RM-40 Cautela Stealth Bomber
The RM-40 Cautela is a strategic bomber with an emphasis on low observability. First coined to complement the existing RM-30 penetration bomber, the RM-40 is the first Gemballa aircraft to feature all-aspect signature reduction measures in order to create the lowest possible signature.
History
In 2007, RM-30 production was hitting full swing as more and more of the Mach 3 bombers rolled off the line and straight into service with the Mikoyan-Guryevich and United Coronadan Air Forces, as well as numerous others around the world. Despite the RM-30's sizeable payload and speeds which could outrun almost any fighter, many felt that an alternative was needed to the RM-30's style of striking.
Shortly after the RM-30 entered production, several nations including those of favourable status with Gemballa met to discuss the option of creating a new bomber which would be able to complement the existing RM-30 fleets. Meeting states spent months working out exactly what they wanted, however finally decided that this new aircraft should sacrifice versatality, payload and performance for survivability in the form of stealth.
The RM-40's designing period was short, three years after the project was founded, the first flight took place in the desert wilderness of United Coronado. Such was the secrecy of this program, flying could only be done at night to hamper the efforts of sattelites detecting the aircraft.
History
In 2007, RM-30 production was hitting full swing as more and more of the Mach 3 bombers rolled off the line and straight into service with the Mikoyan-Guryevich and United Coronadan Air Forces, as well as numerous others around the world. Despite the RM-30's sizeable payload and speeds which could outrun almost any fighter, many felt that an alternative was needed to the RM-30's style of striking.
Shortly after the RM-30 entered production, several nations including those of favourable status with Gemballa met to discuss the option of creating a new bomber which would be able to complement the existing RM-30 fleets. Meeting states spent months working out exactly what they wanted, however finally decided that this new aircraft should sacrifice versatality, payload and performance for survivability in the form of stealth.
The RM-40's designing period was short, three years after the project was founded, the first flight took place in the desert wilderness of United Coronado. Such was the secrecy of this program, flying could only be done at night to hamper the efforts of sattelites detecting the aircraft.
Avionics & Systems
At first, the RM-40 was earmarked to use the standard Gemballa strike radar array which had performed so admirably in the RM-30. This soon ran into problems, however, as the radar of the RM-30 did not suit the low emissions demands of the RM-40 bomber, as the thrice the speed of sound RM-30 has no demand for such a stealthy radar. Engineers first considered designing a new radar, but then they remembered that the didn't need to. Running parallell to the RM-40 project at the time was the project which would eventually yield the GM-25 fighter which featured a very low emissions radar.
Thus, a specifically scaled up version of the GM-25 avionics suite was selected and adapted for use on board the RM-40. As well as a slightly greater range and increased power output, the RM-40's suite places a greater emphasis on strike capabilities whilst the air-to-air function only serves a defensive purpose.
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 RM-40 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 RM-40 can look for long periods of time without being seen in the process. This radar fitted to the RM-40 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 7500 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. To remove the high amounts of heat generated by the MESA, the array is liquid cooled and mounted in a light weight polymer for support.
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 RM-40 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 or armoured vehicles 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 targets. This means the RM-40 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 RM-40 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 RM-40 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 RM-40 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 RM-40, 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.
At first, the RM-40 was earmarked to use the standard Gemballa strike radar array which had performed so admirably in the RM-30. This soon ran into problems, however, as the radar of the RM-30 did not suit the low emissions demands of the RM-40 bomber, as the thrice the speed of sound RM-30 has no demand for such a stealthy radar. Engineers first considered designing a new radar, but then they remembered that the didn't need to. Running parallell to the RM-40 project at the time was the project which would eventually yield the GM-25 fighter which featured a very low emissions radar.
Thus, a specifically scaled up version of the GM-25 avionics suite was selected and adapted for use on board the RM-40. As well as a slightly greater range and increased power output, the RM-40's suite places a greater emphasis on strike capabilities whilst the air-to-air function only serves a defensive purpose.
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 RM-40 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 RM-40 can look for long periods of time without being seen in the process. This radar fitted to the RM-40 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 7500 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. To remove the high amounts of heat generated by the MESA, the array is liquid cooled and mounted in a light weight polymer for support.
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 RM-40 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 or armoured vehicles 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 targets. This means the RM-40 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 RM-40 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 RM-40 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 RM-40 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 RM-40, 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 & Flight Systems
The RM-40 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.
Because of the basic design of the RM-40, if these computers were to fail the aircraft would literally fall from the sky. To protect against this, wind turbines mounted inside the air intakes can be activated to generate power to the system incase of an engine failure.
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 RM-40 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.
