6 billion. After the Bottom Up Review, completed by DOD in September 1993, the planned quantity of F-22s was reduced to 442 at an estimated cost of $71.6 billion.
A $9.55 billion contract for Engineering and Manufacturing Development (EMD) of the F-22 was awarded to the industry team of Boeing and Lockheed Martin in August 1991. Contract changes since then have elevated the contract value to approximately $11 billion. Under terms of the contract, the F-22 team will complete the design of the aircraft, produce production tooling for the program, and build and test nine flightworthy and two ground-test aircraft.
A Joint Estimate Team was chartered in June 1996 to review the F-22 program cost and schedule. JET concluded that the F-22 engineering and manufacturing development program would require additional time and funding to reduce risk before the F-22 enters production. JET estimated that the development cost would increase by about $1.45 billion. Also, JET concluded that F-22 production cost could grow by about $13 billion (from $48 billion to $61 billion) unless offset by various cost avoidance actions. As a result of the JET review the program was restructured, requiring an additional $2.2 billion be added to the EMD budget and 12 months be added to the schedule to ensure the achievement of a producible, affordable design prior to entering production. The program restructure allowed sourcing within F-22 program funds by deleting the three pre-production aircraft and slowing the production ramp. Potential for cost growth in production was contained within current budget estimate through cost reduction initiatives formalized in a government/industry memorandum of agreement. The Defense Acquisition Board principals reviewed the restructured program strategy and on February 11, 1997 the Defense Acquisition Executive issued an Acquisition Defense Memorandum approving the strategy.
The Quadrennial Defense Review Reportwhich was released in mid-May 1997, reduced the F-22 overall production quantity from 438 to 339, slowed the Low Rate Initial Production ramp from 70 to 58, and reduced the maximum production rate from 48 to 36 aircraft per year.
The F-22 EMD program marked a successful first flight on September 7, 1997. The flight test program, which has already begun in Marietta, Georgia, will continue at Edwards AFB, California through the year 2001. Low rate production is scheduled to begin in FY99. The aircraft production rate will gradually increase to 36 aircraft per year in FY 2004, and will continue that rate until all 339 aircraft have been built (projected to be complete in 2013). Initial Operational Capability of one operational squadron is slated for December 2005.
The F-15 fleet is experiencing problems with avionics parts obsolescence, and the average age of the fleet will be more than 30 years when the last F-22 is delivered in 2013. But the current inventory of F-15s can be economically maintained in a structurally sound condition until 2015 or later. None of the 918 F-15s that were in the inventory in July 1992 will begin to exceed their expected economic service lives until 2014.
Function Air superiority fighter
Contractors Lockheed Martin Aeronautical Systems: F-22 program management, the integrated forebody (nose section) and forward fuselage (including the cockpit and inlets), leading edges of the wings, the fins and stabilators, flaps, ailerons, landing gear and final assembly of the aircraft.
Lockheed Martin Tactical Aircraft Systems: Center fuselage, stores management, integrated navigation and electronic warfare systems (INEWS), the communications, navigation, and identification (CNI) system, and the weapon support system.
Boeing: wings, aft fuselage (including the structures necessary for engine and nozzle installation), radar system development and testing, avionics integration, the training system, and flight-test development and management.
Pratt & Whitney: F119-PW-100 engines that power the Raptor.
Major Subcontractors (partial list): Northrop Grumman, Texas Instruments, Kidde-Graviner Ltd., Allied-Signal Aerospace, Hughes Radar Systems, Harris, Fairchild Defense, GEC Avionics, Lockheed Sanders, Kaiser Electronics, Digital Equipment Corp., Rosemount Aerospace, Curtiss-Wright Flight Systems, Dowty Decoto, EDO Corp., Lear Astronics Corp., Parker-Hannifin Corp., Simmonds Precision, Sterer Engineering, TRW, XAR, Motorola, Hamilton Standard, Sanders/GE Joint Venture, Menasco Aerospace.
