| APAGear II Archives | Volume 3, Number 1 | February, 2001 |
In 61st century the advancements in gas turbine technology and especially in neural computing needed in control systems has enabled Earth forces finally field air cushion vehicles that are known in commonly parlance as hovertanks. They have replaced wheeled and tracked vehicles in fighting units first in Human Concordat and later in NEC and CEF.
Hovertanks are logical follow-up of tracked tanks used in Earth for four millennia. Tanks have survived all that time because they have always embraced concept of highly mobile platform capable of carrying heavy weaponry that is well protected from threats of battlefield. Despite advances in technology this concept is still as valid as it has always been and now hovertanks fill the armies of Earth.
Hovertank construction is based on idea of flying on nap-of-the-earth within ground effect height. This phenomena happens when downwash created by air is fanned under hovertank and this creates a pressure buildup that will increase lift and reduce necessary power requirements compared to free hover above ground effect height.
Unfortunately the phenomena known as recirculation might negate ground effect or even increase the necessary lift (and power). Recirculation happens when machine is hovering within ground effect height over rough mobile surfaces like long grass or near vertical obstacles such as walls or the edge of wood. For quite long time only method to void problem of recirculation could be overcome only with bigger engine. This made system very unpractical because the performance was weaker than with comparable helicopters.
Hovertank technology did not really came into age until Human Concordat times when advances in gas turbines and lift fans technology made it practical. Still the system remained unpractical until neural networks and genetic algorithms were used in controlling the airflow of the system and negating most effects of recirculation. When power requirement of a hovertank hovering on its ground effect became at first similar and finally even better to those of a helicopter, it was adopted as extremely mobile universal ground vehicle capable of moving in all kinds of terrain.
The ground effect only affects close to the ground. Hover vehicle body does not provide lift and therefor its engines must generate all lift necessary to keep hover system flying in the air. In practice these power requirements are so huge that genuine flying is virtually impossible. Actual available power depends heavily on vehicle purpose. Most civilian systems have only minute amount of extra power allowing them jump over small man-sized obstacles. Most security and some older military models have enough power to actually lift vehicle from the ground, although just for few seconds allowing system to jump some 50 to 100 meters.
Modern military platforms used by CEF use enough power to actually lift whole body to stay in air and fly there. However, since hover vehicle body is not aerodynamic, and their existing control systems are not configured to serious flying, their performance in air is typically very limited. The fuel consumption is also several times higher than when flying using ground effect. High winds ground contours, temperature and other atmospheric phenomena cause also problems due poor stability of platform. Hovertank flying patterns are roughly similar to hoppers, although they have much higher fuel consumption and considerably worse handling. This makes flying during stressful environment, such as combat, extremely hazardous.
Although the maximum flight height is very poor compared to real helicopters and aircraft military did not consider it as a serious problem. Helicopters fly almost exclusively in NOE heights in battlefield to avoid enemy fire and hovertanks would themselves fly on ground like other ground vehicles. Hovertanks could also do surprise pop-up attacks like hoppers and helicopters and their ground speed was superior to tracked tanks. Flight ability was seen as a bonus in rapid marching from one base to another, not a viable combat maneuver. Hover vehicles have usually very poor aerodynamics because they are designed to fulfill functions of ground vehicles and thus they are slower than helicopters and most hoppers. However, the speed advantage helicopters had over hovertanks was not very high compared to superiority over tracked vehicles both hovertanks and flying systems had.
Final deciding factor was protection. Helicopters cannot be well armored because their rotor blades and complex gearbox systems are extremely vulnerable to enemy fire. Fans of hovertanks no different from other gas turbines and are very vulnerable to foreign objects (especially long, thin objects can easily destroy engine blades). However, hovertank fans could have filters (like helicopters) and be armored (within reason) to withstand enemy fire and environmental effects. Furthermore, hovertanks could carry turret and armor that was similar to those of wheeled and tracked combat vehicles.
Military field tests showed they had a new weapon that would in their minds make both helicopters and ground vehicles obsolete. It had armor of a ground vehicle, with a speed and responsiveness of a helicopter. It could fight like a tank. It could then fly over long stretches of terrain, get refueled on the move and land troops right on target if necessary. However, all these military capabilities did not came without penalties as well. Combining aircraft equipment tolerances, weight requirements and technical complexity to ruggedness requirements of tanks was nothing short of difficult. Production costs were a daylight robbery. Logistical requirements were no less demanding. A large pool of technically highly qualified technicians were necessary to keep up highly complex hovertank force fighting capable. Diagnostics and workshop systems had to be equally high caliber. Spare parts were slow and difficult to produce and finally fuel consumption was outrageous. Then there was a question of actually using it. Highly complicated and capable combat system required equally long and arduous training to fully learn and understand all its strengths and weaknesses. In a way, the ground forces basic combat vehicle had turned into as expensive and complex weapon system as a jet fighter.
Personnel problem was first solved. Human Concordat had invented earlier GRELs as giant combat policemen. They were bred to be massive and awe inspiring fighting machines capable of intimidating rioters into submission with sheer size. Now these huge men were issued to other branches that were suffering from poor morale and desertion. Complicated hover tanks seemed just suitable next specialization for these fighters capable of learning perfectly use and maintenance of even most complicated weapon systems of military. Despite all their efforts HC could not produce fully working GRELs in time. Work on GRELs and their use were still very much sporadic, poorly managed and incapable of coming out with high capability genetically engineered super soldiers that designers had originally wanted for. Their work did, however, provide basis on what future would come out as GRELs, for battlefields of World War Three, when NEC would start its own super soldier program.
Technological complexity problem needed different approach. Designers decided to cut down spare parts problems by fielding a complete vehicle family. Each separate variant model would be built from one base system. Thus large number of parts (and spares) would be common. Not only would it simplify spare part problem but it would help curbing production costs too. Parts and sub-assemblies could be ordered and manufactured in higher lots. Human Concordat managed to solve many technical problems fairly well. Wide variety of experimental and then production models were produced and taken into service during chaotic last hundred or so years.
During Human Concordat era hovertanks were still relatively new development. First models were noisy, unreliable and lightweight systems that were more of curiosity than war winners. Weaponry was more akin to light armored vehicles or combat helicopters and their armor was lightweight and at times even weaker than equivalent separate systems. However, as time went on, the experience cumulated. In the end of HC era hovertanks were fairly modern in sense that their design concepts and tactics had reached maturity. After fielding hundreds of different models the last dozen or so were finally capable war winners that bolstered arsenals of rapidly dissipating Concordat and were eagerly sought after by new small city-states emerging from its shadows.
Following collapse of HC NEC took over the cutting edge of hovertank design. Hovertanks role as capable weapon platform was already well defined as well as experience in its use in battlefield. However, Third World War had started almost immediately after official collapse of Human Concordat and whole Earth system seemed to have changed into a giant battlefield. Furthermore, now there were several countries with hovertank production and design facilities all striving to churn out better weapon systems. NEC found itself beleaguered from the start by several aggressive neighbors and started massive weapon research programs of their own. One example of such programs was development of GRELs as capable battlefield weapons. Another was adopting hovertanks as mainstay of mobile forces of their new military, NECAF. They identified two main goals now as improving hovertanks themselves and producing them in large enough numbers to replace horrendous casualties.
Weapon designers came into conclusion that both requirements could be filled up by making whole hovertank vehicle family more modular. They would build vehicle into a common weapon platform where armor, weaponry and command system modules could be installed according to campaign, battle or even mission. Each hovertank would also have several standardized bodies that could be chosen on assembly line to suit expected task of mission. For example tank hunters would have low bodies so they would show as small target as possible while command versions would have high bodies to allow several officers work inside vehicle. Modular construction made also the repairs in battlefield much faster as entire systems could be easily and rapidly changed. While this did not make hovertanks technically any simpler system, it did mean damaged hovertanks could be brought on-line much faster than before. Actual repairs of broken parts were as difficult and time consuming as before but they could be done in good time with well-equipped workshops safely in rear. While this line of thought relied on large number of expensive spare parts and sub-assemblies kept warehoused close to front it gave NECAF more edge by allowing them return damaged vehicles to frontline faster than their enemies. Modules were mission specific and huge variety was available as new modules were added as technology advanced.
