GM-25 Cuirassier Advanced Air-Superiority Fighter
Overview
The GM-25 is a single seat, twin engined, dedicated Air Superiority Fighter designed for the sole purpose of obtaining and maintaining total tactical aerial superiority within any given battlespace. The GM-25 is the most advanced aircraft ever produced by Gemballa with billions of dollars of government funding being poured into the project over nearly a decade to develop one of the most sophisticated and deadly aircraft in service anywhere around the world. Advanced radar systems, cutting edge low observability technology and an airframe with the potential for super-manoeuvrability are just some of the characteristics of this uncompromising aircraft.
Project Concept
In 1994, the aging IAI Kfir fleet of the Mikoyan-Guryevich Air Force had been slated for retirement after their relative age and incompetency against modern military technologies had become painfully obvious during the Scalietti Emergency in 1992.
In 1992, civil war erupted quickly and without warning within the neighboring country of Scalietti prompting a large-scale intervention by many nations within Texas to quickly diffuse the situation. In June of 1992, rebel forces had seized large swaths of the mountaneous interior of Scalietti and along with it, a large portion of the military hardware owned by Scalietti. Mikoyan-Gurvevich, because of it's close proximity to the beleaguered nation, was one of the first to respond with air strikes on several high profile targets under control of the rebels. The aircraft slated for the job were Mikoyan-Gurevich's long but exemplary serving IAI Kfirs, an aircraft of 1970's vintage. At first againt the lightly armoured and under protected targets at the border of the rebel held territory, the Kfirs suffered no problems. However, in the summer of 1992 the Texan Defence Forces mounted an assualt on the region and Kfirs were slated to provide aerial support to the inwards push. Rebel forces responded with an aerial force which none knew existed, comprising of many ex-Scaliettian F-16's and F-15's along with batteries of potent Surface to Air missiles. Kfirs were shot from the sky with ease and Mikoyan-Gurevich was forced to withdraw from the conflict after the shocking defeat.
By 1993, a project for a new fighter was to be announced. The project would not be offered as a contract to several different companies; only one would receive the funding and support needed to deliver the required aircraft. But announcing the project became the next problem for the Air Force; nobody could decide what shape the aircraft would take. The IAI Kfirs had performed every combat role within the Mikoyan-Guryevich Air Force; no other types were required. Realising that any attempt to create another aircraft designed for every purpose would most likely be disasterous, the project was split into two halves. The first half was the Multirole Fighter Project which eventually resulted in the GM-23 Czapka, the second half was the Air Superiority Fighter Project which aimed to design an aircraft capable of taking on any other in the world.
While the Multirole project progressed flawlessly and resulted in an easy birth, the Air Superiority project was one marred by set backs and squabbles between parties. Even the Mikoyan-Guryevich Air Force themselves had no idea which direction the aircraft should take. After two years of near constant arguments, the project faced two different path. The first path led to an Air Superiority Aircraft which was capable of performing any role, yet optimized for dog fighting. For being technically advanced, yet relatively cheap and easy to maintain and an aircraft which much more conservative than the alternative path. The second path led to an aircraft solely designed for Air Superiority as well as being tricky to build and expensive to keep. An aircraft which could out-perform almost every thing else. Another three months of considerations followed before the Air Force selected; they wanted both.
The first path resulted in the GM-24 Caballero which took to the skies long before it's illustrious counterpart ever did. But the Khe Sanh project, as the 'second path' became known as was shoved under the rug, the government even going as far to say it was cancelled in favour of the GM-24. By late 2010, the GM-25 was ready, and finally entered service after an initial production run of just 50 aircraft.
Avionics
The GM-25's avionics include Cervelo SS-16 radar warning receiver/emissions locator system, Cervelo SB-77 Infra-Red and Ultra-Violet MAWS (Missile Approach Warning System) and the Cervelo DD-20X Active Scan radar. The DD-18X features both long-range target acquisition and low risk of interception of its own signals by enemy aircraft due to its complex set up and frequent channel changing.
The Radar used in the GM-25 is the Cervelo DD-20X Active Scan radar. The 20X is an uprated version of the 18X, being more powerful, less obvious to enemy aircraft and predictably more expensive. The 20X is an active electronically scanned array with the capability to track and engage multiple targets at any one time.
The Cervelo DD-20X Active Scan radar is designed for air superiority and strike operations and features a low-observable, active-aperture, electronically-scanned array that can track multiple targets in any weather, including storms. The Cervelo DD-20X Active Scan changes electromagnetic frequencies at more than 1,000 times per second to greatly reduce the chance of being intercepted by an enemy aircraft. If the GM-25 is spotted, it can then focus its radar emissions on an enemy aircraft, to overload enemy sensors and thus jamming the enemy radar. The DD-20X was designed with the Low Probability of Intecept theorem as paramount with a strong emphasis on the lowest possible observability to other aircraft. Unlke many other radar systems, the DD series of radar has very few moving parts and is much less likely to malfunction in the air than other radar systems employed by other aircraft.
An AESA or Active Electronically Scanned Array radar system represents the forefront of modern radar technology. These radars are deceptively hard to intercept because an AESA radar will change it's frequency every pulse, at up to 1000 times per second. Since the AESA can change its frequency with every pulse, and generally does so using a pseudo-random sequence, integrating over time does not help pull the signal out of the background noise. Nor does the AESA have any sort of fixed pulse repetition frequency, which can also be varied and thus hide any periodic brightening across the entire spectrum. Traditional Radar Warning Receivers are essentially useless against AESA radars. This means that the GM-25 can look for long periods of time without being seen in the process. This radar fitted to the GM-25 employs a very erratic search pattern made possible by the enourmous computing power at the disposal of the crew, further adding confusion to the Radar Warning Receiver at the other end.
Jamming is likewise much more difficult against an AESA. Traditionally, jammers have operated by determining the operating frequency of the radar and then broadcasting a signal on it to confuse the receiver as to which is the "real" pulse and which is the jammer's. This technique works as long as the radar system cannot easily change its operating frequency. When the transmitters were based on klystron tubes this was generally true, and radars, especially airborne ones, had only a few frequencies to chose among. A jammer could listen to those possible frequencies and select the one being used to jam.
Since an AESA changes its operating frequency with every pulse, and spreads the frequencies across a wide band even in a single pulse, jammers are much less effective. Although it is possible to send out broadband white noise against all the possible frequencies, this means the amount of energy being sent at any one frequency is much lower, reducing its effectiveness. Moreover, AESAs can be switched to a receive-only mode, and use the jamming signals as a powerful source to track its source, something that required a separate receiver in older platforms.
AESAs are so much more difficult to detect, and so much more useful in receiving signals from the targets, that they can broadcast continually and still have a very low chance of being detected. This allows the radar system to generate far more data than if it is being used only periodically, greatly improving overall system effectiveness.
The radar utilises a separate transmitter and receiver module for each of the antenna's radiating elements. Making up the array of the AESA radar are over 5000 15cm long individual transmit and receiver modules. Each tiny TRM weighs in at just 50 grams, yet still contains a power output of six watts apiece, a relatively high amount. As the radar operates at microwave frequencies, each module contains Monolithic Microwave Integrated Circuit which are abbreviated to MMICs. The role of an MMIC includes microwave mixing, power amplification, low noise amplification, and high frequency switching, all core features of a high tech radar. To remove the high amounts of heat generated by the AESA, the array is liquid cooled and mounted in a light weight polymer for support.
The modules used in the GM-25 differ greatly from those employed on more conventional aircraft, being far longer and skinnier with internal circuitry being manufactured from Gallium Nitride as opposed to Gallium Arsenide which is how most transmitter and receiver modules are constructed. Despite being considerably longer than a typical module at 15cm or 0.15m, the diamteter of the module is only 0.4cm creating a very narrow and long module for ease of construction purposes. Gallium Nitride was selected at first as an experimental material as it was known that circuits comprised of Gallium Nitride could handle a far greater voltage and temperature compared with Gallium Arsenide, although GaN was considerably more expensive and much harder to manufacture. Thus, using the Gallium Nitride circuitry, each module of the radar constellation makes can produce up to six watts at a time despite being sized around the same as a smaller four watt module. However, due to the increased amount of heat being produced by the radar contellation, each module typically operates at four watts so as not to overload the cooling system.