Should the worst occur, the entire cockpit of the RM-40 is jettisoned and parachuted to the ground along with it's crew. Individual ejection seats are somewhat impractical for an aircraft of this nature.
The cockpit of the RM- also features 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 RM-40's HMDS’s accuracy and very low latency enables the RM-40 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.
Offensive Systems & Armament
The RM-40's Offensive Systems comprise of just one modular weapons bay situated in the very centre of the fuselage. Unlike the RM-30, the RM-40 does not mount any form of self-defence weaponry and relies on it's escorts and stealth for protection.
The weapons bay is situated roughly a metre behind the cockpit and is five metres long, six metres wide and one metre deep, giving a volume of roughly 30 square metres which is enough to fit small to medium diameter bombs as well as rockets and missiles. No ordnance can be mounted outside this weapons bay.
As previously mentioned, the bay is designed to be modular meaning it can be hastily refitted so that the Cautela can accommodate different kinds of armanet. Missile racks can be added within minuted simply by clipping them into place to the top of the bay, without requiring bolts or other more traditional means of attachment. Similarly, the racks can also be replaced easily by traditional bomb-racks. This gives the Cautela the capability to fulfill a multitude of different stike roles and doesn't limit it to using gravity bombs. Unlike the much larger San Real however, the smaller Cautela cannot mount cruise missiles.
Bomb bay doors are hydraulically operated and open flush to the interior of the bay, sliding back on rollers and then wrapping around the curvature of the bay. This is done so as not to cause a significant increase in the RCS as bombs are deployed. Opening and closing the bay takes less than a second as ordnance is pushed clear by hydraulic rams. The bomb-bay can be kept pressurized.
Ordnance can be guided onto their targets by one of two means. The first is the laser targeting pod which is fitted flush to the underside of the fuselage which ensures that laser guided ordnance reaches their target. The weapons officer must first designate the co-ordinates of the target then set the laser. As the weapon is fired, it follows the laser down onto the target.
Radar guided missiles, however, can be guided onto the target using the powerful avionic suite. A radar lock must first be obtained before this method is employed. As previously mentioned, the RM-40 can engage over ten targets with radar guided missiles at a time, while tracking 72.
The RM-40 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.
Because of the basic design of the RM-40, if these computers were to fail the aircraft would literally fall from the sky. To protect against this, wind turbines mounted inside the air intakes can be activated to generate power to the system incase of an engine failure.
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 RM-40 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.
Should the worst occur, the entire cockpit of the RM-40 is jettisoned and parachuted to the ground along with it's crew. Individual ejection seats are somewhat impractical for an aircraft of this nature.
The cockpit of the RM- also features 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 RM-40's HMDS’s accuracy and very low latency enables the RM-40 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.
Offensive Systems & Armament
The RM-40's Offensive Systems comprise of just one modular weapons bay situated in the very centre of the fuselage. Unlike the RM-30, the RM-40 does not mount any form of self-defence weaponry and relies on it's escorts and stealth for protection.
The weapons bay is situated roughly a metre behind the cockpit and is five metres long, six metres wide and one metre deep, giving a volume of roughly 30 square metres which is enough to fit small to medium diameter bombs as well as rockets and missiles. No ordnance can be mounted outside this weapons bay.
As previously mentioned, the bay is designed to be modular meaning it can be hastily refitted so that the Cautela can accommodate different kinds of armanet. Missile racks can be added within minuted simply by clipping them into place to the top of the bay, without requiring bolts or other more traditional means of attachment. Similarly, the racks can also be replaced easily by traditional bomb-racks. This gives the Cautela the capability to fulfill a multitude of different stike roles and doesn't limit it to using gravity bombs. Unlike the much larger San Real however, the smaller Cautela cannot mount cruise missiles.
Bomb bay doors are hydraulically operated and open flush to the interior of the bay, sliding back on rollers and then wrapping around the curvature of the bay. This is done so as not to cause a significant increase in the RCS as bombs are deployed. Opening and closing the bay takes less than a second as ordnance is pushed clear by hydraulic rams. The bomb-bay can be kept pressurized.
Ordnance can be guided onto their targets by one of two means. The first is the laser targeting pod which is fitted flush to the underside of the fuselage which ensures that laser guided ordnance reaches their target. The weapons officer must first designate the co-ordinates of the target then set the laser. As the weapon is fired, it follows the laser down onto the target.
Radar guided missiles, however, can be guided onto the target using the powerful avionic suite. A radar lock must first be obtained before this method is employed. As previously mentioned, the RM-40 can engage over ten targets with radar guided missiles at a time, while tracking 72.
