Firefight Y2K

by Dean Ing

  Before leaving the topic of materials, let’s pause to note research into jet fuels. A gallon of JP-4 stores roughly 110,000 Btu. Some new fuels pack an additional 65,000 Btu into a gallon. Even if the new fuels are slightly heavier, the fuel tank can be smaller. The result is extended range. It seems reasonable to guess that JP-50, when it comes along, will double the energy storage of JP-4.

  VEHICLE CONFIGURATIONS

  Now that we’re in an age of microminiaturization, we have a new problem in defining a vehicle. We might all agree that a vehicle carries something, but start wrangling over just how small the “something” might be. An incendiary bullet carries a tiny blazing chemical payload; but does that make the bullet a vehicle? In the strictest sense, probably yes. But a bullet is obviously not a limiting case-leaving that potential pun unspent-when very potent things of almost no mass can be carried by vehicles of insect size.

  Payloads of very small vehicles could be stored information, or might be a few micrograms of botulism or plutonium, perhaps even earmarked for a specific human target. Ruling out live bats and insects as carriers, since they are normally pretty slapdash in choosing the right target among possibly hundreds of opportunities, we could develop extremely small rotary-winged craft and smarten them with really stupendous amounts of programming without exceeding a few milligrams of total mass. A swarm of these inconspicuous mites would be expensive to produce, but just may be the ultimate use for “clean room” technology in which the U.S. has a temporary lead.

  The mites would be limited in range and top speed, so that a hypersonic carrier vehicle might be needed to bring them within range of the target like a greyhound with plague fleas. The carrier would then slow to disgorge its electromechanical parasites. One immediately sees visions of filters to stop them; and special antifilter mites to punch holes in the filters; and sensors to detect antifilter mite action; and so on.

  It’s hard to say just how small the mites could be after a hundred years of development. One likely generalization is that the smaller the payload, the longer the delay before the payload’s effect will be felt. Take the examples of plutonium or botulism: a human victim of either payload can continue performing his duties for a longer time-call it mean time before failure-if he is victimized by a tinier chunk of poison. Some canny theorists will be chortling, about now, at the vision of a billion mites slowly building a grapefruit-sized mass of plutonium in some enemy bunker. That’s one option, for sure. But the blast, once critical mass is reached, would be ludicrously small when compared with other nuke mechanisms.

  The best use of mites might be as spies, storing data while hunkered down in an inconspicuous corner of the enemy’s war room, scaring the bejeezus out of the local spiders. Or would the enemy’s spiders, too, be creatures of the clean room? Pick your own scenario. . . .

  There is no very compelling reason why mites couldn’t actually resemble tiny flies, with gimbaled ornithopter wings to permit hovering or fairly rapid motion in any direction. There may be a severe limitation to their absolute top speed in air, depending on the power plant. Partly because of square/cube law problems, a mite could be seriously impeded by high winds or rain. A device weighing a few milligrams or less would have the devil’s own time beating into a strong headwind. Perhaps a piezoelectrically driven vibrator could power the tiny craft; that might be simpler than a turbine and tougher to detect. Whatever powers the mite, it would probably not result in cruise speeds over a hundred miles an hour unless an antimatter drive is somehow shoehorned into the chassis. Even with this velocity limitation, though, the mites could probably maneuver much more quickly than their organic counterparts-which brings up a second dichotomy in vehicles.

  Information storage is constantly making inroads into the need for human pilots, as the Soviets proved in their unmanned lunar missions. A military vehicle that must carry life-support equipment for anything as delicate as live meat, is at a distinct disadvantage versus a similar craft that can turn and stop at hundreds of g’s. Given a human cargo, vehicle life-support systems may develop to a point where bloodstreams are temporarily thickened, passengers are quick-frozen and (presumably) harmlessly thawed, or some kind of null-inertia package is maintained to keep the passenger comfortable under five-hundred-gravity angular acceleration. During the trip, it’s a good bet that the vehicle would be under computer guidance, unless the mission is amenable to very limited acceleration. It also seems likely that women can survive slightly higher acceleration than men-an old SF idea with experimental verification from the people at Brooks AFB. Women’s primacy in this area may be marginal, but it’s evidently true that Wonder Woman can ride a hotter ship than Superman. It’s also true that your pocket calculator can take a jouncier ride than either of them. In short, there will be increasing pressure to depersonalize military missions, because a person is a tactical millstone in the system.