Propulsion two Pratt & Whitney F119-PW-100 engines
Thrust 35,000 lbst
Length 62.08 feet, 18.90 meters
Height 16.67 feet, 5.08 meters
Wingspan 44.5 feet, 13.56 meters
Wing Area 840 square feet
Horizontal Tailspan 29 feet, 8.84 meters
Maximum Takeoff Weight
Ceiling
Speed Mach 1.8 (supercruise: Mach 1.5)
Crew one
Armament Two AIM-9 Sidewinders
six AIM-120C Advanced Medium-Range Air-to-Air Missiles (AMRAAM)
one 20mm Gatling gun
two 1,000-pound Joint Direct Attack Munitions (JDAM)
First flight: September 7, 1997
Date Deployed deliveries beginning in 2002
operational by 2004
Unit Costs
DOD's Projected Unit
Prices Before and After Restructuring
Production
--------------------------
Low-rate Full-rate
------------ ------------
Units Unit Units Unit
Estimates cost cost
-------------------------- ---- ------ ---- ------
Before restructuring 76 $142.6 362 $102.8
Restructured without 70 $200.3 368 $128.2
initiatives
Restructured with 70 $200.8 368 $ 92.4
initiatives
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Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Length 67 feet, 5 inches (20.6 meters)
Wing span 43 feet, 7 inches (13.3 meters)
Height 13 feet, 11 inches (4.3 meters)
Maximum takeoff weight 64,000 pounds (29,029 kilograms)
Propulsion 2 Pratt and Whitney YF119 turbofan engines, or
2 General Electric YF120 turbofan engines
Speed Mach 2
Range 865-920 miles (750-800 nautical miles) unrefuelled
-Armament 4 AIM-9 Sidewinder - internal bays in engine intake duct sides
4 AIM-120 AMRAAM - internal bays underneath air intakes
Crew One
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In March 1996, NASA initiated flight testing of a new thrust vectoring concept that could lead to significant increases in the performance of both civil and military aircraft flyingat subsonic or supersonic speed.
The tests at Dryden Flight Research Center are part of a program known as ACTIVE (Advanced Controls Technology for Integrated Aircraft), a collaborative effort of NASA, the Air Force's Wright Laboratory, McDonnell Douglas Aerospace (MDA), and Pratt & Whitney Government Engines & Space Propulsion unit (POW).
The test aircraft is a twin-engine F-15 ACTIVE, a modified version of the Air Force F-15B fighter built by MDA and powered by F-100PW-229 engines, each of which is equippedwith a nozzle that can swivel 20 degrees in any direction, giving the aircraft thrust control inthe pitch (up and down) and yaw (left-right) directions. This vectored (deflected) thrust system could replace conventional drag inducing aerodynamic controls and thereby gain increased fuel economy or range.
The tests began with four flights in March/April, then progressed to the first supersonic flight on April 24. On that occasion, the F-15 ACTIVE successfully demonstrated both pitchand yaw deflections at speeds of Mach 1.2 to1.5. The flight test plan contemplated about 60 flights totaling 100 hours at speeds up to Mach 1.85 and angles of attack (the angle betweenthe aircraft's body/wings and its actual flight path) up to 30 degrees.
The F-15 ACTIVE program is representative ofthe type of flight research conducted by NASA to explore new technologies and new flightregimes. NASA conducts such programsindependently or in cooperation with U.S.industry and the Department of Defense,sometimes in cooperation with internationaldevelopment teams.
Another example of a Dryden flight researchprogram is NASA's High Alpha investigation.High Alpha refers to high angles of attack, aflight regime in which the airflow becomesextremely complex. To provide aircraft manufacturers with a technology base for designinghigh performance aircraft capable of"supermaneuverability" and of maintainingstability/controllability at high angles of attack,NASA conducted the decade-long High Alphaprogram that concluded on May 29, 1996 withthe final flight of NASA's F-18 HARV (HighAlpha Research Vehicle).
In the first phase of the program, initiated in1987, the F-18 HARV explored angles of attackup to 55 degrees. In the second phase, NASA investigated thrust vectoring technology to determine the impact on aircraft maneuverability at high angles of attack. In the final phase, the F-18 HARV's handling qualities were evaluated by 14 different pilots representing NASA, the Department of Defense, and support contractors McDonnell Douglas Aerospace and Calspan Corporation.
Among other flight projects under way at Dryden are two examples of test programs intended to support NASA activities not directly connected with aeronautics advancement. One is a project involving airborne tests of an advanced thermal protection system (TPS) for use on the X-33 Reusable Launch Vehicle. The project employs an F-15B Flight Test Fixture-II (FTF-II) aircraft foratmospheric testing (the ascent and landing phases of the launch vehicle's operation), where the potential threat to the TPS is impact with rain drops, cloud droplets or ice crystals. Test participants include Marshall Space Flight Center and Rockwell International.
