The F-26 STALMA (Short Takeoff Advanced Light Multi-role Aircraft) is an advanced, sixth generation multi-role fighter suitable for Direct Commercial Sales to US and NATO/allies. Designed to replace F-16C and F/A-18C/E combat aircraft in US and NATO air arms, the F-26 is a single seat, single engine, high performance weapon system incorporating variable geometry, supercruise, pitch/yaw thrust vectoring, integrated avionics, enhanced agility and low observability characteristics. Conceived for maximum performance and combat capability, the F-26 is designed for all-weather, supersonic operation at both low and high altitudes. Optimized for air-to-air interception, combat air patrol, air dominance, close-in air-to-air engagements ('dogfight'), carrier air defense, anti-shipping strike, wild weasel/anti-radiation strike, all weather precision attack, interdiction, battlefield close air support, suppression of enemy air defenses, tactical reconnaissance, conventional bombing and tactical nuclear penetration, the F-26 STALMA will counter threats to US and NATO allied air superiority.

Addressing a projected market need for over 6,000 multi-role fighter aircraft during the first quarter of the 21st century, the F-26 STALMA is anticipated to gain a 15% market share upon introduction. With a unit flyaway price in the $40 to $60 million class, Stavatti will begin Low Rate Initial Production (LRIP) of the F-26 in 2007-2009 at an annual production rate of 100 units. Total program revenues are again estimated at over $60 billion.

The aircraft will be produced in single place multi-role fighter (F-26S) and two-place tandem strike fighter/instructional trainer (F-26T) variants. The aircraft primary structure is conventional aluminum, titanium and stainless steel alloys in sheet or extruded form. Carbon fiber, aramid, thermoset and thermoplastic composites are employed as secondary structures. Approximately one third of the airframe consists of conventional alloy construction while two thirds of the airframe consists of composite construction by volume.

The aircraft is designed for an operational service life of 15,000 hours, accumulating an average of 500 hours per annum. Aircraft fatigue life is based upon 18,000 landings and fatigue testing to 75,000 hours. Service life of carrier variants includes 4,000 catapult launches and 4,000 traps. The airframe will exhibit load limits of +15/-6 to 27,850 lbs design gross weight and +9/-3 to 60,750 lbs maximum gross weight. Ultimate load factors are 1.5 times design load factors.

The Short Takeoff Advanced Light Multi-role Aircraft (STALMA) program began in 1989 as a conceptual light weight fighter (LWF) suitable for the replacement of F-16C and F/A-18C multi-mission aircraft in the late 1990s. A contractor initiative, the Stalma evolved as a possible candidate for the USAF Multi-Role Fighter (MRF) program under the Bush Administration. Demonstrating the feasibility of an MRF which exhibits the maneuverability, LO and range characteristics necessary to perform air superiority and deep strike missions, by 1992 STALMA development goals focused upon production by 2003 at a unit flyaway cost of $25 million.

The introduction of the ARPA ASTOVL program in 1993 and the 1995 initiation of the Tri-Service Joint Advanced Strike Technology (JAST) project, resulting in the current Joint Strike Fighter (JSF) program, quelled the necessity for DoD MRF development. Shifting emphasis toward the production of a dedicated export fighter, Stalma development continued as a commercial venture. Responsible for the STALMA, Stavatti Corporation was established in 1994 as an aerospace defense contractor dedicated to the design and manufacture of military and general aviation aircraft.

STALMA Advanced Design began August 1994. By 1995, the core Stalma configuration was frozen following substantial CFD analysis of the configuration. Critical structural design completed in 1997. Initial engineering was conducted utilizing traditional means. Detail design and component engineering is performed utilizing CAD/CAM platforms. Completion of development and production engineering is based on SGI and IBM workstations employing CATIA for design and various CFD/FEA solvers for simulation and analysis. Stavatti assigned the company F-26 designation to the STALMA series in September 1998.

