Despite the impressive combat load of 7260 kg, the massive armor protection of the cockpit, represented by the size of titanium armor plates on screw mounts, as well as the high survivability of the vehicle thanks to the power plant based on 2 General Electric TF34-GE-100 turbojet engines, heavy attack aircraft A -10C "Thunderbolt II" has only about 10-12 years of service in the US Air Force. The fact is that the average age of the "Warthogs" gliders is approaching 30 years, and sooner or later the fatigue of the structure will still make itself felt. Another important detail can be considered a decent radar signature of the A-10C, which will not make it possible to avoid detection not only by mobile radars of modern military air defense systems, but also by smaller decimeter 1L122E Garmon radars capable of detecting Thunderbolt II at a distance of 50 and more than kilometers.
For this reason, high hopes on the part of the US Air Force Command today are pinned on both the partial replacement of the Thunderbolts with the new F-35A and the latest F-16C “blocks”, and on the development of the latest combat trainers that perfectly combine the functions of training machines and attack aircraft capable of fighting the advanced military air defense weapons without going into the radius of their destruction. Also, unlike the A-10C, the emphasis in the performance characteristics of new vehicles will be made on increasing the range, as well as on the possibility of safe operation directly in the extreme part of the affected area of modern self-propelled anti-aircraft missile systems, which can only be achieved by reducing the RCS and integration of complex complexes of electronic and optical-electronic countermeasures. In the United States, several programs have already been launched to develop light UBS, claiming to be the main attack aircraft of the Air Force. At the same time, the most significant of them belong to the previously little-known companies Textron AirLand and Stavatti Aerospace.
The brainchild of the first company is the Scorpion combat trainer, which has already taken off its wings in 2013, which managed to participate as an advanced air platform for the testing program of tactical missiles of the AGM-114 "Hellfire" family and promising 70-mm guided missiles WGU -59 / B APKWS II ("Advanced Precision Kill Weapons System"). The company "Stavotti Aerospace" submitted for consideration at once 2 related projects of light attack aircraft under the general name "Machete" with indexes SM-27 (turboprop version) and SM-28 (jet version). But these machines, according to the resource "Defense Technology", are only at the level of technical sketches. Nevertheless, the cars managed to catch the fancy of the command of the American Air Force. Moreover, according to some sources, the Air Force expressed a desire to acquire about 100 attack aircraft of this type. It is absolutely inappropriate to draw final conclusions at the moment, because the Scorpion and two modifications of the Machete have a number of technical disadvantages and advantages, some of which may become decisive when choosing a particular vehicle for the needs of the Air Force in the 21st century.
TEXTRON AIRLAND SCORPION: A PERSPECTIVE TWO-ENGINE ATTACK SPARK WITH AN ADVANCED CREW CABIN INFORMATION FIELD INTEGRATED INTO THE NETWORK
In the development of the promising combat training aircraft "Scorpion" several very well-known units that are part of "Textron AirLand" took part at once. Among them are Bell, Cessna and Beechcraft. Despite the fact that their fame was achieved by their active work in the civil aviation sector, they had previously gained experience in the design of multipurpose combat helicopters, as well as light attack aircraft A-37 "Dragonfly" with a combat radius of about 350-400 km and a maximum load of 1860 kg (the last car was developed by the Cessna company).
"Scorpion" received a fairly perfect airframe design with a straight high-winged wing and an original design of the tail unit. Vertical stabilizers are not all-turning (only small edge segments are deflected - rudders), but they have a 20 - 25-degree V-shaped camber, which partially reduces the radar signature of the aircraft. The horizontal tail is also not all-turning, but is represented only by small elevators that form the trailing edge. This is a significant drawback (in comparison with our Yak-130), due to which the maneuverability of the Scorpion UBS is sharply reduced. The aircraft does not have the ability to reach high transonic speeds as well as long-term maneuvering, which is dictated by the low total thrust of two Honeywell TF731 turbojet engines of 3600 kgf, which brings the thrust-to-weight ratio to 0.48 kgf / kg (at normal takeoff weight) and to 0, 38 kgf / kg (at maximum weight).
The aircraft will not be able to emerge victorious in forced close combat not only with fighters such as the MiG-23MLD, but also with combat training aircraft such as Yak-130 and L-15. Due to the lack of developed aerodynamic slugs at the root of the wing, the "Scorpion" is unable to reach large angles of attack, but thanks to a large straight wing with an area of about 20-22 m2, after accelerating to 750-800, it can make a single intense turn for a short time., in demand for an operational turn in the direction of the battlefield. Also, such a wing design makes it possible for the Scorpion to reach a practical ceiling of 14 km, which is a kilometer more than most other light attack aircraft. The fuel consumption of the less powerful TF731 is relatively low, due to which the range with a maximum combat load of 1500-2000 kg can reach 1700 km, which is 3 times more than that of the A-10C. Due to this, the car can circle for about 4-5 hours over the theater of operations, located 300 km from the home airfield. No known multipurpose UBS possesses such abilities. The "spaced-apart" twin-engine power plant (known in the F-14, MiG-29, Su-27, T-50 PAK FA, J-11/15/16 families) makes the Scorpion a much more tenacious product than aircraft with closely spaced engines.