The cooling system is comprised of of several water veins which interlock throughout the radar constellation, connected to a pump just fore of the cockpit which pumps water from a cooled reservoir through the veins and then recirculates the water back into the reservoir. An eight bladed fan continually recirculates the air throughout the constellation preventing pockets of warm air forming and continually passing air over the veins for maximum effectiveness. Although this system sounds very simple, it is a proven effective method of cooling machinery which operates at very high temperatures.
Through clever packaging and "clumping" of modules, the GM-25 can easily fit it's 5000 very narrow modules together while still retaining a wavelength long enough to give the radar sufficient range. Should additional range be required at the expense of radar power, certain modules can deactivate so that the radar only contains 1500 modules instead.
This information gathered by the Radar Warning Receiver, Missile Approach Warning Receiver and the Active Scan radar itself is processed by two Indeon Common Integrated Processors (CIP). Each CIP can process 12 billion instructions per second and has one gigabyte of memory, allowing it to store a wealth of information and making the system nearly impossible to overload. Information can be gathered from the radar and other onboard and offboard systems, where it is then filtered by the CIP which will effectively 'gist' the meanings of the signals onto several cockpit displays, enabling the pilot to remain on top of complicated situations by having all the information simply presented onto the data displays in the ergonomic cockpit.
Integrated into the DD20X is the Cervelo S5 Terrain following radar. The system works by transmitting a radar signal towards the ground area in front of the aircraft. The radar returns can then be analysed to see how the terrain ahead varies, which can then be used by the aircraft's autopilot to maintain a reasonably constant height above the earth. This technology enables flight at very low altitudes, and high speeds, avoiding detection by enemy radars and interception by anti-aircraft systems. This allows the pilot to focus on other aspects of the flight besides the extremely intensive task of low flying itself.
Adding to the powerful Avionics array is the Battlespace Network function which allows the GM-25 to connect to and share information gathered from other aircraft in the area. The Battlespace Network is essentially a secure satellite connection for which data, in simplified form, is transmitted between two or more aircraft and is theoretically capable of linking the entire airforce of a nation.
The DD-20X can both scan and track targets as well as communicate simultaneously through the use of both processing units as well as the use of designation when it comes to antennae which make up the constellation of data sending and receiving equipment.
The DD-20X can also identify target aircraft simply from their radar signature. The DD-20X can 'paint' a picture of an aircraft from the radar signals which bounce off it, and can then scan the image it has created against a database of known aircraft. This means the GM-25 can identify whether or not a target is friendly, hostile or neutral in combat long before it crosses the visual horizon and can prevent suprise attacks against the aircraft. The database of aircraft is stored in the aircraft's 100TB harddrive and can be accessed with ease through the use of the Common Integrated Processors, then filtered through to the cockpit displays or transmitted to other aircraft.
The sheer power and capability of the DD-20X means that it can scan and track almost any aerial or ground target no matter the size of the enemy's radar cross section. From a distance of 500km, the DD-20X can successfully detect a target which has a radar cross section of roughly five square metres and can detect a target with a cross section of less than 10 square centimetres from fifty kilometres away. As well as doing this, the extremely stealthy nature of the GM-25 means it can look and track without being seen by enemy aircraft.
In total, the GM-25 can simultaneously track and record movements for a total of 72 different aerial or ground targets and engage up to sixteen at once using active radar homing missiles. This gives the GM-25 the ability to address any numbers deficit it may go into battle facing by effectively fighting multiple aircraft at any one time.
The SS-16 is a passive receiver system capable of detecting the radar signals in the environment. It is composed of 30 antennas smoothly blended into the wings and fuselage that provide all around coverage plus azimuth and elevation information in the forward sector. With significantly greater range than the radar, it enables the GM-25 to limit its own radar emission to preserve its stealth. As a target approaches, the receiver can set the SS-16 radar to track the target with a very narrow radar wave, which can be as focused as precisely to 1° by 1° in azimuth and elevation.
Also operated by the MAWS is the "Blinder" system. When a missile approaches the A565, the MAWS, through a seperate countermeasure system, will "blind" the missile with a powerful beam of infra-red light. This causes the missile to lose the track on any target due to its receiver seeing only heat surrounding it and not the pin prick from the engines that it was originally chasing.
Cockpit and Flight Systems
The GM-25 features a sophisticated digital fly-by-wire system. The computers "read" position and force inputs from the pilot's controls and aircraft sensors, along with pre-programmed mission waypoints to detect and plot exactly what the aircraft should be doing as opposed to what it is actually doing. Due to the highly unstable nature of most modern fighter jets, the GM-25 in particular, flight without computers is physically impossible therefore the system is honed and well backed up. The fly-by-wire system is one of the few components which is granted emergency power in the event of an engine failure. The computers solve differential equations to determine the appropriate command signals that move the flight controls in order to carry out the intentions of the pilot.
The programming of the digital computers enable flight envelope protection. In this aircraft designers precisely tailor an aircraft's handling characteristics, to stay within the overall limits of what is possible given the aerodynamics and structure of the aircraft. For example, the computer in flight envelope protection mode can try to prevent the aircraft from being handled dangerously by preventing pilots from exceeding preset limits on the aircraft's flight-control envelope, such as those that prevent stalls and spins, and which limit airspeeds and g forces on the airplane. Software can also be included that stabilize the flight-control inputs in order to avoid pilot-induced oscillations.
Since the flight-control computers continuously "fly" the aircraft, pilot's workloads can be reduced to a minimum while in transit. Stalling, spinning and other undesirable performances are prevented automatically by the computers while still permitting a great deal of 'freedom' to the pilot when engaging in a dogfight.
The cockpit of the GM-25 is an entirely digital 'glass cockpit' display without any traditional analogue instruments. Data is gathered and processed by a multitude of computers, Global Positioning devices and air pressure monitors to accurately determine characteristics of the aircraft.
The GM-25 is a single seat, twin engined, dedicated Air Superiority Fighter designed for the sole purpose of obtaining and maintaining total tactical aerial superiority within any given battlespace. The GM-25 is the most advanced aircraft ever produced by Gemballa with billions of dollars of government funding being poured into the project over nearly a decade to develop one of the most sophisticated and deadly aircraft in service anywhere around the world. Advanced radar systems, cutting edge low observability technology and an airframe with the potential for super-manoeuvrability are just some of the characteristics of this uncompromising aircraft.
Project Concept
In 1994, the aging IAI Kfir fleet of the Mikoyan-Guryevich Air Force had been slated for retirement after their relative age and incompetency against modern military technologies had become painfully obvious during the Scalietti Emergency in 1992.
In 1992, civil war erupted quickly and without warning within the neighboring country of Scalietti prompting a large-scale intervention by many nations within Texas to quickly diffuse the situation. In June of 1992, rebel forces had seized large swaths of the mountaneous interior of Scalietti and along with it, a large portion of the military hardware owned by Scalietti. Mikoyan-Gurvevich, because of it's close proximity to the beleaguered nation, was one of the first to respond with air strikes on several high profile targets under control of the rebels. The aircraft slated for the job were Mikoyan-Gurevich's long but exemplary serving IAI Kfirs, an aircraft of 1970's vintage. At first againt the lightly armoured and under protected targets at the border of the rebel held territory, the Kfirs suffered no problems. However, in the summer of 1992 the Texan Defence Forces mounted an assualt on the region and Kfirs were slated to provide aerial support to the inwards push. Rebel forces responded with an aerial force which none knew existed, comprising of many ex-Scaliettian F-16's and F-15's along with batteries of potent Surface to Air missiles. Kfirs were shot from the sky with ease and Mikoyan-Gurevich was forced to withdraw from the conflict after the shocking defeat.
By 1993, a project for a new fighter was to be announced. The project would not be offered as a contract to several different companies; only one would receive the funding and support needed to deliver the required aircraft. But announcing the project became the next problem for the Air Force; nobody could decide what shape the aircraft would take. The IAI Kfirs had performed every combat role within the Mikoyan-Guryevich Air Force; no other types were required. Realising that any attempt to create another aircraft designed for every purpose would most likely be disasterous, the project was split into two halves. The first half was the Multirole Fighter Project which eventually resulted in the GM-23 Czapka, the second half was the Air Superiority Fighter Project which aimed to design an aircraft capable of taking on any other in the world.