  Possibly the most personalized form of vehicle, and one of the more complex per cubic centimeter, would be one that the soldier wears. Individualized battle armor, grown massive enough to require servomechanical muscles, could be classed as a vehicle for the wearer. The future for massive man-amplifying battle dress doesn’t look very bright, though. If the whole system stands ten meters tall it will present an easier target; and if it is merely very dense, it will pose new problems of traction and maneuverability. Just to focus on one engineering facet of the scaled-up bogus android, if the user hurls a grenade with his accustomed arm-swing using an arm extension fifteen feet long, the end of that extension will be moving at roughly Mach I. Feedback sensors would require tricky adjustment for movement past the trans-sonic region, and every arm-wave could become a thunderclap! The user will have to do some fiendishly intricate rethinking when he is part of this system-but then, so does a racing driver. Man-amplified battle armor may pass through a certain vogue, just as moats and tanks have done. The power source for this kind of vehicle might be a turbine, until heat-seeking missiles force a change to fuel cells or, for lagniappe, a set of flywheels mounted in different parts of the chassis. The rationale for several prime movers is much the same as for the multi-engined aircraft: you can limp home on a leg and a prayer. Aside from the redundancy feature, mechanical power transmission can be more efficient when the prime mover is near the part it moves. Standing ready for use, a multiflywheel battle dress might even sound formidable, with the slightly varying tones of several million-plus RPM flywheels keening in the wind.

  For certain applications including street fighting, there may be a place for the lowly skateboard. It’s a fact that the Soviets have bought pallet loads of the sidewalk surfers, ostensibly to see if they’re a useful alternative to mass transit. It’s also true that enthusiasts in the U.S. are playing with motorized versions which, taking the craze only a step further, could take a regimental combat team through a city in triple time. But if two of those guys ever collide at top speed while carrying explosives, the result may be one monumental street pizza.

  No matter how cheap, dependable, and powerful, a military vehicle must be designed with an eye cocked toward enemy weapons. Nuclear warheads already fit into missiles the size of a stovepipe, and orbital laser-firing satellites are only a few years away. A vehicle that lacks both speed and maneuverability will become an easier target with each passing year. By the end of this century, conventional tanks and very large surface ships would be metaphors of the Maginot Line, expensive fiascos for the users.

  The conventional tank, despite its popularity with the Soviets, seems destined for the junk pile. Its great weight limits its speed and maneuverability, and several countries already have antitank missile systems that can be carried by one or two men. Some of these little bolides penetrate all known tank armor and have ranges of several kilometers. Faced with sophisticated multistage tank killer missiles, the tank designers have come up with layered armor skirts to disperse the fury of a high-velocity projectile before it reaches the tank’s vitals. Not to be outdone, projectile designers have t
oyed with ultrahigh-velocity projectiles that are boosted almost at the point of impact. It may also be possible to develop alloy projectile tips that won’t melt or vaporize until they’ve punched through the tank’s skirt layers. Soon, the tanks may employ antimissile missiles of their own, aimed for very short-range kills against incoming antitank projectiles. This counterpunch system would just about have to be automated; no human crew could react fast enough. The actual mechanism by which the counterpunch would deflect or destroy the incoming projectile could be a shaped concussion wave, or a shotgun-like screen of pellets, or both. And it’s barely possible that a tank’s counterpunch could be a laser that picks off the projectile, though there might not be time to readjust the laser beam for continued impingement on the projectile as it streaks or jitters toward the tank.

  Given the huge costs of manufacturing and maintaining a tank, and the piddling costs of supplying infantry with tank-killing hardware, the future of the earthbound battle tank looks bleak. It’s wishful thinking to design tanks light enough to be ACV’s. Race cars like the Chaparral and the formidable Brabham F1, using suction for more traction, are highly maneuverable on smooth terrain. Still, they’d be no match for homing projectiles; and with no heavy armor or cargo capacity for a counterpunch system, they’d almost surely be gallant losers.

