The UD-4 Utility Dropship, better known colloquially as the "Cheyenne", is a type of combat utility spacecraft manufactured by UA Northridge and primarily used by the United States Colonial Marine Corps. The Cheyenne is designed for rapid troop deployment, dropping from the belly of USCM spacecraft in orbit and delivering Marines and equipment quickly to a planet's surface. They typically carry the M577 Armored Personnel Carrier, although they can also be used to transport other equipment and even Marines directly in the field.
The UD-4 has the ability to take off and land vertically from unprepared sites, and can also operate as a ship-to-ship transport. Additionally, the Cheyenne has many variable weapons hardpoints and a fixed internal cannon, allowing it to be used in a gunship role in support of ground troops.
- 1 Development and Overview
- 2 Flight
- 3 Armament
- 4 Variants
- 5 Notable Ships
- 6 Behind the Scenes
- 7 Trivia
- 8 Appearances
- 9 Gallery
- 10 References
- 11 Navigation
Development and Overview
The Cheyenne evolved from a Department of Defense requirement formulated at the end of the Tientsin conflict that called for a multi-role light aerospace shuttle with vertical take-off and landing (VTOL) capabilities, able to lift loads of up to 16,000 kg into orbit. Although initially designed as a pure transport, the UD-4's abilities have since been expanded to include operation as a close-support gunship. Since its inception, the Cheyenne has proven to be a stable and reliable platform, extremely popular with pilots, and has become arguably the definitive dropship design, influencing numerous derivatives and successors. Despite its complex construction and maintenance requirements, it is famed for its reliability and combat survivability, with some units claiming never to have dropped below 95% operational capacity.
The primary airframe, a structural web extending the length of the craft and encompassing the payload bay, is constructed of superplastic-formed diffusion-bonded metal matrix composites (MMC) — structural members are formed from gold- and chrome-doped zirchonium oxide-reinforced fibers in a titanium aluminide matrix, giving exceptional lightness, strength and oxidation resistance. The fuselage skin consists of tri-layer plates — an inner carbon-carbon composite layer bonded to a middle layer of single-crystal carbon (able to withstand the heating of atmospheric re-entry), with a ceramic outer layer provides thermal and oxidation resistance during high-altitude, high-speed flight.
In line with its primary role as a transport vehicle, the Cheyenne is constructed around its 103.6 cubic meter (9.5 l 4.5 w × 2.4 h) payload bay. The bay includes a 3.92 meter wide, hydraulically-activated deck ramp, able to carry a fully-loaded M577 APC or a HALOS stores pallet and raise the cargo completely into the payload space from ground level. Automatic latches within the bay extend to hold the cargo securely in place once the deck is raised. An additional small gantry for crew access is found at the rear of the payload space.
Either side of the payload bay are the Cheyenne's fuel tanks and weapons bays, with the cockpit forward. To the rear is additional fuel tanking and oxidant tanks for extra-atmospheric flight, as well as a small bay housing the craft's Fire Control Jamming Suite (FCJS) towed drone, ahead of the butterfly-tail control surfaces. The Cheyenne features a retractable tricycle skid undercarriage, including an oversized rear skid strut able to absorb the impact of repeated planetary put-downs.
Survivability is high on the list of UD-4 features, and the airframe has proven crashworthy at low speeds and altitudes. The cockpit, fuel tanks and engine cowlings are protected by a sandwich of Venlar ballistic armor layers sufficient to stop light ground fire and spent missile fragmentation, while the craft's ceramic outer skin provides limited ablative properties against pulsed lasers. Though not designed to slug it out with ground or space defenses, the Cheyenne has proven to be exceptionally rugged, capable of withstanding considerable punishment while still remaining airborne.
However, it should be noted that the dropship can be prevented from lifting into orbit by only light damage. Any breach of the fuselage skin will seriously compromise the craft's high-speed thermal protection, while even a tiny hole can cause oxidation or "burn through" when atmospheric speeds exceed Mach 5.0. As a result, a sensor net is bonded to the inside of the skinning to monitor for breaches, differential hull temperature and ionization. If a breach is detected, a warning is flashed to the cockpit monitors to notify the crew.