While the Multirole project progressed flawlessly and resulted in an easy birth, the Air Superiority project was one marred by set backs and squabbles between parties. Even the Mikoyan-Guryevich Air Force themselves had no idea which direction the aircraft should take. After two years of near constant arguments, the project faced two different path. The first path led to an Air Superiority Aircraft which was capable of performing any role, yet optimized for dog fighting. For being technically advanced, yet relatively cheap and easy to maintain and an aircraft which much more conservative than the alternative path. The second path led to an aircraft solely designed for Air Superiority as well as being tricky to build and expensive to keep. An aircraft which could out-perform almost every thing else. Another three months of considerations followed before the Air Force selected; they wanted both.
The first path resulted in the GM-24 Caballero which took to the skies long before it's illustrious counterpart ever did. But the Khe Sanh project, as the 'second path' became known as was shoved under the rug, the government even going as far to say it was cancelled in favour of the GM-24. By late 2010, the GM-25 was ready, and finally entered service after an initial production run of just 50 aircraft.
Avionics
The GM-25's avionics include Cervelo SS-16 radar warning receiver/emissions locator system, Cervelo SB-77 Infra-Red and Ultra-Violet MAWS (Missile Approach Warning System) and the Cervelo DD-20X Active Scan radar. The DD-18X features both long-range target acquisition and low risk of interception of its own signals by enemy aircraft due to its complex set up and frequent channel changing.
The Radar used in the GM-25 is the Cervelo DD-20X Active Scan radar. The 20X is an uprated version of the 18X, being more powerful, less obvious to enemy aircraft and predictably more expensive. The 20X is an active electronically scanned array with the capability to track and engage multiple targets at any one time.
The Cervelo DD-20X Active Scan radar is designed for air superiority and strike operations and features a low-observable, active-aperture, electronically-scanned array that can track multiple targets in any weather, including storms. The Cervelo DD-20X Active Scan changes electromagnetic frequencies at more than 1,000 times per second to greatly reduce the chance of being intercepted by an enemy aircraft. If the GM-25 is spotted, it can then focus its radar emissions on an enemy aircraft, to overload enemy sensors and thus jamming the enemy radar. The DD-20X was designed with the Low Probability of Intecept theorem as paramount with a strong emphasis on the lowest possible observability to other aircraft. Unlke many other radar systems, the DD series of radar has very few moving parts and is much less likely to malfunction in the air than other radar systems employed by other aircraft.
An AESA or Active Electronically Scanned Array radar system represents the forefront of modern radar technology. These radars are deceptively hard to intercept because an AESA radar will change it's frequency every pulse, at up to 1000 times per second. Since the AESA can change its frequency with every pulse, and generally does so using a pseudo-random sequence, integrating over time does not help pull the signal out of the background noise. Nor does the AESA have any sort of fixed pulse repetition frequency, which can also be varied and thus hide any periodic brightening across the entire spectrum. Traditional Radar Warning Receivers are essentially useless against AESA radars. This means that the GM-25 can look for long periods of time without being seen in the process. This radar fitted to the GM-25 employs a very erratic search pattern made possible by the enourmous computing power at the disposal of the crew, further adding confusion to the Radar Warning Receiver at the other end.
Jamming is likewise much more difficult against an AESA. Traditionally, jammers have operated by determining the operating frequency of the radar and then broadcasting a signal on it to confuse the receiver as to which is the "real" pulse and which is the jammer's. This technique works as long as the radar system cannot easily change its operating frequency. When the transmitters were based on klystron tubes this was generally true, and radars, especially airborne ones, had only a few frequencies to chose among. A jammer could listen to those possible frequencies and select the one being used to jam.
Since an AESA changes its operating frequency with every pulse, and spreads the frequencies across a wide band even in a single pulse, jammers are much less effective. Although it is possible to send out broadband white noise against all the possible frequencies, this means the amount of energy being sent at any one frequency is much lower, reducing its effectiveness. Moreover, AESAs can be switched to a receive-only mode, and use the jamming signals as a powerful source to track its source, something that required a separate receiver in older platforms.
AESAs are so much more difficult to detect, and so much more useful in receiving signals from the targets, that they can broadcast continually and still have a very low chance of being detected. This allows the radar system to generate far more data than if it is being used only periodically, greatly improving overall system effectiveness.
The radar utilises a separate transmitter and receiver module for each of the antenna's radiating elements. Making up the array of the AESA radar are over 5000 15cm long individual transmit and receiver modules. Each tiny TRM weighs in at just 50 grams, yet still contains a power output of six watts apiece, a relatively high amount. As the radar operates at microwave frequencies, each module contains Monolithic Microwave Integrated Circuit which are abbreviated to MMICs. The role of an MMIC includes microwave mixing, power amplification, low noise amplification, and high frequency switching, all core features of a high tech radar. To remove the high amounts of heat generated by the AESA, the array is liquid cooled and mounted in a light weight polymer for support.
The modules used in the GM-25 differ greatly from those employed on more conventional aircraft, being far longer and skinnier with internal circuitry being manufactured from Gallium Nitride as opposed to Gallium Arsenide which is how most transmitter and receiver modules are constructed. Despite being considerably longer than a typical module at 15cm or 0.15m, the diamteter of the module is only 0.4cm creating a very narrow and long module for ease of construction purposes. Gallium Nitride was selected at first as an experimental material as it was known that circuits comprised of Gallium Nitride could handle a far greater voltage and temperature compared with Gallium Arsenide, although GaN was considerably more expensive and much harder to manufacture. Thus, using the Gallium Nitride circuitry, each module of the radar constellation makes can produce up to six watts at a time despite being sized around the same as a smaller four watt module. However, due to the increased amount of heat being produced by the radar contellation, each module typically operates at four watts so as not to overload the cooling system.
The cooling system is comprised of of several water veins which interlock throughout the radar constellation, connected to a pump just fore of the cockpit which pumps water from a cooled reservoir through the veins and then recirculates the water back into the reservoir. An eight bladed fan continually recirculates the air throughout the constellation preventing pockets of warm air forming and continually passing air over the veins for maximum effectiveness. Although this system sounds very simple, it is a proven effective method of cooling machinery which operates at very high temperatures.
Through clever packaging and "clumping" of modules, the GM-25 can easily fit it's 5000 very narrow modules together while still retaining a wavelength long enough to give the radar sufficient range. Should additional range be required at the expense of radar power, certain modules can deactivate so that the radar only contains 1500 modules instead.
This information gathered by the Radar Warning Receiver, Missile Approach Warning Receiver and the Active Scan radar itself is processed by two Indeon Common Integrated Processors (CIP). Each CIP can process 12 billion instructions per second and has one gigabyte of memory, allowing it to store a wealth of information and making the system nearly impossible to overload. Information can be gathered from the radar and other onboard and offboard systems, where it is then filtered by the CIP which will effectively 'gist' the meanings of the signals onto several cockpit displays, enabling the pilot to remain on top of complicated situations by having all the information simply presented onto the data displays in the ergonomic cockpit.
Integrated into the DD20X is the Cervelo S5 Terrain following radar. The system works by transmitting a radar signal towards the ground area in front of the aircraft. The radar returns can then be analysed to see how the terrain ahead varies, which can then be used by the aircraft's autopilot to maintain a reasonably constant height above the earth. This technology enables flight at very low altitudes, and high speeds, avoiding detection by enemy radars and interception by anti-aircraft systems. This allows the pilot to focus on other aspects of the flight besides the extremely intensive task of low flying itself.
Adding to the powerful Avionics array is the Battlespace Network function which allows the GM-25 to connect to and share information gathered from other aircraft in the area. The Battlespace Network is essentially a secure satellite connection for which data, in simplified form, is transmitted between two or more aircraft and is theoretically capable of linking the entire airforce of a nation.
The DD-20X can both scan and track targets as well as communicate simultaneously through the use of both processing units as well as the use of designation when it comes to antennae which make up the constellation of data sending and receiving equipment.
