The 3707 is a variable-geometry passenger and freight vessel with a length of 86.5 meters and a wingspan of between 45.9m and 85.8m. Debuting in the late-2200s, it was capable of transporting passengers and cargo between any two sufficiently large runways at speeds of over Mach 12 and was seen as a beacon of versatility. Its main wings can extend to maximise lift during subsonic operation, sweep backwards to minimise structural load and drag during supersonic flight and ascent to orbit, and in later models, its canards can sweep upwards during re-entry to maintain a high-drag profile, allowing it to access orbital space stations and ground-based airfields.
Douglas 3707
Development
Development of the 3707 officially started with Douglas Aerospace Corporation's VLHST (Very Large Hypersonic Transport) program at the turn of the 2270s, with the proliferation of scramjets in aerospace applications. This and the development of lightweight solutions to thermal management during hypersonic cruise led to an arms-race between several of the largest aerospace manufacturers: NASA, on the behalf of the United Alliance; Douglas Aerospace Corporation, on the behalf of America; and Strauss Aerospatiale, on the behalf of Europe. These companies raced to develop a competitor for the Douglas DAC-10 Skyfarer and Strauss A-C38 subsonic heavy transport aircrafts, capable of transporting cargo and passengers at speeds upwards of Mach 12, while carrying a similar capacity to the aforementioned heavy models. The primary advantages the VLHST program had over older, obsolete programs such as Concorde and the Boeing 2707 were the introduction of scramjets and lightweight heat shielding, and the reduction in fuel spent per mile of travel implicit in achieving hypersonic speeds.
The VLHST program, and development of the 3707, would halt in 2278. It resumed several years later in 2286 following the success of several hypersonic bombers developed by NASA during the interstitial that led to advances in the design of the scramjets required for hypersonic flight and the lightweight insulation needed to withstand aerodynamic heating for hours at a time. This pause in development also allowed further time to reduce the weight of the components responsible for moving the variable-sweep wings. Between 2289 and 2291, the 3707 would undergo several revisions before Douglas Aerospace Corporation began taking orders from airliners.
Entering service several years after the Strauss AX-58, a competing aircraft akin to a scaled-up Concorde, the 3707 suffered setbacks after a series of disasters occurring during hypersonic cruise relating to the expansion of the hull during thermal stress. Nevertheless, the 3707 remained in service for almost seven decades, albeit it never caught up with its European competitor.
Design
The 3707 airframe takes the basic shape of a lens in its front profile and stretches back, ending with the rearward tail, with the upper decks protruding softly from just above the nose to 3/4ths the length of the frame.
Performance
During subsonic and supersonic flight below FL600, the 3707 operates in an open cycle mode, in which air is allowed to flow into the aircraft via its PACKs. When hypersonic speeds, or altitudes exceeding FL600 are achieved, the 3707 transitions to a closed cycle mode, in which the PACK valves are shut and the on-board air is supplied and regulated via an on-board air supply.
Strauss A3707
In 2337, nearly two decades before the retirement of the 3707 series, a joint venture between Strauss Aerospatiale and Douglas Aerospace Corporation would see a modernisation of the classic 3707. This collaboration would see several fatal flaws from earlier designs ironed out. Most notably, a flaw in the microcorrugations of the hull in earlier models that caused rapid failure of the hull under some circumstances.
A3717-X
An experimental model seeing service between 2360 and 2410, the A3717-X began as an experiment in fitting RCS jets and chemical rockets to permit a climb to orbit from hypersonic cruise. While initially only considered a testbed for the development of heat shielding, it saw limited service in transporting resources between orbital outposts and Cape Canaveral.
A3701
A shortened variant of the A3707, entering service in 2351 and seeing retirement in 2380.
A3707-R
The Refit model was introduced in the 2380 by Universal Aérospatiale under Strauss-Douglas as the A3707-R, under an increase in demand for vessels capable of bridging passengers and cargo between standard airports on Earth and orbital points of interest. The refinement and miniaturization of several technologies including fusion engines and passive radiation allowed these technologies to debut on the Refit model. Its lower surface is coated with lightweight insulation and its upper surface acts as an effective passive radiator, allowing for a safer thermal profile at all flight regimes. The addition of RCS thrusters and a fusion engine allows it to reach orbit, manoeuvre effectively in space and reach almost anywhere within the Solar System. The 3707-R saw large-scale use during its service before the newer A4000 series rendered it obsolete.