Thrust
Aside from the airframe, possibly the next greatest difference between the Mach 3-capable RM-30 San Real and the stealthy Cautela are there propulsion methods. Whilst the turbo-assisted ramjets of the RM-30 are considered state of the art engines, a much less exotic design was considered for the RM-40 as high speeds no longer became an issue.
Being a stealth jet, the maximum speed of the Cautela was always going to be subsonic. When an aircraft passes through the speed of sound, the shockwaves formed as a result cause a marked increase in the aircaft's radar cross section which undoes all the signature reducing methods employed on the airframe. To this end, designers opted for simple turbofans for two reasons; their efficiency at high subsonic speeds and the bypass air being able to be employed as a coolant for the exhaust temperatures.
Thrust is provided by two Azzuri TR-GT400 turbofans. 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 RM-40 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.
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.
With afterburning deleted, the engines have a maximum thrust of 32,000lbf which can propel the RM-40 to a limited top speed of Mach 0.99. A typical cruise speed for the aircraft would be considered 0.9 Mach.
Thrust Vectoring
In order to reduce the RCS of the Cautela as much as possible in all scenarios, thrust-vectoring was adopted to offer pilots an alternative to using the traditional control surfaces which can infact cause an increase in the radar cross section of an aircraft. Gemballa first pioneered it's version of Fluidic TVC on the GM-25 AASF and the Cautela becomes only the second aircraft in Gemballa's history to use it's design, albeit modified.
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 system on the RM-40 gives a yaw thrust vectoring effect only. 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.
Aside from the airframe, possibly the next greatest difference between the Mach 3-capable RM-30 San Real and the stealthy Cautela are there propulsion methods. Whilst the turbo-assisted ramjets of the RM-30 are considered state of the art engines, a much less exotic design was considered for the RM-40 as high speeds no longer became an issue.
Being a stealth jet, the maximum speed of the Cautela was always going to be subsonic. When an aircraft passes through the speed of sound, the shockwaves formed as a result cause a marked increase in the aircaft's radar cross section which undoes all the signature reducing methods employed on the airframe. To this end, designers opted for simple turbofans for two reasons; their efficiency at high subsonic speeds and the bypass air being able to be employed as a coolant for the exhaust temperatures.
Thrust is provided by two Azzuri TR-GT400 turbofans. 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 RM-40 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.
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.
With afterburning deleted, the engines have a maximum thrust of 32,000lbf which can propel the RM-40 to a limited top speed of Mach 0.99. A typical cruise speed for the aircraft would be considered 0.9 Mach.
Thrust Vectoring
In order to reduce the RCS of the Cautela as much as possible in all scenarios, thrust-vectoring was adopted to offer pilots an alternative to using the traditional control surfaces which can infact cause an increase in the radar cross section of an aircraft. Gemballa first pioneered it's version of Fluidic TVC on the GM-25 AASF and the Cautela becomes only the second aircraft in Gemballa's history to use it's design, albeit modified.
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 system on the RM-40 gives a yaw thrust vectoring effect only. 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.
Everything about the airframe of the RM-40 Cautela enforces the obsessive drive to reduce it's Radar Cross Section by as much as possible. From the distinctive flying wing fuselage to the specially designed air intakes to the brand of paint used, every piece of the exterior of the aircraft is specialized technology designed to do one thing only, evade radar waves.
A clean flying wing is theoretically the most aerodynamically efficient (lowest drag) design configuration for a fixed wing aircraft. It also offers high structural efficiency for a given wing depth, leading to light weight and high fuel efficiency. This is because the flying wing does not feature a defined fuselage nor tailplane essentially giving it one flight surface to produce drag with. Crucially for stealth aircraft, the flying wing design also means that there are no surfaces mounted at angles to each other which can reflect radar waves. Unfortunately, a clean flying wing shape is wildly impractical for any avation due to the need for equipment carried however by keeping protuding devices and portals to a bare minimum, designers can not only reduce drag but minimize the chance of a detection, and this is just the route which Gemballa engineers strove for.
While many flying wings have stability issues around the normal axis, the presence of Fluidic Dynamic Thrust Vectoring on the RM-40 negates this issue, creating a very stable airframe. The RM-40 still mounts traditional ailerons and elevators.
The exterior of the Cautela is painted with ferrofluidic paint comprised of carbonyl iron. Ferrofluid is a liquid which becomes strongly magnetized in the presence of a magnetic field. This paint is more commonly known as "iron ball paint," consisting of several million tiny iron balls that are painted onto the surface of the aircraft. Radar waves induce molecular oscillations from the alternating magnetic field in this paint, which leads to conversion of the radar energy into heat. The heat is then transferred to the aircraft and dissipated. While this particular paint does not work effectively for all radar waves, this does cover what is considered the typical frequencies on which military radars operate on.