  All this is not to suggest that the tank’s missions will be discarded in the future, but those missions will probably be performed by very different craft. We’ll take up those vehicles under the guise of scout craft.

  More vulnerable than the tank, an aircraft carrier drawing 50,000 tons on the ocean surface is just too easy to find, too sluggish to escape, and too tempting for a nuclear strike. It’s more sensible to build many smaller vessels, each capable of handling a few aircraft-a point U.S. strategists are already arguing. Ideally the aircraft would take off and land vertically, as the Hawker Harrier does. Following this strategy, carriers could be spread over many square kilometers of ocean reducing vulnerability of a squadron of aircraft.

  A pocket aircraft carrier might draw a few hundred tons while cruising on the surface. Under battle conditions the carrier could become an ACV, its reactor propelling it several hundred kilometers per hour with hovering capability and high maneuverability. Its shape would have to be clean aerodynamically, perhaps with variable-geometry catamaran hulls.

  Undersea craft are harder to locate. Radar won’t reveal a submerged craft, and sonar-a relatively short-range detection system unless the sea floor is dotted with sensor networks-must deal with the vagaries of ocean currents, and temperature and pressure gradients as well as pelagic animals. There may be a military niche for large submersibles for many years to come, perhaps as mother ships and, as savant Frank Herbert predicted a long time ago, cargo vessels.

  A submerged mother ship would be an ideal base for a fleet of small hunter-killer or standoff missile subs. These small craft could run at periscope depth for a thousand miles on fuel cells, possibly doubling their range with jettisonable external hydride tanks. A small sub built largely of composites would not be too heavy to double as an ACV in calm weather, switching from ducted propellers to ducted fans for this high-speed cruise mode. From this, it is only a step to a canard swing-wing craft, with schnorkel and communication gear mounted on the vertical fin. The sub packs a pair of long-range missiles on her flanks just inside the ACV skirt. The filament-wound crew pod could detach for emergency flotation. High-speed ACV cruise mode might limit its range to a few hundred kilometers. The swing wings are strictly for a supersonic dash at low altitude, using ducted fan and perhaps small auxiliary jets buried in the aft hull, drawing air from the fan plenum.

  Heavy seas might rule out the ACV mode, but if necessary the little sub can broach vertically like a Poseidon before leveling off into its dash mode. With a gross weight of some thirty tons it would require some additional thrust for the first few seconds of flight-perhaps a rocket using hydride fuel and liquid oxygen. The oxygen tank might be replenished during undersea loitering periods. Since the sub would pull a lot of g’s when re-entering the water in heavy seas, the nose of the craft would be built up with boron fibers and polymer as a composite honeycomb wound with filaments. The idea of a flying submersible may stick in a few craws, until we reflect that the SUBROC is an unmanned flying submersible in development for over a decade.

  On land, military cargo vehicles will feature bigger, wider, low-profile tires in an effort to gain all-terrain capability. Tires could be permanently inflated by supple closed-cell foams under little or no pressure. If the cargo mass is distributed over enough square meters of tire “footprint,” the vehicle could challenge tracked craft in snow, or churn through swamps with equal aplomb. The vehicle itself will probably have a wide squat profile (tires may he as high as the cargo section) and for more maneuverability, the vehicle can be hinged in the middle. All-wheel drive, of course, is de rigeur.

  It’s a popular notion that drive motors should be in the wheels, but this adds to the unsprung portion of the vehicle’s weight. For optimal handling over rough terrain, the vehicle must have a minimal unsprung weight faction-which means the motors should be part of the sprung mass, and not in the wheels which, being between the springing subsystem and the ground, are unsprung weight.

  Relatively little serious development has been done on heavy torque transmission via flexible bellows. When designers realize how easily a pressurized bellows can be inspected, they may begin using this means to transmit torque to the wheels of cargo vehicles.