The DD-20X can also identify target aircraft simply from their radar signature. The DD-20X can 'paint' a picture of an aircraft from the radar signals which bounce off it, and can then scan the image it has created against a database of known aircraft. This means the GM-25 can identify whether or not a target is friendly, hostile or neutral in combat long before it crosses the visual horizon and can prevent suprise attacks against the aircraft. The database of aircraft is stored in the aircraft's 100TB harddrive and can be accessed with ease through the use of the Common Integrated Processors, then filtered through to the cockpit displays or transmitted to other aircraft.
The sheer power and capability of the DD-20X means that it can scan and track almost any aerial or ground target no matter the size of the enemy's radar cross section. From a distance of 500km, the DD-20X can successfully detect a target which has a radar cross section of roughly five square metres and can detect a target with a cross section of less than 10 square centimetres from fifty kilometres away. As well as doing this, the extremely stealthy nature of the GM-25 means it can look and track without being seen by enemy aircraft.
In total, the GM-25 can simultaneously track and record movements for a total of 72 different aerial or ground targets and engage up to sixteen at once using active radar homing missiles. This gives the GM-25 the ability to address any numbers deficit it may go into battle facing by effectively fighting multiple aircraft at any one time.
The SS-16 is a passive receiver system capable of detecting the radar signals in the environment. It is composed of 30 antennas smoothly blended into the wings and fuselage that provide all around coverage plus azimuth and elevation information in the forward sector. With significantly greater range than the radar, it enables the GM-25 to limit its own radar emission to preserve its stealth. As a target approaches, the receiver can set the SS-16 radar to track the target with a very narrow radar wave, which can be as focused as precisely to 1° by 1° in azimuth and elevation.
Also operated by the MAWS is the "Blinder" system. When a missile approaches the A565, the MAWS, through a seperate countermeasure system, will "blind" the missile with a powerful beam of infra-red light. This causes the missile to lose the track on any target due to its receiver seeing only heat surrounding it and not the pin prick from the engines that it was originally chasing.
Cockpit and Flight Systems
The GM-25 features a sophisticated digital fly-by-wire system. The computers "read" position and force inputs from the pilot's controls and aircraft sensors, along with pre-programmed mission waypoints to detect and plot exactly what the aircraft should be doing as opposed to what it is actually doing. Due to the highly unstable nature of most modern fighter jets, the GM-25 in particular, flight without computers is physically impossible therefore the system is honed and well backed up. The fly-by-wire system is one of the few components which is granted emergency power in the event of an engine failure. The computers solve differential equations to determine the appropriate command signals that move the flight controls in order to carry out the intentions of the pilot.
The programming of the digital computers enable flight envelope protection. In this aircraft designers precisely tailor an aircraft's handling characteristics, to stay within the overall limits of what is possible given the aerodynamics and structure of the aircraft. For example, the computer in flight envelope protection mode can try to prevent the aircraft from being handled dangerously by preventing pilots from exceeding preset limits on the aircraft's flight-control envelope, such as those that prevent stalls and spins, and which limit airspeeds and g forces on the airplane. Software can also be included that stabilize the flight-control inputs in order to avoid pilot-induced oscillations.
Since the flight-control computers continuously "fly" the aircraft, pilot's workloads can be reduced to a minimum while in transit. Stalling, spinning and other undesirable performances are prevented automatically by the computers while still permitting a great deal of 'freedom' to the pilot when engaging in a dogfight.
The cockpit of the GM-25 is an entirely digital 'glass cockpit' display without any traditional analogue instruments. Data is gathered and processed by a multitude of computers, Global Positioning devices and air pressure monitors to accurately determine characteristics of the aircraft.
The cockpit of the GM-25 also features the Laertes IV Advanced Ejection Seat manufactured under licence from Symmetriad Aerospace Systems. Symmetriad Aerospace Systems not only provided the ejection seat for the GM-25, but also the AMS-4 G-Suit and AHG-1 helmet along with it.
The AHG-1 helmet also plays an important role in keeping the pilot fully up to date with his or her surroundings. Rather than projecting the information pertaining to the aircraft onto the canopy as many Heads Up Displays would, the AHG-1's Helmet Mounted Display displays biocular video and symbology information on the helmet visor, providing pilots with all information necessary to execute both day and night missions under a single integrated configuration. The system enables pilots to accurately cue onboard weapons and sensors using the helmet display. In tandem with this is the Night Vision function which can activate across the visor fully or only half, allowing the pilot to see a half-illuminated and half-dark image when flying at night.
The HMD also allows the aircraft systems to alert pilots of potential threats and hazards, significantly improving situational awareness. Advanced night imagery is provided by the helmet mounted night camera and aircraft Distributed Aperture System (DAS). The GM-25's HMDS’s accuracy and very low latency enables the GM-25 to negate the need of a HUD. The HMDS is the “virtual” HUD of the aircraft.
In addition to this, the HMD can also 'paint' targets which have been identified on radar and alert the pilot to their real time position in the air by placing a thin box around their location.
The HMD is usually a clear piece of glass, which automatically polarizes if the pilot is facing into the sun.
Navigation functions of the GM-25 are comprised of three seperate systems which are unrelated to one another should one system fail. Only one set of data from one navigation system is displayed at any one time; other systems can be selected mid flight by turing a knob to the right of the cockpit labelled "NavSet."
The first and oldest way of navigating is through a directional gyroscope which requires a known heading to be input to the mechanism first. Once the pilot has adjusted the gyro to a known direction, the gyro then measures an aircraft's movement and subsequent changes of direction to inform the pilot of the current heading of the plane. This mechanism is entirely hydraulically operated and is startingly simple in it's operation, as such the aircraft can be navigated with a complete electronics failure. Point to point navigation must be done by hand when using the directional gyro.
The second way of navigating uses a global positioning system feature. Global Positioning Software simply put is a way of determining your exact position on earth by sending a transmitting beam to a satellite in orbit, the satellite responding with your position on earth. As such, this system requires an active connection to a satellite in order to function. It should be noted that aircraft do not have the same trouble connecting to satellites as what motorists do due to the level at which planes fly. GM-25 can connect with military satellites through a secure connection, or if one isn't available, can connect to civillian navigation satellites by forging a secure and encyrpted connection. In order to avoid detection of this transmitting signal, GM-25 can scramble it's transmissions by sending multiple beams per second or only connecting to the sattelite when a change of direction is being performed. Despite the extra precautions, this method is still the least secure navigation method available. GPS can also determine the aircraft's speed and altitude from it's position.
The third way uses a sophisticated electronic directional gyroscopic system which takes a reading of the GM-25's direction from a control tower on take off and then procedes to save this direction as a known direction. Just like on a typical directiona gyro system, the aircraft then determines it's heading relative to the known heading which it saved before. The advantages over the mechanical gyro system are profound; margin for error is considerably less and the system can navigate towards two set points with no workload for the pilot except for entering the data. Using the Battlespace Command fucntion, the GM-25 can communicate with control towers or other aircraft to keep checking it's accuracy and minimize the probability of going off course. This is the most secure way for the GM-25 to navigate, however only direction of travel can be determined.
When essential data such as altitude and airspeed aren't being determined by the GPS, a small pitot tube and pressure nozzles are kept inside the left engine intake near flush to the top of the induct to measure air pressure and thus determine the data mechanically rather than hydraulically. The pilot can choose which set of data he wants to display and can check data against another set of data for error.
Offensive Systems
The GM-25 has two internal weapons bays mounted side by side in the underside of the fuselage which can carry three long range missiles, six medium range missiles or twelve short range missile in each two bays. The missile racks can be replaced with bomb racks that can permit carrying four medium bombs or sixteen small diameter bombs in each bay or a combination of both. Carrying missiles and bombs internally enhances its stealth capability and returns lower drag due to the absense of underwing armament permitting higher speeds, both maximum and cruise, and a much longer range due to less fuel being required. Launching ordnance requires opening the weapons bay doors for less than a second. The ordnance is pushed clear of the airframe by hydraulic arms where they then fire at the target. This reduces the GM-24's chance of detection by enemy radar systems due to launched ordnance and also allows the GM-24's to launch missiles and ordnance while maintaining very high speeds. For a typical air-to-air mission, all of the GM-25's ordnance can be carried internally so as to minimise the probability of a radar intercept.
