Allison on Airliners-Jet Engines part 2

By Steve Allison

The introduction of jet aircraft was one of the most significant changes in airline history. There are those who would argue that the change wasn't for the better. In the old days, air travel was very civilised. Aircraft flew at low altitude by today's standards; passengers could enjoy the scenery. Flights to far off international destinations took days but they would fly during daylight hours and then night stop. The jet engine was however the first step in bringing air travel to the masses. Prior to that, air travel was the preserve of the wealthy.



Air travel has become popular with ordinary people

In order to achieve the best performance, jet aircraft need to fly at very high altitudes. The advantage for passengers is that they fly above the weather where the air is usually smooth. The disadvantage of flying at high altitude is that the air is too thin to breath. The solution is to pressurise the cabin so that passengers can breathe normally without oxygen masks. Jet airliners are much faster than the older piston aircraft and so there was no longer any need to night stop and transport passengers to hotels.



Jet airliners fly above the weather

The first jet airliner to enter service was the de Havilland Comet and the first fare paying passenger flight was between London and Johannesburg. SAA had operated 2 Comets leased from BOAC. The Comets were British registered but operated by SAA crew. They wore the livery of both BOAC and SAA.

Unfortunately, when the Comet was designed, the fatigue on the airframe due to pressurising and depressurising hadn't been understood. The Comet suffered from structural failures and was withdrawn from service.

Boeing learned from the failure of the comet and built the 707, which first flew in 1954 and entered airline service in 1958. Although not the first jet airliner, it was without doubt, the first one that was successful and is widely regarded as the aircraft that introduced the jet age. It had 4 Pratt & Whitney JT3 engines housed in pods under the wings.



Flying away too far off lands is commonplace

The first 707 to arrive in South Africa was registered ZS-CKC and was named "Johannesburg". SAA aircraft names were themed; all the 707's were named after South African cities. Along with the introduction of the 707, SAA also introduced a new livery, the famous orange tail. The aircraft was configured for 139 passengers in 2 classes, first and economy. That is 50 passengers less than a 737-800 is capable of carrying.

Whilst the 707 was a very significant aircraft in the history of airline transport, it didn't really bring air travel to the ordinary person. Flying was no longer purely for the very wealthy and elite, business travel became commonplace. Air travel was still expensive and very few people could afford to fly away on holiday.



The real game changer, the Boeing 747

The real game changer was another Boeing product, the 747, which was actually designed as a freighter. The Cockpit on the upper deck was to enable the nose section to be opened for easier loading. The 747 was bigger than anything the airline world had seen before, earning it the nickname "Jumbo Jet". It entered service in 1970 and is still the backbone of the long haul fleet for many airlines around the world.



The wing area of the 747 is the size of four 3-bedroom homes

The 747 has the capacity, depending on configuration to carry up to 550 passengers, 3 times as many as the 707. The tail of a 747 is 19,5M tall, equivalent to a six story building. The wing area is the equivalent to the floor space of four family homes.



The Airbus A380

The airline industry has moved on and Boeing's competitor Airbus now builds the biggest passenger carrying airliners, the A380. It was however the mighty Boeing 747 that really brought air travel to the masses. The ability to carry so many passengers brought the ticket price down to affordable levels and people started to fly to distant destinations on holiday and to visit family. Airline travel, thanks to the 747 has really made the world a smaller place.


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