The first YF-26 STALMA Prototype Air Vehicle (YF-26 PAV-1) is scheduled for roll-out in 2005, augmented by a second prototype (YF-26 PAV-2) in 2006, and ten Production Representative Test Vehicles (PRTVs). Upon completion of 2,500 hours of a 5,000 hour, pre-production/concurrent flight test program, the first Production Representative Delivery Articles (PRDA) F-26 STALMA aircraft will be available for LRIP in 2007/2009. The F-26 STALMA will be produced in single seat multi-role fighter (F-26S) and two place tandem fighter/trainer (F-26T) variants.

F-26 wings are of hydraulically actuated, variable-geometry cantilever mid-wing monoplane type. Wing/fuselage interface is of blended wing/body design. Wing sweep varies from 5º (unswept) to 70º (maximum sweep) with wing span being 57 ft, 0 in and 30 ft 7.5 in respectively. Unswept gross wing area (wing only-excluding canard) is 385 sq t; exposed wing area is 282 sq ft. Aspect ratio varies from 8.5 unswept to 1.95 fully swept. Wing sweep is automatically controlled via a Mach Sweep Programmer (MSP) with manual override. The mean wing airfoil is a modified NACA 66(2)-215. Wing dihedral is approximately 0º. Wing incidence is approximately 0º

Wing structure consists of two Ti-6A1-4V titanium and one Elgiloy cobalt-chromium-nickel alloy spar, fifteen titanium ribs, and multiple graphite/titanium stringers. Titanium face sheets are mated to the spar/rib structure, forming a titanium fuel tank. Wing skins are IM9/RP-46 graphite. Wing leading and trailing edges are graphite/aramid with titanium.

Each wing is equipped with full span leading edge slats and trailing edge, double-slotted Fowler Flaps for lift augmentation. Maximum trailing edge flap deflection is 65º. Leading and trailing edge flaps are actuated by Bertea/National Water Lift/Parker hydraulic cylinders. The wing is equipped with 0.20c flapperons for subsonic roll.

Each wing incorporates four stores pivot hardpoints; two rated are at 5,000 lbs carriage capacity at +9g, one is rated at 3,000 lbs carriage capacity at +9g and one is rated at 1,000 lbs carriage capacity at +9g. Each wing features three hardpoints which are plumbed for external fuel carriage. Standard external tanks include 370 USG and 600 USG types. Stores pylons pivot automatically to align all stores with the streamline throughout the wing sweep envelope. Wing sweep is limited to 35º with full stores complement. Jettison of inboard wing store permits full wing sweep, thereby limiting each wing to three stores stations in the fully swept position. Wing sweep lockout controls inhibit wing sweep beyond 35º with full stores complement.

The F-26 fuselage is a semi monocoque alloy and composite structure composed of three modules. Consisting of the forward fuselage, mid fuselage and rear fuselage, the fuselage modules employ triple redundant construction composed of an alloy spaceframe core, a graphite unibody and aramid body panels. Critical fuselage loads are distributed equally amongst the alloy subframe and the graphite unibody.

The alloy subframe (Ti-6A1-4V titanium, 7075 aluminum, 7050 aluminum, scandium aluminum, Elgiloy and PH 15-7 stainless steel) provides a solid mounting platform for all critical airframe components and a fatigue resistant, design load carriage structure. The subframe is of geodetic configuration, building upon design methodologies pioneered by Sir Barnes Wallis/Vicker's Wellesley & Wellington Bomber and Brant Goldsworthy. The graphite unibody (IM9/RP-46) provides fuselage form definition and unitary structural integrity. The aramid (Kevlar 49/RP-46) body panels provide aerodynamic definition and combat damage tolerance.

The F-26 canard foreplanes are all moving, variable incidence units. Each canard is located abeam the top of the aircraft shoulder air inlets. Leading edge sweep is -32º and trailing edge sweep is -51º. Canard span is 6 feet with canard area and aspect ratio being 33.75 sq ft and 1.066 respectively. Canard mean airfoil is a modified NACA 65A0045 section. Canard dihedral is 3º. The canards are a cantilever structure composed of three titanium spars and eight titanium ribs.

Incorporating titanium stringers, canard skins are aeroelastically tailored graphite/epoxy to prevent departure. The canards employ graphite/Kevlar® leading and trailing edges with titanium backing. Canards may be operated collectively for pitch control, or differentially for assisted roll authority.