Crew: Two
Unit Cost: N/A
Powerplant
Two higher-thrust version Pratt & Whitney F100-PW-229 engines (with newly developed axisymmetric thrust-vectoring engine exhaust nozzles) rated at 29,000 lbs. of thrust each at full power
Dimensions
Length: 63.7 ft, excluding flight test nose boom
Wingspan: 42.8 ft
Canard span: 25.6 ft
Height: 18.5 ft - F-15
Weights
Empty: 35,000 lb
TOW: 47,000 lb
Performance
Speed: Mach 2.0 (speeds limited to Mach 1.2)
Ceiling: 60,000 feet
Range: N/A
Armament
One internal M61A2 20-mm cannon, three internal weapons bays, underside bay for four AIM-120A AMRAAMs and two lateral intake bays each with two AIM-9M sidewinder AAMs. Revised bays for 1,000 lb JDAMs replacing two AIM-120s and AIM-9X AAMs. Four underwing stores stations with provision for two AGM-137A Tri-Service Standoff Arrack Missiles and / or fuel tanks.
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F-15 Strike Eagle (http://www.fas.org/man/dod-101/sys/ac/f-15.htm)
In fact, the S-37 is in the class of Su-27 as seen from comparison of its scale model to the advanced Su-27 Flanker model presented at the same meeting. Moscow Aerospace (MAKS 97) provided additional data on S-37 and confirmed that dimensions, performance and tandem triplane layout of the S-37 are similar to that of Su-37. First public photographs of the S-37 suggested that the front part of the fuselage including the 'hooded cobra' LERX could have come from the original S-37 canard-delta. If true, this could possibly clear up the origins of the S-37 index.
Forward Swept Wing
The early Soviet designs to feature moderately forward swept wing were Belyaev's DB-LK and Babochka aircraft and Mikoyan Gurevitch PBSh-2 (MiG-6) biplane. Captured at the end of WWII, German FSW Junkers Ju-287 was test flown by German and Russian crews. A six engined EF-131 was build and underwent extensive structural and flight testing until 1947, when theme was closed. At about the same time Pavel Tsybin build several testbeds LL (Letauchaya Laboratoriya) -1, -2 and -3 with stright, swept back and forward swept wings respectively (40 degrees). The LL-1 and LL-3 rocket powered gliders performed number of powered flights and provided TsAGI with much needed FSW data. In one of the flights LL-3 reached Mach 0.97 in dive.
Sukhoi Fifth-generation Fighter Philosophy
The FSW is a better performer at high angles of attack in post-stall manoeuvring much needed in close-in dogfight. The fact that Simonov had chosen FSW for his fifth-generation fighter once again confirms Sukhoi's commitment to the superagility as a crucial requirement for the next generation air-superiority fighter. This approach, so much different from western concepts of stealth, supercruise and BVR engagements, was taken to the limits in Su-37. The FSW S-32 fitted with TVC expected to outperform its stalemate in close-in dogfight involving post-stall flight regimes. Having the edge in manoeuvring, the S-32 is clearly catching up in stealth with US and European new-generation fighters. However even with its internal weapon bay and RAM coating, the new Sukhoi is a very different concept than F-22. The heavy accent on RAM rather than radar absorbing structures (RAS) is obvious. The reason for such attitude is not clear, although a combination of the technology limitations and operational doctrine is most likely candidate. The major components of radar stealth - RAM coatings and surface quality - are subject to the production and maintenance tolerance as it was shown by USAF F-117 and B-2 operational experience. Untightened screws, scratches or unfastened access panels were known to greatly deteriorate the RCS of the aircraft, reducing the engineering efforts put into aircraft design. It remains to be seen how Sukhoi will overcome the looser production standards of the Russian aircraft plans.
The Afghanistan experience where Sukhoi's encountered a thread of the shoulder launched infrared homing surface-to-air missiles such as Redeye, Stinger and SA-7, forced Sukhoi team to work on the reduction of the infrared signature of the Su-25. The results materialized in the Su-25T development - Su-25TM (Su-39 in Sukhoi's nomenclature). The installation of the intake cones hiding the turbine blades and efficient mixing of the exhaust with cold air reduced the IR signature of the Frogfoot from front and rear aspects. This fourfold reduction at expense of 2% lower SFC is indeed an impressive achievement. Further experiments with low visibility involved the advanced Flanker development prototypes, aircraft of 700 (Su-35,-37) and 600 (Su-30) series. These fighters wear eye catchy new camouflage schemes designed to reduce the visual signature of the aircraft on the ground and in the sky. One of the most interesting examples of Sukhoi experiments was a scheme applied to 701, designed to deceive space based optical systems. Some effort was directed in reduction of the radar cross sections of advanced Flankers as well. The Su-34,-32FN have optimized radar random shape, lack variable geometry intakes and were reported to have partial RAM coating. Recently Sukhoi stated that basic export models of Su-30MK can be treated with RAM to fulfill customer requirement for a lower RCS aircraft. Clearly benefitting from previous research, the S-37 prototype relies heavily on the Sukhoi's state of the art low observable technology. The forward swept wing, a conformal underfuselage weapon station(s), use of RAM and the inward-canted tailfins, suggest a further reduction of the aircraft radar signature down from similarly sized Flanker's 3-5 sq m. The extend of the reduction of the IR signature of the S-37 exhausts will depend on the choice of the trust vectoring nozzle. The F-22 type flat 2D nozzle can give a better results while 2D nozzle might contradict to Simonov's superagility ideas favouring 3D exhaust. The Saturn-Lulka was reported to work on reduction of the IR signature of the axi-symmetric trust vector controlled (TVC) Al-37FU power plant on non-afterburning regimes.
