Vault 10
06-05-2008, 00:34
OOC: This thread can be used both for ordering and discussion.
http://www.ejectionsite.com/ejctpic/s4s.gif (http://www.ejectionsite.com/ejctpic/siiiss.gif)
Preamble
History of Ejection Seats
While the aircraft were flying at low speeds, all it took to escape one was a parachute. But already late in WWII, speeds and g-forces have climbed to a level making that barely if at all possible.
Just in the years after the World War II, without major wars, the Martin-Baker ejector seats alone have saved over 7,200 lives. For comparison, US and UK, the prime users of Martin-Baker seats, have about the same number of aircraft combined, of them just 3,000 fighters. Even in peacetime a large percentage of military aircraft end their lives in a crash, hopefully ejecting the crew, and in wartime it's over 50%.
This makes ejector seats the most frequently used life-saving safety equipment, ahead of body armour and lifeboats. Their installation is actually not just a life-saving, but also an economical decision: due to their high rate of use, they save much more in new pilot training than their cost.
As an example, in 1999 US already started financing Zvezda to produce their K-36 seats, known for the highest ejection success rate ever and some of the most unbelievable escapes, to be installed into the F-22 Raptor. International relations have eventually sunk the deal, but the fact that USAF almost stepped over itself and installed a Russian-made part into their halo fighter shows its importance.
But, out of safety equipment, ejector seats are also among the most dangerous. The ejection itself is often unsuccessful: the seats have to pull pilots out of heavily damaged or nearly-crashing aircraft. And as if it wasn't enough, in the case of success, the pilots still rarely land without injuries.
Even short-term subjection to the acceleration produced by the ejector seat, 12g to 14g, is damaging and dangerous for the human body. Typical injuries include broken joints, crushed vertebrae, and worse; very often, the pilot, though still able to live his life, ends up in a condition requiring retirement. This is especially exacerbated as more female pilots enter the forces, since their build makes women receive more severe injuries in ejection.
So, as good as some of the modern seats are, they still have room for improvement, and the requirements are constantly increasing. Modern ejection seats are already more complex devices than any pre-WWII aircraft, containing 1500-2000 functional parts.
http://upload.wikimedia.org/wikipedia/commons/6/6b/Ejectionseat.jpg (http://en.wikipedia.org/wiki/Image:Ejectionseat.jpg)
Fig.1. A typical 3rd generation seat ejection with a deployment charge and rocket assistance.
For the last 60 years, there have been 3 generations of ejector seats.
The first generation, starting from late-WWII experiments through 1950s, used simple powder charges to shoot the pilot outside, where he was on his own to free himself from the seat and deploy the parachute. Thanks to low airspeeds, the g-forces were survivable and the separation easy.
Starting in 1960s, the seats were equipped with additional rocket propulsion, allowing for low-altitude ejection, though high g-forces are nonetheless found of them. Martin-Baker Mk.7 family is a typical example. The century series fighters and SR-71 are the most known examples of second generation seats applications.
Third generation seats, developed in mid-1980s and entering wide use in 1990s, are characterized by accelerations within 15g, universal zero-zero capability, and electronic control. Martin-Baker Mk.16 and BAE ACES-II, found on the latest Western fighters, are typical examples. Automatic pilot separation and automatic parachute deployment are also a standard feature of these seats.
Fourth generation so far has been only theoretical, although some experiments with basic prototypes have been conducted, both in UK, Russia and US, as the CREST program.
Zvezda K-36 and its derivatives (K-37) are the only seats to day considered approaching it, and so being 3.5th generation, implementing some, but far from all features expected from the fourth.
Design History
http://www.ejectionsite.com/crest/4thgeneration.jpg (http://www.ejectionsite.com/crest/4thgeneration.jpg)
Fig.2. Ejection of a 4th generation prototype, powered by four rockets.
The Symmetriad is a large independent company, predominantly operating within the territories of Vault 10, specializing in high-reliability systems, and mostly known for its nuclear reactors, control systems, and spacecraft components.
The Laertes IV seat, the latest in the Symmetriad line of ejector seats, has been specifically designed for high-performance fighter aircraft. In the pre-design evaluation, a research board was formed to study the reasons for crashes without ejections. Overall, the team came to the following conclusions:
* Modern ejection seats offer reliable means of leaving the aircraft, if activated in time, if the canopy is ejected, and if the flight vector is close to level.
* The most common cause of failure to escape is human factor, specifically failure to activate the seat, or to do it in time.
* The second most common problem is righting the seat after an ejection in non-level flight, such as in sharp turns, canopy facing sidewards or downwards, or after loss of control.
* Both of these issues exacerbate gravely with aerodynamically unstable aircraft, which can't be controlled by a human, and enter uncontrolled stall with random directions and violent accelerations, should the avionics fail.
* Accelerations higher than 6g, in flight conditions, often prevent ejection, causing immediate loss of reasoning ability and loss of consciousness in a few seconds, even with the g-suit. As the ejection usually follows a sharp manoeuvre to avoid a crash or a munition, these are a frequent cause of failure to activate the seat.
* Negative g-forces can prevent seat activation already at -2g. Such turns are instinctively avoided by human pilots, but new aerodynamically unstable aircraft are just as likely to cause negative g-forces as positive. This makes timely ejection a greater issue for such aircraft.
* Accelerations in excess of 12g, produced by modern seats, can't be sustained by most humans without injury in the flight conditions associated with ejection.
* Apart from acceleration, a significant factor is its onset rate, or dG. High onset rate increases the injuring effect of g-forces.
* Seat design influences the effect acceleration has on the pilot. Since seat ergonomics are usually considered secondary to weight and performance, the modern seats do not fully utilize the potential for effect minimization.
* Weight reduction measures, especially through simplification of the seat, lead to noticeable increase in injury potential for insignificant (<0.1%) decrease in aircraft weight. Heavier seats dampen the effect of ejection itself and wind strike, and allow for improved performance.
Based on this summary, the team formed a following set of requirements for the new seat:
* In-flight ergonomics would have to be improved, particularly considering retaining the ability to control the aircraft at high accelerations. The seat would have to be adjustable for pilots of various build, and adjust automatically in flight to avoid distraction.
* Since human factor is so significant, automated ejection would be desirable, both for G-LOC conditions and major avionics failures.
* The seat would have to eject the pilot with lower force, in order to reduce injury, and deliver the force smoothly if possible. Force control would be essential to clear the aircraft with minimal acceleration.
* Control of the seat's flight post-ejection would have to be significantly improved, considering unpredictable behaviour of newer aircraft in emergency.
To meet these requirements, after prolonged experiments and engineering efforts, an all-new seat design was created, to replace the older L3 model in first high-performance and eventually all applications.