The F-26 empennage consists of a cantilever V-tail mounted at a 55º dihedral angle. Empennage Leading edge sweep is largely 52º, with component sections varying from 40º to 82º. Empennage span is 12 ft, 6 in with unit area and aspect ratio being 114.85 sq ft and 1.36 respectively. Empennage root airfoil is a modified NACA 65A0045 section, with root incidence set at approximately 1º. The empennage configuration was selected to provide directional control while compensating for varying pitching moments associated with wing flap deployment and variable geometry static margin effects. Compensating for a close-coupled arrangement, a distinctive notch in the empennage accommodates the wing throughout the complete range of wing sweep. Yaw, pitch and roll control is provided by ruddervators, acting collectively for pitch control , independently for yaw control and differentially for supersonic roll control. The ruddervator tip contains antennas/warning receivers. Construction consists of four serpentine IM9/RP-46 spars, titanium ribs and IM9/RP-46 geodetic subframe with IM9/RP46 external skins.

The F-26S STALMA is powered by a single augmented turbofan rated in the 40,000 lb st class. The turbofan is mounted in a modular, universal engine bay capable of accommodating alternative powerplants of a similar thrust class. The F-26S STALMA is designed to accept up to three distinct powerplants including either the Pratt & Whitney F119-PW-100 Afterburning Turbofan rated in 35,000 lb st class with reheat, the Pratt & Whitney F135 Afterburning Turbofan rated in the 40,000 LB st class with reheat or the General Electric Aircraft Engines F136 Afterburning Turbofan rating in the 40,000 LB class with reheat. The F-26 STALMA turbofans are largely interchangeable with the F/A-22 RAPTOR F119 powerplant, or F/A-35 JSF F135/F136 powerplants with exception of Stavatti's integration of a custom Lo-Observable, axisymmetric thrust vectoring nozzle.

All F-26 STALMA powerplants of either P&W or GEAE type feature Full Authority Digital Engine Control (FADEC) with hydromechanical backup. The F119/F135 turbofans are of two-shaft, low bypass ratio type with three stages of snubless wide-chord fan blades. F119/F135 compressors are of multi-stage type, while the turbines are of single stage, contra-rotating type. F-26S STALMA self-start capability is provided by an Allied Signal G250 APU.

JP-8 fuel is supplied via a pressurized fuel delivery system composed of nine independent fuel cells, including seven, self-sealing stainless steel fuselage tanks and two self-sealing titanium wing tanks. Total internal fuel capacity is 17,835 lbs (2743.7 US Gal). Standard Aircraft Design Weight internal fuel load for Air-to-Air engagement immediate upon departure is 10,670 lbs (1,641.5 US Gal).

Fuel tanks are fitted with tear-resistant self-sealing cells lined with reticulated foam. An On-Board Inert Gas Generation System (OBIGGS) is available as a customer option. A single point refueling interface is located on the lower fuselage, while gravity refueling may be accomplished via two gravity feed ports on either side of the top fuselage. Provisions for in-flight refueling include a dorsal fin integrated Universal Aerial Refueling Receptacle Slipaway Installation (UARRSI) and a left fuselage mounted retractable in-flight refueling probe, allowing the F-26 to receive fuel from either flying-boom or probe-and-drogue tanker aircraft.

Powerplant mass flow is supplied by a dual air inlet system. Airflow for optimum subsonic, high AoA performance is supplied by a ventral pitot inlet. Airflow for optimum supersonic, high performance cruise is supplied by twin, shoulder mounted, bifurcated internal compression variable shock inlets. The air intake system is capable of delivering mass flows between 300 and 400 lbs/s over a range of Mach numbers in excess of Mach 2.8. Developed to maintain high pressure recoveries throughout the flight envelope, the inlet system serves the demands of the F-26 F119-PW-100/F135 or F136 powerplant.