The AHG-1 helmet also plays an important role in keeping the pilot fully up to date with his or her surroundings. Rather than projecting the information pertaining to the aircraft onto the canopy as many Heads Up Displays would, the AHG-1's Helmet Mounted Display displays biocular video and symbology information on the helmet visor, providing pilots with all information necessary to execute both day and night missions under a single integrated configuration. The system enables pilots to accurately cue onboard weapons and sensors using the helmet display. In tandem with this is the Night Vision function which can activate across the visor fully or only half, allowing the pilot to see a half-illuminated and half-dark image when flying at night.
The HMD also allows the aircraft systems to alert pilots of potential threats and hazards, significantly improving situational awareness. Advanced night imagery is provided by the helmet mounted night camera and aircraft Distributed Aperture System (DAS). The GM-25's HMDS’s accuracy and very low latency enables the GM-25 to negate the need of a HUD. The HMDS is the “virtual” HUD of the aircraft.
In addition to this, the HMD can also 'paint' targets which have been identified on radar and alert the pilot to their real time position in the air by placing a thin box around their location.
The HMD is usually a clear piece of glass, which automatically polarizes if the pilot is facing into the sun.
Navigation functions of the GM-25 are comprised of three seperate systems which are unrelated to one another should one system fail. Only one set of data from one navigation system is displayed at any one time; other systems can be selected mid flight by turing a knob to the right of the cockpit labelled "NavSet."
The first and oldest way of navigating is through a directional gyroscope which requires a known heading to be input to the mechanism first. Once the pilot has adjusted the gyro to a known direction, the gyro then measures an aircraft's movement and subsequent changes of direction to inform the pilot of the current heading of the plane. This mechanism is entirely hydraulically operated and is startingly simple in it's operation, as such the aircraft can be navigated with a complete electronics failure. Point to point navigation must be done by hand when using the directional gyro.
The second way of navigating uses a global positioning system feature. Global Positioning Software simply put is a way of determining your exact position on earth by sending a transmitting beam to a satellite in orbit, the satellite responding with your position on earth. As such, this system requires an active connection to a satellite in order to function. It should be noted that aircraft do not have the same trouble connecting to satellites as what motorists do due to the level at which planes fly. GM-25 can connect with military satellites through a secure connection, or if one isn't available, can connect to civillian navigation satellites by forging a secure and encyrpted connection. In order to avoid detection of this transmitting signal, GM-25 can scramble it's transmissions by sending multiple beams per second or only connecting to the sattelite when a change of direction is being performed. Despite the extra precautions, this method is still the least secure navigation method available. GPS can also determine the aircraft's speed and altitude from it's position.
The third way uses a sophisticated electronic directional gyroscopic system which takes a reading of the GM-25's direction from a control tower on take off and then procedes to save this direction as a known direction. Just like on a typical directiona gyro system, the aircraft then determines it's heading relative to the known heading which it saved before. The advantages over the mechanical gyro system are profound; margin for error is considerably less and the system can navigate towards two set points with no workload for the pilot except for entering the data. Using the Battlespace Command fucntion, the GM-25 can communicate with control towers or other aircraft to keep checking it's accuracy and minimize the probability of going off course. This is the most secure way for the GM-25 to navigate, however only direction of travel can be determined.
When essential data such as altitude and airspeed aren't being determined by the GPS, a small pitot tube and pressure nozzles are kept inside the left engine intake near flush to the top of the induct to measure air pressure and thus determine the data mechanically rather than hydraulically. The pilot can choose which set of data he wants to display and can check data against another set of data for error.
Offensive Systems
The GM-25 has two internal weapons bays mounted side by side in the underside of the fuselage which can carry three long range missiles, six medium range missiles or twelve short range missile in each two bays. The missile racks can be replaced with bomb racks that can permit carrying four medium bombs or sixteen small diameter bombs in each bay or a combination of both. Carrying missiles and bombs internally enhances its stealth capability and returns lower drag due to the absense of underwing armament permitting higher speeds, both maximum and cruise, and a much longer range due to less fuel being required. Launching ordnance requires opening the weapons bay doors for less than a second. The ordnance is pushed clear of the airframe by hydraulic arms where they then fire at the target. This reduces the GM-24's chance of detection by enemy radar systems due to launched ordnance and also allows the GM-24's to launch missiles and ordnance while maintaining very high speeds. For a typical air-to-air mission, all of the GM-25's ordnance can be carried internally so as to minimise the probability of a radar intercept.
For strike missions and for ordnance which cannot be mounted internally, the GM-25 also provides six underwing pylons rated for various loads. The two inner-most pylons are rated for the heaviest of loads (3,000kg), the middle and outer pylons are rated to hold medium loads (1500kg). In addition to this, two wingracks mounted on the extremities of the wing are able to carry short range missiles. The maximum ordnance mounted on a wing is, however, three metric tonnes therefore each pylon cannot carry it's maximum payload on a mission without overloading the wing. Where possible, ordnance should be spread over the pylons.
Carrying ordnance externally should always be avoided where possible due to the detriment this poses to the aircraft's radar cross section, cruising fuel consumption and to a lesser extent, maneuverability. While the GM-25 is generally capable of performing strike missions, it is more effective to leave these roles to other aircraft and allow the GM-25 to perform the roles at which it truly excels.
The last ditch weapon of the GM-25 is the 20mm ZZII Automatic Revolver Cannon mounted in the right wing root of the aircraft. In summary, the ZZII is a gas operated, single barrel weapon with a linkless feed system. Due to it's selective fire nature, the ZZII can fire at anywhere 1000rpm right up to 3000rpm at a rate which can be toggled by the pilot.
The gun is spring mounted into the wing and ballasted by rubber to keep the gun stable while firing without placing severe stresses onto the airframe from the sizeable recoil produced when firing. The ZZII is a very accurate weapon, able to put 90% of it's shots within a two metre radius from a distance of one kilometer. The weapon isn't aimed in the sense, but able to be alligned to the target by the radar and the 'crosshairs' of the weapon can be displaced on the HMD of the pilot.
Spent rounds are stored behind the gun not far from where they are rejected and can be removed after the flight.
Thrust
Thrust is provided by two Azzuri TR-GT400LE turbofans with afterburning. The Azzuri company is best known for its work on civillian airliners with transport giant Los Rios, producing turbo fan engines for large subsonic airliners. Due to the vast expertise of the Azzuri company when it comes to producing reliable yet efficient turbine engines for aircraft, Gemballa had no problems signing them up as a contractor to provide the propulsion for the GM-25 aircraft.
The turbofans of the GM-25 are constructed from a blend of materials which are used in tandem as well as in isolation from one another. A Turbine engine produces exhaust and internal temperatures far beyond that of a piston engine therefore new materials had to be developed in order to resist these temperatures. Composite materials were selected on the premise that they not only had the heat resistance to withstand temperatures at which steel would bend, but they are also much lighter than metals and would improve the power to weight ratio of the engine itself.
Components of the turbofan aft of the compressor fans, including the internal turbines of the turbofan as well as the turbine shaft, are constructed out of a composite ceramic material to resist against the extreme temperatures of the propulsion system. A ceramic is an inorganic, non-metallic solid prepared by the action of heat and subsequent cooling, this results in a crystalline substance. The ceramic material used within the turbine is silicon carbide, or a carbon ceramic material.
Silicon Carbide is exceedingly hard, synthetically produced crystalline compound of silicon and carbon. The modern method of manufacturing silicon carbide for the abrasives, metallurgical, and refractories industries is basically the same as that developed by Acheson. A mixture of pure silica sand and carbon in the form of finely ground coke is built up around a carbon conductor within a brick electrical resistance-type furnace. Electric current is passed through the conductor, bringing about a chemical reaction in which the carbon in the coke and silicon in the sand combine to form SiC and carbon monoxide gas. A furnace run can last several days, during which temperatures vary from 2,200° to 2,700° C (4,000° to 4,900° F) in the core to about 1,400° C (2,500° F) at the outer edge. The energy consumption exceeds 100,000 kilowatt-hours per run. At the completion of the run, the product consists of a core of green to black SiC crystals loosely knitted together, surrounded by partially or entirely unconverted raw material. The lump aggregate is crushed, ground, and screened into various sizes appropriate to the end use.