Powerplant
The scarce availability of trust vectoring Saturn-Lulka Al-41F engineered for the Mikoyan's article 1.42 forced Sukhoi to seek a replacement for the originally planned powerplant. According to MAPO MIG sources, the limited number of Al-41F are involved in Mikoyan's Article 1.42 tests and not available to Sukhoi's competitor. Reluctance of MAPO MIG made a trust-vectoring control (TVC) Al-37FU (sometime referred as Al-31FU where FU stands for Forsazh, Upravlaemoye soplo - afterburning, articulated nozzle) powerplant used in Sukhoi's Su-37 a natural choice for fifth-generation fighter, but would have been premature for the first S-32 airframe. Additionally, the availability of the Al-37FU could be a problem since all prototypes are involved in flight tests on the Su-37 and in the bench endurance tests. At the time of the Su-37 first flight only three Al-37FU were built.
The ultimate S-32 powerplant - Al-37FU - operates in automatic and manual modes. In manual mode the nozzle deflection angle is set by the pilot, and in automatic mode the axi-symmetric nozzles are controlled by the MNPK Avionika full-authority, digital fly-by-wire flight control system (FCS). The movable in pitch axis nozzle deflects ±15 degree at 30 deg/s by a pair of hydraulic jacks. The production Al-37FU will use jet fuel instead of hydraulic liquid to drive the nozzles. Surprisingly, as a temporal solution, instead of similar and widely available Su-27 Flanker's Al-31F powerplants, the S-32 prototype received a pair of Perm Aviadvigatel D-30F6 engines used on MiG-31 Foxhound interceptors. Designed by the 1980, this full authority digital engine control (FADEC) engine comprises six interchangeable modules and a core module.
Although powerplant accumulated several thousand flight hours and experienced no operational drawbacks, it has estimated 300 hrs life between overhauls (Russian engine maintenance is very different from western philosophy and term 'overhauls' has a different meaning). There were no reports on TVC versions of D-30F6.
The photographs of S-37 Berkut, show two details: the starboard tail sting is slightly longer than the port one and the two auxiliary intakes on the top of the fuselage. There are three reasonable explanations to the sting asymmetry: a) it houses a breaking or a spin recovery shute b) it is due to the asymmetric engine installation typical for prototypes. The port engine will be used to test a 3D TVC nozzle which will require adequate space for the yaw vectoring c) Sukhoi used two 2D nozzles oriented perpendicular to each other to control pitch and yaw separately. Combined action give a pseudo 3D effect. This last explanation is least likely since Lulka reported to have 3D TVC nozzle 'in the pocket' at the time of Farnborough 96. Auxiliary intakes could be used during take offs for increased air flow to the engines. These could have been repositioned from the underside of the aircraft due to the reduces radar cross section considerations or/and lack of the space taken by internal missile bay(s).
Avionics
In early September, defence-ministry acquisition chief Col Gen Anatoly Sitnov noted: 'What is the use of developing the Sukhoi fifth-generation fighter, if the aircraft's cockpit dates back to a second- or third-generation design?' While Sitnov statement clearly implying the state of the art of the S-32, one can hardly expect that a first test airframe will incorporate all innovations planned for the series production. Similarly, the sole Su-37 demonstrator flies with a counterweight instead of the advanced radar hence the aircraft is intended to explore among other things the trust vectoring modes of the new powerplant. However, the Su-37 fighter will have the top notch avionics suit which is tested on other 700 series airframes - Sukhoi Su-35s. It is expected that the sophistication of S-32 cockpit and avionics suit should at least match that of forth-and-a-half generation Su-35 and Su-37 aircraft. The cockpit of the S-32 does most certainly feature the color liquid crystal MFDs and wide angle HUD. The test proven in Su-37 demonstrator inclined pilot seat, a fixed pressure sensitive throttle and side-stick controller will also find its way to the cockpit of new fighter expected to impose even greater G-loads on pilot than superagile Su-37.
The type of the radar intended for S-32 is not known. The size of the random seems to be somewhat smaller than that of Su-27 family, possibly implying the smaller diameter antenna. Since the S-32 lacks the Flanker's sting, the placement of the rearward facing radar will be challenging at best.
