OVERVIEW
The SM-73 Rigel™ is an Advanced Anti-Submarine Warfare (ASW) and Multi-mission Maritime Aircraft (MMA) Concept presently undergoing consideration to enter into full scale development and engineering design by Stavatti Military Aerospace primarily as a private sector sponsored, commercial initiative to meet anticipated future NATO/Allied Anti-Submarine Warfare needs. An entirely new MMA designed specifically for the Anti-Submarine Warfare/Anti-Surface Warfare (ASW2) mission, the SM-73 will provide a flexible platform suitable for SAR, EW, Carrier Battle Group AWACs, and ELINT. Also directly suitable for civilian firebomber/ forestry protection roles, the SM-73 is envisioned to be a capable successor to the Lockheed P-3C Orion
A next generation, fixed wing, Short Take Off and Landing (STOL) aircraft, the SM-73 will provide significant internal fuselage volume to carry a wide variety of sensors and processing equipment while enabling sustained patrol speeds between 145 and 210 KTAS. With a warload of 25,000 lbs distributed over a Common Rotary Launcher equipped Internal Weapons Bay and eight external stores hardpoints, the SM-73 will be a highly integrated, Search and Destroy platform which can provide 3 hours on-station patrol with a mission radius of over 1,350 nm.
The SM-73 Rigel™ will be produced in multiple variants including produced in variants including Land-based Maritime Patrol and Anti-Submarine Warfare (SM-73 ASW), Elint (SM-73 EP) and Airborne Early Warning and Control (SM-73 AEW&C).
Designed to succeed the P-3C, Dassault Alantique ATL/2 and the BAE Nimrod, the SM-73 is an alternative to the P-8A Poseidon.
The SM-73 is the ASW/MMA member of Stavatti's SM-70 family of military transport, maritime patrol/anti-submarine warfare and regional commercial transport aircraft. A series of fixed wing, twin engine turboprop transport aircraft that benefit from a common wing, empennage and powerplant arrangement, the SM-70 series includes the SM-72 Medium Transport, the SM-73 Rigel™ Anti-Submarine Warfare/Maritime Multi-mission Aircraft (ASW/MMA) and the SM-74 Turboprop Regional Airliner (TRA). These three models will feature unique fuselage configurations to satisfy specific mission and market requirements.
The SM-73 would likely be manufactured at a single production facility and may enter Low Rate Initial Production (LRIP) between 2014 and 2018, or approximately six to eight years after the introduction of the SM-27 Machete. The SM-73 program is managed by Stavatti Military Aerospace. Stavatti anticipates production of between 15 and 30 SM-73s annually by 2017.
ACCOMMODATION
The SM-73 has a crew of eight to ten including one pilot, one co-pilot, one NAV/COM operator, One Offensive Systems Operator, three sensor operators (including a MAD operator and Acoustic Sensor Operators) and one in-flight technician. The SM-73 may carry a relief crew including a pilot and a copilot, raising the total number of crew members to ten. The flight deck accommodates a standard crew of four including two pilots (a pilot in command and a co-pilot), the NAV/COM operator and the Offensive Systems Operator. The flight deck is equipped with crashworthy seats. The Main Cabin is divided into forward and aft tactical compartments which are separated by the Internal Weapons Bay and connected by fully enclosed port and starboard access corridors.
The tactical compartments house an operations crew of four plus the two person relief flight crew. The forward tactical compartment contains advanced electronic, magnetic and sonic detection equipment while the aft compartment contains sleeping bunks, a galley, and a lavatory. The main cabin and flight deck is pressurized to an equivalent 6,000 ft altitude. Interior access is provided by port and starboard forward cabin doors and a nose gear wheel well hatch with access ladder.
POWERPLANT
The SM-73 is powered by two 14,500 SHP D-27 turbopropfan free turbine propulsion engines with a shaft output of 950 RPM. The propulsion engines drive two 17 ft 6 in diameter, eight bladed propellers. The propulsion engines drive an integrated auxiliary axial flow compressor that interfaces on-demand with the propulsion engines through a clutch in the engine gearbox. When the CCW system is engaged, the compressors draw approximately 31% of the SHP from the propulsion engines for the purpose of producing compressed air to supply the aircraft CCW/BLC system.
