The 707's wings are swept back at 35 degrees. This means that the wings are not straight lines. Boeing made a yaw damper for swept-wing planes, which was needed because swept-wing planes move strangely if there is not a yaw damper.
On one flight, the yaw damper was switched off to give the new pilots some more experience with the plane. One pilot made a bad move, and the plane went out of control. Three of the engines were ripped off of the wing. The plane crashed near Seattle at Arlington, Washington. Four people on board died.
In his autobiography, Tex Johnston said he was flying on a 707 and he thought that there was something wrong with the yaw damper, because the plane was moving strangely. He went to the cockpit and helped fix the plane.
The 707 used air from the engines to pressurize the cabin.
The P&W JT3D-3B engines have special doors which open when the plane is taking off. The doors help to give more air to the engines. The doors close when the plane is in the air.
Pratt & Whitney decided to make the JT8D-219 the new engines for planes made from the Boeing 707. A lot of these are for military planes which were designed from the Boeing 707.
The first orders for the 707 happened on October 13, 1955. Pan Am ordered 20 707s. There was a lot of competition between the 707 and the Douglas DC-8. A lot of big airlines only used the DC-8. Boeing decided to make some more changes to the 707's wing so that it could fly further. The new version was called the 707-320.
Pan Am was the first airline that used the 707. The plane's first flight was from New York to Paris on October 26, 1958. It stopped for fuel in Gander, Newfoundland. Qantas was the first airline from outside the United States to use the 707.
The 707 became a very popular jet airliner. It helped air travel grow a lot. Air traffic control was also upgraded.
At the end of the 1960s, the 707 was too small to fly all the passengers that wanted to fly. Boeing made the Boeing 747 because of this. The 707's engines were also too old.
During the Falklands War the Argentine Air Force used 707s to patrol. Some of them were caught by Royal Navy Sea Harriers.
Trans World Airlines was the last U.S. airline to fly passengers on a 707. The flight happened on October 30, 1983.
Most 707s are now private jets or cargo planes.
What the Boeing 720 was first called. American Airlines always called its 720s 707s.
The "707-120" was the first type of 707. The plane could hold 179 passengers. This type often had to stop for fuel in the North Atlantic. It had four Pratt & Whitney JT3C-6 turbojets. The first flight with passengers was on October 26, 1958. 56 were built, plus 7 short body −138s; the last −120 was delivered to Western in May 1960.
The "707-138" was a −120 which was ten feet shorter than the others. It could also fly further.
The "707-120B" had Pratt & Whitney JT3D-1 turbofan engines. They were a lot better than the others. The −120B had some changes made to the wings. 72 were made.
The "707-220" had more powerful Pratt & Whitney JT4A-3 turbojet engines. Five of these were made, but only four were delivered. The first one began being used in December 1959.
The "707-320 Intercontinental" is a longer version of the 707-120. This type could hold more passengers, and had some changes made to the wings. It first took off on January 11, 1958.
The 707-420 was the same as the −320, but it had Rolls-Royce Conway 508 engines. Lufthansa was the first to carry passengers on this type of plane in March 1960.
The "707-320B" had a few changes made to the outside of the plane, as well as new engines. The wing was changed. This plane was first used in June 1962 by Pan Am.
The "707-320C" could be changed from a passenger plane into a cargo plane. More 707-320Cs were made than any other type. The 707-320C had a cargo door added, as well as some other changes to the wing and the floor.
Many militaries have used the 707 for many different things.
The Boeing E-3 Sentry is a U.S. military airborne warning and control system (AWACS) aircraft. It has some of the Boeing 707's design.
The Canadian Forces also used Boeing 707s. These were called the CC-137 Husky (707-347C) from 1972 to 1997.
"Boeing 717" was what Boeing called the C-135 Stratolifter and KC-135 Stratotanker. The McDonnell Douglas MD-95's name was changed to Boeing 717 after Boeing bought McDonnell Douglas.
In the 1980s, the USAF bought 250 used 707s for parts for the KC-135E Stratotanker.
707s are not used anymore by big airlines. However, as of December 2012, 10 707s were being used. John Travolta owns a 707-138B.
As of May 2011, the 707 has had 170 hull-loss accidents. 2,739 people have died in Boeing 707 accidents. A hull-loss accident is when the plane is damaged so much that it cannot be fixed.
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Fischer-Tropsch process
The Fischer–Tropsch process (or Fischer–Tropsch Synthesis or F-T) is a set of chemical reactions that changes a mixture of carbon monoxide gas and hydrogen gas into liquid hydrocarbons (like gasoline or kerosene).
The Fischer–Tropsch process involves many kinds of reactions, which lead to both wanted and unwanted results. The desirable reactions create chemicals called alkanes. Sometimes the gas methane (natural gas) is produced, which is generally undesirable. Sometimes, different kinds of alcohol are produced in small amounts.
Many steps are required to make the gases needed for the F-T process. For example, all chemicals entering the reactor must have all sulfur removed. For factories that start out with methane and want to make a liquid hydrocarbon (like kerosene), another important reaction is "steam reforming", which turns the methane into CO (carbon monoxide) and H (hydrogen gas).
This is the chemical equation for how steam reforming works.
The reaction above describes one molecule of HO (steam) plus one molecule of CH (methane) converts into one molecule of CO (carbon monoxide) and three molecules of H (hydrogen gas).
A catalyst is a substance added to change the rate of a chemical reaction, generally to make it faster. Many different catalysts can be used for the Fischer–Tropsch process. The most common catalysts are the metals cobalt, iron, and ruthenium. These metals are all transition metals. The metal nickel can also be used, but generally with unwanted results. A nickel catalyst in the reaction usually produces a lot of methane, which is undesirable.
Cobalt seems to be the most active catalyst (it has the greatest and fastest effect on the process). When the input is a natural gas, cobalt catalysts are very good for the Fischer-Tropsch process. Iron catalysts are better when the input gas is of lower quality (less pure) such as coal or biomass.
Most metals used for this process (like cobalt, nickel, and ruthenium) remain in their metal form when added to the process. However, iron catalysts behave very differently. Often, iron catalysts change form and chemical phase, like converting into various oxides and carbides during the reaction. It is important to control all of the iron reactions during the process, or else the process may not work correctly.
Fischer-Tropsch catalysts are famous for being extremely sensitive to the addition of sulfur. Even a tiny amount of sulfur can have an undesirable impact on the reaction. Cobalt catalysis is more sensitive to sulfur than iron.
High-Temperature Fischer-Tropsch (or HTFT) is performed at temperatures of 330°C-350°C. HTFT uses an iron-based catalyst. Sasol used HTFT in Coal-to-Liquid plants (CTL). Low-Temperature Fischer-Tropsch (LTFT) is performed at lower temperatures and uses a cobalt-based catalyst. Shell used LTFT in an integrated Gas-to-Liquid (GTL) plant in Bintulu, Malaysia.