General Design
Laertes IV, or simply L4, is an electronically controlled fourth generation ejection seat, designed for pilots or crews of practically any weight and build, focused on maximum flight ergonomics, prevention of ejection injury and high ejection reliability. It keeps the acceleration under all but the most extreme ejection conditions within 9g, and allows ejection from any pitch and roll combination, at any altitude and airspeeds from zero to Mach 3 and over.
The seat is built predominantly of aluminium-lithium alloy, aramide and carbon fibre composites to keep reasonable weight, although due to feature-rich design is on the heavier side of the spectrum. It is slightly larger than most seats, supporting the pilot over a larger area.
L4 still can be installed into any aircraft capable of fitting K-36 seat and most aircraft capable of fitting Martin-Baker Mk.16 or BAC ACES II seat These include almost all modern aircraft, particularly F-14 to F-35, Typhoon, Mirage, all Russian combat aircraft, all bombers supporting ejector seats, and a number of other planes and helicopters (provided the blades are jettisoned).
Ejection
http://www.freewebs.com/vault_10/ejdiagram.png[/URL]
Fig.3. Separation of pilot and equipment from the seat after the ejection.
To reduce vertical acceleration, the seat uses throttled and time-spread initial impulse. The propellant load is divided into 48 cartridges, which are activated individually, their number depending on pilot weight and current g-load. To minimize the Gz onset rate, firing is done in 4 steps, extending the telescopic cylinders.
Since occasionally canopy jettisoning fails, the seat is equipped with a bar above the headrest, breaking the canopy and protecting the crewman's head, without interfering with the view.
After clearing the aircraft, further propulsion is provided by six hybrid-fuel rockets with 3-dimensional thrust vectoring, four behind the backrest and two under the seat. Each rocket contains 3.2kg of peroxide and polyethylene fuel, similar to MLSA-10 engine, providing combined thrust up to 30kN. Their thrust and direction are controlled by the seat's processor, which operates them to clear the aircraft and then keep vertical position, as monitored by the seat's inertial navigation system. Although it keeps track of acceleration, airspeed and altitude independently, for optimum performance the seat should be linked to avionics and loaded with aircraft's 3d model, to better clear the surfaces.
Hybrid rockets were selected for their high safety, high controllability, and high Isp, sufficient to bring the loaded seat from 700 km/h to full stop, or propel it several miles away from the crash site, if desired. However, their primary purpose is still clearing the aircraft and righting the seat into a position suitable for separation or landing. An additional, centreline rocket is installed, but is never used at this point in ejection, being reserved for manual activation in failure cases.
At high airspeed, the seat will also deploy additional side, front and head aramide netting for pilot retention and windblast protection, and turn its underside to the wind to protect the pilot. If installed on high-speed aircraft (over 800KEAS, i.e. Mach 1.3 at sea level or Mach 2.4 at 10km), the seat is fitted with an extended footrest panel. After the seat pulls the pilot's legs in, the panel will fold upwards and extend additional front netting, both serving to deflect the wind.
Landing
Normally, once the aircraft is cleared, the pilot activates separation (as on any other seat), at which the seat would deploy his parachute, so he has full control over the landing. However, since the L4 seat is able to eject an unconscious pilot, it also requires a mechanism for landing him, so a larger seat parachute is installed. If the pilot doesn't pull the handle to separate, the seat deploys its parachite, and, using control rockets, lands together with the pilot. Eight cushioning airbags, fully protecting the pilot, are provided to soften normal landing, avoid injury in unstable landing, and provide buoyancy in water landing.
Upon landing, the seat offers an array of mounted survival equipment. First, in case of water landing, an oxygen bottle is provided, and, if the appropriate mask is used, the pilot is already plugged to oxygen-rich air supply. Most of the standard equipment is also detached together with the crewman, such as the liferaft, the radio beacon, and the rucksack with survival equipment, all of these mounted underneath the seat. Additional supplies may be mounted on the back of the seat, as long as the combined weight does not exceed 320kg. They have to be retrieved from the seat.
Control System
http://www.ejectionsite.com/ejctpic/a10-2.gif
Fig.4. Control subsystems of the ejection seat.
The control system of Laertes IV is fully electronic, with a high degree of autonomy, including its own backup batteries and ejection control processor. Additionally, it features an independent flight monitoring processor, connected to aircraft's avionics, directly to the sensors (if possible), and, optionally, to a dedicated Symmetriad altimeter. A digital inertial navigation system and a GPS/Lightcom receiver are installed within the seat, with place reserved for the customer's own satellite receiver, if he desires to install it. Flight conditions are monitored continuously, evaluating the risk both independently and using information from the avionics.
If the system predicts a high risk of crash, that can't be avoided by the avionics or the pilot in the remaining time, the seat sends out a warning and sets into the ejection position. Unless manually overriden in the time remaining to the point of no return, the seat sends a command to jettison the canopy and activates.
The parameters of risk assessment, threshold risk, by default 80%, and time for override can be adjusted by the customer, or, if allowed, by the pilot through the avionics.
Automatic ejection, apart from reducing human factor issues, has shown to also have a slight positive effect on pilot performance. When it is active, the pilot can closely concentrate on combat or collision avoidance until the last second, without worrying about timing the ejection.
After the ejection, the system usually operates all the mechanisms automatically, but manual (more precisely, semi-automatic) control over propulsion is also possible once the aircraft is cleared, by pulling the body against the harness belts, somewhat similar to a paraglider. Normally, rockets are rather stopped, to save fuel for emergencies at landing.
As Laertes IV contains a GPS/Lightcom receiver and INS, it has basic information about terrain the ejection occurred about, complemented by the scanning laser altimeter. In case the terrain is determined to be dangerous, and there is no manual intervention, the seat attempts to propel itself towards safer terrain, using its ram-air parachute and the control rockets. If the pilot is separated, the seat attempts to land clear of him, but within reach. The GPS/Lightcom navigation and terrain data receiver is detachable from the seat, and provided with a screen so it can be carried and used by the pilot, if rescue is not expected.
Ergonomics
http://www.freewebs.com/vault_10/F104C1.GIF (http://www.ejectionsite.com/f104seats/f104c1lf.JPG) http://www.ejectionsite.com/texans/sju17.gif (http://www.ejectionsite.com/ejctpic/mbmk16_front.jpg)
Fig.5. The ergonomics of 2nd-gen. Lockheed C-1 ejection seat, compared to 3rd-gen. Martin-Baker Mk.14 and Mk.16 (click).
As mentioned, an unusually large role in the design was given to the pilot ergonomics - usually a secondary consideration, making its evolution slow. Even third-generation seats are, in terms of comfort, a stool with a headrest, still putting the aircraft lightness over pilot convenience. Laertes IV has revolutionized this field.
