Supersonic/Hypersonic Attack Aircraft (SHAAFT)
The SHAAFT (Supersonic/Hypersonic Attack AircraFT) is an airborne weapons system designed for operational use in the year 2025. It is capable of putting munitions on target, anywhere in the world, within four hours after takeoff. It is a direct result of the defined mission requirements of Global Reach/Global Power and specifically, Global Force Projection. The SHAAFT can fight and win two major regional conflicts simultaneously. It also complies with the current force draw down in which the majority of all US military forces will be based in the continental United States (CONUS). Flight line operations would require cryogenic support for the fuel needs of SHAAFT. It cruises to and from the target at mach 12 and at 100,000 feet. It is a completely reusable vehicle, like most USAF aircraft. The SHAAFT will deploy various weapons to destroy nearly any type of essential enemy target, dependent on real-time battlefield information or existing intelligence data to destroy targets. The SHAAFT will also serve as the base component to accomplishing in-theater dominance with the SHMAC and access to space with the SCREMAR.
The goal of the SHAAFT is to cause enough destruction and chaos in the first hours of a conflict such that the enemy realizes war is a futile choice. The enemy is then crippled and nearly defenseless against subsequent attacks from conventional forces in a protracted war. It would also serve as an extremely effective deterrent force, since the enemy would know that any military movement could be utterly upset if not completely destroyed within a matter of hours from its discovery. But unlike conventional aircraft, the hypersonic flight regime makes SHAAFT a difficult, and therefore highly survivable, target.
A hypothetical attack scheme consists of five SHAAFTs, dispensing nearly 50 hypersonic, precision strike, cruise missiles, for example, SHMACs. These would hit vital targets such as command, control, and communications facilities (C3I network), power centers, transportation hubs, and potential space launch complexes. This attack alone would not cripple an advanced country's war machine, but it would severely disrupt their war-fighting operations to the point that they are no longer able to immediately continue any operations. Within hours of the initiation of hostilities, the enemy's infrastructure would be in shambles with their ground forces unable to communicate, maneuver, or fight a coordinated battle. The hostiles would then be unable to defend themselves against conventional military forces.
In the event that an enemy is able to perform some form of ASAT warfare, the SHAAFT would also serve as a staging vehicle for the SCREMAR reusable access to space vehicle. The SHAAFT/SCREMAR combination could be used to repair and replace damaged satellites. The system would be used in peacetime for routine replacement and replenishment of satellites, which would also produce operational experience that could be adapted to a critical wartime situation.
General Mission Requirements
The reasons for avoidance of overseas basing are extremely important. The SHAAFT, incorporating hypersonic technology, will be costly. Thus, few would ever be produced. This craft is essentially a "golden bullet" that will aid the United States (US) in deterring conflicts, or if that fails, to win a war, hopefully in a short period of time.
Overseas basing provides the advantage of reduced range. But with shrinking defense budgets, such basing can no longer be relied upon. The security and stability of these foreign assets cannot be guaranteed in the year 2025. Basing the SHAAFT at large CONUS bases would enable a secure area in which to operate for years. Bases would be chosen such that infrastructure and geographic positioning could best support the hypersonic mission.
CONUS basing of the SHAAFT allows for security and stability in aircraft maintenance. But keeping the mission of global reach/global power restricted to one aircraft saves a great deal of money. That is, the logistics usually required to maintain a fleet of attack aircraft are extensive and time-consuming, utilizing precious resources that could be saved.
The SHAAFT attempts to eliminate the swarms of tankers, airlifters, and support personnel that are normally required to sustain overseas operations. This aircraft takes off, deploys munitions, and returns, without refueling. Therefore, the SHAAFT saves money by reducing the logistics footprint required. It could save more money by stopping a war that would certainly cost billions. Had Desert Storm been prevented by a preemptive strike with well-placed munitions, the US could have saved many dollars in hardware and, more importantly, saved lives.
The reasons that the SHAAFT must go hypersonic match the new face of warfare. It must make nearly instantaneous attacks while hiding under the cloak of survivability. If this attack aircraft travels at mach 12 and 100,000 feet, it is improbable that 2025-era enemy technology would be able to overtake it. Considering the amount of time that it would take to detect, track, identify, and then launch an interceptor that must climb to 100,000 feet and then overtake the SHAAFT, the chances of losing the SHAAFT to an interceptor or surfaced launched missiles are next to impossible.
