The Amazing Boeing 747. Carry a Fifth Engine under the wing, unique design features -6

5th pod apparently not a fake
▻http://www.avcom.co.za/phpBB3/viewtopic.php?t=81315&p=929037#p928874

For transportation of spare engines, early 747s could accommodate a non-functioning fifth-pod engine... Carrying #cargo internally is always more efficient but the fuel cost due to drag from carrying an engine like this is sometimes less than the cost of hiring a cargo plane to haul a spare engine somewhere to where there is already a short-hop passenger flight going - especially if there is some urgency involved.

A few explanations:
▻https://www.youtube.com/watch?v=_LHxbKZ7bfk

The special wing with fitfh-engine attachment was standard on that 747 subtype - before the advent of wide-body airliners with cargo doors that nowadays can easily accommodate a high-bypass turbofan engine. On the #Vickers VC-10, the configuration for ferrying a fifth engine required a mounting frame - much less elegant: ▻http://www.vc10.net/Technical/oddities.html (bottom of the page)

Detail of the optional fan cover and mounting pod:

http://p.chateau.free.fr/FIFTHPODTWA/FIFTHPOD-3.jpg

And for the fifth-engine fans (I know you’re out there !) here is another entirely different way to mount a fifth engine on a 747:
▻http://www.dvice.com/sites/dvice/files/styles/blog_post_media/public/images/pw_turbo747_3.jpg?itok=kEzdbqWT
▻http://www.dvice.com/archives/2012/05/pratt_whitney_u.php

Sidney Jo-Burg -> short hop ?
 :-D

Un grand bravo pour la simplicité de l’explication de pourquoi, il vaut mieux laisser les étages du compresseur libres.