Being designed for fighters, it, of course, doesn't share the softness of car seats. Instead, attention was given to minimizing the effect of g-loads and pilot fatigue, but keeping good access to the controls, similar to racing seats, but more sophisticated.
The crewman is fixed in the deep bucket seat using a six-point harness and leg restraints, tension on all of which is electronically controlled depending on the g-load.
While most 3rd generation seats have no adjustments at all or just one axis, the Laertes IV offers three full and five partial degrees of freedom, with twelve adjustable parameters. The user can control seat position over X-axis (fore/aft), Z-axis (height) and yaw; adjust recline of the footrest, lower backrest, upper backrest; control armrests Y-axis and Z-axis position; control the tilt of the extended side panels; and adjust vibration dampening level.
All of these measures allow the seat to perfectly fit pilots of any build, and at the same time hold the pilot better in lateral direction without causing discomfort. Their control is done by simply pushing them into desired positions, with assistance of the electric motors, which also control all elements in flight, adjusting them to reflect changes in position.
The headrest is a suspended element, which semi-automatically follows the head movement in pitch, yaw, Z-axis and Y-axis, with adjustable stiffness. This is done so the headrest could be made wider and more enveloping, but the pilot can easily check his six.
An important feature is called "G-feedback", and involves the seat first being calibrated, measuring the pressure the pilot's body and parts of body exert on the seat under different g-loads without any motion. Afterward, the seat, measuring the forces and knowing acceleration from its INS, separates the forces intentionally exerted by the pilot from simple weight, and so follows his movements. For instance, the armrest can follow the arm slightly up or down, assisting with upwards movement, but depressing almost as if it wasn't there in downward movement. Similarly, the backrest and the headrest follow the pilot if he leans forward, but recline easily if he exerts force with his back.
This feature is only active under high accelerations, to make controlling the aircraft easier. Without it, at 6g each arm would have to lift 30kg to move up from the armrests, effectively restricting the pilot to throttle and stick only control [voice control is impossible under such g-load as well, and even just breathing and staying conscious requires special training].
Some elements have more automatic control. In particular, under high g-load or negative g-load the seat will recline, moving forward at the same time to keep the pilot's hands on the controls, and lifting up if visibility is reduced. Individual operators' g-tolerance profiles, build data, and recline preferences can be loaded into the seat to keep a balance between g-tolerance, comfort, and visibility.
Human body is affected by lateral g-force at least 25% less than by longitudinal, this increasing to 40% for short exposure, and to 60% for negative g-force (see NASA g-tolerance data (http://en.wikipedia.org/wiki/G-force#NASA_g-tolerance_data)).
Thus, under extreme recline of 60 degrees the effective g-force is about 12% lower than in straight position, or 10% lower than with the usual recline of 15 degrees. For short manoeuvres these figures double, to a 20% advantage over a typical seat in positive or 50% in negative g-force. In effect, at high loads, it equates to an extra g. Thus, if normally exceeding +6g or -2g is considered pilot error (aircraft g-ratings of 9-10g are strength reserve), with Laertes IV in full recline the pilot in g-suit would be capable of a +7g or -3g manoeuvre.
Other ergonomic measures are implemented as well. Modern helmets, loaded with helmet displays, voice control, and other features, apart from their structural and isolating role, are heavy devices. At high g-load, the helmet exerts major force on the crewman's head, adding to other problems. The automatically adjusted L4 headrest provides partial helmet support. If the appropriate associated helmet and suit are used, a further increase of +0.5g is possible.
An additional comfort feature is the seat's vibration-absorbing suspension, which utilizes a combination of passive shock absorbers and linear electric motors, digitally controlled to counteract vibration. This provides soft ride, with only very mild vibrations, when the aircraft is out of danger or controlled by autopilot, thus considerably extending crew endurance. A simple "stiffness" control determines how closely the seat will follow aircraft's vibrations. The seat can induce controlled vibrations in its parts separately, massaging the back and all of the body in flight.
If linked to the avionics, L4 will automatically determine when the pilot is in combat situation. With this function, as soon as the pilot starts to operate the controls, vibration suppression is deactivated, so his hands move together with the cockpit.
Additional equipment
http://www.freewebs.com/vault_10/K-36.gif
Fig.6. A pilot in a g-suit and a helmet, in the legendary K-36 seat.
The seat itself is a very important component, but due to its innovative designs not all of its features can be utilized by standard flight suits and helmets. Therefore, some special equipment is offered, usable only with Laertes IV suit, but offering significant advantages.
AMS-4 Flight Suit
One of the most crucial pieces is the Symmetriad AMS-4 Acceleration Management Suit, or, simply speaking, g-suit.
Normally, a g-suit works by compressing the pilot's legs to restrict blood flow inside them, and allow for greater blood flow into the head, under high positive g manoeuvres. Thanks to it, if an average human loses vision at 4g and quickly passes out at 5g, a pilot wearing a g-suit and trained in its use can sustain 6g without loss of vision and stay conscious at 7g and sometimes slightly above.
There are some downsides to this, however. In particular, a standard constant-pressure suit is a problem at negative G-forces, since it only facilitates excess blood pressure in the brain, a dangerous and potentially lethal condition.
Generally, the downsides are outweighed by the advantages, but they are not inavoidable. Introduction of the Laertes IV seat allowed to make some changes in g-suit operation, due to its extended ergonomics and control capabilities.
AMS-4, designed specifically for the L4, builds upon that. It is a full-body flight suit, worn over only an undergarment overall. Together with moving all control valves to the seat, this lightens the suit significantly, and improves the ergonomics. The suit is constructed of strong and fireproof aramide fibre.
Under g-forces, the suit utilizes dynamic pneumatic pressure control over the entire body, rather than static as usual. Pumping action, synchronous to the heartbeat, is applied to the limbs rather than simple compression, to keep the blood still flowing, increasing the time that can be spent at high acceleration, and avoiding health risks. Additionally, together with the L4 control unit, monitoring the pilot's breath rate, AMS-4 and the seat's backrest vibration control assist pilot breathing at high accelerations.
At negative g-force, on the contrary, the suit below the neck can be slightly depressurized, causing the blood to flow to the lower body under pressure. By itself, this is no good, but while human limbs and torso only experience minor bruising after blood overpressure, similar condition inside the head causes redouts and potentially brain insult. Thus, the suit to the greatest extent prevents blood from rushing to the wearer's head, keeping it in the lower parts of body. All of this is synchronized with seat's position control, changing body position such as blood flow is no longer oriented towards the head, so the pressure can be released sooner.
The suit is completely ventilated and air conditioned, provided the aircraft contains appropriate systems. AMS-4 is usually not completely airtight, to improve ventilation, but can be sealed with two hermetical zipper seals.