Armament
The armament of the S-32 will most likely never get close to the air-to-air arsenal of Mikoyan's article 1.42, enjoying super long range K-37. However the ram jet version of AA-12 Adder, R-77PD (RVV-AE-PD), seems to be the most appropriate long stick for the new fighter. The missile's collapsible lattice stabilizers give R-77 family the compactness well suited for the internal weapon bay(s) of the stealth S-32. However, the aerodynamically superior lattice stabilizers have reportedly a much greater RCS than conventional surfaces, thus potentially revealing the position of the aircraft at the moment of the missile launch. The exact number of weapon bays is not known, although the total number of the hardpoints will be fourteen. The use of the internal/external weapon loads will depend on the mission.
S-37/S-32 vital statistics
Wingspan: 16.7 m
Length overall: 22.6 m
Height overall 6.40 m
Weight empty, equipped : 24,000 kg (52,910 lb)
Max T-O weight : 34,000 kg (74,960 lb)
Max level speed at height : 2,500km/h (1,350 knots)
Max level speed at S/L : 1,400km/h (756 knots)
Service ceiling : 18,000 m (59,050 ft)
Range with max fuel at height : 1,782 nm (3,300 km/2,050 miles)
Number of hardpoints: 14: 2 wingtip, 6-8 underwing, 6-4 conformal underfuselage
Air-to-air : R-77, R-77PD, R-73, K-74
Air-to-surface: X-29T, X-29L, X-59M, X-31P, X-31A, KAB-500, KAB-1500
Name: S37 Berkut
Constructor: Sukhoi
Armament: 14 hardpoints
Length: 22m60
Max Speed: 2500 km/h
Ceiling: 18000 m
height: 6m40
Weight Max: 34000 kg
Range: 3300 km
Span: 16m70
Crew: 1
Engines: 2
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F-22 Raptor
The F-22 program is developing the next-generation air superiority fighter for the Air Force to counter emerging worldwide threats. It is designed to penetrate enemy airspace and achieve a first-look, first-kill capability against multiple targets. The F-22 is characterized by a low-observable, highly maneuverable airframe; advanced integrated avionics; and aerodynamic performance allowing supersonic cruise without afterburner.
Stealth: Greatly increases survivability and lethality by denying the enemy critical information required to successfully attack the F-22
Integrated Avionics: Allows F-22 pilots unprecedented awareness of enemy forces through the fusion of on- and off-board information
Supercruise: Enhances weapons effectiveness; allows rapid transit through the battlespace; reduces the enemy’s time to counter attack
The F-22's engine is expected to be the first to provide the ability to fly faster than the speed of sound for an extended period of time without the high fuel consumption characteristic of aircraft that use afterburners to achieve supersonic speeds. It is expected to provide high performance and high fuel efficiency at slower speeds as well.
For its primary air-to-air role, the F-22 will carry six AIM-120C and two AIM-9 missiles. For its air-to-ground role, the F-22 can internally carry two 1,000 pound-class Joint Direct Attack Munitions (JDAM), two AIM-120C, and two AIM-9 missiles. With the Global Positioning System-guided JDAM, the F-22 will have an adverse weather capability to supplement the F-117 (and later the Joint Strike Fighter) for air-to-ground missions after achieving air dominance.
The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission. There are two basic external configurations for the F-22:
Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks.
Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations.
An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration. Prior to its selection as winner of what was then known as the Advanced Tactical Fighter (ATF) competition, the F-22 team conducted a 54-month demonstration/ validation (dem/val) program. The effort involved the design, construction and flight testing of two YF-22 prototype aircraft. Two prototype engines, the Pratt & Whitney YF119 and General Electric YF120, also were developed and tested during the program. The dem/val program was completed in December 1990. Much of that work was performed at Boeing in Seattle, Lockheed (now known as Lockheed Martin) facilities in Burbank, Calif., and at General Dynamics' Fort Worth, Texas, facilities (now known as Lockheed Martin Tactical Aircraft Systems). The prototypes were assembled in Lockheed's Palmdale, Calif., facility and made their maiden flight from there. Since that time Lockheed's program management and aircraft assembly operations have moved to Marietta, Ga., for the EMD and production phases.
The F-22 passed milestone II in 1991. At that time, the Air Force planned to acquire 648 F-22 operational aircraft at a cost of $86.6 billion. After the Bottom Up Review, completed by DOD in September 1993, the planned quantity of F-22s was reduced to 442 at an estimated cost of $71.6 billion.