The main technological "feature" of the "Scorpions" is the principle of placement of missile and bomb weapons, comparable to the 5th generation fighter aircraft. In particular, for this, an internal weapons compartment of 4, 3x0, 9 m is provided, capable of accommodating combat "equipment" weighing 1400 kg. The range of weapons is quite rich: from "narrow bombs" GBU-39/53 / B (SDB / II, - Small Diameter Bomb) in the amount of 8-12 units, to tactical JAGM missiles with a range of 28 km and equipped with a three-channel homing head (active radar Ka-band sensor, IR sensor and semi-active laser aiming sensor at the target designator "spot"). There are other weapon options. The inner compartment reduces the aircraft's radar signature and improves aerodynamic qualities, which have a direct impact on fuel consumption. If necessary, additional weapons can be placed on 6 underwing suspension points. The strong tactical side of the "Scorpion" can be considered a large cockpit canopy with decent visibility, which allows the pilot and system operator to quickly navigate in a difficult tactical situation.
Also, in order to maximize information illumination of the crew, the promising UBS is equipped with two completely duplicating instrument panels of the pilot and the system operator, due to which, if necessary, the assigned functions can be exchanged. In the cockpit, you can see 2 large-format vertically oriented LCD MFIs with split matrices and an additional button frame (on the right side of the dashboard). On 4 working areas of these indicators, the artificial horizon, heading direction, altimeter, navigation map with given waypoints are displayed, as well as a tactical map with terrain relief, on which naval, ground and air target markers of the enemy, detected as their own optical electronic or radio technical means, and third-party target designation means (tactical fighters, RTR / RER aircraft, RQ-4A / B / C reconnaissance UAVs).
The electronic "stuffing" of the light attack aircraft "Taxtron AirLand Scorpion" deserves special attention. Firstly, in recent years on the network, citing US sources, there was information about endowing the Scorpion with hardware capabilities for establishing tactical communications with the AH-64D Apache Longbow Block III attack helicopters (later known as the AH-64E Apache Guardian). Such tactical communication can be based on encrypted radio data exchange channels "Link-16" in the decimeter range, as well as on a centimeter Ku-band radio channel TCDL, designed for communication between the Apaches and various shock-reconnaissance drones, including the MQ-9 "Reaper" … The TCDL radio channel has a frequency range of 14400-15350 MHz and provides for the software introduction of a 5 MHz tuning step for terminals. The speed of transmitting radio command data to controlled units will be 64 Kbps, while the speed of receiving telemetric and radar information from Reapers and Apaches to RVT Scorpions video terminals can be 10.71 Mbps. Due to the high frequency of the TCDL network-centric radio channel, in practice, the communication range will be no more than 100 - 150 km. To increase it, you may need either repeaters based on the Global Hawks, or more powerful transmitters, which is unrealizable on such small combat units as Apache, Reaper, and, accordingly, Textron AirLand Scorpion.
In addition to integration into tactical networks of the XXI century, high combat qualities of UBS / light attack aircraft "Scorpion" are also provided by the advanced ventral "turret" optoelectronic complex MX-15i "True HD". The module of the complex includes two infrared sensors with resolutions 640x512 and SXGA (1280x1024). The first ("Thermal Imager"), despite the lower resolution, has an optical approximation of 50X, the second ("High Defenition Thermal Imager") - 30X. Under normal meteorological conditions, such a zoom makes it possible to track enemy armored vehicles or vehicles at a distance of 50-65 km, or identify a surface target of the "corvette / frigate" class at a similar distance. The third sensor of the MX-15i complex is a color TV viewfinder with increased light sensitivity (“Color low-light continuous zoom”) with a maximum resolution of 1920x1080 (FullHD). Also included in the MX-15i are a regular daylight FHD TV channel ("Daylight step-zoom spotter"), a 20-kilometer LRF laser rangefinder and a 750 mW laser designator with a wavelength of 860 nm. The MX-15i is interfaced with the UBS "Scorpion" weapon control complex via a modern interface of the MIL-STD-461/810 standard.
Having taken off for the first time on December 12, 2013, already in July 2014, the first prototype "Scorpion", to the maximum "equipped" with fuel in the PTB and an additional tank in the gargrot, was able to make a transatlantic flight to the British RAF "Fairford" airbase in order to further participation in the Farnborough Air Show. The vehicle covered more than 4500 km, which demonstrated the ability of long-term air patrol with stable operation of avionics and TF-731 engines. The vehicle is completely ready for reconnaissance and limited strike operations against irregular enemy military units with outdated armored vehicles with missing active protection systems, optical-electronic countermeasures, and also not covered by modern military air defense equipment. Considerably ahead of the A-10C family in terms of combat range, versatility and stealth, the lightly armored Scorpion cannot reliably hide a crew of 2 pilots from 12, 7-14, 5-mm machine guns, as well as larger-caliber automatic weapons, which prohibits the approach of the attack aircraft to the enemy at a distance of less than 4 km.