The design factors of hovertank itself still follow the four basic tenets that have been used with armored fighting vehicles for over four millennia. These tenets are mobility, firepower, protection and command.
Mobility of hovertank makes it possible to go into battle by itself and move quickly across dangerous battlefield with the fighting. Mobility also helps hovertank to avoid enemy fire. Typical modern hovertank has top speed of around 200 kilometers per hour while it flies at 2 to 5 meters over the ground.
Heart of hovertank is two spool-augmented turbofans. The hovertank engines have much higher bypass ratio and higher pressure ratio (and better fuel economy) than multi mach capable heavy jet fighter engines. This is achieved by bypassing air from the low-pressure compressor, or fan, past the rest of the engine to rejoin the hot core flow in the exhaust. While this engine design makes it inefficient in flight speeds excess of mach 1, it is ideal to fuel economy at subsonic speeds. The fuel economy and power are further improved by increasing the engine pressure ratio. Engine efficiency is further enhanced with wide chord blade design. This makes possible for engine to achieve high pressure with fewer stages of blades. Engine is also simpler and cheaper and its structure is tougher and system is able to withstand more battle damage.
Hovertank needs always more thrust, better fuel economy and lighter engine weight. These inevitably lead into greater maximum temperatures at inlet of compressor driving engine. Rising heat compromises reliability and engine life, which are countered by turbine blade design. Material technology has allowed designers to use ceramics in both blades and bearings in hot parts of engine. This allows designers to drop out lubricating traditional metal bearings and instead concentrate on using dynamic airflow to prevent fixed and moving parts ever coming into control. This has allowed engine heat to increase so high that combustion chamber design have to follow it as well. Out-flowing air has to have equal temperature everywhere despite fantastic heat release. Cool spots are fuel inefficient and hot spots could cause engine damage. This is achieved with compressed air controlling with originally by-passed air. Whole process is automatically computer controlled.
Hovertanks use primary and secondary vectored thrust fans. Primary system is built into vehicle body and it is used to keep hovertank flying. Most of the power of two engines is reserved for that. However, engines have considerable excess power reserves in case hovertank must areas where ground effect might not be present. This reserve makes it possible for hovertank to actually hover high above ground but its poor aerodynamic shape would make it vulnerable to crosswinds and possibly accident. This all requires plenty of air to intakes and thrust reserves.
Problem is that hovertank operates with relatively small airflow ejected with high energy. To reduce hovering fuel burn, as well as deal with reingestion problems, it is necessary to increase total airflow, and thus designers decided to opt for a tandem fan design. There are both intakes and release fans throughout the engine length between two fan stages. Some of the air from release fans is then released through a row of nozzles in the lift ducts crisscrossing hovertank bottom. Extra fuel can be inserted to these fans giving hovertank extra lift necessary to overcome obstacles. At the same extra air is being inserted as well from intakes as well. This makes engine design somewhat cumbersome, and very long, compared to modern jet engines but it also reduces considerably fuel consumption.
Engines considerable power reserves are usually used to jump over obstacles. Hovertank typically flies for few seconds and could go over gullies or houses of hundreds of meters long. Jump capability is very useful in combat too as hovertank can do similar pop-up attacks as helicopters or for example rise for a few seconds above ground effect level to scout area with its sensors. Hovertanks ability to jump has been found to be very useful in hilly terrain and in battles amongst huge sand dunes of Western Desert. There CEF hovertank units could quite often jump across ridges to surprise unsuspecting enemies, then fire devastating volley and disappear back behind dunes in few seconds to move rapidly to next suitable position.
Secondary vectored thrust fans are smaller and usually equipped with afterburners. These fans use excess power to give hovertanks capability to make rapid maneuvering while slow maneuvers are done with nozzles of primary systems. This capability is supplemented with 3-D vectoring found in some primary vectored thrust nozzles used to control airflow even further. While this box-like nozzle is heavier than structurally better circular type it enables hovertank to be pointed rapidly at wanted direction. This is highly important in surprise situations, where crew needs a little bit more extra maneuverability to avoid incoming missiles.
Hovertank is thus very agile beast (within a reason). High mass and high speed make hovertank (or any vehicle for that matter) clumsy at top speed but its powerful maneuvering jets made it quite nimble compared to tracked tanks in combat. Jet engines can increase their propulsion very quickly and their peak power outputs are high. This brute force approach is necessary as hovertank design and layout is not optimal for aerial maneuvers.
Excess power is therefor usually used to jump over obstacles but there are several risks as well. High flyweight means huge mass to control. As long as hovertank is flying in ground effect primary system power reserves can be used to help in maneuvering. When all primary power is used to jump the tank becomes very big and very clumsy rock flying directly forwards. The problem goes only worse if weather is bad. Furthermore there is no way of telling what it is going to land at the end of the jump, especially if one has to jump without seeing exactly where to land. This often causes accidents and therefor jumping long distances is allowed only in extreme emergency (usually in combat).
Hovertanks are above of all meant for ground combat, which requires heavy armor and plenty of weaponry. These requirements increase total weight, which is somewhat lighter than heavy tracked main battle tanks. Hovertank engine design is a compromise as well. Cumbersome tandem fan engines and airflow ducts make it longer and ultimately larger than ground vehicle of similar armor and weaponry. This makes hovertank larger target as well. A penetrating hit to one of side mounted jet engines typically cripples hovertank. However, engines themselves can be armored to roughly similar degree to modern main battle tanks as engines are kept inside armored hull.
Fans on the other hand are lightly armored compared to rest of the vehicle because they need to move at all times. Fan protection remains a basic problem with all hovertank designs as a lucky hit may destroy fan with potentially catastrophic consequences. At high speeds hit to critical fan might cause hovertank to touch ground and subsequently crash. Designers have constructed some redundancy to system with neural network controls redistributing the workload if parts of system are not operational. However, most total losses to hovertanks still happen when a fan doing critical maneuvering thrust is hit during high-speed movement. CEF has tried to invent tactics that would minimize these risks but being front-line weapon systems hovertanks are always used in situations where enemy fire is always present and lethal.
Furthermore, the downward flow of air coming from fans is very hot. Thus it is forbidden to stand or work directly below hover tank without Individual Protection Suit, IPS. This is a problem when moving in military bases or among friendly civilian population in peacetime. Hot air can cause fires in hot dry climates or even burns to passers-by. In these situations hovertanks may use flexible skirt that enables them to direct some air directly under them and move like conventional hovercrafts. These removable skirts are used only when absolutely necessary because skirt-using hovertanks are extremely clumsy due their huge size and inability to fully use maneuvering jets. In these situations CEF regulations stress wearing seat belts, observing traffic regulations, calm mind, cautious defensive driving and taking others into consideration as hovertank pilots are not alone on the road.
Perhaps most intriguing capability of hovertanks is their ability to be dropped from both air and space. Airdrops can be done without any preparations as fans provide gentle and consistent deceleration. Space drops require protective cocoon that is ejected at suitable height. After that actual landing follows same procedures as air drops. From military standpoint this enables CEF to drop a combat ready hovertank unit almost anywhere in the enemy territory without having to use airfields. Because most landings are airdrops, CEF hovertank units have tremendous strategic mobility at very short notice. There are some risks as well. Any engine failure leads to certain death. Poor air maneuvering means poor weather causes plenty of troubles and hovertanks are practically sitting ducks to enemy air defenses. Still, they are considered better protected than parachuting troops and equipment that is even more vulnerable. Therefor actual drops are preplanned carefully with air superiority and plenty of covering from air and orbit if necessary.
Major weakness of hovertanks remains to be the outrageous fuel consumption. Despite all engine technology improvements jumping above ground effect height still burns fuel in huge quantities. This movement is, however, equally important for rapid marches. CEF has recognized that fuel consumption as Achilles heel of hovertank equipped units. Hovertanks have therefor been equipped with refueling booms for refueling on the move. There are also cheap extra fuel tanks that can be attached to hovertanks for longer marches. Carrying these tanks is hazardous in combat as a hit to fuel tank could detonate whole vehicle. Therefor these tanks can be jettisoned when fighting starts. Furthermore, CEF fields highly mobile logistical units with rapid refueling and rearming assets to support hovertank equipped units.