Some other features of the suit serve to improve resistance to lateral shocks during unstable flight and ejection. The joints of the suit are immersed in dilatant fluid, which stiffens them under undue shocks, while providing no resistance to humanly possible movements. This serves to prevent neck and joints injuries.
One last feature is exploited during ejection. The tubes inside the suit are pressurized over the entire body, inflating and serving as a protection against the underpressure at high altitude.
If the pilot ends up in the water, the suit lands already inflated, further minimizing the risk of sinking.
AHG-1 Helmet
Another optional piece of equipment is the Symmetriad AHG-1 helmet.
First, to reduce the weight of empty structure, the helmet's shell is built of NSMC-developed carbon nanotube reinforced polymer and metal matrix composite materials. Underneath, a lightweight composite serves for shock absorption.
This helmet, being developed in 2008, is also equipped with the latest avionics systems, including a full projected helmet-mounted stereo display, active noise cancellation, and filtered microphone to improve the work of voice control systems.
But the most noticeable change concerns the air connection. The AHG helmet doesn't have the familiar look of an elephant's head, since it doesn't need to connect to a distant air supply. Instead, the helmet is connected by a much shorter tube to the headrest, which on Laertes IV moves almost freely, through which it follows to the seat's air control system, which in its turn is connected to aircraft's facilities.
This offers three major advantages. First of all, the helmet is lighter, and supported by the headrest, so the pilot can withstand higher g-forces. Second, the air pressure is closely controlled, so the seat effectively breathes for the pilot when he has difficulties doing so on his own, assisting the lungs and controlling oxygen content. Third, in ejection the pilot is continuously supplied with an air mixture, so he can safely eject from high altitudes, and, in case of a water landing or out-of-water ejection, isn't in danger of suffocation. The seat's air management system also includes full NBC protection, for when the worst comes to worst.
Specifications
http://www.freewebs.com/vault_10/16F.gif (http://www.martin-baker.com/getdoc/a04cd081-64ce-48b7-bb06-bcfab87c7c03/Mk-F16F---Rafale.aspx)
Fig.6. Key components of a modern ejection seat.
Seat weight
** Empty, minimal version: 95 kg
** Empty, with standard features: 110 kg
** With standard features, full rescue and survival equipment: 160 kg
** Standard throw weight: 240 kg (seat, equipment, pilot, gear)
** Maximum throw weight: 300 kg
** Baseplate, firing cylinders and mountings: 30 kg
** Total system weight: 140 ... 200 kg
Dimensions
** Length, compacted: 85 cm
** Length, maximum recline, extension and legroom: 200 cm
*** Not necessary to provide, but pilot height or recline might be limited
** Height: 120 cm compacted, 200 cm maximum
** Width: 90 cm minimum, 110 cm maximum
Pilot requirements
** Minimum pilot weight: 20 kg
** Maximum pilot weight (with gear): 140 kg
** Minimum pilot height: 130 cm
** Maximum pilot height: 220 cm
** Seat use training time: 75 hours on land plus 15 hours in flight
Ejection conditions
** Altitude: -50m...60,000 m
*** Negative altitude presumes underwater ejection, positive is limited by seat's air supply to pressurize the helmet, and can be extended by special gear.
** Airspeed, at sea level: 0...520m/s (Mach 1.5)
** Maximum airspeed, absolute: 1900m/s at 30,000m (Mach 6)
*** Absolute airspeed is limited by the heat produced by atmospheric reentry from Mach 5 and above at extreme altitude.
** Maximum airspeed, medium altitude: 1050KEAS, or 900m/s at 10,000m (Mach 3.0)
*** These numbers include reserve; aircraft actually rated for these speeds should install the high-speed modification.
Ergonomics features
** Minimum recline: 10 degrees
** Maximum recline: 60 degrees
** G-feedback effective range: -4g...+11g
*** This is not the operational range for the pilot or the seat, but just the range where the G-feedback is still effective.
** Ejection g-force, typical: 8g
** Ejection g-force, maximum: 14g (only in manual override)
** G-force onset rate, normal: 400g/second
Cost and modifications
Minimal version:
The minimal version does not include autonomous flight monitoring, automatic terrain navigation, motorized seat adjustment, vibration suppression, and G-feedback.
** Cost: $300,000
Standard package:
All features described above are included.
** Cost: $500,000
Secondary seats:
In aircraft with more than 1 crew member, some of the control avionics don't have to be duplicated, provided all the seats are linked together. All standard features are still included in secondary seats, at a reduced cost.
** Cost: $400,000
Additional equipment:
** AMS-4 g-suit package: $250,000
---- Of these, air management and health monitoring system - $150,000
---- 5 suits (due to limited lifetime) - $100,000
** Additional AMG-4 g-suits: $20,000 each
** AHG pilot helmet, basic systems only: $100,000
** AHG pilot helmet, including all in-built avionics and associated software: $150,000
Special offers:
** Complete package, per single-seater aircraft: $900,000
** Complete package, additional seats: $750,000
The complete package includes a full-feature Laertes IV ejector seat, the AMS-4 suit package, the AHG pilot helmet with all avionics, installation of all equipment, all associated rescue equipment, related software, and unlimited access to LightCom satellite network for the aircraft in question.
It saves $100,000 per seat, compared to separate purchase of all components.
Domestic production rights are available for $60 billion for the seat alone, $20 billion for the suit or the helmet, or $90 billion for all together. The cost includes equipping factories fitted with Symmetriad-approved machinery, to ensure that high product quality is maintained.
Installation and Distribution
Laertes IV seat can be both integrated as a part of a new aircraft, and installed into most of the modern aircraft.
In case of aircraft designed with L4 in mind, it's desirable to provide a slightly longer cockpit to allow for seat recline. Almost all modern aircraft still may use the seat, but in case of smaller cockpits the maximum recline would usually be restricted to 45-50 degrees, and pilot height to 190-200cm.
The L4 seat is best suited for all types of fighters, supersonic bombers, reconnaissance planes, helicopters, and other high-performance aircraft. Installation on other aircraft is also possible, usually with minor modification. Additionally, trainer aircraft, due to their higher ejection rate, benefit more from this seat, not injuring the pilot, though a minimal package is sufficient for trainers.
All of the advanced features can work independently, but benefit greatly from a connection to the aircraft's avionics.
Customers can order professional installation at $50,000 per seat, including aircraft check-up, all sensors installation, required modification, and flight testing, or can perform it on their own. The installation is free for allies and partners.
If professionally installed, or used as a part of a new aircraft, the seat is guaranteed for at least 98% rate of successful ejection and landing, with a compensation in case of failure.