The SHAAFT would launch SHMAC missiles hundreds of miles from the hostile airspace of the enemy. Such a standoff attack would provide several layers of defense to the SHAAFT. First, the cruising velocity and altitude are unmatched by any current aircraft. Also, it is improbable that future adversaries would have the research and technology base to attain this envelope, although not impossible. Second, the aircraft never passes over a threat area. Enemy forces would undoubtedly see the SHAAFT coming, but a counterattack would have to occur far from their home base. Combined with the speed of the SHAAFT, the enemy force now has to fly a long way to intercept. Third, hypersonic cruise missiles like the SHMAC increases the synergy of the attack. These three layers of defense provide extensive protection against enemy forces.
The SHAAFT also serves as the staging vehicle for the SCREMAR. The achieve orbit, a transatmospheric vehicle (TAV), such as the SCREMAR, has to produce a large velocity change typically on the order of 25,000 feet per second for a LEO. The greater the velocity provided by the staging vehicle, the less the TAV/orbiter has to produce on its own, thus resulting in a smaller size or greater payload for the TAV. The overall effects of having the SHAAFT fly at different hypersonic speeds (i.e., mach 8 versus mach 12, are covered in greater detail in chapter 5.
Because of CONUS basing, the SHAAFT would require a large range. Because of the unusual flight regime and cryogenic fuels, tanker aircraft would be of little support (unless an entirely new tanker fleet were developed, which, under current budgetary constraints, is not foreseeable). Depending on the enemy, the SHAAFT can attain a range of 14,000 nautical miles.
This large range requires a vehicle that is aerothermodynamically designed for a high lift-to-drag ratio. The range is directly related to the mach number-the faster the flight velocity, the farther the range. This range also includes the turning radius. At mach 12, the radius of a 2-g turn is 480 statute miles. The equivalent turn diameter equals about half the width of the US. Such a turn would take approximately 23 minutes, requiring long-term straining maneuvers of the pilot.
Pay load concerns include both the weight and volume. The SHAAFT is designed to carry a payload of 50,000 pounds. If the SHAAFT carries 10 cruise missiles at 4,000 pounds each, that leaves 10,000 pounds for pylons and supporting hardware on the aircraft. Furthermore, the SHAAFT is designed to carry an orbital vehicle. For instance, the SCREMAR, would be placed into low-earth orbit, requiring the volume of a light F-15.
SHAAFT Vehicle Concepts
The "Zero-Stage" Flying Wing
Because the SHAAFT will be taking off from conventional runways and operating across such a huge airspeed spectrum, the design team will have numerous challenges to overcome. How will an aircraft configured to cruise at mach 12 take off from a runway and remain airborne at low speeds? These two speed regimes demand completely different wings, propulsion systems, and fuel systems. If the SHAAFT were to use turbofans for takeoff, then switch to ramjets, and then scramjets for hypersonic cruise, it would have to carry thousands of pounds of extra weight in the form of inert turbofan engines.
To overcome this problem, a two-stage vehicle is proposed. The "zero-stage"
is an unmanned launch platform upon which the SHAAFT attack vehicle will
achieve flow conditions conducive to ramjet operation (figure 2-1). The
purpose of the launch platform is to lift the SHAAFT off of a conventional
runway, then accelerate it to mach 3.5 at 65,000 feet. At this point, the
SHAAFT will be able to ignite its dual-mode ramjet/scramjet engines, separate
from the launch platform, and accelerate up to mach 12 and 100,000 feet.
The launch platform will then return to base and accomplish a fully automated
Figure 2-1. Zero-Stage Flying Wing.
The concept of developing two independent aircraft seems extremely expensive in that two technologically advanced platforms must be produced. The SHAAFT will carry a substantial price tag, but the launch platform will be relatively inexpensive and will actually save large sums of money. A large majority of an airplane's cost comes from development and research. The technology to build the zero stage has already been developed (at least partially) in such aircraft as the high-speed civil transport (HSCT) and operational aircraft such as the Concorde. In addition, its mission is so narrow and specific that it will not require complex systems and components.