The F-26 cockpit is configured for single pilot seated on a Martin Baker MK16 zero/zero ejection seat. Developed to assure reduced pilot workload, the cockpit is pressurized using an AiResearch air conditioning system. Standby pilot oxygen is provided by a Litton molecular sieve oxygen generating system (MSOGS). Incorporating a single piece bubble canopy, 360º all around, 13º over-the-nose and 40º over-the-side visibility is provided. The canopy is of iridium coated, frameless, clamshell type, electrically pivoted upward and aft for cockpit access. The canopy is defrosted and purged of precipitation using a perimeter high pressure, hot air system.

Featuring a HOTAS flight controls arrangement, the F-26 man/ machine interface consists of a centrally mounted control column and full deflection, pilot adjustable rudder pedals. Displays and instrumentation consist of traditional analogue and advanced Full-Color, Multi-Functional Liquid Crystal Displays.

The F-26 pilot's primary visual reference instrument is an Ericsson EP-17 Head-Up Display (HUD) offering a 20º x 28º Field-of-View with color raster video.

Secondary visual referencing is accomplished via four LCDs (two 9.5 x 10.5 in, one 6 x 8 in and one 6 x 6 in displays for a total display area of 285 sq in) and nineteen analogue flight and reference instruments. Facilitating both VFR and IFR operations, the cockpit is designed to comply with Generation III night vision standard and operability with Helmet Mounted Cuing Systems (HMCS).

The F-26 features an advanced integrated avionics system, incorporating proven operational capability and leading technologies. A modular platform, the aircraft was developed to incorporate a variety of avionics as Line Removable Units (LRUs). Avionics integration is performed by Stavatti as per customer requirements, although the Block 10, Preferred Weapon System Configuration is noted. All F-26 avionic systems are integrated via a MIL-STD-1553B Interface/Data Bus.

The aircraft radar and weapons fire control system consists of a Raytheon Systems Company AN/APG-79 multi-mode radar with AESA. Aircraft flight, navigation and communications avionics consist of the Litton LN-100G Ring Laser Gyro INS/Embedded GPS (for basic navigational data and primary attitude reference system), the Rockwell Collins AN/ARN-153 Advanced Digital TACAN, Rockwell Collins AN/ARN-112 or Rockwell Collins ARN/ALN-147 ILS, Rockwell Collins ADF receiver and HSI, Rockwell Collins AN/ARC-210(V) or Rockwell Collins AN/ARC-186R airborne transceiver, Raytheon KY-58 TSEC secure voice system, AN/APX-76V interrogator and AN/APX 111 or AN/APX-113 or Litton AN/APX-109 IFF transponder, intra-flight data link and additional units. Pending Availability, USAF/USN F-26S will be upgraded to benefit from an integrated comm/nav/ID system produced by TRW designated the ICNIA TRW AN/ASQ-220. The aircraft incorporates provisions for a Lockheed Martin LANTIRN externally mounted sensor/designator package including an AN/AAQ-13 navigation and a AN/AAQ-14 targeting pod or integrated Raytheon ATFLIR.

Data processing functions are accomplished by an array of approximately 20 computers. All F-26S computers are developed specifically for the Stavatti application and benefit from photonic processors implementing Zhegalkin logic. F-26 computers/processors are programmed in the FORTH computer language. Computers are grouped into four functions: avionics, flight control, aircraft subsystems and central integration. The Core System Mainframe (CSM) integrates aircraft systems management and serves as a back-up to all peripheral systems.

Principal computers include: one central computer (CC), one Mach Sweep Programmer (MSP), one Aircraft Integrity Analysis Computer (AIAC), three Central Air Data Computers (CADC), one Peripheral Performance Computer (PPCC), four FBW/PBW Flight Control Computers (FCC), three Mission Computers (MC), Enhanced Stores Management Computer (ESMC), one Tactical Environment Computer (TEC) and three Systems Integration Processors (SIP).

The F-26 is equipped with a Cockpit Video Recording (CVR) system as well as a crash survivable Flight Data Recorder (FDR), an onboard fatigue monitoring system, a crash survivable Crash Position Indicator (CPI) and a crash survivable Underwater Locator Beacon (ULB). A non-existant Halon replacement agent will be employed for avionic system fire suppression as soon as such a compound is invented/mil qualified/certified.