A $9.55 billion contract for Engineering and Manufacturing Development (EMD) of the F-22 was awarded to the industry team of Boeing and Lockheed Martin in August 1991. Contract changes since then have elevated the contract value to approximately $11 billion. Under terms of the contract, the F-22 team will complete the design of the aircraft, produce production tooling for the program, and build and test nine flightworthy and two ground-test aircraft.
A Joint Estimate Team was chartered in June 1996 to review the F-22 program cost and schedule. JET concluded that the F-22 engineering and manufacturing development program would require additional time and funding to reduce risk before the F-22 enters production. JET estimated that the development cost would increase by about $1.45 billion. Also, JET concluded that F-22 production cost could grow by about $13 billion (from $48 billion to $61 billion) unless offset by various cost avoidance actions. As a result of the JET review the program was restructured, requiring an additional $2.2 billion be added to the EMD budget and 12 months be added to the schedule to ensure the achievement of a producible, affordable design prior to entering production. The program restructure allowed sourcing within F-22 program funds by deleting the three pre-production aircraft and slowing the production ramp. Potential for cost growth in production was contained within current budget estimate through cost reduction initiatives formalized in a government/industry memorandum of agreement. The Defense Acquisition Board principals reviewed the restructured program strategy and on February 11, 1997 the Defense Acquisition Executive issued an Acquisition Defense Memorandum approving the strategy.
The Quadrennial Defense Review Reportwhich was released in mid-May 1997, reduced the F-22 overall production quantity from 438 to 339, slowed the Low Rate Initial Production ramp from 70 to 58, and reduced the maximum production rate from 48 to 36 aircraft per year.
The F-22 EMD program marked a successful first flight on September 7, 1997. The flight test program, which has already begun in Marietta, Georgia, will continue at Edwards AFB, California through the year 2001. Low rate production is scheduled to begin in FY99. The aircraft production rate will gradually increase to 36 aircraft per year in FY 2004, and will continue that rate until all 339 aircraft have been built (projected to be complete in 2013). Initial Operational Capability of one operational squadron is slated for December 2005.
The F-15 fleet is experiencing problems with avionics parts obsolescence, and the average age of the fleet will be more than 30 years when the last F-22 is delivered in 2013. But the current inventory of F-15s can be economically maintained in a structurally sound condition until 2015 or later. None of the 918 F-15s that were in the inventory in July 1992 will begin to exceed their expected economic service lives until 2014.
Function Air superiority fighter
Contractors Lockheed Martin Aeronautical Systems: F-22 program management, the integrated forebody (nose section) and forward fuselage (including the cockpit and inlets), leading edges of the wings, the fins and stabilators, flaps, ailerons, landing gear and final assembly of the aircraft.
Lockheed Martin Tactical Aircraft Systems: Center fuselage, stores management, integrated navigation and electronic warfare systems (INEWS), the communications, navigation, and identification (CNI) system, and the weapon support system.
Boeing: wings, aft fuselage (including the structures necessary for engine and nozzle installation), radar system development and testing, avionics integration, the training system, and flight-test development and management.
Pratt & Whitney: F119-PW-100 engines that power the Raptor.
Major Subcontractors (partial list): Northrop Grumman, Texas Instruments, Kidde-Graviner Ltd., Allied-Signal Aerospace, Hughes Radar Systems, Harris, Fairchild Defense, GEC Avionics, Lockheed Sanders, Kaiser Electronics, Digital Equipment Corp., Rosemount Aerospace, Curtiss-Wright Flight Systems, Dowty Decoto, EDO Corp., Lear Astronics Corp., Parker-Hannifin Corp., Simmonds Precision, Sterer Engineering, TRW, XAR, Motorola, Hamilton Standard, Sanders/GE Joint Venture, Menasco Aerospace.
Propulsion two Pratt & Whitney F119-PW-100 engines
Thrust 35,000 lbst
Length 62.08 feet, 18.90 meters
Height 16.67 feet, 5.08 meters
Wingspan 44.5 feet, 13.56 meters
Wing Area 840 square feet
Horizontal Tailspan 29 feet, 8.84 meters
Maximum Takeoff Weight
Ceiling
Speed Mach 1.8 (supercruise: Mach 1.5)
Crew one
Armament Two AIM-9 Sidewinders
six AIM-120C Advanced Medium-Range Air-to-Air Missiles (AMRAAM)
one 20mm Gatling gun
two 1,000-pound Joint Direct Attack Munitions (JDAM)
First flight: September 7, 1997
Date Deployed deliveries beginning in 2002
operational by 2004
Unit Costs
DOD's Projected Unit
Prices Before and After Restructuring
Production
--------------------------
Low-rate Full-rate
------------ ------------
Units Unit Units Unit
Estimates cost cost
-------------------------- ---- ------ ---- ------
Before restructuring 76 $142.6 362 $102.8
Restructured without 70 $200.3 368 $128.2
initiatives
Restructured with 70 $200.8 368 $ 92.4
initiatives
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Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Trapezoid-shaped air inlets are located underneath each wing, with the leading edge forming the forward lip of a simple fixed-geometry two-shock system. The placement of the intakes underneath the wings has the advantage in removing them from the sides of the fuselage so that a large boundary-layer scoop is not needed. Instead, the thin boundary layer which forms on the wing ahead of the inlet is removed through a porous panel and is vented above the wing. An auxiliary blow-in inlet door is located on each of the upper nacelles just ahead of the engine to provide additional air to the engines for takeoff or for low speeds. The inlet ducts leading to the engines curve in two dimensions, upward and inward, to shield the faces of the compressors from radar emitters coming from the forward direction.
