The Valiant was a large flying aircraft carrier used by UNIT during the early 21st century. It contained various rooms including a conference room and many engine corridors.
History
Every detail of it was designed by "Harold Saxon", and it was used for the first Human contact with the Toclafane. (DW: The Sound of Drums) The Doctor, Martha Jones and Jack Harkness teleported onboard using Jack's Vortex manipulator at the co- ordinates 58.2 North 10.2 East.
In the following year in an erased timeline, the Valiant formed the base of operations for the Master. The Jones family (with the exception of Martha Jones, who had escaped and Leo Jones) and Captain Jack Harkness were imprisoned on the ship, as was the Doctor. It also held the paradox machine inside the Doctor's TARDIS. When the timeline was erased, the Valiant was the only point in space and time not to revert, instead moving directly through time, due to it being the "eye of the storm", that is, of the paradox machine. (DW: Last of the Time Lords) This effectively makes anyone who was on the Valiant to begin with and off it at the reversal killed by Jack, and anyone the opposite way around having a duplicate on Earth.
The Valiant was fitted with a mounted energy weapon almost identical to the gun used to destory the Sycorax meaning the technology could have been salvaged from the remains of the Torchwood institute. During the Sontaran invasion of Earth in 2009 Colonel Mace called in the Valiant which was referred to as Hawk Major. The powerful turbines were used to clear the Sontaran's fog away from the ATMOS factory and the energy weapon was used to blast apart the factory, killing many Sontarans. It is unknown if the weapon was installed after the Master's defeat or if Harry Saxon himself had it incorporated into the initial design.
The Valiant was eventually destroyed when the New Dalek Empire attacked Earth following its transportation to the Medusa Cascade. A massive invasion force of Daleks swarmed the ship, destroying it with their laser guns. (DW: The Stolen Earth)
- Over the comms system Jack Harkness heard a soldier reporting that the shields were down which could mean that the Valiant also had some kind of protective force-shield.
Propulsion
The Valiant used what appeared to be large Turbofan engines.
The Valiant seems to be able to rotate these engines to lower itself toward the ground as seen in (DW: The Poison Sky) As it was designed by the Master, it was more advanced than any current Earth vehicle due to the fact that it has been previously mentioned to have had the reverse-engineered Jathaa sunglider technology built into it. As a back-up it could have some alternative form of travel, like Anti-gravity propulsion. All of which allow it to not only hover high in up in the Earth's atmosphere but to move across the globe to any destination deemed necessary.
Weapons
It is unknown what sort of weapons the Valiant utilises, Apart from the reverse-engineered Jathaa Sunglider weapon. It could possibly feature a series of CIWS turrets and short range missiles, but as a United Nations ship it might not as it is stated to be neutral territory (DW: The Sound of Drums)
Behind the Scenes
The Valiant's design was very similar to that of Cloudbase, the headquarters of Spectrum from Captain Scarlet and the Mysterons and to Helicarriers used by the fictional Marvel Comics organization SHIELD. The Valiant's weapon system looks like the one that was salvaged from a Jathaa sunglider and the Death Star's planetkilling weapon system from Star Wars. A similar-looking vessel, commanded by an elite British air corps, also appears in the fantasy film Sky Captain and the World of Tomorrow.