The Symmetriad doesn't place restrictions on sale of life-saving equipment such as ejector seats; all nations and companies may order them.
http://www.ejectionsite.com/ejctpic/s4s.gif (http://www.ejectionsite.com/ejctpic/siiiss.gif)
Preamble
History of Ejection Seats
While the aircraft were flying at low speeds, all it took to escape one was a parachute. But already late in WWII, speeds and g-forces have climbed to a level making that barely if at all possible.
Just in the years after the World War II, without major wars, the Martin-Baker ejector seats alone have saved over 7,200 lives. For comparison, US and UK, the prime users of Martin-Baker seats, have about the same number of aircraft combined, of them just 3,000 fighters. Even in peacetime a large percentage of military aircraft end their lives in a crash, hopefully ejecting the crew, and in wartime it's over 50%.
This makes ejector seats the most frequently used life-saving safety equipment, ahead of body armour and lifeboats. Their installation is actually not just a life-saving, but also an economical decision: due to their high rate of use, they save much more in new pilot training than their cost.
As an example, in 1999 US already started financing Zvezda to produce their K-36 seats, known for the highest ejection success rate ever and some of the most unbelievable escapes, to be installed into the F-22 Raptor. International relations have eventually sunk the deal, but the fact that USAF almost stepped over itself and installed a Russian-made part into their halo fighter shows its importance.
But, out of safety equipment, ejector seats are also among the most dangerous. The ejection itself is often unsuccessful: the seats have to pull pilots out of heavily damaged or nearly-crashing aircraft. And as if it wasn't enough, in the case of success, the pilots still rarely land without injuries.
Even short-term subjection to the acceleration produced by the ejector seat, 12g to 14g, is damaging and dangerous for the human body. Typical injuries include broken joints, crushed vertebrae, and worse; very often, the pilot, though still able to live his life, ends up in a condition requiring retirement. This is especially exacerbated as more female pilots enter the forces, since their build makes women receive more severe injuries in ejection.
So, as good as some of the modern seats are, they still have room for improvement, and the requirements are constantly increasing. Modern ejection seats are already more complex devices than any pre-WWII aircraft, containing 1500-2000 functional parts.
http://upload.wikimedia.org/wikipedia/commons/6/6b/Ejectionseat.jpg (http://en.wikipedia.org/wiki/Image:Ejectionseat.jpg)
Fig.1. A typical 3rd generation seat ejection with a deployment charge and rocket assistance.
For the last 60 years, there have been 3 generations of ejector seats.
The first generation, starting from late-WWII experiments through 1950s, used simple powder charges to shoot the pilot outside, where he was on his own to free himself from the seat and deploy the parachute. Thanks to low airspeeds, the g-forces were survivable and the separation easy.
Starting in 1960s, the seats were equipped with additional rocket propulsion, allowing for low-altitude ejection, though high g-forces are nonetheless found of them. Martin-Baker Mk.7 family is a typical example. The century series fighters and SR-71 are the most known examples of second generation seats applications.
Third generation seats, developed in mid-1980s and entering wide use in 1990s, are characterized by accelerations within 15g, universal zero-zero capability, and electronic control. Martin-Baker Mk.16 and BAE ACES-II, found on the latest Western fighters, are typical examples. Automatic pilot separation and automatic parachute deployment are also a standard feature of these seats.
Fourth generation so far has been only theoretical, although some experiments with basic prototypes have been conducted, both in UK, Russia and US, as the CREST program.
Zvezda K-36 and its derivatives (K-37) are the only seats to day considered approaching it, and so being 3.5th generation, implementing some, but far from all features expected from the fourth.
Design History
http://www.ejectionsite.com/crest/4thgeneration.jpg (http://www.ejectionsite.com/crest/4thgeneration.jpg)
Fig.2. Ejection of a 4th generation prototype, powered by four rockets.
The Symmetriad is a large independent company, predominantly operating within the territories of Vault 10, specializing in high-reliability systems, and mostly known for its nuclear reactors, control systems, and spacecraft components.
The Laertes IV seat, the latest in the Symmetriad line of ejector seats, has been specifically designed for high-performance fighter aircraft. In the pre-design evaluation, a research board was formed to study the reasons for crashes without ejections. Overall, the team came to the following conclusions:
* Modern ejection seats offer reliable means of leaving the aircraft, if activated in time, if the canopy is ejected, and if the flight vector is close to level.
* The most common cause of failure to escape is human factor, specifically failure to activate the seat, or to do it in time.
* The second most common problem is righting the seat after an ejection in non-level flight, such as in sharp turns, canopy facing sidewards or downwards, or after loss of control.
* Both of these issues exacerbate gravely with aerodynamically unstable aircraft, which can't be controlled by a human, and enter uncontrolled stall with random directions and violent accelerations, should the avionics fail.
* Accelerations higher than 6g, in flight conditions, often prevent ejection, causing immediate loss of reasoning ability and loss of consciousness in a few seconds, even with the g-suit. As the ejection usually follows a sharp manoeuvre to avoid a crash or a munition, these are a frequent cause of failure to activate the seat.
* Negative g-forces can prevent seat activation already at -2g. Such turns are instinctively avoided by human pilots, but new aerodynamically unstable aircraft are just as likely to cause negative g-forces as positive. This makes timely ejection a greater issue for such aircraft.
* Accelerations in excess of 12g, produced by modern seats, can't be sustained by most humans without injury in the flight conditions associated with ejection.
* Apart from acceleration, a significant factor is its onset rate, or dG. High onset rate increases the injuring effect of g-forces.
* Seat design influences the effect acceleration has on the pilot. Since seat ergonomics are usually considered secondary to weight and performance, the modern seats do not fully utilize the potential for effect minimization.
* Weight reduction measures, especially through simplification of the seat, lead to noticeable increase in injury potential for insignificant (<0.1%) decrease in aircraft weight. Heavier seats dampen the effect of ejection itself and wind strike, and allow for improved performance.
Based on this summary, the team formed a following set of requirements for the new seat:
* In-flight ergonomics would have to be improved, particularly considering retaining the ability to control the aircraft at high accelerations. The seat would have to be adjustable for pilots of various build, and adjust automatically in flight to avoid distraction.
* Since human factor is so significant, automated ejection would be desirable, both for G-LOC conditions and major avionics failures.
* The seat would have to eject the pilot with lower force, in order to reduce injury, and deliver the force smoothly if possible. Force control would be essential to clear the aircraft with minimal acceleration.
* Control of the seat's flight post-ejection would have to be significantly improved, considering unpredictable behaviour of newer aircraft in emergency.
To meet these requirements, after prolonged experiments and engineering efforts, an all-new seat design was created, to replace the older L3 model in first high-performance and eventually all applications.