The zero stage will be required to accelerate down a long runway (no short field capability required), lift off without the use of complex lifting devices, accelerate straight ahead to mach 3.5, release the SHAAFT, and then return to base. It must carry enough fuel for a radius of 5,000 miles at the higher mach number. It will not perform any demanding maneuvers or be subject to aeromechanically exhaustive flight regimes. Because of these limited demands, the launch platform will not incur large development or production costs. Furthermore, it greatly simplifies the design of the cruiser and dramatically reduces its size requirements.
Current design proposals consist of the following configuration, as studied by the National Aeronautics and Space Administration's (NASA) Boeing HSCT Study in 1989.10 The proposed design is similar in platform to the HSCT, powered by six afterburning turbofans, each producing 50,000 pounds of thrust. A delta wing with a span of 160 feet and an area of 6,370 square feet would be able to take off with a gross weight of 2,000,000 pounds at 290 mph and a lift coefficient of 1.5.
It is essential that the SHAAFT be able to return to its home base or another SHAAFT-equipped recovery base. In order to do this, it will have to be able to land on a conventional runway. When it returns from a mission it will be much lighter than when it took off, having burned thousands of pounds of fuel. (The weight of the fuel is more than any other component on the aircraft, including structures and propulsion.) However, due to its aerodynamically configured shape, it will have to land extremely fast. It will need the assistance of a parachute braking system to slow down. Each SHAAFT would possess its own zero-stage vehicle, along with one extra for sustained operations through any contingency, in order to allow all five SHAAFTs to launch at once.
Sizing and building the SHAAFT design will be the most difficult process. In this section, attempts to size the vehicle were made to fulfill mission requirements. The first step in deriving a platform involved the aerodynamic forces and how to use them to come up with a vehicle. The second step involved simple lift, drag, thrust, and weight trade studies to derive a generic design for the 14,000-mile journey to enemy territory and back. The third step verifies vehicle size using the Breguet range equation.
A unique phenomenon of high mach number flight is the effect of shock
interaction. The nose of the SHAAFT would create a conical shock around
the body; such a shock results in significant pressure drag and must be
overcome by propulsion systems. If the lower portion of the SHAAFT could
keep the outer wing tips even slightly attached to the bottom portion of
the conical shock, then the resulting total pressure on the bottom of the
wing would be much higher than the top. This is the basic idea behind a
waverider. The effect of the waverider can be modeled mathematically. If
the bottom of the vehicle follows the same pattern as the stream lines
of air, then it can be drawn as attached to the shock, as was done in a
study by Dr Charles Cockrell of NASA Langley Research Center in 1994.11
This can be seen in figure 2-2, where a mach cone is generated mathematically
in front of the waverider.
Figure 2-2. Conically Derived Waverider.
The waverider, which matches the flow (streamsurface), attaches to the shock and obtains a large lift-to-drag ratio (L/D), which enables much further range when compared to other hypersonic bodies. Although getting a shock wave to attach perfectly is impossible in reality, the initial shock angle can be made as oblique as possible, reducing pressure drag. When combined with the high aerodynamic heating of hypersonic flight, the waverider background surfaces in the conceptual proposal for the SHAAFT: an aerothermodynamically configured vehicle.
Overcoming drag in excess of 358,000 pounds will be required by the power plant of the SHAAFT. A 10,000-mile flight at mach 12 lasts approximately 74 minutes (this range subtracts the range of the zero stage). This figure includes time from zero-stage separation to engine shut-down and glide-in (in which no fuel is spent), therefore, extra fuel will be available for emergency contingents. The 74-minute flight will require the most amount of thrust for the least amount of fuel.
For mach 12 flight, the large heating rates (which will be discussed later) cause dissociation of atomic oxygen. Typical, large-molecule hydrocarbon fuels- such as JP-4, JP-8, JP-12, gasoline, and other petroleum-based fuels- would suffer incomplete burning and poor efficiency under these conditions. The other fuel alternative is cryogenics such as liquid hydrogen, liquid methane, and others. Liquid hydrogen allows for the highest ISP; its light molecular weight and high energy combustion rate make it ideal for the mach 12 mission.