Fuel considerations create unique tactical considerations to hovertank units. Their endurance in range is similar to many ground vehicles but this endurance drops rapidly in flight and higher speeds. Keeping engines in idle while waiting for immediate take-off order uses plenty of fuel as well. Shutting down engines saves fuel but then engine start-up and system checks necessary for movement can take several minutes. This is too long to avoid enemy artillery if position has been found out. On the other hand, their high speed enables hovertanks to quickly fly to battlefield, fight highly intensive short engagement and rapidly return back to rearm and refuel. If logistics support is kept close to front the turnaround trip could be just ten minutes. Hovertanks are in the meanwhile kept in well camouflaged positions ready to move if necessary to mount highly violent counterattacks and strikes on enemy units while moving away to logistics point and then dispersing. In practice this seldom succeeds and hovertanks will usually stay on battlefield supporting infantry. In these circumstances fuel and munitions are brought to their positions.
Hovertanks twin jet engines nominally use jet fuels like kerosene as fuel. Actually CEF has chosen liquid hydrogen and oxygen as base fuels. Hydrogen is extremely flammable and dangerous to handle but it is extremely easy to create from water with electricity. Water is plentiful in habitable planets where there is also oxygen hovertanks need to fly. This is seen as best choice for obtaining fuel locally. However, hovertanks jet engines are no different from any gas turbine that can burn just about any liquid combustible fuel. Turbines can use even alcohol but all these fuels reduce engine effectiveness and increase wear and tear and may even force to complete engine overhaul. Therefor these improper fuels are used only in extreme emergencies.
CEF has had experiments of various exotic fuels such as slurries of high-energy materials, such as carbon or boron, suspended in specially formulated hydrocarbon bases. These fuels offer several advantages over regular fuels, such as higher energy concentrations per unit of base weight and as well as higher density. They have been used at first in systems where weight issues are critical such as missiles and various space systems. However, these fuels tend also be highly dangerous to users. They are extremely volatile, hazardous to health and often acidic bringing problems to long term storage, safety and general availability. However, most of these problems are shared by hydrogen too so CEF has been introducing (relatively speaking) cheapest and easiest to handle formulas of such liquids into hovertank use as well. These rare and expensive fuels are originally intended to be extra energy boosters for emergency use. There has also been field-testing of hovertanks changed to run with such exotic fuels only. However, cost of introduction of such fuels throughout CEF is nothing short of staggering.
Firepower enables hover tank to destroy the enemy forces and support friendly forces effectively at all ranges. Hovertanks weaponry must also be easy to use and be capable of reacting against multiple simultaneous targets. In addition, fire must be effective in move and in all environments.
Hovertank is very much like a helicopter as a weapon platform with recoil having major impact on all weapon system design. Light hovertank platform combined with high recoil forces from heavy weaponry cause typically reconciliation problems. Therefor flight-control has automatic bias to cancel out recoil forces. Military hovertanks have typically super-accurate air-data system giving readouts of airflow angles and speeds on hovering as well as on hear-hovering. Fire-control system takes into consideration hovertank position, altitude, and pitch and tilt as well as recoil forces to automatically cancel out recoil upon firing.
Anyway, hovertank designers prefer weapons where recoil does not offer a major problem. Such weapons are usually various low caliber automatic cannons, rocket launchers and missiles as well as high-energy weapons. Weapons with high recoils such as conventional large-caliber cannons are usually avoided. These kinds of weapons cannot be easily readjusted against. However, such weapons have their place, especially when there is no requirement for firing on the move. For example, conventional artillery can be fired from hovertank platform that is stationary on ground (and soil takes recoil) but not when it is hovering or moving. However, this requirement is not vital as field artillery typically fires from stationary location its round and then moves rapidly to avoid enemy counter-battery fire. Hovertank offers excellent mobility necessary for such platform to change shooting location quickly.
Human Concordat had already had directed energy weapons such as lasers, particle weapons and microwave projectors in widespread service. These weapons form standard hovertank weaponry for most close and medium range fighting. Laser (Light Amplification by Stimulated Emission of Radiation) is based on stimulated radiation principle postulated first by Albert Einstein in 1917 although first working laser was constructed in 1960. In practice laser works by warming a matter which moves additional energy to individual atoms and molecules. This additional energy cause electrons move from lowers energy levels into much higher. After a few Pico seconds electrons return to lower energy levels and release a single energy kvant. This released energy kvant is called photon. In stimulated emission the electrons do not return to lower energy levels randomly but return is caused by another kvant hitting atom. When kvant released with right energy hits to atom with additional energy, it does no more absorb the kvant. Instead atom moves to lower energy level releasing a kvant with same energy, phase and direction as kvant that hit the atom. By using this technique through matter that has been subject to laser emission, the number of identical kvants comes very high. When number of kvants is very high, they can cause damage to target.
High-energy lasers used by military affect in target with severe effects. For one they weaken the structure when temperature in hit location increases. Secondly the rapidly increasing temperature causes in target a shock wave that damages especially well structures with poor heat conductivity like glass and plastic. In addition the vaporization of matter in hit location causes X-ray radiation with could cause severe malfunctions in electronic systems. Finally even a beam with low energy can destroy visionics systems and even cause blindness to unprotected personnel.
Various scientists first presented the principles of particle accelerators in early 20th century and first workable particle accelerator was started in 1952. It is based on electrical properties of atomic particles such as neutrons, electrons and protons. If electrical current moves through vacuum tube electrons move from cathode to anode. Heating the cathode with electrical current may increase the release of electrons. If tube has some gas in it, the electrons ionize the atoms of gas forcing them to release new electrons. Electrical field in tube starts to also move these newly ionized electrons causing further ionization. This leads to electrical discharge in vacuum tube. If cathode has channels (holes) the system emits so called channel radiation. This radiation is made of particles. What particle is released depends on what gas was used in vacuum tube. For example with hydrogen gas the channel radiation is made of protons. Particles can then be guided with magnetic fields and accelerated with electrical fields to relativistic speeds and then released towards target. With enough high-speed particles, such a beam can cause damage to target as well.
The characteristics of particle accelerators are roughly same as comparable laser systems. They do have lesser range in atmosphere due beam attenuation and atmospheric turbulence causing ionization of beam. On the other hand they emit much more X-ray radiation and thus have much higher tendency to disrupt electronic systems. This is extremely useful capability in modern battlefield, where practically all vehicles and weapons systems are filled with electronics.
CEF hovertanks used weapon concept commonly known as a particle accelerator but officially they were called Directed Energy Combination Weapons (DECW). They were based on combining lasers and particle accelerators to provide better performance. At first a laser would be fired to ionize the atmosphere. This would increase range of particle accelerator system that would be fired nanoseconds later through same beam. Furthermore, DECW was tunable to match individual atmospheric conditions of each planet so it would always fire through suitable "window" in given atmospheric conditions to ensure peak performance. Particle accelerator also could be switched off and all the energy released through laser system if necessary. Theoretically it would have turned DECW into a long-range military laser system. This capability was, however, seldom used as rockets and missiles were intended to provide long-range firepower.
DECW was a beam weapon. Therefor it did not need to take lead when firing at targets in ground battle ensuring high accuracy when firing moving targets. There was no detectable recoil, which made it perfect weapon for hovertank use. In addition the combination system made single weapon capable of firing particle beam at short-range targets and laser beam to long-range targets. This made it theoretically possible to switch to weapon with best performance at any given range. However, there were problems as well. DECW was complicated electronic weapon system and thus extremely expensive and difficult to repair in field conditions. Despite all the tuning options atmospheric and battlefield conditions such as rain and fog and dust reduced its effectiveness in long ranges.