General Design
Laertes IV, or simply L4, is an electronically controlled fourth generation ejection seat, designed for pilots or crews of practically any weight and build, focused on maximum flight ergonomics, prevention of ejection injury and high ejection reliability. It keeps the acceleration under all but the most extreme ejection conditions within 9g, and allows ejection from any pitch and roll combination, at any altitude and airspeeds from zero to Mach 3 and over.
The seat is built predominantly of aluminium-lithium alloy, aramide and carbon fibre composites to keep reasonable weight, although due to feature-rich design is on the heavier side of the spectrum. It is slightly larger than most seats, supporting the pilot over a larger area.
L4 still can be installed into any aircraft capable of fitting K-36 seat and most aircraft capable of fitting Martin-Baker Mk.16 or BAC ACES II seat These include almost all modern aircraft, particularly F-14 to F-35, Typhoon, Mirage, all Russian combat aircraft, all bombers supporting ejector seats, and a number of other planes and helicopters (provided the blades are jettisoned).
Ejection
http://www.freewebs.com/vault_10/ejdiagram.png[/URL]
Fig.3. Separation of pilot and equipment from the seat after the ejection.
To reduce vertical acceleration, the seat uses throttled and time-spread initial impulse. The propellant load is divided into 48 cartridges, which are activated individually, their number depending on pilot weight and current g-load. To minimize the Gz onset rate, firing is done in 4 steps, extending the telescopic cylinders.
Since occasionally canopy jettisoning fails, the seat is equipped with a bar above the headrest, breaking the canopy and protecting the crewman's head, without interfering with the view.
After clearing the aircraft, further propulsion is provided by six hybrid-fuel rockets with 3-dimensional thrust vectoring, four behind the backrest and two under the seat. Each rocket contains 3.2kg of peroxide and polyethylene fuel, similar to MLSA-10 engine, providing combined thrust up to 30kN. Their thrust and direction are controlled by the seat's processor, which operates them to clear the aircraft and then keep vertical position, as monitored by the seat's inertial navigation system. Although it keeps track of acceleration, airspeed and altitude independently, for optimum performance the seat should be linked to avionics and loaded with aircraft's 3d model, to better clear the surfaces.
Hybrid rockets were selected for their high safety, high controllability, and high Isp, sufficient to bring the loaded seat from 700 km/h to full stop, or propel it several miles away from the crash site, if desired. However, their primary purpose is still clearing the aircraft and righting the seat into a position suitable for separation or landing. An additional, centreline rocket is installed, but is never used at this point in ejection, being reserved for manual activation in failure cases.
At high airspeed, the seat will also deploy additional side, front and head aramide netting for pilot retention and windblast protection, and turn its underside to the wind to protect the pilot. If installed on high-speed aircraft (over 800KEAS, i.e. Mach 1.3 at sea level or Mach 2.4 at 10km), the seat is fitted with an extended footrest panel. After the seat pulls the pilot's legs in, the panel will fold upwards and extend additional front netting, both serving to deflect the wind.
Landing
Normally, once the aircraft is cleared, the pilot activates separation (as on any other seat), at which the seat would deploy his parachute, so he has full control over the landing. However, since the L4 seat is able to eject an unconscious pilot, it also requires a mechanism for landing him, so a larger seat parachute is installed. If the pilot doesn't pull the handle to separate, the seat deploys its parachite, and, using control rockets, lands together with the pilot. Eight cushioning airbags, fully protecting the pilot, are provided to soften normal landing, avoid injury in unstable landing, and provide buoyancy in water landing.
Upon landing, the seat offers an array of mounted survival equipment. First, in case of water landing, an oxygen bottle is provided, and, if the appropriate mask is used, the pilot is already plugged to oxygen-rich air supply. Most of the standard equipment is also detached together with the crewman, such as the liferaft, the radio beacon, and the rucksack with survival equipment, all of these mounted underneath the seat. Additional supplies may be mounted on the back of the seat, as long as the combined weight does not exceed 320kg. They have to be retrieved from the seat.
Control System
http://www.ejectionsite.com/ejctpic/a10-2.gif
Fig.4. Control subsystems of the ejection seat.
The control system of Laertes IV is fully electronic, with a high degree of autonomy, including its own backup batteries and ejection control processor. Additionally, it features an independent flight monitoring processor, connected to aircraft's avionics, directly to the sensors (if possible), and, optionally, to a dedicated Symmetriad altimeter. A digital inertial navigation system and a GPS/Lightcom receiver are installed within the seat, with place reserved for the customer's own satellite receiver, if he desires to install it. Flight conditions are monitored continuously, evaluating the risk both independently and using information from the avionics.
If the system predicts a high risk of crash, that can't be avoided by the avionics or the pilot in the remaining time, the seat sends out a warning and sets into the ejection position. Unless manually overriden in the time remaining to the point of no return, the seat sends a command to jettison the canopy and activates.
The parameters of risk assessment, threshold risk, by default 80%, and time for override can be adjusted by the customer, or, if allowed, by the pilot through the avionics.
Automatic ejection, apart from reducing human factor issues, has shown to also have a slight positive effect on pilot performance. When it is active, the pilot can closely concentrate on combat or collision avoidance until the last second, without worrying about timing the ejection.
After the ejection, the system usually operates all the mechanisms automatically, but manual (more precisely, semi-automatic) control over propulsion is also possible once the aircraft is cleared, by pulling the body against the harness belts, somewhat similar to a paraglider. Normally, rockets are rather stopped, to save fuel for emergencies at landing.
As Laertes IV contains a GPS/Lightcom receiver and INS, it has basic information about terrain the ejection occurred about, complemented by the scanning laser altimeter. In case the terrain is determined to be dangerous, and there is no manual intervention, the seat attempts to propel itself towards safer terrain, using its ram-air parachute and the control rockets. If the pilot is separated, the seat attempts to land clear of him, but within reach. The GPS/Lightcom navigation and terrain data receiver is detachable from the seat, and provided with a screen so it can be carried and used by the pilot, if rescue is not expected.
Ergonomics
http://www.freewebs.com/vault_10/F104C1.GIF (http://www.ejectionsite.com/f104seats/f104c1lf.JPG) http://www.ejectionsite.com/texans/sju17.gif (http://www.ejectionsite.com/ejctpic/mbmk16_front.jpg)
Fig.5. The ergonomics of 2nd-gen. Lockheed C-1 ejection seat, compared to 3rd-gen. Martin-Baker Mk.14 and Mk.16 (click).
As mentioned, an unusually large role in the design was given to the pilot ergonomics - usually a secondary consideration, making its evolution slow. Even third-generation seats are, in terms of comfort, a stool with a headrest, still putting the aircraft lightness over pilot convenience. Laertes IV has revolutionized this field.