Several types of powerplants were considered, based upon the findings
of the 1992 US Air Force Scientific Advisory Board. For this application,
specific impulse was the paramount variable(fig. 2-3). Specific impulse
is defined as:
Figure 2-3. Specific Impulse Variation.
Two alternatives exist for SHAAFT propulsion: rockets and dual-mode ramjet/scramjets. Rockets have excellent acceleration characteristics but poor cruising characteristics. Because rockets have such poor specific impulse, requiring their own oxidizers, ramjet/scramjets are the best alternative. Their air breathing technology, combined with hydrogen fuel, allows for the most "bang for your buck". As seen in figure 2-3, the ISP of such a combination lies between 1,400 second and 1,800 second. Since this aircraft would become operational around the year 2020, an ISP of 1,700 second will be assumed for the design point.
The negative consequence to hydrogen fuel is the extremely large volume it occupies which will cause the majority of sizing problems with the SHAAFT. One key to overcoming the density problem is using "slush" hydrogen. Dr F. S. Billig of Johns Hopkins University computed the density of different slush hydrogen,12 and these can be viewed in table 1. For the technology level of 2020, a level of 50 percent solidification was assumed, resulting in a density of 5.11 lbm/ft3. Using this denser hydrogen, the overall fuselage volume can be reduced, reducing drag.
Table 1 - Density Values of Slush Hydrogen (All Values at Triple Point)
Percent Solid by Weight
To judge the size of the SHAAFT, a trade study was conducted to measure lift, drag, fuel requirements, and required fuel storage space. For the study, a lift coefficient of 0.125 and a drag coefficient of 0.025 were used to estimate appropriate aircraft length. These coefficients were chosen from experimental data performed by Dr T. Eggers and Dr R. Radespiel of the German Institute for Design Aerodynamics in 1993.13 It was also matched with the mathematically derived "L/D Barrier" for conical flow derived waveriders, as seen in figure 2-4. At cruise speed, the maximum L/D is given by the expression:
The (L/D)max value with this equation for mach 12 is 5.0, which matched
the values used in spreadsheet iterations.
Figure 2-4. L/D Barrier for Waveriders.
Figure 2-5. Supersonic/Hypersonic Attack Aircraft (SHAAFT).
The first step in the trade study was to pick an initial waverider size. With this, wing area was calculated using simple triangular geometry. Figure 2-5 shows the basic geometry of the proposed SHAAFT. Knowing that lift is given by the equation:
L = CL q S
lift coefficient was found. Using coefficient of lift and drag plots derived by Dr Cockrell during experimental testing, drag coefficient was found. With the familiar drag equation:
D = CD q S
drag for the vehicle was found. With this value, thrust was known, since thrust equals drag in level, unaccelerated flight. With thrust, and the assumed ISP of 1,700 seconds, the fuel flow was calculated. When multiplied by the total flight time, a fuel mass was obtained. This fuel mass was divided by the 50 percent slush hydrogen density to obtain a fuel volume.
Fuel volume was compared to available tank volume from initial waverider dimensions chosen. Using traditional aircraft design, the fuel tank accounted for 50 percent of total aircraft volume. With an actual fuel volume calculated, the aircraft size was changed to try to match available fuel volume with required fuel volume. Aircraft weight was calculated with this volume of fuel, and the assumption that five pounds were required per square foot of wing area. This information was revealed in meetings with personnel of Wright Laboratory's Flight Dynamics Directorate, Wright-Patterson AFB, Ohio. This results in a SHAAFT body weight of 28,500 pounds, not including the 50,000 pound payload weight.
With the trade study, the fuel mass required met the fuel mass available
at a waverider length of 190 feet. The tail end of the SHAAFT has a wingspan
of approximately 60 feet. This design requires approximately 875,000 pounds
of slush hydrogen to complete the 10,000 statute mile journey. The effects
of the different iterations can be seen in figure 2-6. This particular
iteration showed that the aircraft volume was too small, requiring further
Figure 2-6. SHAAFT Sizing.
The Breguet range equation can be used to verify the aircraft size. With the assumption of cruise flight only and at constant velocity, the equation is
where V is velocity, Ct is thrust specific fuel consumption, L/D is the (L/D)max for the SHAAFT at mach 12, Wi is initial weight and Wo is final weight.