In order to operate in all speed and altitude regimes from VTOL hover to hypersonic trans-atmospheric flight, the UD-4 has two types of powerplant, both of which incorporate variable geometry to allow them to operate in such a wide range of flight windows. The main engines are a pair of Republic Dynamics TF-900 variable-cycle turbines, each producing 310 kN of static thrust. At subsonic speeds, these operate as turbofans, generating the massive thrust required for VTOL operation whilst also providing superior fuel efficiency. During horizontal flight, engine exhaust is ducted through the dropship's aft variable nozzles; in hover, core air is sent aft while fan bypass air is ducted forward, to the craft's vertical exhaust nozzle, located beneath the cockpit. During supersonic flight, the turbines' bypass air is instead routed through the core, and they operate as turbojets capable of supercruise. The redundancy offered by the Cheyenne's twin-engine layout serves to increase safety, and the ship is capable of flying and hovering on only one engine whilst still half-loaded.
In addition to its turbines, the UD-4 is also fitted with two TF-220/A-14 ramrockets for high-altitude high-speed flight. As with the turbines, these engines feature variable geometry to allow them to operate at a wide range of speed envelopes, working as ramrockets from the supersonic to hypersonic regimes and switching to pure rocket power for trans-atmospheric flight. At low speeds (below Mach 1.5), the ramrocket is extremely inefficient, but efficiency increases progressively as the dropship approaches Mach 2, at which point the engine comes into its own. At this point, the Cheyenne's main turbine engines are generally shut down and the transition is made to ramrocket power. Maximum speed on ramrocket power is anything up to Mach 12. When approaching a planetary body's atmospheric boundary, the ramrocket converts to pure rocket engine, at which point the UD-4's onboard supply of oxidant is added to the fuel mix for extra-atmospheric flight.
During standard shuttle operations, the Cheyenne will usually carry sufficient fuel to drop from orbit and return for a low-orbit rendezvous with its parent ship. Drops can be carried out both powered and unpowered, although a burn from the rocket engines is usually required to enter a descent envelope from orbit.
Crew and avionics
The Cheyenne has a crew of two, comprising a pilot and a Crew Chief/Weapons Officer. The spacious pressurized cockpit is accessed by way of a ladder at the front of the payload bay — this ladder is telescopic to allow access even when the cargo ramp is lowered. Within the cockpit, the flight crew sit in tandem, with the pilot ahead and to the right of the Weapons Officer. The Martin-Siekert R2102 ejection seats are cleared for operation at any altitude below 10,000 m and speeds below Mach 1. In the event of an emergency, explosive cord blows off the Cheyenne's canopy, allowing the crew to eject safely. Canopy transparencies are made from single-crystal quartz and flash-coated with gold, germanium, molybdenum and iridium to provide protection against bright light and short-wavelength lasers. The coatings also act as a radar reflecting surface, preventing the entire cockpit volume from becoming a radar-reflecting cavity.
The instrumentation and control layout is essentially conventional, with a right-handed displacement-type control stick and left-handed throttles. An array of fingertip buttons allow for hands-on-throttle-and-stick control of key sensors, weapons and defense aids. Flight systems employ digital fly-by-light controls overseen by a powerful Herriman-Weston 5/480 flight computer. In flight, engine thrust and exhaust nozzle settings are automatically set to their optimum positions depending on speed, altitude, and the pilot's throttle and stick input. The dropship also features an intelligent autopilot facility that allows the computer to fly all phases of a mission profile with no physical pilot input, including ingress and egress to the target zone as well as landing and docking cycles. The Cheyenne features no manual reversion capability since the craft is too inherently unstable to be flown without computer assistance. The UD-4's avionics are specifically designed to facilitate maximum cockpit efficiency. Essential flight information is provided to the pilot as required on a wide-angle heads-up-display (HUD) and three integrated multi-function displays (MFDs). A voice control system helps reduce the pilot's workload and can be employed for data entry, selecting communications channels, switching operating modes for the MFDs and weapons selection.
At subsonic speeds, the lifting body configuration generates little lift and the pilot becomes increasingly reliant on the flight software and lift from the vectored thrust engines to keep the dropship stable in the air. Stall speed is very high, and as the Cheyenne approaches the stall it tends to fly increasingly nose-high. As transition is made through the stall speed, vertical lift from the nose and stern nozzles are bled in to prevent departure.