Being designed for fighters, it, of course, doesn't share the softness of car seats. Instead, attention was given to minimizing the effect of g-loads and pilot fatigue, but keeping good access to the controls, similar to racing seats, but more sophisticated.
The crewman is fixed in the deep bucket seat using a six-point harness and leg restraints, tension on all of which is electronically controlled depending on the g-load.
While most 3rd generation seats have no adjustments at all or just one axis, the Laertes IV offers three full and five partial degrees of freedom, with twelve adjustable parameters. The user can control seat position over X-axis (fore/aft), Z-axis (height) and yaw; adjust recline of the footrest, lower backrest, upper backrest; control armrests Y-axis and Z-axis position; control the tilt of the extended side panels; and adjust vibration dampening level.
All of these measures allow the seat to perfectly fit pilots of any build, and at the same time hold the pilot better in lateral direction without causing discomfort. Their control is done by simply pushing them into desired positions, with assistance of the electric motors, which also control all elements in flight, adjusting them to reflect changes in position.
The headrest is a suspended element, which semi-automatically follows the head movement in pitch, yaw, Z-axis and Y-axis, with adjustable stiffness. This is done so the headrest could be made wider and more enveloping, but the pilot can easily check his six.
An important feature is called "G-feedback", and involves the seat first being calibrated, measuring the pressure the pilot's body and parts of body exert on the seat under different g-loads without any motion. Afterward, the seat, measuring the forces and knowing acceleration from its INS, separates the forces intentionally exerted by the pilot from simple weight, and so follows his movements. For instance, the armrest can follow the arm slightly up or down, assisting with upwards movement, but depressing almost as if it wasn't there in downward movement. Similarly, the backrest and the headrest follow the pilot if he leans forward, but recline easily if he exerts force with his back.
This feature is only active under high accelerations, to make controlling the aircraft easier. Without it, at 6g each arm would have to lift 30kg to move up from the armrests, effectively restricting the pilot to throttle and stick only control [voice control is impossible under such g-load as well, and even just breathing and staying conscious requires special training].
Some elements have more automatic control. In particular, under high g-load or negative g-load the seat will recline, moving forward at the same time to keep the pilot's hands on the controls, and lifting up if visibility is reduced. Individual operators' g-tolerance profiles, build data, and recline preferences can be loaded into the seat to keep a balance between g-tolerance, comfort, and visibility.
Human body is affected by lateral g-force at least 25% less than by longitudinal, this increasing to 40% for short exposure, and to 60% for negative g-force (see NASA g-tolerance data (http://en.wikipedia.org/wiki/G-force#NASA_g-tolerance_data)).
Thus, under extreme recline of 60 degrees the effective g-force is about 12% lower than in straight position, or 10% lower than with the usual recline of 15 degrees. For short manoeuvres these figures double, to a 20% advantage over a typical seat in positive or 50% in negative g-force. In effect, at high loads, it equates to an extra g. Thus, if normally exceeding +6g or -2g is considered pilot error (aircraft g-ratings of 9-10g are strength reserve), with Laertes IV in full recline the pilot in g-suit would be capable of a +7g or -3g manoeuvre.
Other ergonomic measures are implemented as well. Modern helmets, loaded with helmet displays, voice control, and other features, apart from their structural and isolating role, are heavy devices. At high g-load, the helmet exerts major force on the crewman's head, adding to other problems. The automatically adjusted L4 headrest provides partial helmet support. If the appropriate associated helmet and suit are used, a further increase of +0.5g is possible.
An additional comfort feature is the seat's vibration-absorbing suspension, which utilizes a combination of passive shock absorbers and linear electric motors, digitally controlled to counteract vibration. This provides soft ride, with only very mild vibrations, when the aircraft is out of danger or controlled by autopilot, thus considerably extending crew endurance. A simple "stiffness" control determines how closely the seat will follow aircraft's vibrations. The seat can induce controlled vibrations in its parts separately, massaging the back and all of the body in flight.
If linked to the avionics, L4 will automatically determine when the pilot is in combat situation. With this function, as soon as the pilot starts to operate the controls, vibration suppression is deactivated, so his hands move together with the cockpit.
Additional equipment
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Fig.6. A pilot in a g-suit and a helmet, in the legendary K-36 seat.
The seat itself is a very important component, but due to its innovative designs not all of its features can be utilized by standard flight suits and helmets. Therefore, some special equipment is offered, usable only with Laertes IV suit, but offering significant advantages.
AMS-4 Flight Suit
One of the most crucial pieces is the Symmetriad AMS-4 Acceleration Management Suit, or, simply speaking, g-suit.
Normally, a g-suit works by compressing the pilot's legs to restrict blood flow inside them, and allow for greater blood flow into the head, under high positive g manoeuvres. Thanks to it, if an average human loses vision at 4g and quickly passes out at 5g, a pilot wearing a g-suit and trained in its use can sustain 6g without loss of vision and stay conscious at 7g and sometimes slightly above.
There are some downsides to this, however. In particular, a standard constant-pressure suit is a problem at negative G-forces, since it only facilitates excess blood pressure in the brain, a dangerous and potentially lethal condition.
Generally, the downsides are outweighed by the advantages, but they are not inavoidable. Introduction of the Laertes IV seat allowed to make some changes in g-suit operation, due to its extended ergonomics and control capabilities.
AMS-4, designed specifically for the L4, builds upon that. It is a full-body flight suit, worn over only an undergarment overall. Together with moving all control valves to the seat, this lightens the suit significantly, and improves the ergonomics. The suit is constructed of strong and fireproof aramide fibre.
Under g-forces, the suit utilizes dynamic pneumatic pressure control over the entire body, rather than static as usual. Pumping action, synchronous to the heartbeat, is applied to the limbs rather than simple compression, to keep the blood still flowing, increasing the time that can be spent at high acceleration, and avoiding health risks. Additionally, together with the L4 control unit, monitoring the pilot's breath rate, AMS-4 and the seat's backrest vibration control assist pilot breathing at high accelerations.
At negative g-force, on the contrary, the suit below the neck can be slightly depressurized, causing the blood to flow to the lower body under pressure. By itself, this is no good, but while human limbs and torso only experience minor bruising after blood overpressure, similar condition inside the head causes redouts and potentially brain insult. Thus, the suit to the greatest extent prevents blood from rushing to the wearer's head, keeping it in the lower parts of body. All of this is synchronized with seat's position control, changing body position such as blood flow is no longer oriented towards the head, so the pressure can be released sooner.
The suit is completely ventilated and air conditioned, provided the aircraft contains appropriate systems. AMS-4 is usually not completely airtight, to improve ventilation, but can be sealed with two hermetical zipper seals.