It is also important to note that Ct is related to the previously mentioned ISP:
Thus if ISP is 1,700 seconds, Ct is 0.000588 pound/pound mass seconds. V is 11,891 feet/second, L/D is five, Wi is 954,000 pounds, and fuel mass required is 875,000 pounds, then Wo is approximately 78,500 pounds. Using the Breguet range equation, the mathematical range is over 25,000 miles, far exceeding the 14,000-mile requirement. However, the reason the mathematical range is nearly double what is needed is because the equation does not account for the excessive amount of fuel that is needed to takeoff and accelerate the SHAAFT to its cruise condition where it is most efficient. Approximately half the fuel will be spent taking off and accelerating the SHAAFT while also covering a large range. The extra calculated range is to ensure sufficient range throughout the entire flight. It also does not account for the large turning radius, given by the equation:
Here, R is turn radius, V is velocity, g is acceleration due to gravity, and n is the load factor of the turn. The SHAAFT would slow to mach 8 for turning and simultaneously launch SHMAC missiles. This gives a velocity of 11,890 feet per second. At a constant inch 2-g inch turn, the radius is approximately 480 miles, assuming a 50,000 pound payload is still in the aircraft.
Flight Control Systems
Payloads will be placed on the back end of the SHAAFT, requiring room and center of gravity considerations. By the year 2020, the level of fly-by-wire technology should be very commonplace, and application of such technology to the waverider concept should be simple. The pilot would have a typical control stick, interfaced with a black box computer. The pilot's inputs would be fed into two outboard split ailerons, giving both yaw and roll control, and into inboard elevons, giving both pitch and roll control. During cruise flight, such control inputs would be very minor, as surface deflections produce extreme moments at mach 12.
Payloads would have to be located near the center of gravity of the SHAAFT. When these payloads are deployed, the shifting center of gravity could be disastrous if not properly accounted for in fuel ballast and in placement of loads along the fuselage. As 50,000 pounds of equipment depart the SHAAFT, the separation should occur smoothly and quickly to avoid dangerous situations.
The unique mission and design of the SHAAFT will require facilities that are currently very rare or nonexistent. In addition to cryogenic storage and handling equipment, it will need an extensive facility to mate the SHAAFT with the launch platform. This would most likely be performed with a crane structure that would raise the SHAAFT into the air while the wing taxied into position beneath it (not unlike the space shuttle being mated to the Boeing 747). Automated facilities and technicians would then mate the two craft together.
Another consideration which can not be overlooked is the reality of an in-flight emergency developing and the SHAAFT being forced to land at a base which is not equipped to handle it. In this situation, some manner of getting the "Golden Bullet" back to the US would be imperative. This would be accomplished by dispatching a zero-stage wing to act as a ferry. The launch platform has extensive volume within its wings that is used up quickly during supersonic flight-but acting as a ferry, this range and endurance would increase substantially due to the low drag incurred by subsonic velocity. The alternative base would be equipped with a simple mating device, or if emergency demands, one could be airlifted to the foreign base. Once the two crafts are mated, the launch platform will take off and return to CONUS. It is important to remember that the SHAAFT is essentially a flying gas tank and that most of its weight comes from fuel. It would obviously be drained of unnecessary fuel and payload for the trip back to the US to reduce the workload on the launch platform. The zero-stage launch platform would use conventional, hydrocarbon fuels for all points in its mission, landing at specific points around the globe to refuel.
After being brought to mach 3.5 by the zero stage launch platform, the SHAAFT would release and pitch up, automatically initiating the start of ramjets. From there, it would accelerate and increase in altitude until it reaches the cruise phase.
The cruise phase, at mach 12 and 100,000 feet, consists of the majority of the flight, including attack or SCREMAR transatmospheric vehicle deployment. The SHAAFT would continue at its cruise speed throughout the entire envelope, with the exception of takeoff, landing. This is due to safety considerations for the SHAAFT. If it entered or departed the target area at a much slower speed, to reduce negative aerothermodynamic effects, it would be vulnerable to more conventional types of attack. For instance, if an enemy country expected a SHAAFT attack, it could set up remote-based (possibly sea based, fleet launched) aircraft or SAM sites that do, and most likely will, have the capability in 2025 to destroy mach 5+/- aircraft.