The turbine propulsion engines are mounted, one per wing, in a tractor configuration whereby the tip of the propeller is located immediately aft of the wing channel‘s trailing edge, with the wing channel approximately the same radius as the propeller. This propeller location/engine arrangement is a principal element of the lift enhancing, channel wing configuration. The turbine propulsion engines are housed in individual nacelles featuring an extended nacelle boom/aft section. This provides additional volume to house the CCW compressors and electronic countermeasures and avionic systems. Individual nacelles are supported vertically by engine support pylons mounted ventrally to the nacelles and supported directly by landing gear support sponsons integrated into the wing channel.
The D-27 turbopropfan, designed by ZMDB Progress of Zaporozhye, Ukraine and produced by OAO Motor Sich Joint Stock Company (JSC), presently powers the Antonov AN-70. D-27 design began in 1985 with the AN-70 prototype rolling out in 1992 and the AN-70 first flight occurring in 1994. To enhance SM-70 series performance, it is likely that an Improved Performance Derivative D-27 (IPD D-27) will be produced specifically for the Stavatti application either entirely by Motor Sich, or through a Joint Venture company involving Motor Sich in partnership with a United States turbine engine manufacturer. A U.S. joint venture partner for IPD is not yet negotiated, however, potential candidates include a new company formed specifically by Stavatti Heavy Industries, Ltd., in joint venture with Motor Sich to produce IPD D-27 engines in the U.S. The IPD D-27 Turbopropfan will build upon the success of the proven D-27 powerplant, while increasing overall powerplant performance to create a propulsion system that develops a maximum of 15,000 to 18,000 SHP.
The SM-73 has provisions for Internal and External weapons carriage. Internal weapons are carried in an Internal Weapons Bay while external weapons are carried on wing-mounted, external hardpoints.
The SM-73 Internal Weapons Bay measures 20 ft long, 10 ft high and 10 ft wide and is equipped with a Common Rotary Launcher Assembly (RLA). Common to the B-1B, the SM-73 RLA can carry up to 8 GBU-3 1 JDAMS or 10 SFWs or 4 JSOW/JASSM or 28 GBU-38s/Mk 82s and a variety of dedicated ASW stores including the MK 46 and MK 50 torpedoes. The RLA is removable, allowing the Internal Weapons Bay to be equipped with a variety of payload configurations including vertical bomb ejector racks for the carriage of ordinance.
SM-73 external weapons are carried on eight (8) wing mounted external hardpoints/stores pylons. SM-73 external hardpoints feature NATO standard 14-in lug suspension and are rated for 2,500 lbs. Mounted ventrally on the wing channels, the external hardpoints are placed for expedient stores loading. Stores pylons and weapons management systems are integrated per a MIL-STD-1760 Weapons Interface Data Bus.
Typical stores and ordinance carried by the SM-73 will include the AIM-9 Sidewinder for self-protection, the AGM-65 Maverick, the GBUI-39/B Small Diameter Bomb, the GBU-38 JDAM/MK 82, the GBU-32 JDAM/MK 83, the GBU-31 JDAM/MK 84, the CBU-89 Gator Mine, CBU-97/CBU-105 SFW, AGM-84D Harpoon, AGM-84E SLAM, AGM-84H SLAM-ER, AGM-154 JSOW, AGM-158 JASSM, Gabriel Mk.3 A/S, MK 55 Aircraft Laid Bottom Mine, MK 62 Quick Strike Mine, MK 63 Quick Strike Mine, MK 64 Destructor Mine, MK 65 Quick Strike Mine, MK 54 Depth Bomb, MK 46 Torpedo, MK 50 Advanced Lightweight Torpedo (ALWT), MK 60 CAPTOR, and B61-11 thermonuclear device.
The SM-73 flight deck features a fully integrated avionics suite that includes the Honeywell SPZ-8500 integrated avionics and CNI-MS digital flight management system. A Smiths WMS-Maritime system is employed for SM-73 weapons/stores management. The primary SM-73 COMM is the AN/ARC-210(V).