DECW's power requirements were extremely high despite use of technically advanced superconducting magnets, capacitors and coils used. Actually highly destructive DECWs were not possible until materials that were superconducting in high temperatures were invented. Then the bulky cooling system could be done with and compared to old systems for example capacitors had several orders of magnitude higher capacity. In addition superconducting cables and coils no (in practice however a little) waste heat when electric current is lead through them.
Hovertanks DECW weapons were recharged between shots from huge superconducting capacitor banks. They could be recharged from any electric source but CEF usually changed entire capacitor bank during rearming from empty to full to avoid spending long time on recharging. The empty capacitors were then recharged in good time in logistics points for next swap. Most logistics vehicles carried field generators allowing directly recharge capacitors if necessary as well. In case of emergency hovertanks own engines could be used to generate electricity for recharging DECW capacitor banks. It was discouraged due fuel consumption.
CEF troopers were not entirely happy with DECW. It could only fire at line of sight targets and had no ability to fire special munitions. DECW could also be fooled with countermeasures like aerosols and their effectiveness (damage inflicted) was fell as range increased. Long-range fire requirements were fulfilled with missiles because hovertank recoil compensation constraints force designers only choose low recoil weapons. Missiles could carry all kinds of warheads, fly far beyond effective beam weapon ranges and hit targets without line of sight.
Light, Medium or Heavy Vehicle Missile System (LVMS, MVMS and HVMS respectively) were installed to hovertanks moving in battlefield. Numbers and size varied according to class and mission. For example anti-tank vehicles could carry massive battery of HVMS while workshop vehicles of logistics might be armed with just few (or none) LVMS missiles for self-defense. Common set of missile pods were introduced allowing commanders to tailor mixture of various missile types and warheads for each mission. All CEF hovertanks used vertical launch system, VLS. It was simply a row of suitably sized launch silos fitted into a common missile box. This box was then inserted into a payload slot constructed into free space within hovertank hull. Hermetically sealed containers with missiles were just inserted to these standardized payload slots. Missile box bottom was connected to movement system exhaust piping allowing exhaust gases of missile launch to be ejected under hover tank to reduce infrared signature of launch. Advantage of VLS was that it offered 360-degree launch capability without heavy and potentially unreliable mechanical turrets or launchers. Because VLS fires the missile directly upwards hover tank crews tilted their vehicle 4 degrees left so that the malfunctioning missile would not drop on top of them. Misfiring missiles and their missile boxes containers were simply ejected from tank via floor exhaust gas tubes. It was truly an idiot proof launch system.
Once fired missile would then turn towards target and start flying and attacking in selected height and attack profile. These could be chosen according to enemy defenses. For example low flying missiles were difficult to detect from ground clutter but highflying missiles had much smaller chances of accidentally hitting some tree branch before attack. Attack profile was important because of variable target armor and defense system configurations in use. Diving missiles could hit targets usually weak roof while pop-up missiles would fly low to avoid detection by staying in ground clutter and then suddenly ascend and then descent in front of tank to provide more difficult targets for active defensive systems. Missile could also just fly directly against target if so selected.
VLS had only one weakness. This configuration forces missile to fly a split second upwards and then stabilize its flight towards wanted direction. This creates a dead zone close to tank where it cannot hit because missile is still not effectively guided. At selected moment missile ejects its booster engine and missiles starts following commands flying towards target. This dead zone extends to close range around hovertank but CEF does not keep it a crippling problem because DECW is expected to be able to deal with close range targets. However, it is a problem in terrain with plenty of cover, where several enemies could surprise hovertank simultaneously. CEF therefor stresses tactics that hovertanks should avoid moving alone so they could rely on each other to provide additional missile fire if necessary.
VLS fire-control system capability varied according to hovertank configuration. At minimum it allowed firing missiles to a target provided by BISN, computer AI or human commander orders. In antitank units computer AI systems could command automatically battles of entire demibrigades. They could command missile fire of entire units by ordering any combination or any types of missiles from one to all of vehicle in orderly volleys to any number of targets. This was necessary as amount of sheer missiles in a single volley could be increased so high it would overwhelm defense systems of enemy hovertanks. If enemies had no defense systems the shock effect of huge missile volley hitting multiple targets and destroying them simultaneously would demoralize enemy unit offering CEF a good chance to turn entire enemy attack into a nightmare.
DECWs were very good in destroying hard point targets such as vehicles and installations but they were not terribly good against area targets like infantry. CEF envisaged soft target destruction as a two-tier system. First there should be an offensive weapon system for suppressing enemy infantry so they could not use their own weapons against hovertanks. Second was self-defense system to protect against enemy infantry trying to destroy it in close assault, where other weapon systems or hovertank could not be used.
Most common infantry suppression systems in hovertank were automatic grenade launchers and aerosol flamers. Grenade launchers are simply enlarged machineguns that fire cannon sized grenades on direct fire or indirect fire to point targets or large area. Since these launchers can fire a large family of grenades the ammunition load can be tailored to meet variety of threats and environments. For example fleshettes can be used against soft targets, while shaped charge warheads with fragmenting sleeves were intended against heavier armored infantry units. Incendiaries were always popular because they could be used for burning undergrowth and to flush infantry out from their hideouts. Various gas munitions could be used for that as well. Grenade launchers could also be fired against targets without line of sight. Sometimes CEF used also true machineguns and automatic cannons as well.
Aerosol flamer is a very different system. It fires liquid that at first evaporates into aerosol gas. A high-speed pump then ejects this fuel aerosol towards target. Employing inert gas stream to remove premature ignition reduces concentration of aerosol next to hovertank. Volatile liquid hydrocarbons (like butane) are most amenable fuels. It is easy to suspend them in air as aerosol cloud of required dilution. Aerosol flamers have similar ranges to vehicle flame-throwers they were originally constructed to replace. Because the cloud is heavier than air it flows to tunnels, trenches and holes that infantry uses as cover. Aerosol flamer covers target with a cloud -which is then ignited- in a split second.
The power advantage of exploding fuel air mix is five times as high as with ordinary explosives. It is a pure blast weapon without fragmentation effect of conventional anti-infantry weaponry. Blast causes internal damage to human body. Effects of shock wave to human body are highly complex but greatest harm arises from the passage of shock wave through gas filled cavities of the body. Pulmonary damage is typical. Lungs are squeezed fiercely as the shock wave decelerates into the thoracic cavity. Bubbles of air may then be forced into blood circulation by collapsing lungs causing brain damage or rapid death that is typical to air embolism. There is often damage to abdominal organs too. Victims often suffocate from combination of bleeding and crushed lungs.
Probability of death is much higher with fuel air weapons than with conventional explosions and in addition infantry body armor does not offer good protection against blast making aerosol flamer very effective anti-infantry weapon. It can also be used against weak structures as relatively small overpressures have great effect on housing. Giant pressure wave explodes minefields as well. CEF uses aerosol flamers for destroying foliage too if hovertank needs to blast its way through the jungle, for example when making a path. This is often necessary because hovertanks cannot push trees down (due lack of real friction on earth to brace themselves) and as such cannot be equipped with bulldozer blades.
Protection is a very large concept and includes not just armor but also other factors like reducing observability, avoiding getting hit and if necessary to reduce the effects of a hit. Modern battlefield is extremely dangerous place filled with anti-tank missiles, infantry anti-tank squads, indirect fire and drones.
The protection of tank starts with careful thinking put to minimizing silhouette (to make target smaller), design (to reduce radar cross section, and increase chances of hit ricocheting) and reduction of observable factors (like sound, heat, magnetic field, exhausts). If these factors fail, Vehicle Protection System (VPS) was designed to protect hovertank and take care all of those threats. It was divided into two fundamental approaches. They were passive and active protection methods.
Armored protection forms the cornerstone of passive approach. Typical hover tank armor uses homogenous ceramics only on body itself. The armor proper is a secret combination of metals, ceramics, fibers and rubber layers sandwiched together. There are various elements such as honeycombed mesh to channel heat dissipation and extremely hard crystals fitted into softer material to help deflect kinetic energy threats. Armor is also modular allowing rapid change of damaged parts, tailoring the armor to match mission and to add new protection technology to match advances on enemy weaponry. This sandwiched compound armor is basis of all other armor and it offers a good protection against both kinetic energy threats and especially Monroe effect based threats.