Meanwhile, the design of the nose of the fuselage provides for the placement of modern compact airborne radars with AFAR type AN / APG-83 SABR, etc., which will open up additional opportunities for the crew to work with surface and air targets, including the independent use of the Harpoon anti-ship missile system on ranges of more than 50-60 km, as well as long-range air combat for self-defense or support of friendly troops. Due to the use of composite structural elements, the effective scattering surface of the UBS "Scorpion" is significantly lower than that of the A-10C, but not minimal, since there is a large number of rounded elements, including air intakes. There are also direct air ducts to the turbojet engine compressor, which causes additional reflections from the blades, requiring the use of inclined radio absorbing gratings. Due to the lack of the possibility of rapprochement with enemy targets at a distance of 2-3 km, the Scorpion is not equipped with a rapid-fire 30-mm AP GAU-8, which practically to zero reduces the possibility of hitting a modern tank equipped with an active protection complex from the first approach.
SINGLE-ENGINE STAVATTI AEROSPACE MACHETE - LIGHTWEIGHT AND CHEAP KAMIKAZE WITH AVENGERS ON BOARD
Despite the fact that the US Air Force command nevertheless showed a genuine interest in the promising SM-27/28 Machete light "attack aircraft of the future" project from Stavatti Aerospace, these machines have an extremely dubious and contrasting set of technical features. In particular, the "turboprop" modification of the SM-27 attack aircraft provides for the installation of an upgraded Pratt & Whitney Canada PW127G theater with a high-torque 2-section 16-blade propfan located immediately behind the turbocharger. The power of the unit is 2920 hp. As you know, such engines demonstrate excellent efficiency at speeds of 0, 7 - 0, 8M and can operate at extreme conditions. But it is not entirely clear how one such engine will cope with the "lifting" of a machine with a takeoff weight of the order of 7, 5-8, 5 tons, a length of 11, 5 m and a wing span of 14 m.
The weight of the complete GAU-8 / A "Avenger" cannon alone reaches 1830 kg, and another 2 tons of missile and bomb "equipment" at 8 suspension points (plus about 2 more tons), and fuel … there can be no question of any maneuvering superior to the Thunderbolt or Scorpion. The practical ceiling will also be limited to 5-7 kilometers. The range, at best, will be 700-900 km, while the Stavatti manual for 2004 indicates all 1250-1300 kilometers. The two-seater cockpit has absolutely no reservation, which strictly prohibits rapprochement with enemy targets defended by anti-aircraft artillery. Undoubtedly, the movable front horizontal tail and all-turning elevators will improve the flight performance of the SM-27 "Machete", but this will not be enough for the "agility" of the reaction over an active theater of operations.
The turbojet modification of the Machete, the SM-28, has much more promising prospects for advancement in the US Air Force or Air Force. Looking at the fuselage design of a promising attack aircraft, the installation of a compact General Electric F414-GE-400 engine with an afterburner thrust of 10,000 kgf (these turbojet engines are installed on deck-based fighters F / A-18E / F) suggests itself. Consequently, the thrust-to-weight ratio, the maximum loads on the wing close to the straight wing and the overload of the machine will increase. With an increase in the sweep of the wing and the modernization of the power units of the airframe, a good attack aircraft with a thrust-to-weight ratio of 1, 1 kgf / kg and a maximum speed of 1400 km / h can be obtained. The plans to deploy the massive GAU-8 cannon will apparently have to be revised and limited to the lighter M61 "Vulcan" family, especially since the aircraft will still be deprived of booking and participation in cannon "duels" with a well-armed ground enemy may end for pilots SM-28 deplorable.
Very interesting points are: the absence of an internal weapons compartment, a completely straight vertical tail and an outstanding aircraft cannon module. All these details in no way fit into the list of measures to reduce the radar signature of an aircraft of the XXI century. Instead of semi-submerged or at least shortened external suspension units, the sketches of "Stavatti" show huge pylons adding about 0.3-0.5 m2 to the total RCS.
It is possible that at the moment the US Air Force is attracted by the extremely low cost of a flight hour of the turboprop version of the SM-27, which is only $ 1000, as well as the estimated unit price of $ 6 million, but in reality they are unlikely to justify themselves. Modernization of the jet version of the SM-28 attack aircraft with the F414-GE-400 engine, as well as an increase in the sweep of its wing also does not bode well, since the stall speed will sharply increase from 180-200 km / h to 230 km / h, and the range will decrease to 500 - 700 km. Considering that more than 10 years have passed since the development of the concept of the "promising" SM-27/28 attack aircraft, and the projected machines have remained "raw" products with a load of flaws and "flaws", we can safely state that 2 prototypes undergoing active fire tests Textron AirLand Scorpion combat trainers are by far ahead of the untested single-engine Machete concept.