Primary SM-73 ASW sensors include the Raytheon AN/ASQ-208 digital Magnetic Anomaly Detector (MAD) mounted in an aft fuselage probe, Cubic AN/ARS-5 with integrated SRS sonobuoy system with Hazeltine AN/ARR-78(V) communications link and Raytheon AN/APS-137(V) Inverse Synthetic Aperture Radar (ISAR). Sensor data is processed with the AN/UYS-2 Proteus and the AN/ASQ-212. Also featuring a Raytheon AN/APQ-122 terrain following radar, EW variants may be fitted with an Elta EL/M-2022 Maritime Surveillance Radar or Litton AN/APS- 145 Airborne Surveillance System. AWACS variants will feature a fuselage dorsal AN/ALR-73 detection system. The SM-73 FLIR includes the AN/AAS-36/37 while OASIS III is incorporated for over-the-horizon targeting of air-to-surface missiles. The SM-73 features a ventrally mounted, retractable L-3 Wescam MX-20 Advanced Imaging Multi-Spectral System, or equivalent, in the aircraft nose section. The SM-73 is equipped with a ventral aft fuselage-mounted sonobuoy dispensing system capable of delivering up to 64 standard size sonobuoys.
SM-73 avionics and sensors will be integrated about a MIL-STD-1553B Interface/Data Bus with Data Bus Wiring used throughout the system architecture to reduce wiring bundles. The SM-73 will employ a comprehensive navigation/ communications suite with the SM-73 avionics system emphasizing mission completion, reliability, flexibility and ease of serviceability. Avionics may be of a variety of types including either COTS or MOTS. Wherever possible, avionics are of modular LRU type with BIT.
The avionics/sensor suite is designed and integrated by Stavatti based upon customer specifications, however, Stavatti Military Aerospace has developed a Standard Configuration for baseline SM-73 avionics for those customers who desire to procure an aircraft with a proven, integrated suite of baseline avionics. A detailed listing of principal avionics and sensors which will be considered to be Standard Configuration Avionics are provided on the SM-73 Performance & Specifications webpage.
The cockpit is equipped with a Cockpit Video Recording (CVR) system capable for recording at least 120 minutes of HUD symbology, the external HUD field of view, cockpit LCD MFD symbology and all aircraft communication system audio. The aircraft is also equipped with a crash survivable Flight Data Recorder (FDR) capable of storing the last 90 minutes of flight data for post-crash flight reconstruction. The aircraft is fitted with a Crash Position Indicator (CPI) and a survivable Underwater Locator Beacon (ULB). Halon 1301 will be employed for avionic system fire suppression within sealed avionic bays.
FLIGHT DECK
The SM-73 features a cockpit designed for two-person, human-centered, reduced workload operations. The flight deck design accommodates a wide spectrum of male and female crewmembers encompassing the 1st percentile female through the 99th percentile male (NATO) population range, corresponding to crewmembers ranging from 5 ft 4in/100 lbs through 6 ft 4 in/250 lbs.
Employing a traditional yoke, full deflection rudder pedals, and FADEC engine control system, the SM-73 panel features redundant, dual instrumentation and displays. The primary pilot flight reference instrument is a Honeywell-produced derivative of the Primus Epic Integrated Avionics system that includes a total of six 10 x 13 in multi-functional Liquid Crystal Flat Panel Displays with Integrated Primary Flight Display (IPFD) and Integrated Navigation (INAV) technology. To interface with the Primus Epic system, a side-mounted cursor control system and keyboard interface is provided for the pilot and co-pilot. The Honeywell Visual Guidance System Head-Up Display (VGS HUD) offering a 25 x 30 degree field of view is provided for both the pilot and co-pilot. For in-flight emergencies, all SM-70 series aircraft are equipped with stand-by analog instruments including attitude and airspeed indicators as well as an altimeter, HSI, and clock.
Cockpits are designed for day/night VFR/IFR operations and are Generation IV night-vision compliant. With avionics integrated about a MIL-STD-1553B interface/data bus, all SM-70 series models feature additional avionic and sensor systems appropriate to their mission profiles. For crew comfort, the cockpit is pressurized to 6,000 ft equivalent atmosphere at altitude with standby crew oxygen provided by a Carlton OBOGS.
The SM-73 Rigel™ has an integrated self-protection system consisting of BAE Systems/Tracor AN/ALE-47 dispensers, the BAE Systems DASS-2000 integrated multispectral threat warning and countermeasures, the AN/AAR-47 missile warning system, the AN/ALR-56 Radar Warning Receiver (RWR), the AN/ALR-69 enhanced radar warning system and/or the ITT AN/ALQ-172 Electronic Countermeasures. A detailed listing of Electronic Counter Measures which will be considered to be Standard Configuration Avionics are provided on the SM-73 Performance & Specifications webpage.