Design
The A3707-R airframe is fairly similar to its predecessor, albeit with several differences: instead of tapering nearly to a point, the back of the hull serves as a fairing containing the fusion engine and power plant responsible for providing thrust during spaceflight, and the one vertical stabilizer on the classic 3707 is replaced with a dual vertical stabilizer. Control during high AoA manoeuvres, such as re-entry and stall recovery, is performed by the swivelling of the canards and vertical stabilizers on the forward axis. This also helps maintain aerodynamic stability in spite of a backwards-offset center of mass incurred by the additional weight of the engine and fairing, helped also by the lifting properties of the fairing. To combat aerodynamic instability, the front canards were reduced in size and the maximum sweep of the main wings was increased to 65 degrees, adjustments which both also reduced hull stress during re-entry.
Specifications
Characteristics
Crew: 3 on duty, 4 occupants
Capacity: 35 passengers
Length: 86.5m
Wingspan: 45.9m to 85.8m
Max wingsweep: 65°
Wing area: 477m2
Max interior width: 12.3m
Height: 9.26m
Empty weight: 260t
Max Takeoff Weight: 610t
Fuel capacity: 260t
Powerplants: 6x Olympian Reheating turbofans, 73,300lbf each; 2x Infinity scramjet, 1,500,000lbf each; 1x Zeus TMZ-600 Compact Fusion Reactor, 15,000,000lbf
Performance
Runway requirement: 10,000ft
Scram cruise speed: Mach 13.5 (temperature limited)
Maximum re-entry speed: Mach 24 (heat shield depending)
Reheat cruise speed: Mach 3.5
Supercruise speed: Mach 2.6
Range: 5,500nmi
Open-cycle ceiling: 80,000ft
Stall: 160-175 @ Flaps 40, 200-230 @ Flaps 0
Rate of climb: 6-7,000fpm
Spaceflight
50t Fusion Pellets
260t Jet Fuel
Zeus ICE Stats:
Exhaust velocity: 10,600km/s, Capable of 12g at max load
dV provided 50t Fusion Pellets and 260t Jet Fuel:
Initial mass: 570t Final mass: 520t dV: 973.2km/s
dV provided 50t Fusion Pellets and no Jet Fuel:
Initial mass: 310t Final mass: 260t dV: 1864km/s
dV provided 100t Fusion Pellets, and no Jet Fuel:
Initial mass: 310t Final mass: 210t dV: 4128km/s
Anatomy
Deck 3 (Flight & Living)
Flight Deck
The center of operations during atmospheric flight, this part of the vessel houses the main consoles to be used by the captain and first officer, and a flight engineer console to be used by the flight engineer. This deck is overlooked by a large window providing the crew direct visual contact with the outside environment. Digital cameras and basic mirror instruments are provided for extending the pilots' effective field of view below the nose of the vessel, used commonly during runway landings.
In the scenario that the spaceflight bridge (see: deck 2) is rendered inoperable, the flight deck provides marginal instrumentation for basic space navigation and communication. In the scenario that the flight deck is rendered inoperable, the spaceflight bridge provides instrumentation for standard flight.
Passenger Seating Area
Passenger Seating Area houses 25 seats for short-term passengers and a spiral staircase linking Deck 3 to Decks 2 and 1.
Bathrooms & Quarters
Each quarter houses a bed, a desk, a monitor for monitoring the status of the vessel, a shower, an a toilet.
Dining & Rec
Large rooms for crew and passengers to gather.
Deck 2 (Engineering)
Spaceflight Bridge
Located forward of concourse, the bridge provides advanced instrumentation for spaceflight and heavier shielding than anywhere else on the ship. Three seats mounted such that occupants' backs face the floor and their feet face the back of the vessel provide comfort during 1g burns and tolerable positioning when the vessel is resting under gravity.
Concourse
A large room housing several consoles for monitoring the internals of the vessel with great detail.
Waste & Septic
Mounted directly below the quarters on deck 3. These compartments house equipment for filtering recyclable waste and jettisoning unrecyclable or hazardous waste.
Propellant Tanks
These sectors house tanks that hold resources useful for manoeuvring the vessel, including jet fuel, fusion pellets, and LMP-103S monopropellant.
Maintenance Tunnels
A series of accessways along the hull that allow human crewmembers to personally inspect aspects of the ship and conduct repairs.