Though the airframe is nominally stressed to +6 g, manoeuvres in conventional flight greater than +3 g are prohibited due to the excessive stall speed, which can cause the Cheyenne to prematurely depart controlled flight. When fully loaded, turns greater than +1 g are prohibited. At very low speeds and at altitudes below 500m, VTOL hovering flight is recommended. The Cheyenne is at its nimblest in the hover; here, response is crisp in all axes and the dropship is a very steady weapons platform.
GAU-113/B rotary canon
The UD-4 incorporates a nose-mounted GAU-113/B, a 6,000 rpm, six-barrelled 25 mm rotary canon driven by a pneumatic motor turned by the craft's engines. The gun is mounted in a powered cupola beneath the nose that can rotate 180 degrees to either side and by an angle of 60 degrees downwards. Ammunition for the gun consists of a mix of Armour Piercing Incendiary (API), Armour Piercing Discarding Sabot (APDS) and High Explosive Incendiary (HEI) rounds, fed from a 900-round drum beneath the cockpit. Typically, a dropship will carry at least two spare ammo drums on board, which can be reloaded manually by a crew member from inside the cockpit.
Notably, the caseless rounds for the canon do not carry their own propellant; instead, the GAU-113/B uses a binary propellant system in which hypergolic liquid fuels, stored and loaded separately, are fed into the chamber via spray nozzles, reacting simultaneously to explode and propel the shell. Such binary propellant systems are unusual (the only other such weapon in USCM service is the RE700 mounted aboard the M577 APC) but offer significant weight, rate-of-fire and reliability advantages over traditional caseless weapon designs.
In addition to its internal canon, the UD-4 can also carry a variety of explosive ordnance in its weapons pods and secondary weapons bays. The two primary weapons pods are attached to cross-folded pylons mounted just forward of the ramrocket intakes, which sit flush against the fuselage when stowed. During subsonic flight, these 4.4 m pylons can be deployed crosswise to expose the ordnance within the pods. However, they cannot be deployed at anything above subsonic speeds due to the adverse drag and torsion effects the pylons would generate. The pods contain weapon hardpoints capable of carrying up to 16 Banshee rockets, six Zeus rockets and four SGW guided missiles each.
Two secondary weapon bays on the port and starboard side also fold flush against the dropship fuselage when not in use, but will swing out to expose the ordnance within and allow exhaust space for weapons launch; unlike the main weapon pods, the secondary bays can be deployed at supersonic speeds up to Mach 2.4 without adverse effects on dropship handling. These bays house a further 14 hardpoints for air-to-air and air-to-ground missiles, as well as Matra-IL rocket pods.
Mk.16 Banshee 70
The 150 mm Banshee 70 system is unquestionably one of the most important unguided weapons in service with the United Americas. In Colonial Marine use, it is most commonly associated with the UD-4 dropship, being found in the 16-tube LAU-190/A launchers mounted in the Cheyenne's weapons pods. An 150 mm unguided, spin-stabilized air-to-surface munition, the Banshee can be fitted with a variety of warheads for a wide range of mission profiles.
Mk. 10 Zeus
The Mk.10 Zeus is a 70 mm unguided rocket that has been in USCM service for over sixty years, in its various forms. A small, spin-stabilized rocket, the Zeus can be fitted with either a smart-fused antipersonnel fragmentation warhead or a smoke warhead for laying particulate smoke screens.
The Mk.88 SGW is a short ranged (under 1,500 m) 120mm guided missile designed as a simple, cheaper alternative to the Hellhound II versus light armor and prepared positions such as hangars or gun emplacements. It comprises a rocket with a low-impulse motor steered by fold-out fins and guided by an imaging infrared seeker in the nose. It carries a 2.2 kg shaped-charge warhead. The SGW is a fire-and-forget weapon — once a target has been locked-up by the dropship, the missile self-guides to the target.