STRUCTURE
The SM-73 is of fail-safe, semi-monocoque construction composed of an alloy internal substructure consisting of Titanium load bearing elements with Aircraft Aluminum and Graphite Reinforced Plastic (GRP) as load-bearing stressed external skins and Kevlar Reinforced Plastic (KRP) secondary structural skins. Approximately 46% of the aircraft structure is composite by weight, with the remaining 54% is advanced aerospace alloys Approximately 34% of the SM-73 primary structure is GRP, while 10% is KRP. Principal composite materials employed throughout the SM-73 structure include Hexcel IM-9 Graphite Fiber/Polyimide Resin as the GRP and Dupont Kevlar/Polymer Resin as the KRP. The primary Polyimide resins employed include high-temperature, autoclave cured RP46, BIM-AC non-mutagenic/non-carcinogenic polyimide, AMB-21polyimide or DMBZ-15 polyimide.
A significant number of aircraft components are made from Titanium, which totals 22% of the aircraft structural weight. Chosen due to its high strength to weight ratio and resistance to galvanic corrosion when fastened to composite materials, titanium components are produced using laser forming, laser machining and traditional aerospace Titanium part production methodologies. Aluminum alloys constitute approximately 33% of the aircraft primary structure by weight, with principal aluminum alloys employed including Alcan/Alcoa produced aluminum alloys such as 7150-T7751 Aluminum, 7075-T651 Aluminum, 7055-T7751 Aluminum and other high performance aircraft aluminum.
The SM-73 benefits from advanced structural manufacturing techniques where primary alloy structural members including fuselage frames and ribs are unitized, single-piece construction produced by Stavatti qualified Industry Team Members. Individual alloy structural members, including primary spars, ribs, longerons and frames are mechanically fastened together using rivets or bolts or welded using inert/laser processes. Composite materials are mechanically fastened to the alloy substructure using rivets, bolts and proprietary fastening systems, or alternatively, co-cured to high temperature titanium elements during the component autoclave cure cycle. The SM-70 features no bonded components.
The SM-73 is designed for a maximum limit load factor of +4.5/-2.0 at MTOW. The composite and corrosion resistant alloy construction offers a minimum 40-year service life corresponding to approximately 60,000 flight hours.
The SM-73 features a fuselage of elliptical cross section measuring 16 ft 6 inches wide x 12 ft high externally. Separated into a ventral cargo hold/avionics/sensor compartment and a main cabin/passenger deck, the fuselage provides a 13 ft 10 in W floor in the main cabin. The main cabin is divided into two primary crew sections separated by an Internal Weapons Bay (IWB). The cabin crew sections include a 25 ft long forward cabin that incorporates primary tactical workstations, sensor controls, offensive and defensive control systems and submarine detection operation equipment, including MAD workstations. Aft of the IWB is a 29 ft long rear cabin featuring sonobuoy sensor and data processing workstations, an all-electric galley, and a large crew rest area incorporating bunks and a large capacity lavatory station. The forward and rear cabins are connected through two fully enclosed walkways located port and starboard of the IWB. Each walkway measures 22 in wide at the floor and 36 in at their widest points. The walkways are 20 ft long. The main cabin, including forward, walkway and aft compartments, is pressurized to 6,000 ft equivalent elevation at an operating altitude of 36,000 ft.
Of modular four-section construction, the SM-73 fuselage includes a reduced drag nose section and reduced base-drag aft fuselage with aft drop-down cargo ramp. The fuselage is of fail-safe sandwich construction is composed of a distinct inner skin and outer skin. Unique to Stavatti, the double-hull fuselage design is composed of load-bearing Aluminum inner and Aluminum and KRP outer skins separate on the order of six inches by an internal sandwich structure composed of a titanium keel, multiple titanium longerons and titanium frames. To augment the Aluminum frames, Titanium frames are also employed in the fuselage sandwich structure, constituting approximately one-third of all frames. Over 75% of the SM-73 fuselage is composed of Aluminum, 25% of the fuselage is Titanium, and approximately 5% is KRP.
The SM-73 is a high-wing model plane with traditional vertical and horizontal stabilizers. SM-73 wings are high-wing, dorsal fuselage mounted cantilever, M-planform and Channel-Wing configuration. Inspired by work performed by Georgia Tech Research Institute (GTRI) and NASA Langley Research Center regarding Pneumatic Channel Wing Powered-Lift Advanced Super STOL Aircraft, the SM-73 wing combines a semi-elliptical, compound swept planform with a powered-lift channel wing, double slotted Fowler Flaps with leading edge slats and significant boundary layer control.