  The suspension of many future wheeled vehicles may depart radically from current high-performance practice. Most high-performance vehicle suspensions now involve wishbone-shaped upper and lower arms, connecting the wheel’s bearing block to the chassis. A rugged alternative would be sets of rollers mounted fore and aft of the bearing block, sliding vertically in chassis-mounted tracks. The tracks could be curved, and even adjustable and slaved to sensors so that, regardless of surface roughness or vehicle attitude above that surface, the wheels would be oriented to gain maximum adhesion. Turbines, flywheels, fuel cells and reactors are all good power plant candidates for wheeled vehicles.

  The bodies of these vehicles will probably be segments of smooth-faced composite, and don’t be surprised if two or three segment shapes are enough to form the whole shell. This is cost-effectiveness with a vengeance; one mold produces all doors and hatches, another all wheel and hardware skirts, and so on. On the other hand, let’s not forget chitin.

  Chitin is a family of chemical substances that make up much of the exoskeletons of arthropods, including insects, spiders and crabs. The stuff can be flexible or inflexible and chemically it is pretty inert. If biochemists and vehicle designers get together, we may one day see vehicles that can literally grow their skins and repair their own prangs. As arthropods grow larger, they often have to discard their exoskeletons and grow new ones; but who’s betting the biochemists won’t find ways to teach beetles some new tricks about body armor?

  Some cargo-including standoff missiles, supplies, and airborne laser weapons-will be carried by airborne transports. In this sense a bomber is a transport vehicle. Here again, advanced composite structures will find wide use, since a lighter vehicle means a higher payload fraction. Vertical takeoff and landing (VTOL), or at least very short takeoff and landing (VSTOL), will greatly expand the tactical use of these transports which will have variable-geometry surfaces including leading and trailing edges, not only on wings but on the lifting body. Consider a VSTOL transport. With its triple-delta wings fully extended for maximum lift at takeoff, long aerodynamic “fences” along the wings front-to-rear guide the airflow and the lower fences form part of the landing gear fairings. Wing extensions telescope rather than swing as the craft approaches multimach speed, and for suborbital flight the hydrogen-fluorine rocket will supplant turbines at around thirty kilometer altitude. In its stubby double-delta configuration the craft can skip-glide in the upper atmosphere for extended range, it
s thick graphite composite leading surfaces aglow as they slowly wear away during re-entry. During periodic maintenance, some of this surface can be replaced in the field as a polymer-rich putty.

  As reactors become more compact and MHD more sophisticated, the rocket propellant tanks can give way to cargo space although, from the outside, the VSTOL skip-glide transport might seem little changed. Conversion from VSTOL to VTOL could be helped by a special application of the mass driver principle. In this case the aircraft, with ferrous metal filaments in its composite skin, is the mass repelled by a grid that would rise like scaffolding around the landing pad. This magnetic balancing act would be reversed for vertical landing-but it would take a lot of site preparation which might, in turn, lead to inflatable grid elements rising around the landing site.

  Once an antimatter drive is developed, cargo transports might become little more than streamlined boxes with gimbaled nozzles near their corners. Such a craft could dispense with lifting surfaces, but would still need heat-resistant skin for hypersonic flight in the atmosphere. But do we have to look far ahead for cargo vehicles that travel a long way? Maybe we should also look back a ways.

  For long-range transport in the lower atmosphere, the dirigible may have a future that far outstrips its past. Though certainly too vulnerable for deployment near enemy gunners, modern helium-filled cargo dirigibles can be very cost-effective in safe zones. Cargo can be lifted quietly and quickly to unimproved dump areas, and with a wide variety of power plants. The classic cigar shape will probably be lost in the shuffle to gain more aerodynamic efficiency, if a recent man-carrying model is any guide. Writer John McPhee called the shape a deltoid pumpkin seed, though its designers prefer the generic term, aerobody. So: expect somebody to use buxom, spade-nosed aerobodies to route cargo, but don’t expect the things to fly very far when perforated like a collander from small-arms fire. The aerobody seems to be a good bet for poorer nations engaged in border clashes where the fighting is localized and well-defined. But wait a minute: what if the gasbags were made of thin, self-healing chitin? Maybe the aerobody is tougher than we think.