The leading edge of the YF-23A's wing is swept back at 40 degrees, and the trailing edge is swept forward at the same angle. When viewed from above, the wing has the planform of a clipped triangle. On the YF-23A, every line in the planform is parallel to one or the other of the wing leading edges, which has become one of the guiding principles in stealthy design. The wing is structurally deep, and there is ample room for fuel inside the wing box.
The wing has leading-edge slats which extend over about two-thirds of the span. The trailing edge has a set of flaps inboard and a set of drooping ailerons outboard. In contrast to the Lockheed YF-22A, no speedbrake is fitted to the YF-23A.
The all-flying twin V-tails are set far apart on the rear fuselage. They are canted 50 degrees outwards in an attempt to avoid acute corners or right angles in elevation or front view. These all-flying tail sections are hinged at a single pivot. Their leading and trailing edges are parallel to the main wings but in a different plane. The all-flying canted tails double as shields for the engine exhaust in all angles except those immediately above or hehind the aircraft.
In the YF-23A, Northrop elected not to use thrust-vectoring for aerodynamic control. This was done in order to save weight and to help achieve better all-aspect stealth, especially from the rear. All controls are by aerodynamic surfaces. The V-tails work in pitch, roll, and yaw. The wing trailing edge controls provide roll control and lift augmentation, but they also function as speedbrakes and rudders. For straight line deceleration, the control system commands the outer ailerons to deflect up and the inboard flaps to deflect down, thus producing a decelerating force but creating no other moments. Yaw control can be provided by doing this on one side only.
There is a midair refuelling receptacle located on the upper fuselage behind the pilot's cockpit. Like the YF-22A, the YF-23A has a fly-by-wire system that controls the settings of the aerodynamic surfaces in response to inputs from the pilot.
The edge treatment is sustained on the fuselage afterbody, where a jagged-edged boat-tail deck fills in the gap between the two V-tails and blends the engine exhausts into the low-RCS planform. Unlike the YF-22A, the YF-23A does not use thrust vectoring. The exhaust nozzles are located well forward on the upper fuselage, between the tails, and are of the single expansion ramp type. There is one variable external flap on top of each nozzle, and the lower half of each nozzle is faired into a curved, fixed ramp. The engines exhaust into tunnels or trenches cut into the rear fuselage decking. These trenches are lined with head-resistant material, cooling the engine exhaust rapidly and making for a weaker IR source.
In the pursuit of stealth, all of the weapons carried by the F-23 were to have been housed completely internally. The forward section of the fuselage underbelly was flat, with a capacious weapons bay immediately aft of the nose gear bay. The bay could carry four AIM-120 AMRAAM air-to-air missiles. The missiles were to be launched by having the doors open and the missiles extend out into the airstream on trapezes. The missiles would then drop free and the motor would fire. The doors would then immediately shut, minimizing the amount of time that they were open and thus possibly causing more intense radar returns. It was planned that production F-23 would have had a stretched forebody, accommodating an extra missile bay for a pair of AIM-9 Sidewinders or ASRAAM air-to-air missiles in front of the AMRAAM bay. In addition, production F-23s would have carried a 20-mm M61 Vulcan cannon fitted inside the upper starboard fuselage just above the main weapons bay.
Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120
engines and the other with Pratt & Whitney YF-119 engines. First take off of "Gray Ghost" 27th Aug 1990 on Edward AFB, 26th Oct 1990 second prototype. First programm durated 65 hours divided into 50 flights, ended by second prototype 18th Dec 1990. After extensive flight testing 23th Apr 1991 the YF-22 was
selected for production.