Next layer of defense is reactive element made of explosive plates. When this plate contacts with ammunition with high energy, it explodes outwards from tank. Each explosive plate has uneven internal lining of metal causing outward jet stream disturbing incoming round. This considerably weakens penetration of incoming ammunition. It is especially effective against Monroe effect based weapons. Each explosive plate is also covered with metal sheet so that it does not explode from just small arms rounds but only from ammunition that can have serious damaging effect on vehicle.
Explosion of reactive armor is no different from any other explosion and it is dangerous to people around hovertank. It also creates a large amount of small particles that could be sucked into engine intakes. Therefor whenever reactive element has explosion, the engine intake filters increase their foreign particle separation standards to avoid explosion sending something to cripple tank that was just saved from penetrating hit. This reactive armor can be defeated with tandem shaped charges or pre-detonating systems that explode reactive armor plates before actual round hits. However, CEF believes that partial protection is better than no protection at all. There are several methods of dealing with these kinds of munitions, such as extra layers of reactive plates and explosive plate shaping and positioning. Furthermore, outer coating of hovertank is usually a rough surfaced non-magnetic mass. It is difficult to make magnetic weapons and thrown antitank grenades to stick to this kind of surface. Additionally rough surface creates more shadows (helping against observation) and reduces slightly signature against radar as well.
Most modern weapons systems have long engagement ranges and must therefor use variety of electromagnetic sensors for achieving target lock-on and guidance. While designers do realize they cannot make system as large as hovertank invisible to these sensors every small bit helps making enemy work more difficult. For example while hovertanks usually use jet turbines for propulsion some reconnaissance versions employ extensively electric systems to mask noise and exhaust fumes. However, in most hovertanks the fooling of enemy sensors and guidance systems is concentrated on outer coating material selection. Sensor sweep areas are usually ultraviolet, entire infrared spectrum as well as microwave areas.
Ultraviolet radiation allows easy detection of equipment in snowy conditions. Usually snow reflects large amount (65-85%) of ultraviolet spectrum radiation while camouflage (white) painted equipment reflects less than 15%. Equipment is thus seen as contrast to ordinary snowy environment. Hovertank imitate snow therefor with camouflaging themselves with real snow and adding special pigments with similar ultraviolet properties than snow for arctic conditions. Because equipment and surrounding environment have similar reflective properties in warm summer, these special pigments are usually employed only in winter camouflage paints.
Infrared spectrum is countered with variety of methods. Special pigments in camouflage paint help in certain (close to visible area) wavelengths. More radical methods are used against thermal infrared systems. Infrared radiation intensity is related to absolute temperature (in Kelvin) times four. This heat intensity must be reduced to avoid recognition and possible target lock-on. Variety of cooling methods, hot system insulation and low emissive surfaces are used.
First, hovertank surface temperature can be lowered. Cooling can be arranged by installing a super absorbing material that is then soaked with liquid (such as water). Material will absorb water (in excess of 200 times its own weight) and release it with slow expiring. This cools down surface of hovertank as well. These materials work especially well in weather conditions when moisture expiring is slow such as in autumns in temperate climates. Second method is to add external cooling in form of surrounding air. Engine exhausts form a large infrared signature that has proven difficult to conceal. Biggest continuous heat source in hovertank is its hot exhaust jets fanned out to allow system float in air. CEF fields various exhaust baffles mixing cooling air to this jet to reduce emitted heat.
Specialized reconnaissance hovertanks put considerably more emphasis on infrared detection avoidance. They usually employ cooling piping within outer surface as well insulating layers around heat intensive equipment like jet turbines). CEF has had good results in reducing signature but it has problems as well. Piping is quite bulky and it makes hovertank structurally weaker. This reduces armor protection that CEF sees vital for front line service.
Various low emissive materials -such as vanadium oxide- are generally used as coating material. It behaves like a normal paint when temperature is below 68 Celsius. When temperature increases it becomes less radiating and works like a metal surface. Vanadium oxide behavior is based on fact that it is semi conductive up to 68 Celsius and above that it is conducting. There are also various materials that have different radiation properties in various wavelengths like beryllium oxide.
These materials are essentially passive in nature but there is also a family of electric conducting polymers that allow hovertank defensive suite to change property of its surface by reflecting incoming emissions on various ways. This allows -at least in theory- hovertank to fool sensors by matching its emissions to those by surrounding nature (based on data fetched with other sensors) or tailoring its reflections to match enemy sensor in use. These active materials -and artificial intelligence systems necessary- are highly expensive and usually used only in reconnaissance vehicles. CEF is studying various other promising materials as well. For example Langmuir-Blodgett surfaces allow electric conducting polymers with anisotropy qualities. However, all properties of these coatings are not fully known. In the end, material research, selection, use and care is essentially searching for best compromise and so far there has been no perfect solution to all problems. Similarly sensors have gotten better and better exploiting loopholes in protection.
Microwave propagation is the final part of electromagnetic spectrum. There are two basic ways to achieve passive protection. First is to use transparent materials that do not radiate such emissions such as composites. Second is to use radar absorbent materials on coating. CEF uses this extensively in rough outer surface coating of hovertanks. The absorbing layer is usually some 15-millimeter thick foam material that is imbued in outermost coating. Another absorbent material technique is dielectric. Usually material has resistive layer at one-fourth distance of metal coating and it can be charged to function at set frequency. Because radar frequencies differ, the number of layers is increased to match what enemy is expected to use. In practice this means using material layers with variable impedance. The outermost layer has usually same impedance as vacuum so that structure would not reflect any radiation but this does not really succeed. Some reconnaissance systems use 'smart' skins where outer layer is made of polymers. This coating allows hovertank to change its electromagnetic qualities to match those of enemy sensor. While these systems have been used mostly in infrared areas there are some systems expanding this to millimeter wave area and beyond. In practice such systems are very expensive and used only in limited number of systems.
Hovertank surface painting is matte (to avoid reflections) camouflage (to reduce visibility) which naturally varies according to battlefield. CEF uses wide variety of camouflage colors to match surroundings. Paint shapes are formed using computer generated paint schemes. Some of these schemes are formed to fool particular weaknesses of expected enemy sensor equipment. Actual results have been mixed. CEF uses typically four-color scheme where two main colors are chosen according to terrain and mixed with two minor colors. For example in evergreen forests the main colors are dark green and black with brown and light green used as minor colors. CEF strives to paint all its equipment with similar camouflage pattern in same area so that its enemies could not identify various units according to individual camouflage patterns. This is marked difference to Terra Novan custom where many regiments use individualized camouflage patterns.
Stationary hovertanks are always camouflaged with camouflage nets that every hovertank carries with. Local foliage is used to improve camouflage if unit is expected to hide there for long time. This camouflage is usually removed when rapid departure is expected or imminent. CEF fears that in such a hurry someone might not clear all foliage enough far away from hovertank causing engine intakes accidentally suck in small tree branches. Decoys and elaborate ruses are used as well to protect actual hovertank hideouts if possible.
Hovertanks must be able to fight in every environment and weather. This is taken into account already in design. It has heater and cooling system to interior to keep vital equipment running at peak performance. For desert operations air intakes have special filters that help keeping the dust away. Similarly materials choices take into account needs of preventing heat enlargement of jamming the mechanical systems in heat and cold. Specialized systems like electrical heating and pure oxygen tanks have also been connected to ensure engine startup in cold. Crews also get extra training to be able to cope with these environmental problems as well.