The SM-73 will benefit from the Channel Wing. Originally developed by Willard Custer during the 1950s, the “Custer Channel Wing” realizes high local lift coefficients and corresponding effective downward deflection of propulsive thrust through the placement of an aircraft's engine-driven propeller at the trailing edge of a 180º circular arc wing channel. Placing the propeller at the trailing edge of the circular arc channel increases airspeed over the channel's upper wing surface and augments lift production.
AIAA 2002-3275: Pneumatic Channel Wing Powered-Lift Advanced Super-STOL Aircraft
Experimental Development and Evaluation of Pneumatic Powered-Lift Super-STOL Aircraft
As a structural element, the wing channel is a mounting point for aircraft landing gear sponsons that incorporate port and starboard main landing gear bogies, respectively. The sponsons provide additional volume for avionics systems, electronic warfare systems, storing ground handing systems and in the case of the port sponson, serve as the interface for the aircraft Single Point Refueling System (SPRS). The sponsons are also the primary ventral mounting fixture for the engine support pylons.
The SM-73 empennage is a fixed horizontal stabilizer mounted dorsally to the aft fuselage section and a single, dorsally mounted vertical stabilizer. The horizontal stabilizer is connected structurally to the aircraft fuselage at its root chord while the tip chord is mounted to the trailing portion of the aircraft engine nacelles, providing a rigid cantilever body for nacelle attachment. The vertical stabilizer is connected structurally to the aircraft aft fuselage at its root chord. The horizontal stabilizer is composed of four titanium spars augmented by titanium ribs with mechanically fastened GRP skins. The vertical stabilizer is composed of two titanium and one GRP spar with GRP external skins. Numerous GRP construction internal ribs and false spars are employed throughout the vertical tail structure. The rudder is composed of GRP external skins with titanium and GRP internal elements, including spars and ribs.
FUEL SYSTEM
The SM-73 is equipped with a standard Internal Fuel System (IFS) that provides approximately 70,000 lbs of jet fuel, corresponding to 10,450 USG of JP-8 or 10,770 USG of JP-4. The IFS consists of eight discrete, sealed-cell fuel tanks contained within the SM-73 wings. Fuel tanks include two tanks mounted in the inboard wing sections (one tank per inboard wing) and four tanks mounted in the channel wing sections (two tanks per channel wing section) and two feeder/reserve tanks located within each engine nacelle. The OBIGGS aircraft fuel system is pressurized using the Carlton NC1069. Provisions for in-flight refueling include a dorsal fuselage integrated Universal Aerial Refueling Receptacle Slipaway Installation (UARRSI) located immediately above and aft of the flight deck as well as a retractable probe for USN drogue refueling located on the starboard forward fuselage.
The SM-73 will feature full-authority, four channel digital Fly-By-Wire (FBW) flight controls with artificial force-feedback and yaw dampening. The SM-73 is equipped with a 4,000 psi hydraulic system for landing gear extension/retraction and flap extension and retraction. The SM-73 electrical system is driven by two 40kVA alternators and supplies 115-volt, three-phase, 400-cycle AC power and 28Vdc per MIL-STD-704D. Power is generated by engine driven alternators, the APU or a Ram-Air Turbine for in-flight emergencies.
Aircraft Self-start capability and onboard electric power generation is provided by a Honeywell 331-250 or Hamilton Sunstrand APU mounted within the aircraft wing/fuselage junction box. The 331-250 APU provides 90kVA and 447kW.
SM-73 Landing gear is hydraulically retractable, tricycle type consisting of a tandem wheel forward retracting nose unit and two quad-wheel trucks to serve as main gear, each of which retract into wing mounted sponsons. SM-73 nose-wheels use a Goodyear Type VII 39 x 13, 16 ply Flight Leader tire rated to 225 mph at a maximum inflation pressure of 115 psi. Main wheels use the Goodyear Type VII 40 x 14, 24 ply Flight Leader tire rated to 225 mph at 170 psi. The nose wheel is steerable while all landing gear struts incorporate hydraulically actuated kneeling to improve cargo handling. All wheels are equipped with Goodrich carbon disk brakes.