Components of the turbine fore of the compression chamber and also components outside of the turbine itself are constructed from Aermet. Aermet is an ultra-high strength type of alloy steel where the main alloying elements are cobalt and nickel, but chromium, molybdenum, and carbon are also added. Aermet 100 was selected over Aermet 310 and Aermet 340 because of the greater fracture toughness that the 100 variant offers over Aermet 310 and Aermet 340, fracture resistance being paramount on the blades of the pair of compressor fans.
Because of the advanced materials being used within the turbofan engine itself, the GT-400LE can burn and run "hotter" and "faster" than nearly all other turbofan engines because it does not leave itself susceptible to damage when it operates at said conditions. This not only improves the overall thrust output of the engine, but also improves the efficiency by allowing the turbofan to operate at the condition which best suits what the aircraft is experiencing, both in terms of drag and air density.
Variable altitude engine intakes are featured on both engines reducing the risk of compressor stall. A compressor stall is a situation of abnormal airflow resulting from a stall of the fan blades within the compressor of a jet engine. Compressor stalls result in a loss of compressor performance, which can vary in severity from a momentary engine power drop (occurring so quickly it is barely registered on engine instruments) to a complete loss of compression (compressor surge) necessitating a reduction in the fuel flow to the engine.
For an edge in maneuvreability, the GM-25 employs Fluidic Dynamic Thrust Vectoring instead of a more typical nozzle or paddle system. In short, Fluidic Dynamic TVC operates by injecting a secondary jet of air or fluid into the exhaust of the engine, deforming the primary jet of exhaust gasses which is being forced out the back of the engine, aiming it in a different direction. In this case, the secondary jet of air is obtained from the turbofan engine itself, using the by-pass air. Fluidic Dynamic Thrust Vectoring
Carrying ordnance externally should always be avoided where possible due to the detriment this poses to the aircraft's radar cross section, cruising fuel consumption and to a lesser extent, maneuverability. While the GM-25 is generally capable of performing strike missions, it is more effective to leave these roles to other aircraft and allow the GM-25 to perform the roles at which it truly excels.
The last ditch weapon of the GM-25 is the 20mm ZZII Automatic Revolver Cannon mounted in the right wing root of the aircraft. In summary, the ZZII is a gas operated, single barrel weapon with a linkless feed system. Due to it's selective fire nature, the ZZII can fire at anywhere 1000rpm right up to 3000rpm at a rate which can be toggled by the pilot.
The gun is spring mounted into the wing and ballasted by rubber to keep the gun stable while firing without placing severe stresses onto the airframe from the sizeable recoil produced when firing. The ZZII is a very accurate weapon, able to put 90% of it's shots within a two metre radius from a distance of one kilometer. The weapon isn't aimed in the sense, but able to be alligned to the target by the radar and the 'crosshairs' of the weapon can be displaced on the HMD of the pilot.
Spent rounds are stored behind the gun not far from where they are rejected and can be removed after the flight.
Thrust
Thrust is provided by two Azzuri TR-GT400LE turbofans with afterburning. The Azzuri company is best known for its work on civillian airliners with transport giant Los Rios, producing turbo fan engines for large subsonic airliners. Due to the vast expertise of the Azzuri company when it comes to producing reliable yet efficient turbine engines for aircraft, Gemballa had no problems signing them up as a contractor to provide the propulsion for the GM-25 aircraft.
The turbofans of the GM-25 are constructed from a blend of materials which are used in tandem as well as in isolation from one another. A Turbine engine produces exhaust and internal temperatures far beyond that of a piston engine therefore new materials had to be developed in order to resist these temperatures. Composite materials were selected on the premise that they not only had the heat resistance to withstand temperatures at which steel would bend, but they are also much lighter than metals and would improve the power to weight ratio of the engine itself.
Components of the turbofan aft of the compressor fans, including the internal turbines of the turbofan as well as the turbine shaft, are constructed out of a composite ceramic material to resist against the extreme temperatures of the propulsion system. A ceramic is an inorganic, non-metallic solid prepared by the action of heat and subsequent cooling, this results in a crystalline substance. The ceramic material used within the turbine is silicon carbide, or a carbon ceramic material.
Silicon Carbide is exceedingly hard, synthetically produced crystalline compound of silicon and carbon. The modern method of manufacturing silicon carbide for the abrasives, metallurgical, and refractories industries is basically the same as that developed by Acheson. A mixture of pure silica sand and carbon in the form of finely ground coke is built up around a carbon conductor within a brick electrical resistance-type furnace. Electric current is passed through the conductor, bringing about a chemical reaction in which the carbon in the coke and silicon in the sand combine to form SiC and carbon monoxide gas. A furnace run can last several days, during which temperatures vary from 2,200° to 2,700° C (4,000° to 4,900° F) in the core to about 1,400° C (2,500° F) at the outer edge. The energy consumption exceeds 100,000 kilowatt-hours per run. At the completion of the run, the product consists of a core of green to black SiC crystals loosely knitted together, surrounded by partially or entirely unconverted raw material. The lump aggregate is crushed, ground, and screened into various sizes appropriate to the end use.
Components of the turbine fore of the compression chamber and also components outside of the turbine itself are constructed from Aermet. Aermet is an ultra-high strength type of alloy steel where the main alloying elements are cobalt and nickel, but chromium, molybdenum, and carbon are also added. Aermet 100 was selected over Aermet 310 and Aermet 340 because of the greater fracture toughness that the 100 variant offers over Aermet 310 and Aermet 340, fracture resistance being paramount on the blades of the pair of compressor fans.
Because of the advanced materials being used within the turbofan engine itself, the GT-400LE can burn and run "hotter" and "faster" than nearly all other turbofan engines because it does not leave itself susceptible to damage when it operates at said conditions. This not only improves the overall thrust output of the engine, but also improves the efficiency by allowing the turbofan to operate at the condition which best suits what the aircraft is experiencing, both in terms of drag and air density.
Variable altitude engine intakes are featured on both engines reducing the risk of compressor stall. A compressor stall is a situation of abnormal airflow resulting from a stall of the fan blades within the compressor of a jet engine. Compressor stalls result in a loss of compressor performance, which can vary in severity from a momentary engine power drop (occurring so quickly it is barely registered on engine instruments) to a complete loss of compression (compressor surge) necessitating a reduction in the fuel flow to the engine.
For an edge in maneuvreability, the GM-25 employs Fluidic Dynamic Thrust Vectoring instead of a more typical nozzle or paddle system. In short, Fluidic Dynamic TVC operates by injecting a secondary jet of air or fluid into the exhaust of the engine, deforming the primary jet of exhaust gasses which is being forced out the back of the engine, aiming it in a different direction. In this case, the secondary jet of air is obtained from the turbofan engine itself, using the by-pass air. Fluidic Dynamic Thrust Vectoring
The FDTVC gives the GM-25 a three dimensional thrust vectoring effect. The pilot may choose to 'lock' the control surfaces into place and fly only using the thrust vectoring of the engines to change direction should he wish to keep his RCS as small as possible. While control surfaces such as ailerons and thrust vectoring nozzles such as the 'iris' system can cause huge increases in RCS while they are in use, FDTVC causes no such issue as all moving parts are mounted internally, altering the direction of the jet doesn't require any difference to the exterior configuration of the aircraft.
Mounted to the extreme rear of the aircraft are a pair of powerful contrail detectors which can prevent the aircraft from leaving a tell-tale streak across the sky. The contrail detectors then change the fuel mixture entering the engines in an effort to prevent a contrail from being created, or will direct the pilot to attain an altitude where a contrail will not be left.
Both engines are rated at 41,000lbf per engine, resulting in a phenomenally high maximum speed of 2850km/h at altitude or well above Mach 2 (twice the speed of sound). The GM-25 can supercruise at Mach 1.9 (2000km/h).
Airframe
The GM-25 was designed to be as 'slippery' as possible by effectively removing all drag inducing external features and mounting them inside the airframe, further enhancing its stealth and performance. Many features such as radar antennae can be blended in to the fuselage to avoid creating any perpendicular surfaces which attract radar attention and also do not produce any vortecies or turbulence which can improve the stability of the GM-24 when travelling at high speeds. As mentoned before, ordnance required for generic missions, for example standard short to medium range interceptions or Combat Air Patrol, can be carried internally in the two weapons bays, negating the need to mount weapons, fuel or other objects on the wings or the fuselage.