ABC warfare is constant threat with modern armies and CEF provides all its vehicles with a degree of protection. Coating material protects surfaces from acid gases and hovertank is completely airtight with slight overpressure always kept inside to keep particles away. Actual radiation is protected against with hovertank armor having layer of boron. Hull interior has usually anti-radiation plastics sheets attached as well. These sheets absorb radiation changing their composition to a limit. Sheets are then changed in logistics points when necessary. Variety of warning systems informs use of ABC weapons. Staying outside is dangerous in ABC warfare situation. Therefor CEF has taken several steps to allow crew stay inside as long as possible. Main reason for crew to leave hovertank is for receiving orders and for rearming and refueling their vehicle. Commands can be relayed via BISN and rearming and refueling can be done with remotely controlled arm. This arm can also do heavy work like reloading ammunition or capacitor banks onboard. There are a variety of specialized tools, such as welder or shovel, available for it as well.
Environmental system of hovertank can keep it operating without any kind of contact to outside world for at least a week (and sometimes for month) but it is not completely circulatory system. Hovertanks have -despite all efforts- so small interiors that staying within for weeks is extremely mentally stressful to its human crew and it is questionable if a crew can stay in hovertank longer than few days. On the other hand, GRELs have proven to be mentally hard enough to cope with it.
Despite all the armor and camouflage it is inevitable hovertank is going to get hit sooner than later and its armor penetrated. Therefor hovertank design has taken several steps to reduce hit effectiveness. Penetrating hit causes extreme heat and splintering and fragmentation. Interior walls have therefor special antiballistic armor that catches at least some fragments as well dissipates some of the tremendous vibration caused by non-penetrating hit. This layer provides additional protection to sandwiched armor that is somewhat flexible by itself and has space within armor to protect against spalling caused by high explosive squash head rounds.
In order to reduce hit effects hovertanks vital locations (like crew fighting space, ammunition storage and fuel tanks) are isolated from each other. Hovertank layout has also been designed to further isolate and protect vital systems by surrounding these systems with less important systems to increase armor protection. Additional redundancy has been added with duplication and even triplication of some systems. In case some part is destroyed another part of system could take over its functions. For example computer system of hovertank had numerous separated parts, all which could take over if some part was destroyed. Similarly data buses have been multiplied so a penetrating hit in one position does not cause crippling data loss.
A catastrophic hit to engines would force hovertank to make either forced landing or just crash. Comfortable seats, seatbelts and air bags protect crew from high speed or high altitude crashes. Seat design gives protection from neck injuries. Despite all this a crash is traumatic experience where crew often dies, especially if speed is high and heavy hovertank starts to swirl upon touching ground. CEF has been testing ejector seats for hovertank crew but they have found it causing considerable weakness in armor protection of hovertank itself. Unless weapon system advances make armor completely obsolete CEF believes best protection for crew is still thick armor. Therefor ejector seats have not been installed to hovertanks even while technology and know-how exists.
Heat effect lead to fire that is extremely dangerous to hovertanks, which carry hydrogen as fuel and plenty of ammunition as missiles. Fuel and ammunition storage space hits do not necessarily destroy vehicle immediately. Storage hatches have been built to direct force of explosion outwards so that explosion does not necessarily kill the crew. There has been mixed results from these design features. Usually a hit is enough to destroy vehicle as a viable combat system and start serious fires but not bad enough to kill entire crew immediately. Fire protection system can recognize starting liquid/aerosol or HEAT liquid metal flame in less than millisecond and extinguish it in less than 10 milliseconds with halon gas. This prevents severe damage to systems or burns to crew. Crew also wears IPS to protect them from fire and smallest fragments of those that penetrate crew fighting space armor. IPS is, however, just a flame resistant suit. It does not protect from heat itself but allows crew to act in situation. Crew can then try to put out the fire with hand extinguishers or leave the hovertank without having to fear severe burns immediately.
If hit is severe enough hovertank might have to be evacuated. CEF believes that well trained and experienced crews are most difficult to replace system in battlefield. Therefor each crewmember has own hatch for quick evacuation. There is usually extra hatch on vehicle floor as well so crew can bail out in enemy fire as well. IPS suit has special loop built in neck. It makes rescuing wounded crewmen easier as wounded can be risen quickly through tight hatches to tank roof. Finally crew carries in their person necessary survival equipment and personal weaponry to stay alive in battlefield and wait until CEF forces would arrive to rescue them. CEF has special rescue teams that have a doubly duty of rescuing beleaguered crews as well as their hovertanks. These teams have usually both medical experts to help crew as well as maintenance professionals to evaluate effects of hits on vehicles.
Active part of VPS consists of warning and jamming systems and active defenses. It integrates the sensors and systems into single automatic system that selects automatically or manually suitable countermeasures to each threat.
First warning systems sweep the battlefield around hovertank. Passive systems are used most of the time because of active systems make hovertank too easy to find. BISN provides also warning signals to the system. When incoming projectile is found active sensors are usually turned on to pinpoint its location. If missile flies past vehicle countermeasures are not used but instead warning is issued to BISN.
Assuming the projective is a threat the countermeasures must be initiated. Because of huge size of electromagnetic spectrum and amount of possible guidance systems the measures are equally numerous. Because not even GRELs are quick enough to use missile protection systems the computer typically takes it all over. One might have to use smoke screen (which has metal aerosol and can block several areas of electromagnetic spectrum), laser dazzler (which jams the laser guided weaponry), flares (which confuse heat seekers), noise jamming (to jam command guided weapons) or any or all combination of these or other systems. Some of these passive systems are anti-infantry weapons too in emergency. Flares are sometimes shot to make terrain burn in order to flush infantry out of there. Laser dazzler can increase its intensity and luminance so high it blinds infantry and destroys their visionics. Smoke screen has carbon monoxide and tiny metal particles, which make breathing through gas mask very difficult and might cause suffocation.
There are variety of sound (weapon noise) and light (muzzle flash) searching systems too but they are mostly useful for provide warning against infantry and infantry anti-tank weapons. These warning systems are by no means always correct. Confusing messages, jamming, hovertanks own noise, decoys and dust and fires in battlefield cause often several false alarms. This is dangerous as crews get frustrated to false alarms until they start to ignore alarms. This leads sooner than later to real threat coming past warning system. Therefor cautious and patient infantry can get fairly close to hovertank even while its sensors should pick up their emissions and warn hovertank crew.
Countermeasures do not fool or stop all projectiles. They do not stop determined infantry trying to attack vehicle with satchel charges either. To deal with these problems VPS switches to active defense systems next. Active defense part of VPS consists usually one or two weapon pallets. Usually one is put on turret (or hull) roof and another to hull glasis to give additional protection from threats emerging from front. This is recognized to be most dangerous direction. Weapon pallet has usually a laser anti missile system.
When VPS finds out that countermeasures do not work it orders active defenses to fire. Laser system fires a string pattern of short pulses towards missile. Usually a single hit is enough as missile fuel explodes or heated up electronics is confused. Missile system is not as efficient against massive kinetic energy objects such as field gun rounds. It can destroy them too but with a lower degree of confidence. VPS uses its own laser capacitor banks but it is connected to capacitor banks of other weapon systems of hovertank (usually DECW used as main weapon) so that this vital piece of equipment does not run out of energy in emergency. VPS is very effective against infantry as well as it has high rate of fire and it can bath a set area with short, highly intensive laser beams. This is not often used, as defense against missiles is considered far more vital.
Second duty of VPS laser system is aerospace defense. While DECWs and missile systems might be used against slowly moving air targets like helicopters and other hovertanks they are not effective against high-speed targets like jet fighters. VPS can engage them since it has speed to engage hypervelocity antitank missiles. Since VPS range is small it is pure vehicle defensive system. Purpose-built aerospace defense systems exist and they are fielded on their own weapon platforms, many of which are mounted on hovertanks as well.
Infantry close attacks can be very dangerous to hovertanks and they often happen in jungles and urban fighting. Because VPS laser system is almost always used for anti missile defense and infantry suppression systems might be engaging targets at long ranges additional protection is needed. Hovertanks carry antipersonnel system, which consists of bouncing directional charges. System fires the charge to direction of threat and explodes it in correct range. The fragments are directed downwards to destroy enemy infantry in position and to minimize effect on own infantry although the fragmentation direction can be changed if necessary. This system has secondary function to shoot down missiles. It is not as accurate as laser system but it can be used for that duty in case of emergency.