Some other features of the suit serve to improve resistance to lateral shocks during unstable flight and ejection. The joints of the suit are immersed in dilatant fluid, which stiffens them under undue shocks, while providing no resistance to humanly possible movements. This serves to prevent neck and joints injuries.
One last feature is exploited during ejection. The tubes inside the suit are pressurized over the entire body, inflating and serving as a protection against the underpressure at high altitude.
If the pilot ends up in the water, the suit lands already inflated, further minimizing the risk of sinking.
AHG-1 Helmet
Another optional piece of equipment is the Symmetriad AHG-1 helmet.
First, to reduce the weight of empty structure, the helmet's shell is built of NSMC-developed carbon nanotube reinforced polymer and metal matrix composite materials. Underneath, a lightweight composite serves for shock absorption.
This helmet, being developed in 2008, is also equipped with the latest avionics systems, including a full projected helmet-mounted stereo display, active noise cancellation, and filtered microphone to improve the work of voice control systems.
But the most noticeable change concerns the air connection. The AHG helmet doesn't have the familiar look of an elephant's head, since it doesn't need to connect to a distant air supply. Instead, the helmet is connected by a much shorter tube to the headrest, which on Laertes IV moves almost freely, through which it follows to the seat's air control system, which in its turn is connected to aircraft's facilities.
This offers three major advantages. First of all, the helmet is lighter, and supported by the headrest, so the pilot can withstand higher g-forces. Second, the air pressure is closely controlled, so the seat effectively breathes for the pilot when he has difficulties doing so on his own, assisting the lungs and controlling oxygen content. Third, in ejection the pilot is continuously supplied with an air mixture, so he can safely eject from high altitudes, and, in case of a water landing or out-of-water ejection, isn't in danger of suffocation. The seat's air management system also includes full NBC protection, for when the worst comes to worst.
Specifications
http://www.freewebs.com/vault_10/16F.gif (http://www.martin-baker.com/getdoc/a04cd081-64ce-48b7-bb06-bcfab87c7c03/Mk-F16F---Rafale.aspx)
Fig.6. Key components of a modern ejection seat.
Seat weight
** Empty, minimal version: 95 kg
** Empty, with standard features: 110 kg
** With standard features, full rescue and survival equipment: 160 kg
** Standard throw weight: 240 kg (seat, equipment, pilot, gear)
** Maximum throw weight: 300 kg
** Baseplate, firing cylinders and mountings: 30 kg
** Total system weight: 140 ... 200 kg
Dimensions
** Length, compacted: 85 cm
** Length, maximum recline, extension and legroom: 200 cm
*** Not necessary to provide, but pilot height or recline might be limited
** Height: 120 cm compacted, 200 cm maximum
** Width: 90 cm minimum, 110 cm maximum
Pilot requirements
** Minimum pilot weight: 20 kg
** Maximum pilot weight (with gear): 140 kg
** Minimum pilot height: 130 cm
** Maximum pilot height: 220 cm
** Seat use training time: 75 hours on land plus 15 hours in flight
Ejection conditions
** Altitude: -50m...60,000 m
*** Negative altitude presumes underwater ejection, positive is limited by seat's air supply to pressurize the helmet, and can be extended by special gear.
** Airspeed, at sea level: 0...520m/s (Mach 1.5)
** Maximum airspeed, absolute: 1900m/s at 30,000m (Mach 6)
*** Absolute airspeed is limited by the heat produced by atmospheric reentry from Mach 5 and above at extreme altitude.
** Maximum airspeed, medium altitude: 1050KEAS, or 900m/s at 10,000m (Mach 3.0)
*** These numbers include reserve; aircraft actually rated for these speeds should install the high-speed modification.
Ergonomics features
** Minimum recline: 10 degrees
** Maximum recline: 60 degrees
** G-feedback effective range: -4g...+11g
*** This is not the operational range for the pilot or the seat, but just the range where the G-feedback is still effective.
** Ejection g-force, typical: 8g
** Ejection g-force, maximum: 14g (only in manual override)
** G-force onset rate, normal: 400g/second
Cost and modifications
Minimal version:
The minimal version does not include autonomous flight monitoring, automatic terrain navigation, motorized seat adjustment, vibration suppression, and G-feedback.
** Cost: $300,000
Standard package:
All features described above are included.
** Cost: $500,000
Secondary seats:
In aircraft with more than 1 crew member, some of the control avionics don't have to be duplicated, provided all the seats are linked together. All standard features are still included in secondary seats, at a reduced cost.
** Cost: $400,000
Additional equipment:
** AMS-4 g-suit package: $250,000
---- Of these, air management and health monitoring system - $150,000
---- 5 suits (due to limited lifetime) - $100,000
** Additional AMG-4 g-suits: $20,000 each
** AHG pilot helmet, basic systems only: $100,000
** AHG pilot helmet, including all in-built avionics and associated software: $150,000
Special offers:
** Complete package, per single-seater aircraft: $900,000
** Complete package, additional seats: $750,000
The complete package includes a full-feature Laertes IV ejector seat, the AMS-4 suit package, the AHG pilot helmet with all avionics, installation of all equipment, all associated rescue equipment, related software, and unlimited access to LightCom satellite network for the aircraft in question.
It saves $100,000 per seat, compared to separate purchase of all components.
Domestic production rights are available for $60 billion for the seat alone, $20 billion for the suit or the helmet, or $90 billion for all together. The cost includes equipping factories fitted with Symmetriad-approved machinery, to ensure that high product quality is maintained.
Installation and Distribution
Laertes IV seat can be both integrated as a part of a new aircraft, and installed into most of the modern aircraft.
In case of aircraft designed with L4 in mind, it's desirable to provide a slightly longer cockpit to allow for seat recline. Almost all modern aircraft still may use the seat, but in case of smaller cockpits the maximum recline would usually be restricted to 45-50 degrees, and pilot height to 190-200cm.
The L4 seat is best suited for all types of fighters, supersonic bombers, reconnaissance planes, helicopters, and other high-performance aircraft. Installation on other aircraft is also possible, usually with minor modification. Additionally, trainer aircraft, due to their higher ejection rate, benefit more from this seat, not injuring the pilot, though a minimal package is sufficient for trainers.
All of the advanced features can work independently, but benefit greatly from a connection to the aircraft's avionics.
Customers can order professional installation at $50,000 per seat, including aircraft check-up, all sensors installation, required modification, and flight testing, or can perform it on their own. The installation is free for allies and partners.
If professionally installed, or used as a part of a new aircraft, the seat is guaranteed for at least 98% rate of successful ejection and landing, with a compensation in case of failure.
The Symmetriad doesn't place restrictions on sale of life-saving equipment such as ejector seats; all nations and companies may order them.