The Boeing 747 has been a gamechanging aircraft in so many ways. Despite being built many decades ago, it has kept up with the times and shaped modern aviation. One unique feature of the Boeing 747 is its ability to fly with five engines. Sound ridiculous? Here’s what we mean.
The groundbreaking Queen
With so many airlines are saying goodbye to their passenger Boeing 747s, it can be easy to think of the Queen as a bit of a dinosaur. However, this aircraft was a groundbreaking piece of machinery in so many ways and served to shape modern commercial aviation as we know it today.
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One of the unique features of the 747 was its fifth pod. This ‘spare’ engine mount gave it the ability to lug along an extra engine, something it was capable of doing even on a revenue flight. Of course, the efficiency of the flight would take a hit, but reportedly there were no issues with handling as a result.
Back in 2016, this spare pod was put to good use by Australian flag carrier Qantas. It needed to get a replacement engine to Johannesburg in South Africa fast, and by far the quickest and easiest way to do this was by using the fifth pod on a 747 that was headed that way anyhow.
QF63 strapped a six-ton Rolls-Royce engine onto its spare pod, and successfully ferried the engine to its destination. For passengers on that flight, it must have been an odd sight to look out of the window and see three powerplants!
Using the fifth pod
The fifth pod is located under the port size (left) wing and is located close to the body. Of course, the engine isn’t powered for the flight but is just mounted there for transportation.
You might think that the weight of this extra engine causes balance issues. However, because the mounting is so close to the fuselage, the weight of the engine is close enough to the center of gravity that it doesn’t cause a problem, although it does increase drag and fuel burn.
The Boeing 747 is not the only aircraft that can fly with five engines, however. In fact, many older aircraft such as the DC-8 and 707 used to have fifth pods installed for transportation of spare engines.
More uses of the fifth pod
One of the most notable uses of the fifth pod in recent times has been the Virgin Orbit 747, affectionately known as Cosmic Girl. This 747 launches rockets into space, for the purposes of faster and easier satellite deployment.
In order to ferry the LauncherOne rocket up to flight level, Virgin adapted the fifth pod to accommodate the payload. Although it required some fairly extensive modifications, the natural ability of the 747 to carry a pylon under its wing in the fifth pod position made this even easier.
Another contemporary use is likely to be seen when the Rolls-Royce testbed enters into service. This ex-Qantas 747 is currently being adapted by AeroTec for the purposes of testing Rolls-Royce powerplants. Some will be installed in place of one of the four existing engines, but AeroTec has also been asked to reroute fuel, electrical equipment, and hydraulic systems so that an extra fifth engine can be mounted and tested.
Did you know the 747 could fly with five engines? Let us know what you think in the comments.