Length 67 feet, 5 inches (20.6 meters)
Wing span 43 feet, 7 inches (13.3 meters)
Height 13 feet, 11 inches (4.3 meters)
Maximum takeoff weight 64,000 pounds (29,029 kilograms)
Propulsion 2 Pratt and Whitney YF119 turbofan engines, or
2 General Electric YF120 turbofan engines
Speed Mach 2
Range 865-920 miles (750-800 nautical miles) unrefuelled
-Armament 4 AIM-9 Sidewinder - internal bays in engine intake duct sides
4 AIM-120 AMRAAM - internal bays underneath air intakes
Crew One
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In March 1996, NASA initiated flight testing of a new thrust vectoring concept that could lead to significant increases in the performance of both civil and military aircraft flyingat subsonic or supersonic speed.
The tests at Dryden Flight Research Center are part of a program known as ACTIVE (Advanced Controls Technology for Integrated Aircraft), a collaborative effort of NASA, the Air Force's Wright Laboratory, McDonnell Douglas Aerospace (MDA), and Pratt & Whitney Government Engines & Space Propulsion unit (POW).
The test aircraft is a twin-engine F-15 ACTIVE, a modified version of the Air Force F-15B fighter built by MDA and powered by F-100PW-229 engines, each of which is equippedwith a nozzle that can swivel 20 degrees in any direction, giving the aircraft thrust control inthe pitch (up and down) and yaw (left-right) directions. This vectored (deflected) thrust system could replace conventional drag inducing aerodynamic controls and thereby gain increased fuel economy or range.
The tests began with four flights in March/April, then progressed to the first supersonic flight on April 24. On that occasion, the F-15 ACTIVE successfully demonstrated both pitchand yaw deflections at speeds of Mach 1.2 to1.5. The flight test plan contemplated about 60 flights totaling 100 hours at speeds up to Mach 1.85 and angles of attack (the angle betweenthe aircraft's body/wings and its actual flight path) up to 30 degrees.
The F-15 ACTIVE program is representative ofthe type of flight research conducted by NASA to explore new technologies and new flightregimes. NASA conducts such programsindependently or in cooperation with U.S.industry and the Department of Defense,sometimes in cooperation with internationaldevelopment teams.
Another example of a Dryden flight researchprogram is NASA's High Alpha investigation.High Alpha refers to high angles of attack, aflight regime in which the airflow becomesextremely complex. To provide aircraft manufacturers with a technology base for designinghigh performance aircraft capable of"supermaneuverability" and of maintainingstability/controllability at high angles of attack,NASA conducted the decade-long High Alphaprogram that concluded on May 29, 1996 withthe final flight of NASA's F-18 HARV (HighAlpha Research Vehicle).
In the first phase of the program, initiated in1987, the F-18 HARV explored angles of attackup to 55 degrees. In the second phase, NASA investigated thrust vectoring technology to determine the impact on aircraft maneuverability at high angles of attack. In the final phase, the F-18 HARV's handling qualities were evaluated by 14 different pilots representing NASA, the Department of Defense, and support contractors McDonnell Douglas Aerospace and Calspan Corporation.
Among other flight projects under way at Dryden are two examples of test programs intended to support NASA activities not directly connected with aeronautics advancement. One is a project involving airborne tests of an advanced thermal protection system (TPS) for use on the X-33 Reusable Launch Vehicle. The project employs an F-15B Flight Test Fixture-II (FTF-II) aircraft foratmospheric testing (the ascent and landing phases of the launch vehicle's operation), where the potential threat to the TPS is impact with rain drops, cloud droplets or ice crystals. Test participants include Marshall Space Flight Center and Rockwell International.
Crew: Two
Unit Cost: N/A
Powerplant
Two higher-thrust version Pratt & Whitney F100-PW-229 engines (with newly developed axisymmetric thrust-vectoring engine exhaust nozzles) rated at 29,000 lbs. of thrust each at full power
Dimensions
Length: 63.7 ft, excluding flight test nose boom
Wingspan: 42.8 ft
Canard span: 25.6 ft
Height: 18.5 ft - F-15
Weights
Empty: 35,000 lb
TOW: 47,000 lb
Performance
Speed: Mach 2.0 (speeds limited to Mach 1.2)
Ceiling: 60,000 feet
Range: N/A
Armament
One internal M61A2 20-mm cannon, three internal weapons bays, underside bay for four AIM-120A AMRAAMs and two lateral intake bays each with two AIM-9M sidewinder AAMs. Revised bays for 1,000 lb JDAMs replacing two AIM-120s and AIM-9X AAMs. Four underwing stores stations with provision for two AGM-137A Tri-Service Standoff Arrack Missiles and / or fuel tanks.
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F-15 Strike Eagle (http://www.fas.org/man/dod-101/sys/ac/f-15.htm)