AGM-220C Hellhound II
The Hellhound II is a multi-role tactical missile designed for use against vehicles, armor, buildings and bunkers. Based around a greatly enlarged version of the Hellhound I airframe, the missile employs a three-stage motor consisting of a launch boost engine, an in-flight sustained motor and a third-stage booster designed to accelerate the weapon during its terminal attack phase. As well as tracking a designated target selected by the Cheyenne's Weapons Officer, the Hellhound II also features an autonomous targeting mode, in which it will proceed to a given grid reference before commencing a search for targets selected from an internal menu of potential targets, or for a target of opportunity. This dual-seeker system combines a high-resolution millimeter-wave radar and infrared imager linked to a sophisticated 12 Mb processor which determines the missile's optimal attack profile and warhead fusing to ensure a kill. The weapon also incorporates a jam-resistant radar and improved countermeasures rejection logic to overcome enemy countermeasures.
The TSAM (Threat Suppression Attack Missile) is a low-cost self-protection weapon designed to defend against airborne missiles, early warning radars, SAM sites and anti-aircraft artillery. Small, short ranged and lightweight, the TSAM design trades off the loiter mode of most modern threat suppression missiles in favor of speed, in order to eliminate a threat rapidly. The Tekell solid motor is a high impulse unit capable of accelerating the missile to hypersonic speeds in less than two seconds; after burnout, the missile coasts to the target. Range is highly variable dependant on launch speed and altitude, although practical limits in an Earth-density atmosphere are 20 km at sea-level, increasing to 60 km at high altitude. While mounted on its pylon, the TSAM is linked to the dropship's ATLIS threat response system, which can automatically launch a missile the moment an enemy radar, missile or guidance laser threat is detected. The weapon itself contains a passive seeker suite consisting of a wide-band superheterodyne receiver cluster with frequency coverage ranging from the VHF/UHF to the millimeter-wave bands, switching to a millimeter-wave radar for terminal homing, giving the missiles a secondary ground attack capability against non-radiating targets.
The AIM-90E is a short-ranged air-to-air missile optimized for dogfight engagements. The Headlock accelerates to hypersonic speeds after launch and then glides the remaining distance to the target, guided by a dual optical/active radar seeker. The warhead consists of 34 explosive darts that are released by the missile as it approaches the target. To ensure a kill, the Headlock's unique fusing system directs these flechettes into an optimum attack pattern upon release, dependent on the target's current aspect.
Small, unguided rockets fired from the Matra-IL 275 Rocket Launcher Pod, which can be mounted to the hardpoints in the UD-4's secondary weapons bays.
The original production version, powered by Atco Wyoming F23 lift turbines, producing 243 kN of thrust each. This initial model was 1.5 m than later variants and featured less payload space. It also lacked the nose gun and secondary weapons bays.
A gunship variant, this was the first to feature the secondary weapon bays and the GAU-113/B rotary canon.
The "B" variant re-engined with F29-L-13 turbines to provide extended atmospheric range.
The definitive production variant of the Cheyenne, the UD-4H included a major redesign of many systems and components. The fuselage was stretched by 1.5 m to allow an extra 16 cubic meters of payload space, making this the first variant capable of carrying the M577 APC, while the lift engines were upgraded to Republic Dynamics TF-900 variable-cycle turbines, each of which produces 310 kN of thrust. The ship's sensors and avionics were extensively upgraded, while the secondary missile bays and nose canon were now fitted as standard.
A USCM life-extension program upgraded all existing UD-4B airframes to "H" standard, which were subsequently designated the UD-4J.
An upgrade of the "H" version, the UD-4L incorporates an improved sensor and fire control system. It was also the first variant to include a comprehensive defensive suite fit.
Notably, two UD-4L dropships were deployed to Hadley's Hope aboard the USS Sulaco. The first, Bug Stomper, was destroyed in action, while the second, Smart Ass, was lost along with the Sulaco.
Behind the Scenes
Designed to transport personnel through any atmosphere and land on a planet's surface, the dropship is similar in theory to a military helicopter. It has weapons pods that open for aerial strike and a ramp to rapidly deploy an Armored Personnel Carrier (APC) upon landing. The name itself is likely taken from Robert A. Heinlien's novel Starship Troopers, in which similar craft are used to deploy ground forces on other planets. Syd Mead and Ron Cobb both developed concepts for the dropship, but director James Cameron was unsatisfied. Unable to communicate what exactly he wanted, Cameron ultimately constructed his own foam core and plastic miniature that closely approximated what he was looking for.