In the attack phase, the SHAAFT would launch missiles/munitions from a considerable distance away from the target. It would have to release its munitions early in the attack phase to allow the munitions to acquire and adjust its course at such high speeds. Once the munitions were released, the SHAAFT would most likely make a constant 2-g turn and head back to the planned landing base. The precise routing would have to be precisely planned knowing that a 180 degree turn going mach 12 may take place over several countries.
If the SHAAFT were launching an orbital vehicle such as the SCREMAR TAV, it would takeoff, adjust its course to get to the desired inclination, and release the TAV going mach 12 at 100,000 feet. This gives the orbital vehicle an extreme advantage in potential and kinetic energy. An even greater advantage is that space access vehicles could be launched from any long runway in the world, rather than specific launch sites. This would be of an extreme advantage in wartime when it is possible and likely that our space centers will be a primary target.
The landing phase would begin approximately 30 minutes prior to landing. While at cruise phase, the SHAAFT will shut down engines and decelerate to subsonic speeds to begin convectively cooling the skin surface. The glide aspects will be very similar to current Space Shuttle landings. It will continue gliding until touchdown, where the pilot can maintain control during the most critical phase of flight. The onboard computers would assist the pilot in setting up the airspeed and altitude adjustments to avoid pilot error.
The landing gear will be relatively small and only capable of operation during landing (due to the zero-stage launch platform). Since the aircraft weight is reduced dramatically during cruise flight (fuel is an enormous percentage of the total weight), and substantially during takeoff with the launch platform, the landing gear does not need to be extremely heavy, at least in comparison with take off requirements. This also assists in overall aircraft design by drastically reducing the weight fraction of the landing gear.
The flying wing zero stage was able to lift the SHAAFT off the ground at conventional airspeeds. But the SHAAFT, being an aerothermodynamically configured vehicle for mach 12 cruise flight, would have much less lifting capability at traditional landing speeds. Therefore, it would have to land at high speeds, nearly 250-300 mph, which is similar to Space Shuttle landing speeds. In order to land this vehicle on large, but typical runways, a self-contained arresting system consisting of drag parachutes being deployed and extremely powerful brakes being applied upon landing would be incorporated into the design.
The inherent attack advantages of a hypersonic cruiser must not degrade its attack capability by deploying slow speed and ineffective munitions. Therefore, the focus of weaponry to be added to the SHAAFT should be newly designed and developed weapons that are capable of supersonic/hypersonic speeds and contain extremely lethal yields. At first sight, the SHMAC missile is an excellent complement to the SHAAFT in that it flies at hypersonic speeds and is extremely lethal. It should also increase the range of the SHAAFT by approximately 1,000 nautical miles. This could allow the SHAAFT to either carry less fuel and more payload (weapons) or be more simply designed with less required weight (in fuel and range). It would also allow the SHAAFT to stay well out of enemy defense zones by using the less expensive, expendable SHMAC to fly into the threat zone. These two systems would be of excellent complement to each other.
Another nearly ideally complementary system to the SHAAFT is the space access mission complement that can be accomplished. With a typical TAV, the size of a light F-15, the SHAAFT could be a rapid, reusable, and extremely advantageous launch platform. It could carry TAV vehicles with the capability to launch them into orbit at any inclination and give them an initial, "free," boost to 100,000 feet and mach 12. This would be of extreme benefit to the simplification of the design of the still futuristic TAV concept.
The primary considerations are that weapons be developed with varied capabilities to be able to attack multiple types or targets depending what appears at the moment as the primary threats. In addition to the SHMAC, penetrating rods, flechettes, conventional bombs, self-guided antiarmor munitions, subnuclear munitions, and whatever is developed in future years are all possible payloads for the SHAAFT. They would all have to be developed much further, but there is a potential for some extremely powerful and lethal weapons arising from hypersonic speeds.