The airframe itself is made predominantly from aviation grade titanium, over 50% of the airframe in total. Aviation grade titanium can be up to eight times stronger than regular titanium while at the same time being only half the weight of steel while still being three times stronger. Advantages of titanium include being lightweight, resistant to very high temperatures, very stable and rust proof, which makes it a prime choice for use on aircraft or other aerospace technologies.
The 'skin' of the GM-25 is made entirely from Carbon Fibre Re-inforced Polymers. CFRPs are comprised of a polymer, in this case epoxy, which is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener", is re-inforced with fibres of carbon which give the material it's strength. CFRPs have an extremely high strength to weight ratio which makes them ideal for use on aircraft. The downside of CFRP's is that they can be extremely expensive to replace and require much more mantinence than more typical aircraft materials such as aluminium would. CFRP's are made into panels which can be easily mounted and removed from the GM-25.
The CFRP skin is then covered by the outer layer of radar-resistant material and paint to reduce the overall RCS of the GM-25.
The GM-25 uses a large fixed compound delta wing to provide lift for the aircraft to fly.
The primary advantage of the delta wing is that, with a large enough angle of rearward sweep, the wing’s leading edge will not contact the shock wave boundary formed at the nose of the fuselage as the speed of the aircraft approaches and exceeds transonic to supersonic speed. The rearward sweep angle vastly lowers the airspeed normal to the leading edge of the wing, thereby allowing the aircraft to fly at high subsonic, transonic, or supersonic speed, while the over wing speed of the lifting air is kept to less than the speed of sound. The delta plan form gives the largest total wing area (generating useful lift) for the wing shape, with very low wing per-unit loading, permitting high maneuverability in the airframe. As the delta's platform carries across the entire aircraft, it can be built much more strongly than a swept wing, where the spar meets the fuselage far in front of the center of gravity. Generally a delta will be stronger than a similar swept wing, as well as having much more internal volume for fuel and other storage.
Another advantage is that as the angle of attack increases, the leading edge of the wing generates a vortex which energizes the flow, giving the delta a very high stall angle. A normal wing built for high speed use is typically dangerous at low speeds, but in this regime the delta changes over to a mode of lift based on the vortex it generates.
While a normal delta wing will produce large amounts of induced drag and will not be able to land at typically slow speeds, a compound delta wing, where the outer of the wing has a lesser sweep angle than the inner of the wing, creates the high-lift vortex in a controlled fashion which greatly reduces the induced drag created and allows the aircraft to fly at acceptably slow speeds. This is or particular importance for landing.
The very sweep nature of the wing means that as the air passes over the wing, it at first flows outwards until it passes the zenith of the aerfoil where it begins to flow back towards the fuselage. This is so when the wing stalls, the loss of lift will occur in the centre of the wing, allowing enough air to pass over the ailerons for them to be of use without the complications which a forward swept wing provides.
The trapezoidal nature of the leading edge of the wing means that the centre of the wing will be the first part to stall, crucially not the outer of the wing where the ailerons are located. This so if the GM-25 happens to stall, the pilot can still control the roll of the plane with the ailerons.
To further boost agility, computer controlled leading edge extensions are mounted on both wings. These are effectively very small delta wings placed so they remain parallel to the airflow in cruising flight, but start to generate a vortex at high angles of attack. The vortex is then captured on the top of the wing to provide additional lift, thereby combining the delta's high-alpha performance with a conventional highly efficient wing planform.
To prevent the spillage of air from underneath the wing, the outward edges of the cropped wing are cantered downwards in an anhedral effect which reduces the dihedral effect of the wing, making the GM-25 a less stable and more agile platform. This feature requires the computing power of the GM-25's extensive data systems to keep it in check however.
Instead of using a traditional three or four piece tailplane, the GM-25 mounts two 'ruddervators' on the fuselage. Controlled by the flight computer, these can act as both elevators, in tandem with ailerons, to control the pitch of the aircraft and can also act as rudders to control the yaw of the aircraft. The primary advantage of ruddervators over a three or four piece tailplane is the lesser drag produced, particularly interference drag, and the simplified hydraulic set up used to control them although they do require a complex flight computer in order to be fully operational.
The ability of the airframe to withstand the stress and heat is a further key factor in the GM-25's speeds, especially in an aircraft using as many polymers as the GM-25. However, while some aircraft are faster on paper, the internal carriage of its standard combat load allows the aircraft to reach comparatively higher performance with a heavy load over other modern aircraft due to its lack of drag from external stores. It is one of only a handful of aircraft that can sustain supersonic flight without the use of afterburner augmented thrust and its associated high fuel consumption. This ability is termed supercruise. This allows the aircraft to hit time-critical, fleeting or mobile targets that a subsonic aircraft would not have the speed to reach and an afterburner dependent aircraft would not have the fuel to reach.
Landing gear struts are made from Aermet 100, which is a light but very durable steel and well accustomed to high compressive stress. Tyres used on the two main landing gear struts are four small high pressure .75 metre diameter tyres which lie in flat fairings along either side of the fuselage. The two nose tyres are smaller 0.5 metre diameter tyres and are inflated to a slightly higher pressure. In standard configuration, the GM-25 is not suitable for carrier landing however a strengthended landing gear and arrestor hook can be fitted. The strengthened landing gear comprises of slightly thicker struts, an increase of 50mm in radius, and a large oleo strut which has more spring travel to allow for rougher landings.
The GM-25's stealth is reliant on radar absorbing paint and its low observance throughout the entire spectrum of sensors including radar signature, visual, infrared, acoustic, and radio frequency. This allows it to cover all angles, unlike the F-117 who focuses on the former and F-22 which conversely focuses on the latter. The materials used on the GM-24 are significantly more durable than those used on aircraft such as the B-2 and F-117, as the RM-30 can be kept out on the flightline instead of in climate controlled hangers, which the B-2 and F-117 require to remain effective.
Mounted to the extreme rear of the aircraft are a pair of powerful contrail detectors which can prevent the aircraft from leaving a tell-tale streak across the sky. The contrail detectors then change the fuel mixture entering the engines in an effort to prevent a contrail from being created, or will direct the pilot to attain an altitude where a contrail will not be left.
Both engines are rated at 41,000lbf per engine, resulting in a phenomenally high maximum speed of 2850km/h at altitude or well above Mach 2 (twice the speed of sound). The GM-25 can supercruise at Mach 1.9 (2000km/h).
Airframe
The GM-25 was designed to be as 'slippery' as possible by effectively removing all drag inducing external features and mounting them inside the airframe, further enhancing its stealth and performance. Many features such as radar antennae can be blended in to the fuselage to avoid creating any perpendicular surfaces which attract radar attention and also do not produce any vortecies or turbulence which can improve the stability of the GM-24 when travelling at high speeds. As mentoned before, ordnance required for generic missions, for example standard short to medium range interceptions or Combat Air Patrol, can be carried internally in the two weapons bays, negating the need to mount weapons, fuel or other objects on the wings or the fuselage.
The airframe itself is made predominantly from aviation grade titanium, over 50% of the airframe in total. Aviation grade titanium can be up to eight times stronger than regular titanium while at the same time being only half the weight of steel while still being three times stronger. Advantages of titanium include being lightweight, resistant to very high temperatures, very stable and rust proof, which makes it a prime choice for use on aircraft or other aerospace technologies.
The 'skin' of the GM-25 is made entirely from Carbon Fibre Re-inforced Polymers. CFRPs are comprised of a polymer, in this case epoxy, which is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener", is re-inforced with fibres of carbon which give the material it's strength. CFRPs have an extremely high strength to weight ratio which makes them ideal for use on aircraft. The downside of CFRP's is that they can be extremely expensive to replace and require much more mantinence than more typical aircraft materials such as aluminium would. CFRP's are made into panels which can be easily mounted and removed from the GM-25.
The CFRP skin is then covered by the outer layer of radar-resistant material and paint to reduce the overall RCS of the GM-25.