Directly underneath the level of paint lies a layer of polychloroprene, a rubber which maintains it's qualities through extreme temperatures. This layer is added to insulate the actual outer carbon fibre layer against the intense heat created when radar waves are being absorbed.
The surfaces for the RM-40 were designed to be flat only, despite slight curves around the engine housing and the cockpit. From below, which is where most radar will be aiming, the surface of the RM-40 is completely flat with only slight bulgings (less than 5mm) to house important equipment.
Engines for the aircraft are mounted inset into the fuselage which helps to mask the intense heat generated by these powerplants. By mounting them, along with their intakes, as flat to the fuselage as possible 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.
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 RM-40 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 RM-40.
Specifications
Crew: 2
Length: 24.2m
Wingspan: 49.9m
Height: 5.16m
Wing area: 485 m²
Empty weight: 72,000 kg
Loaded weight: 160,300 kg
Max takeoff weight 175,000 kg
Powerplants: 2× Azzuri TR-GT400 Turbofans
Dry thrust: 154kN
Fuel capacity: 80,000 kg internally
Performance
Maximum speed: Mach 0.99 (limited)
Cruise: Mach 0.9
Range: 12,250 km
Service ceiling: 56,500 ft
Wing Loading: 329kg/m.sq
Thrust/Weight Ratio 0.229
Hardpoints:
1/2 Internal bays for 25,000kg ordnance
Nuclear Weapon Capable
Radar Guided Missile Capable
Laser Guided Bomb Capable
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.
A clean flying wing is theoretically the most aerodynamically efficient (lowest drag) design configuration for a fixed wing aircraft. It also offers high structural efficiency for a given wing depth, leading to light weight and high fuel efficiency. This is because the flying wing does not feature a defined fuselage nor tailplane essentially giving it one flight surface to produce drag with. Crucially for stealth aircraft, the flying wing design also means that there are no surfaces mounted at angles to each other which can reflect radar waves. Unfortunately, a clean flying wing shape is wildly impractical for any avation due to the need for equipment carried however by keeping protuding devices and portals to a bare minimum, designers can not only reduce drag but minimize the chance of a detection, and this is just the route which Gemballa engineers strove for.
While many flying wings have stability issues around the normal axis, the presence of Fluidic Dynamic Thrust Vectoring on the RM-40 negates this issue, creating a very stable airframe. The RM-40 still mounts traditional ailerons and elevators.
The exterior of the Cautela is painted with ferrofluidic paint comprised of carbonyl iron. Ferrofluid is a liquid which becomes strongly magnetized in the presence of a magnetic field. This paint is more commonly known as "iron ball paint," consisting of several million tiny iron balls that are painted onto the surface of the aircraft. Radar waves induce molecular oscillations from the alternating magnetic field in this paint, which leads to conversion of the radar energy into heat. The heat is then transferred to the aircraft and dissipated. While this particular paint does not work effectively for all radar waves, this does cover what is considered the typical frequencies on which military radars operate on.
Directly underneath the level of paint lies a layer of polychloroprene, a rubber which maintains it's qualities through extreme temperatures. This layer is added to insulate the actual outer carbon fibre layer against the intense heat created when radar waves are being absorbed.
The surfaces for the RM-40 were designed to be flat only, despite slight curves around the engine housing and the cockpit. From below, which is where most radar will be aiming, the surface of the RM-40 is completely flat with only slight bulgings (less than 5mm) to house important equipment.
Engines for the aircraft are mounted inset into the fuselage which helps to mask the intense heat generated by these powerplants. By mounting them, along with their intakes, as flat to the fuselage as possible 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.
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 RM-40 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 RM-40.
Specifications
Crew: 2
Length: 24.2m
Wingspan: 49.9m
Height: 5.16m
Wing area: 485 m²
Empty weight: 72,000 kg
Loaded weight: 160,300 kg
Max takeoff weight 175,000 kg
Powerplants: 2× Azzuri TR-GT400 Turbofans
Dry thrust: 154kN
Fuel capacity: 80,000 kg internally
Performance
Maximum speed: Mach 0.99 (limited)
Cruise: Mach 0.9
Range: 12,250 km
Service ceiling: 56,500 ft
Wing Loading: 329kg/m.sq
Thrust/Weight Ratio 0.229
Hardpoints:
1/2 Internal bays for 25,000kg ordnance
Nuclear Weapon Capable
Radar Guided Missile Capable
Laser Guided Bomb Capable
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.