The aircraft employs hydraulically actuated, retractable tricycle landing gear. The main landing gear consists of independent, trailing link units which retract rearward into afterbody empennage integration fairings. Nose landing gear retracts forward. Main and nose landing gear utilize single wheel units. All landing gear units employ carbon fiber disk brakes and nitrogen charged oleo pneumatic shock struts. The landing gear is capable of unprepared, forward operations and sink rates of 24 ft/s. Maximum landing gear deployment airspeed is 300 kts.

The utility hydraulic system is responsible for normal landing gear operation. In the event of failure, either the primary or utility hydraulic systems may be cross fed for landing gear retraction. Nose landing gear may be gravity extended and mechanically locked and main landing gear may be pneumatically extended and locked in the event of complete system shutdown. An arresting hook suitable for land based recovery is provided. An arresting hook is not necessary for carrier operations. Wheelbase is 15 ft 8.5 in. F-26 wheel track is 9 ft 8 in.

Primary F-26 systems include Flight Control, Hydraulic and Electrical. The F-26 flight control is implemented via a Lockheed Martin Control Systems (LMCS) quadrupleplex, digital Power-By Wire (PBW). The flight control system provides control of the aircraft through the movement of the primary control surfaces. Primary control surfaces consist of ailerons, all moving canard foreplanes, all moving empennage slab sections, spoilers for DLC, and a Pitch/Yaw Balanced Beam Exhaust Nozzle (PYBBEN) dependant upon customer powerplant selection. Deflection of control surfaces is achieved by the control column and rudder pedals. Yaw control is achieved through independent deflection of empennage slab sections. Pitch authority is controlled by symmetrical deflection of canard foreplanes and empennage slab sections. Roll authority is achieved at M= 0.85 through aileron deflection and through differential deflection of canard foreplanes and empennage slab sections at M = 0.86. The PYBBEN will actively augment pitch and yaw control authority.

The F-26 hydraulic system is rated at 4,000 psi and 72 g/m. Hydraulic power is necessary for wing sweep, landing gear actuation, air inlet control, nose wheel steering, wheel brakes, speed brakes, emergency electrical power generation and some flight control actuators. Hydraulic power is supplied by two, independent systems designated as the primary and the utility system. The system is redundant such that in the event of failure of one system, either system is capable of supplying power for wing sweep, flight control operation and landing gear deployment. Hydraulic power for each system is provided by engine driven, variable delivery pumps. Pressurized accumulators are installed in the system to supplant engine-driven pump delivery during transient hydraulic power requirements. Piston type reservoirs are provided for hydraulic fluid storage and surge damping for return line pressures within each system. To insure critical pump inlet pressure for all operating conditions, the reservoirs are pressurized with nitrogen.

The F-26 electrical system supplies 115 volt, three-phase, 400 cycle AC power and 28 volt DC power. Four independent sources are used for power generation consisting of a primary generator, auxiliary power unit (APU), batteries and a secondary generator. AC power is supplied by a single powerplant driven Sunstrand 90 kVA AC generating system. DC electrical power is provided by 28 Volt transformer-rectifier units and four 24 Volt sealed cell batteries.

The F-26 is equipped with a comprehensive integrated internal Electronic Warfare (EW)/Electronic Counter Measures (ECM) system configured specifically for the STALMA. Principal component systems of the F-26 STALMA ECM suite consist of former Hughes (now Raytheon Systems Company) and Elisra/Elta systems including, but not limited to, the Raytheon ALR-67(V)3 Countermeasures Receiving Set, AN/ALQ 135 Internal Countermeasures Set (Optional AN/ALQ-214), AAR-58 Missile Warning System, six Tracor AN/ALE-47 chaff/flare dispensers and an AN/ALE-55 decoy.

