Tandem, or in tandem, is an arrangement in which two or more animals, machines, or people are lined up one behind another, all facing in the same direction. Tandem can also be used more generally to refer to any group of persons or objects working together, not necessarily in line.
The English word tandem derives from the Latin adverb tandem, meaning at length or finally. It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise".
The Grumman F-14 Tomcat is an American carrier-capable supersonic, twin-engine, tandem two-seat, twin-tail, all-weather-capable variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental (VFX) program after the collapse of the General Dynamics-Grumman F-111B project. A large and well-equipped fighter, the F-14 was the first of the American Teen Series fighters, which were designed incorporating air combat experience against smaller, more maneuverable MiG fighters during the Vietnam War.
The F-14 first flew on 21 December 1970 and made its first deployment in 1974 with the U.S. Navy aboard the aircraft carrier USS Enterprise, replacing the McDonnell Douglas F-4 Phantom II. The F-14 served as the U.S. Navy's primary maritime air superiority fighter, fleet defense interceptor, and tactical aerial reconnaissance platform into the 2000s. The Low Altitude Navigation and Targeting Infrared for Night (LANTIRN) pod system was added in the 1990s and the Tomcat began performing precision ground-attack missions. The Tomcat was retired by the U.S. Navy on 22 September 2006, supplanted by the Boeing F/A-18E/F Super Hornet. Several retired F-14s have been put on display across the US.
The McDonnell Douglas F-4 Phantom II is an American tandem two-seat, twin-engine, all-weather, long-range supersonic jet interceptor and fighter-bomber that was developed by McDonnell Aircraft for the United States Navy. It entered service with the Navy in 1961, then was adopted by the United States Marine Corps, and the United States Air Force, and within a few years became a major part of their air arms. A total of 5,195 Phantoms were built from 1958 to 1981, making it the most-produced American supersonic military aircraft in history and a signature combat aircraft of the Cold War.
The Phantom is a large fighter with a top speed of over Mach 2.2. It can carry more than 18,000 pounds (8,400 kg) of weapons on nine external hardpoints, including air-to-air missiles, air-to-ground missiles, and various bombs. Like other interceptors of its time, the F-4 was initially designed without an internal cannon, but some later models incorporated an internal M61 Vulcan rotary cannon. Beginning in 1959, it set 15 world records for in-flight performance, including an absolute speed record and an absolute altitude record.
An articulated bus, also referred to as a slinky bus, bendy bus, tandem bus, vestibule bus, stretch bus, or an accordion bus, is an articulated vehicle, typically a motor bus or trolleybus, used in public transportation. It is usually a single-decker, and comprises two or more rigid sections linked by a pivoting joint (articulation) enclosed by protective bellows inside and outside, and a cover plate on the floor. This allows a longer legal length than rigid-bodied buses, and hence a higher passenger capacity (94–120), while still allowing the bus to maneuver adequately.
Due to their high passenger capacity, articulated buses are often used as part of bus rapid transit schemes, and can include a mechanical guidance system and electric bus or trolleybus.Articulated buses are typically 18 m (59 ft) long, in contrast to standard rigid buses at 11 to 14 m (36 to 46 ft) long. The common arrangement of an articulated bus is to have a forward section with two axles leading a rear section with a single axle, with the driving axle mounted on either the front or the rear section. Some articulated buses have a steering arrangement on the rearmost axle that turns slightly in opposition to the front steering axle, allowing the vehicle to negotiate tighter turns, similar to hook-and-ladder fire trucks operating in city environments. A less common variant of the articulated bus is the bi-articulated bus, where the vehicle has two trailer sections rather than one. Such vehicles have a capacity of around 200 people, and a length of about 25 m (82 ft); as such, they are used almost exclusively on high-capacity, high-frequency arterial routes and on bus rapid transit services.
The Lockheed SR-71 "Blackbird" is a retired long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft that was developed and manufactured by the American aerospace company Lockheed Corporation. Its nicknames include "Blackbird" and "Habu".
The SR-71 was developed in the 1960s as a black project by Lockheed's Skunk Works division. American aerospace engineer Clarence "Kelly" Johnson was responsible for many of the SR-71's innovative concepts. Its shape was based on the Lockheed A-12, a pioneer in stealth technology with its reduced radar cross section, but the SR-71 was longer and heavier to carry more fuel and a crew of two in tandem cockpits. The SR-71 was revealed to the public in July 1964 and entered service in the United States Air Force (USAF) in January 1966.