The Shrike ACA is a compact, high-speed unmanned VTOL combat platform with both air-to-air and air-to-ground attack capabilities. ACAs are an all-important part of the Directorate Military's combat arsenal and are operated in huge numbers by both the Army as well as the Naval Infantry Corps. Their lack of exoatmospheric capability means they find no use in the Navy, although Directorate warships are capable of manufacturing hundreds of the drone fighters in very short periods for use in planetary invasion campaigns.
The Shrike ACA's fuselage is no longer than a small early 21st century four-door car and considerably more narrow, although its wings give it a wider silhouette overall. Unlike most other Directorate fighter and bomber craft, the ACA is non-exoatmospheric, meaning it cannot leave or enter a planetary atmosphere under its own power, and is of a fairly conventional shape that would be readily familiar to aircraft engineers of the current era. The Shrike employs a delta wing design with twin tails, bearing an overall resemblance to the Dassault Rafale or Eurofighter Typhoon jets - albiet covered in black nonreflective stealth plating and with a considerably sleeker, radar-deflecting shape. Each ACA has four weapons pylons under its fuselage: one roughly centered beneath each wing and another just outboard of either side of the fuselage, at the wing roots. There is also a 23mm magnetohydrodynamic gun running ventrally down the middle of the fighter's belly, although space limitations prevent the craft from carrying a large supply of ammunition.
The Shrike ACA's more conventional aerodynamics, as compared to manned Directorate aircraft, is due to its strictly atmospheric nature as well as interior volume limits. Having less internal volume than a typical 20th century compact car leaves little room for non-essentials, even when counting the absence of any human occupants. As such, the small strike craft cannot afford space for sets of secondary pulse jets for maneuvering and control, but instead must rely on conventional flaps and rudders, while its lack of full-coverage energy screens [which would vaporize any air molecules before they reached the aircraft] means it must contend with conventional problems of drag, lift and airflow. Never the less, its formidable power-to-mass ratio, lack of G-force sensitive human occupants and small size means that it can still pull extremely high speeds and conduct complex aerial maneuvers even under maximum thrust. The Shrike is driven by four thrust-vectoring hydrogen ion engines slaved to a pair of very compact nuclear reactors. Unlike most larger Directorate aircraft, precious space was devoted to a converter system that breaks apart hydrogen and oxygen molecules, allowing the drone fighter to be "refueled" with simple fresh water from any planetary lake, river or stream.
Unlike most other Directorate Combat Automata, the Shrike's ancestors have seen centuries of military use: this particular ACA is simply the latest generation of a long line of UAVs stretching all the way back to the times before the Directorate's foundation. The Shrike is a versatile, inexpensive, stealthy and lethal platform deployed in extremely high numbers. Squadrons, and even whole Wings, of the craft can be autonomously guided by a single augmented human or A.I., although the majority of their computing functions are done by their own CPUs on the fly. Despite lacking any ability to vocalize or manipulate objects, they understand human speech and are actually far more intelligent than most other Combat Automata. Moreover, producing one costs less time, resources and money than the powered armor exoskeletons issued to every Army infantry trooper.
Originally, Shrike ACA lacked any kind of integral gun armament and were typically armed with four anti-armor fusion warhead missiles. These powerful, high-speed, energy shielded missiles are capable of destroying even the Directorate's own formidable armored fighting vehicles but are also perfectly adapt for cracking open hardened structures / positions as well as killing airborne targets, although they are rather overpowered for this latter-most task. However, the rise of the Mortis has seen them fitted with a permanent 23mm Magnetohydrodynamic gun for defending against swarms of airborne alien Constructs, while the anti-armor missiles are often traded for more general purpose explosive missiles with much larger blast radii, allowing the drones to effectively obliterate swarms of land-bound enemy creatures.