The GM-25 uses a large fixed compound delta wing to provide lift for the aircraft to fly.
The primary advantage of the delta wing is that, with a large enough angle of rearward sweep, the wing’s leading edge will not contact the shock wave boundary formed at the nose of the fuselage as the speed of the aircraft approaches and exceeds transonic to supersonic speed. The rearward sweep angle vastly lowers the airspeed normal to the leading edge of the wing, thereby allowing the aircraft to fly at high subsonic, transonic, or supersonic speed, while the over wing speed of the lifting air is kept to less than the speed of sound. The delta plan form gives the largest total wing area (generating useful lift) for the wing shape, with very low wing per-unit loading, permitting high maneuverability in the airframe. As the delta's platform carries across the entire aircraft, it can be built much more strongly than a swept wing, where the spar meets the fuselage far in front of the center of gravity. Generally a delta will be stronger than a similar swept wing, as well as having much more internal volume for fuel and other storage.
Another advantage is that as the angle of attack increases, the leading edge of the wing generates a vortex which energizes the flow, giving the delta a very high stall angle. A normal wing built for high speed use is typically dangerous at low speeds, but in this regime the delta changes over to a mode of lift based on the vortex it generates.
While a normal delta wing will produce large amounts of induced drag and will not be able to land at typically slow speeds, a compound delta wing, where the outer of the wing has a lesser sweep angle than the inner of the wing, creates the high-lift vortex in a controlled fashion which greatly reduces the induced drag created and allows the aircraft to fly at acceptably slow speeds. This is or particular importance for landing.
The very sweep nature of the wing means that as the air passes over the wing, it at first flows outwards until it passes the zenith of the aerfoil where it begins to flow back towards the fuselage. This is so when the wing stalls, the loss of lift will occur in the centre of the wing, allowing enough air to pass over the ailerons for them to be of use without the complications which a forward swept wing provides.
The trapezoidal nature of the leading edge of the wing means that the centre of the wing will be the first part to stall, crucially not the outer of the wing where the ailerons are located. This so if the GM-25 happens to stall, the pilot can still control the roll of the plane with the ailerons.
To further boost agility, computer controlled leading edge extensions are mounted on both wings. These are effectively very small delta wings placed so they remain parallel to the airflow in cruising flight, but start to generate a vortex at high angles of attack. The vortex is then captured on the top of the wing to provide additional lift, thereby combining the delta's high-alpha performance with a conventional highly efficient wing planform.
To prevent the spillage of air from underneath the wing, the outward edges of the cropped wing are cantered downwards in an anhedral effect which reduces the dihedral effect of the wing, making the GM-25 a less stable and more agile platform. This feature requires the computing power of the GM-25's extensive data systems to keep it in check however.
Instead of using a traditional three or four piece tailplane, the GM-25 mounts two 'ruddervators' on the fuselage. Controlled by the flight computer, these can act as both elevators, in tandem with ailerons, to control the pitch of the aircraft and can also act as rudders to control the yaw of the aircraft. The primary advantage of ruddervators over a three or four piece tailplane is the lesser drag produced, particularly interference drag, and the simplified hydraulic set up used to control them although they do require a complex flight computer in order to be fully operational.
The ability of the airframe to withstand the stress and heat is a further key factor in the GM-25's speeds, especially in an aircraft using as many polymers as the GM-25. However, while some aircraft are faster on paper, the internal carriage of its standard combat load allows the aircraft to reach comparatively higher performance with a heavy load over other modern aircraft due to its lack of drag from external stores. It is one of only a handful of aircraft that can sustain supersonic flight without the use of afterburner augmented thrust and its associated high fuel consumption. This ability is termed supercruise. This allows the aircraft to hit time-critical, fleeting or mobile targets that a subsonic aircraft would not have the speed to reach and an afterburner dependent aircraft would not have the fuel to reach.
Landing gear struts are made from Aermet 100, which is a light but very durable steel and well accustomed to high compressive stress. Tyres used on the two main landing gear struts are four small high pressure .75 metre diameter tyres which lie in flat fairings along either side of the fuselage. The two nose tyres are smaller 0.5 metre diameter tyres and are inflated to a slightly higher pressure. In standard configuration, the GM-25 is not suitable for carrier landing however a strengthended landing gear and arrestor hook can be fitted. The strengthened landing gear comprises of slightly thicker struts, an increase of 50mm in radius, and a large oleo strut which has more spring travel to allow for rougher landings.
The GM-25's stealth is reliant on radar absorbing paint and its low observance throughout the entire spectrum of sensors including radar signature, visual, infrared, acoustic, and radio frequency. This allows it to cover all angles, unlike the F-117 who focuses on the former and F-22 which conversely focuses on the latter. The materials used on the GM-24 are significantly more durable than those used on aircraft such as the B-2 and F-117, as the RM-30 can be kept out on the flightline instead of in climate controlled hangers, which the B-2 and F-117 require to remain effective.
Engines for the GM-25 are mounted inset into the fuselage which helps to mask the intense heat generated by these powerplants. By mounting them, along with their intakes, flat to the fuselage (ie. without noticable bulges) the engines do not cause a flare in the RCS. Inlets themselves are "'Serpentine," this means the inlets are designed so that it is impossible for a radar beam to detect the face of the compressor blade by bouncing off it and reflecting to the enemy receiver, even if a beam enters the inlet.
Specifications
GM-25A
Crew: 1
Length: 21.3m
Wingspan: 10.4m
Height: 3.86m
Wing Area: 121.04 m²
Wing Loading 242kg/m²
Empty weight: 18,700 kg
Loaded weight: 29,300 kg
Max takeoff weight 34,000 kg
Powerplants: 2× Azzuri TR-GT400LE Three dimensional Thrust vectoring turbofans
Dry thrust: 32,000 lbf
Thrust with afterburner 44,000 lbf
Fuel capacity: 8,500 kg internally, or 12,500 kg with two external fuel tanks
Performance
Maximum speed:
At altitude: Mach 2.68 (2,850 km/h)
Supercruise: Mach 1.9 (2,000 km/h)
Cruise: Mach 0.8 (900km/h)
Range: 3,960 km with 2 external fuel tanks
Combat radius: 1,500km
Ferry range 5,219 km
Service ceiling: 65,000 ft
Armament
Guns: 1× 20 mm ZZ-II gatling gun in right wing root, 500 rounds
Internal ordnance: Potential to carry 6000kg of ordnance across two internal weapons bays, each rated at 3000kg
External ordnance: Potential to carry 6000kg of ordnance per wing across three hardpoints per wing, total of 12,000kg across six external hard points.
Avionics
Cervelo DD-20X AESA Radar
Cervelo SS-16 Detector
Cervelo SDH-5 MAWS
TFR
GPS
Chemring MJU-39/40 flares for protection against IR missiles.
GM-25A
Crew: 1
Length: 21.3m
Wingspan: 10.4m
Height: 3.86m
Wing Area: 121.04 m²
Wing Loading 242kg/m²
Empty weight: 18,700 kg
Loaded weight: 29,300 kg
Max takeoff weight 34,000 kg
Powerplants: 2× Azzuri TR-GT400LE Three dimensional Thrust vectoring turbofans
Dry thrust: 32,000 lbf
Thrust with afterburner 44,000 lbf
Fuel capacity: 8,500 kg internally, or 12,500 kg with two external fuel tanks
Performance
Maximum speed:
At altitude: Mach 2.68 (2,850 km/h)
Supercruise: Mach 1.9 (2,000 km/h)
Cruise: Mach 0.8 (900km/h)
Range: 3,960 km with 2 external fuel tanks
Combat radius: 1,500km
Ferry range 5,219 km
Service ceiling: 65,000 ft
Armament
Guns: 1× 20 mm ZZ-II gatling gun in right wing root, 500 rounds
Internal ordnance: Potential to carry 6000kg of ordnance across two internal weapons bays, each rated at 3000kg
External ordnance: Potential to carry 6000kg of ordnance per wing across three hardpoints per wing, total of 12,000kg across six external hard points.
Avionics
Cervelo DD-20X AESA Radar
Cervelo SS-16 Detector
Cervelo SDH-5 MAWS
TFR
GPS
Chemring MJU-39/40 flares for protection against IR missiles.