Command forms fourth factor of hovertank design. For CEF it means integration of all systems in hovertank to single unified weapon system capable of fighting with extreme effectiveness. For hovertank command consists of sensors to find the enemy, fire control systems to make sure weapons hit their targets, communications to inform what is happening and last but not least human operators who oversee this all.
Combat starts always with finding the enemy. Even more importantly sensors must be used so that enemy cannot get advantage of surprise and cause crippling losses before close combat starts. Most friendly weapon systems need also very accurate information before they can be used efficiently. Hovertank fights almost always with closed hatches. Crew is well protected but cannot really to prisms and periscopes to view what is happening around them. Instead they rely almost entirely to a wide variety of active and passive sensors.
Human eye processes most of its information with eyes and similarly visionics systems using visible spectrum and beyond still form base of all military sensors. These systems use almost exclusively passive systems since active systems (like searchlights, ladars and active infrared systems) are all very easy to locate in battlefield. These systems can only be used in short-range line of sight targets but this is not major problem since most of the ground battle happens in line of sight anyway.
Modern visionics system can exploit entire electromagnetic spectrum simultaneously. Sensors can increase the magnification and sensitivity if necessary. For example far away objects might be magnified for identification or in night sensor sensitivity and contrast amplified to assist finding location of seen object. Vision is stereoscopic and accuracy is almost similar in day and night. Computer processes all the data coming across the spectrum and presents it in a coherent picture of what is happening. For example smoke from burning tank would block vision entirely if seen just on visible spectrum. Infrared part of spectrum could pick up crew escaping from burning wreck and ultra violet picture notice a anti-tank missile launcher hiding under camouflage net right next to them.
Purely optical systems (like oculars) are kept as backup systems only. Modern battlefield is so filled with lasers that chances of blinding are high if someone uses laser dazzler or just by accident. CEF used extensively filtering in visionics to protect troops already. This is not the case with optical systems that can have filters set only certain pre-set wavelengths. Therefor CEF suggested avoiding their use except for emergencies only. If optical systems must be used, CEF ordered that an eye patch should be employed over one eye to avoid loss of both eyes at the same time.
Active systems are used as well. Radar is most popular active system. Pulses of radio waves could be transmitted via some sort of antenna and then received back getting accurate location needed for weapons. Because emitting radar is very easy to locate too CEF often used system where only one was transmitting and everyone else was receiving. Then the received data would be distributed by BISN to everyone else. This turned entire unit into huge phased array radar that could filter out jamming quite well with common information processing.
Third method of finding enemy is magnetic fields. Hovertanks and other vehicles have all some metals that conduct electricity and cause changes in magnetic fields when they move. This is very effective method to tell if something is present but it does not really where the enemy is. Furthermore, its use is severely disturbed by presence of other moving vehicles and it is confused during fighting, where plenty of objects are present. Therefor it was used to provide early warning rather than come out with fire-control data.
Targets must be found out before they can be engaged. If one has to use sensors one has to usually expose oneself from safety of cover. This means that searching hovertank can be located (and fired) by enemy as well. CEF tried to solve this problem with two approaches. First was to maximize cover when using onboard sensors and second was to use drones for reconnaissance.
Hovertank sensors are usually located on top of turret so that their use exposes only a little bit of turret. CEF considered even this too dangerous and thus they fitted a sensor package on top of a mast. This mast could be raised five meters above hover tank turret giving it very good birds eye view of things. Pod itself was small and could be built very stealthy to avoid enemy reconnaissance. CEF hovertanks typically hide themselves behind tree cover or hills or laid low in gullies using their mast mounted sensors to search for enemy. Because energy use of using mast was miniscule compared to movement and weapon systems hovertanks themselves were stationary with engines shut down. When enemies were observed, engines were started, camouflage removed and unit would get ready to fight. Cool-headed commanders could order a sudden attack or move further in road to build ambush.
Mast mounted sensors have their problems as well. It just cannot see beyond line of sight. Besides the earlier and longer range one gets warning or targets information of enemy the better. BISN was obvious solution for relaying information but everyone in CEF agreed that one could never have enough reconnaissance.
Military hovertanks carried usually one vehicle drone that hovertank crew would pilot in the patrol. This small flying drone could be launched from inside and recovered and inserted to its module with manipulative arm typically used in rearming. Vehicle drone was itself unarmed and it carried only a reconnaissance package. Its flight speed was similar to helicopters and endurance was set to two hours. Because only a limited sized module could be carried it was very small and understandably very stealthy. The advantage of drone was that it made reconnaissance of large areas very easy. Since its cost was nothing compared to hovertank drone could be sent to dangerous place to look what was happening so in case it triggered a trap valuable hovertank was not lost. CEF hovertank units kept always at least few reconnaissance drones flying around the clock patrolling their surroundings. Most feared ability of sensors lied in their ability to not just patrol and do reconnaissance but relay the information in real time to BISN. Both sensor pods and all drones carried target designators that made possible to guide semi-active guided munitions into targets. For example a drone could be sent to look behind suspicious hill. If it found enemy the data would be relayed through BISN to hovertanks that could fire their missiles without even seeing the enemy behind the hill. It could also be used to guide semi-active munitions from non-BISN equipped artillery if necessary.
After target had been found it is usually engaged. At this moment the computerized fire control system takes over. Fire Control System (FCS) has to recognize targets, evaluate threats and guide weapon systems to destroy them. At first FCS has to make sure that contact is enemy before firing it because accidental shooting of friendly forces has very bad influence on troop morale. Contact evaluation employs image recognition (computerized shape recognition), IFF systems (usually when fighting with non-BISN equipped troops), BISN information (gives accurate location of all friendly units) and vehicle navigational systems data (as a reference).
Rules of Engagement (ROE) information might also be included to contact evaluation. Some ROEs may for example forbade use of certain weaponry in certain situations and/or locations or forbade engaging some target types (such as civilian refugees). FCS follows these targets too and includes ROE status information so crew can evaluate if/how engage them. Similarly some physical locations have been declared free fire zones where anything moving will be destroyed without any kind of evaluation. Thus FCS ROE information is constantly updated according to situation. Crew can override or redo ROE settings if situation so warrants.
Once a contact has been evaluated as valid target it will be tracked. FCS tracks automatically all targets in range and within vehicles own sensor range, calculates firing solutions and arranges targets to engagement priority according to estimated threat level they form to hovertank or to mission hovertank is fulfilling. Target list can be engaged either in automatic or manual. Some targets like incoming missiles and artillery rounds were automatically engaged as even GRELs were not fast enough to initiate countermeasures manually. CEF hovertanks used manual engagement for most situations but some applications (like aerospace defense) were already without human interaction. Manual fire control uses so called "hunter-killer" system where all crewmen could look and fire independently at any targets they would deem necessary to destroy. The fire control system processes new targets and threats constantly during the firing enabling smooth selection to another target.
After human operator or FCS has made a decision to fire FCS will make final update to firing solution. It takes into consideration several hundred factors varying from foreign particle density of air to DECW barrel temperature. System is then ready to fire. Reaction time of typical hovertank is extremely short due computers, target priority tables and many fully automated systems. First shot takes less than one second from initial detection. With manual fire control that time was less than five seconds.
War is, however, more than just firing enemies and destroying them. One has to also relay information on both own and enemy status, intentions and actions. Reliable long-range communications were absolutely vital to CEF because it could field only limited number of soldiers to fight in entire planet it would invade. It was also reliant to high technology weaponry that would not work efficiently without BISN. Advanced telecommunications technology had enabled CEF to cram satellite communications to box a smaller than cellular phone. It did not need bulky and vulnerable dishes either. This made possible to construct BISN into worldwide system based on satellites. Satellite systems offer practically secure and jamming free high capacity system but they have also a weakness. Satellites themselves are essential microwave relay stations that must remain operational all the time. They are very vulnerable to enemy anti-satellite missions. CEF recognized this problem and had huge stockpile of mass-produced communications satellites and launch systems to replace destroyed ones and to add reliability to communications system. CEF did not trust just to satellites so every vehicle carried radios as well. Radio equipment on military hovertank is excellent even if it is just a backup system. Final part of communications is security. All signals were coded so that even if transmissions were intercepted they would give enemy no advantage. Amount of time and effort given to coding in CEF was extreme because of potential disaster if enemies could use BISN to their advantage.