Overall, the SHAAFT has an extremely varied capability either to attack to or be used as a mother vehicle for various other missions. The standard payload area should be able to accept a myriad of different weapons and clusters of weapons. It should be capable of striking not only multiple targets in one sortie, but striking different target types with the varied types of munitions it can carry. For instance, it would be very feasible for the SHAAFT to fly abreast of a country the size of Iraq, drop a few SHMAC's at primary C3 facilities, then drop precise antiarmor type munitions at key defensive sites. This capability would almost assuredly destroy the enemy's will and capability to wage war within a matter of several hours and a few sorties. High-value targets are key to success. With such a capability, it is assured that we could, on demand and nearly always, completely and definitively put a stop to the war before it begins.
Threats to the SHAAFT
Two possible threats that the SHAAFT could encounter are interceptors or laser weapons. The problems that an interceptor would face are enormous. It would have to detect, track, identify, launch, accelerate while climbing to 100,000 feet, and then overtake a target moving at 12 times the speed of sound. An interceptor that could do this would have to be traveling on the order of mach 20. Even if the enemy did spend the money to develop this super surface-to-air missile (SAM), where would they put it? It does no good to place it near key targets because the SHAAFT is releasing its cruise missiles from 1,000 miles away! An enemy would have to create a ring of super SAMs thousands of miles long around its entire perimeter to keep the SHAAFT from entering. However, if the SHAAFT launches its payload from 1,000 miles out to sea, or over a neighboring country, little ground protection exists.
The other potential threat comes from lasers. The advantage that the laser has is that it can nearly instantaneously track and then fire at a moving target. It does not have to catch up to its target nor can it be outmaneuvered. But its disadvantage is its range and power supply. A laser that was powerful enough to reach both hundreds of miles downrange to the SHAAFT and 100,000 feet in altitude would require enormous energy stores.14 A facility to supply this type of power could not be placed in a van and hidden on a mountain top. It would be a sprawling, high visibility complex that would be easily visible. Once again, if Special Forces units could not neutralize it before the attack occurs, the SHAAFT could attack the site from a thousand miles away or avoid it altogether.
The idea of the Supersonic/Hypersonic Attack Aircraft was derived by taking a look at what the U.S. Air Force will need to accomplish in the year 2025. Gone are the massive enemies of east and west; gone also are the large budgets which could support their armies. Now the United States must deal with regional threats, in a timely manner, in a costly manner, and in a manner safe to the members of U.S. armed forces. The SHAAFT is simply a tool to achieve these ends.
Hypersonics drives the missions of the SHAAFT. The infrastructure-intensive framework of supporting a fleet of turbine-driven attack aircraft reduces to a few supporting facilities in CONUS bases that support the SHAAFT. But the SHAAFT does not replace all existing and future Air Force inventory--it is a means to prevent the costly use of all other weapons. It saves money.
The SHAAFT has been designed to promote the proper usage of energy. By staging, it leaves bulky turbine engines on the ground as it completes the hypersonic attack role. By going hypersonic, the survivability of the SHAAFT increases tremendously. As of now, no known defensive weapons counter the SHAAFT threat; it simply flies too fast and too high. Upon completion of the mission, the aircraft would shut down engines and land on conventional runways, deploying drag parachutes to reduce the braking required. Such braking would occur with landing gear that has already been reduced greatly in weight due to the light airframe that would land back in the CONUS (the flying wing staging aircraft is equipped with bulky, expensive landing gear).
Technological improvements will be required to formalize this design. An operational ramjet/scramjet is key to designing such an aircraft. Aeroacoustic loads on the airframe cause many mechanical loading problems. Aerothermal heating requires the use of advanced heat dissipation materials. Command and control of the aircraft would require computational software and a hydraulics system that can perform under extreme circumstances. But many of the technologies for SHAAFT would be drawn from existing areas of research. The flying wing zero stage would utilize designs from the high-speed civil transport program. Waverider studies would finalize the design of the SHAAFT. Hypersonic research of ramjets would be used for power plant designs. Such measures should be easy in the information-rich age of 2025.
Imagine a single aircraft that could fly up the Mississippi River and simultaneously destroy key facilities at Falcon AFB, Colorado, Cape Canaveral, Florida, and Washington, D.C. A similar blow to some rogue nation would cause them to seriously question their current military and political endeavors. If you ignite conflict with the US, the motto is You'll Get The SHAAFT!
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