The F-26 employs technologies to significantly reduce Radar Cross Section (RCS), infrared signature, electromagnetic signature, visual signature and aural signature. RCS reduction represents the paramount LO feature considered in STALMA design. To reduce RCS, the STALMA employs a geometrically based radar disbursing configuration. Developed utilizing computational RCS modeling techniques employed and/or developed by Stavatti, the STALMA configuration employs facets approximated by curvelinear, polynomial sections. Ultimate F-26 RCS reduction, however, is dependent upon a proprietary combination of bandpass external skins, internal shaping and the implimentation of Cold-Plasma-Cavity Active Stealth Technology. Between the external bandpass skins and the internal graphite hull backed by an alloy geodetic structure is a cavity. Within this cavity a low temperature plasma is achieved. This plasma, as manipulated actively by the aircraft’s computer driven self-protection network, provides an unparalleled level of active stealth technology whereby incoming interrogative radar energy is substantially disrupted such that return signal is mitigated to undetectable levels or chaotic, undeciferable signals. Rather than rely solely upon external shaping, Stavatti proprietary F-26 stealth technology adapts to frequency and bandwidth, allowing maximum LO performance against all air-to-air and ground based radar types alike. F-26 clean, all-aspect RCS is on the order of 0.006 square meters.

To reduce RCS while carrying external stores, the aircraft can be equipped with Radar Elusive Tactical Stores Dispensers (RETSD™), developed by Stavatti. These dispensers allow the STALMA to carry wing mounted external stores without compromising LO features. This allows the STALMA to conduct precision strike and air-to-air engagements with limited detectability. The F-26 also features two independent, internal weapons bays for compact internal stores carriage including both the Stavatti CGM-4 tube-launched short range AAM as well as 250 LB class precision guided munitions. Carriage of compact stores within these internal weapons bays permits a slightly armed F-26 to function in a "clean" RCS configuration.

Reduction of IR emissions is achieved through the use of a dedicated engine bay cooling/IR signature reduction system. Ducting residual inlet air through the Powerplant Signature Reduction Shroud (PSRS), significantly reduces aircraft IR signature both in the subsonic and supersonic regime. Coupled with Lo-Axi™ or similar LO turbofan exhaust nozzle, the aircraft IR signature is substantially reduced.

Aural signature is reduced in part through the PSRS. For enhanced aural signature reduction, Stavatti is considering Active Frequency Damping (AFD) and comparable active noise control systems. Visual signature is reduced through employment of smokeless turbofans and by limiting overall aircraft size.

Protection against Scalar EM Weapons is provided through the application of lossy insulation and active cold plasma manipulation within the cavity between the aircraft graphite unibody and aramid external skins.

F-26 warload capability enables the delivery of conventional and nuclear weapons in various configurations, in air-to-air and air-to-ground modes. Fixed internal armament includes a single 20 mm M61A2 Vulcan cannon. Located in the port mid-fuselage, the cannon is equipped with a retractable muzzle cover. The aircraft is equipped with 1,000 rounds of 20 mm M50 or PGU-28/B Saphei ammunition. Expendable internal armament is carried in two internal weapons bays mounted ventrally within each of the aircraft port/starboard internal compression air intakes. Each internal weapons bay is rated to a 1,000 LB stores carriage capacity.

The F-26 internal weapons bays are configured for the carriage of compact stores, including up to four 250 LB Small Diameter Bombs (SDBs) or Eight Stavatti CGM-4 Compact Short Range AAMs.

External armament includes over 25,000 lbs of stores/ordinance. Stores are carried externally on eight wing and five fuselage hardpoints. Of the thirteen available stores stations, six are rated to 1,000 lbs, two are rated to 3,000 lbs, four are rated to 5,000 lbs and one is rated to 2,500 lbs maximum external carriage capacity at a +9g load factor. Maximum stores station ratings are reduced at greater load factors.

All stores may be jettisoned simultaneously or individually by selection. MIL-STD-1760 Weapon Interface Data Bus serves as aircraft weapon system integration backbone. The F-26 will be qualified and equipped to carry a wide variety of external ordinance. Based upon hardpoint rating, ultimate stores selection will be determined in the field. The aircraft was engineered to incorporate mission flexibility, employing universal weapons mount lugs, typically employing 14 to 30 inch suspension lug spacing and industry standard weapons release pylons. Standard missile and ordinance systems which the STALMA will be qualified to release will include the AIM-9, AIM-120, AGM-65, GBU-32, etc.