Cameron loosely based his design on the Apache AH-64 attack helicopter. Cobb then detailed the ship on paper, from which both full-size and 1/12th scale miniatures were made. In keeping with the Vietnam War undertones of Aliens, the dropship purposefully included design elements that evoked Vietnam-era military aircraft, including the F-4 Phantom II fighter jet and the Huey helicopter.
Several dropship props were built for filming, starting with a six-foot model on which all of the other miniatures were based. Most of the dropship miniatures were constructed from fiberglass, and the majority were stunt versions. Only one miniature featured motorized weapons pods and landing gear. The most complicated model to build was the one used for the dropship's dramatic crash sequence, which had to perform several specific tasks during the crash, including shearing off its landing gear and weapons pods on one side and bouncing and banking in a predefined direction. Eventually the model was mounted on two parallel wires that would guide it along its course, with a third wire mounted to the hull to pull it along. Wires were also used for other aerial sequences, such as when the ship first touches down; the supporting wires were then hidden in-camera with fog and rain effects.
The full-size mock-up of the dropship consisted of an aluminum skin formed over a simple wooden frame, while the cockpit interior was built as a separate set. The full-size prop incorporated many parts cannibalized from various aircraft in its construction — the landing gear consisted of the undercarriage from an Avro Vulcan mated with the flare trays from an English Electric Canberra, while the dropship's forward air intakes were taken from a McDonnell Douglas F-4 Phantom II.
Miniature dropship rockets (Mk.10)
This item is part of the miniature used during filming, and consists of the dropship's left wing Mk.10 Zeus rockets. Made primarily from model plastic, these rockets rest on beveled wood and were once mounted inside of the dropship's left rocket pod. Each rocket has been painted with the body tube being white, the nose cone jet black, and the launch engine grey in color. Wrapped around the back of each rocket is a small strip of red tape. The bottom of the miniature features two long strips of wood that have been cut to appear like unistrut, which feature remnants of glue from being attached to the rocket pod.
This item measures approximately 1.5" x 2.5" x 9.5" (4cm x 6cm x 6cm) and features some wear from production use and age, however it remains in overall very good condition.
This item was sold by the Prop Store sometime before November 15, 2013 at 11:07 and was shipped with a Prop Store Certificate of Authenticity. The item was also a Featured item on the New Additions page at the site and was featured sometime before November 15, 2013 at 11:07.
- Both the UD-4 and its successor the UD-6 take their colloquial names from Native American peoples — in the case of the UD-4, the Cheyenne, who inhabited the Great Plains and Canadian Prairies.
- In the video game Predator: Concrete Jungle, Borgia Industries employs VTOL-capable aircraft notably similar to the Cheyenne in appearance. This is likely intentional, as several references in the game link it with the Alien franchise.
- The Cheyenne has served as the inspiration for numerous similar craft in other films and video games, including the D77-TC Pelican dropship in the Halo franchise (just one of several references to Aliens in the series), the Quantradyne APOD-33 dropships in the StarCraft franchise and the aerial Hunter Killers from the Terminator franchise (the first two films of which were written and directed by Aliens director James Cameron).
- Aside from its role as a troop transport, the UD-4 is also operated as a close-support gunship for Marine ground forces. While this is only implied in Aliens, the craft has been used in this role in other media from the franchise:
- In Aliens versus Predator 2, dropships are seen using their rockets against Xenomorphs and Yautja.
- In Aliens: Colonial Marines, a Cheyenne is seen firing upon the second Acheron Queen when it has the player trapped inside a shipping container. Before this, a dropship is also seen engaging other airborne units.
- The Colonial Marines Technical Manual describes dedicated units of UD-4s used primarily in an air support role rather than as transports.
- Additionally, in Aliens vs. Predator, a similar UD-6 "Mohawk" Dropship is seen firing at ground targets before it is shot down.
- Aliens: Colonial Marines Technical Manual
- Aliens versus Predator
- Aliens versus Predator 2
- Aliens: Colonial Marines/Stasis Interrupted (video game)
- AVP: Evolution
- Alien: River of Pain
- Alien: The Weyland-Yutani Report
- Aliens: Defiance
- Empty Nest (mentioned only)
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