Last but not least link in command concept of design and also most important part of hovertank is human. Although CEF had replaced most humans with GRELs these biological constructs are so humanlike the same concepts apply also for them. Human part of design means putting attention to ergonomics, then to information presentation to crew and finally how crew can act upon all of this. Ergonomics is relatively unknown but vital part in military systems design. Poorly designed layouts and displays often might lead to misunderstanding with tired crew. This kind of slipping could have deadly consequences in combat.
In modern hovertank meters and gauges have been replaced with simple graphical displays. Manual knobs have been set logically so they are easy to find in heat of action and so on. Usually only displays with vital information are shown and other dials stay dark so pilot does not waste time looking at them. All crewmen can use weapon systems without taking their arms from joysticks necessary for moving hovertank as all necessary buttons are attached to control sticks.
Crew sits in comfortable seats that have seatbelts and airbags in case of crashes. There is enough room to crew so that one is not cramped and can stay alert for whole time. Lights are adjusted to be comfortable to eye. Even colors of walls have been thought out. They are light so that even a tiny amount of light inside hovertank would give crew slightly better chances of seeing in case of emergency. Ergonomic means in essence making everything in the cockpit work for crew and not wise versa.
Information displays have advanced considerably. Crew is surrounded by large graphic displays that show three dimensionally of what is happening around them as well as vital information in easy to understand way. This is however just a backup. The heart of hovertanks information presentation is a helmet crewmen wear. All information is directly fed from computers to helmet's visor and to ear phones giving out totally virtual reality. One can use direct feed of visual data of what is happening outside. This picture is then filled up with all information BISN, sensors and FCS represents giving a perfect view of carnage in battlefield. However, most of the GREL crews seem to prefer totally artificial picture where all data is processed and only directly militarily relevant information is presented. Advantage of helmet presentation is that it gives out very clear picture what was happening. It also gives crew somewhat unreal reality of battlefield where everything seems to be in perfect order despite death, smoke and confusion. Some critics say it turns battle into a video game where crew might forget that "Game Over" for players would be their final.
In addition to information presentation hovertank also gives out suggestions for actions to pilot. As FCS lists out targets and evaluates threats it also plots out possible routes and ideas for fighting. This assistance program is based on using relevant historical data of fighting against similar type of enemy. It is based on exploiting known weaknesses on enemy weapon systems. For example, if enemy vehicle is known to have weak spot on turret computer shows it as weak point and automatically suggests firing there. However, final decision and responsibility on course taken relied always on hands of crew.
Like all computer systems inside hovertank this complicated software was highly complicated piece of neural networking. Hovertank computing system was programmed to learn from its own experiences as it had been noticed that learning system could reach excellence performance in control systems like turbine air flow controls and stabilization. Level of learning depended on unique user history of each hovertank. In this way every hovertank system was unique. Some GRELs reported of computer system having unique way of presenting and suggesting its information. This is somewhat similar to Terra Nova, where some Gears have very advanced neural network architecture working on similar principles as Earth computer control systems.
Once crew has been presented the relevant information of the battlefield and they made their decision it must be turned into reality. It is here where the action comes in. Joysticks are most relevant physical means but different needs mean that different systems like keyboard, control ball, VR gloves, voice, touch controls, eye movement and thought control could also be used as supplanting or replacing joysticks in variety of capacity. Which systems were used in each individual situation varied according to taste of crewmen. For example thought control was usually used when selecting almost without conscious thought something from limited well remembered list. Keyboard was method of choice for writing reports and voice was efficient way to give out short orders. One even did not have to be inside hovertank to command it. Crewmen leaving hovertank for example to repair some part that could not be accessed from inside panels or fixed with manipulative arm kept their helmets on. Crewman could then command hovertank and ask information from self-diagnostics or use manipulative while she would be connected to inside with light fiber or wireless radio data link.
Similarly hovertank could also be taken over by another unit in battlefield. Human crew in slave tank could break this master-slave remote control at any time. This link was intended to aerospace defense systems where one hovertank could direct totally fire of entire platoon or troop on its own and it was installed to every command software. It was also very useful in training where master tank could take over if trained crew made bad error of judgement. At times this was used to reactivate abandoned hovertank in battlefield to do something in remote control or leave it run on automatic for some reason. For example if crew had died hovertank could be commanded by master to fight or leave battlefield. Similarly half-destroyed hovertanks left in battlefield could be ordered to awake at certain inputs or carry on some duty (like a bait or reconnaissance).
More exotic control systems were tested too. Direct connect between brains of GREL to hover tank computer was field-tested. The actual connection was somewhat similar to use of cyber spines, cybernetic sensory organs and webblings all connected. Actual tests were extremely successful and cyber crew effectiveness was much higher than with ordinary GREL crew. However, the time needed to install the cybernetic equipment to a single host body was six months and final cost of system was exceedingly high. Still, it has proven so effective that CEF tested the concept continuously for future weapon systems.
For Terra Novans the massive hovertanks and their high pitched whine were harbingers of inhuman legions of almost unstoppable GRELs. For Colonial Expeditionary Force it was just a vehicle, basic weapon platform, for their units. Despite their vast advantages they were not really ultimate and universal war machines capable of anything as cheap popular fiction has made them to be.
CEF never thought that hovertanks were end for itself. They were just a family of platforms that could carry their army with guns, infantry and everything else to battle faster than much more safely than with all the helicopters and wheeled and tracked vehicles.
In rational assessment hovertanks were outgrowth of more ordinary ground vehicles with advantages and disadvantages like any other system. When compared to ground vehicles they were just another combination of four basic tenets of armored vehicle construction with vastly greater mobility compared to other ground vehicles.
It was this mobility that made CEF so deadly. Hovertanks could go anywhere they wanted and deliver a sudden unexpected blow to surprised Terra Novans. This mobility allowed CEF commanders to start and stop fighting almost when they wished and where they wished.
Still there were weaknesses to worry. Helicopters and hoppers were roughly as mobile (although more vulnerable) and could fight on even standing. Fast jets were also as dangerous to them as to any other ground vehicle. Their large sensor profiles vulnerable fans and huge size made them difficult to hide compared to most ground vehicles too.
The real weakness was not found on battlefield. It was the very technological sophistication that made hovertanks so deadly in the first place. Cost of hovertank was similar to military jet, so too was the logistical effort needed in upkeeping. CEF ate up huge quantities of fuel, ammunition, supplies, spare parts and maintenance hours every day. With supply lines to factories in Caprice and Earth severed, CEF could simply not keep enough super tanks combat ready to make the difference.
No matter how skilled their commanders were, no matter how many tanks, gears or helicopters hovertanks destroyed, their every won battle was hollow. CEF always lacked that one last hovertank needed to reach the ultimate victory. Beaten Terra Novan armies could and would replace their losses and return back to battlefield to fight again. All this dragged campaign longer and longer and ate up more and more irreplaceable GRELs, hovertanks and supplies dwindling chances of CEF to achieve victory until in Baja the back of camel was finally broken. The end was inevitable.
After the war the hovertanks have become very rare sight. Attempts to copy the design by Terra Novans have largely been enormously expensive failures. Reasons have varied from poor engine fan technology to inadequate computer software. Expensive and ridiculed Scythe is epitome of some sort of Terra Novan success with hovertank design.
Only place where scores of hovertanks still roam is Port Arthur where remnants of CEF have reborn as totally new military force called Arthurian Korps. Lack of supplies and proper materials has hindered and slowed overhaul of hovertank force whose numbers are diminishing little by little.
The remaining hovertanks are used mainly for exterminating Rover bands in Western Desert but everyone agrees that Cavalry Brigade's hovertanks still represent awesome fighting power well respected by Terra Novans remembering the carnage of War of Alliance.
Welcome to the future.
| APAGear II Archives | Volume 3, Number 1 | February, 2001 |
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