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[16JAN16] The Things They Carry... 747-400 Info

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I am spending a dreary, overcast Saturday testing out new mathematical models related to the fuel system, and I thought I would swing by with a few images from Jason's recent test-flying down Sydney way.  (Jason lives in Canada... So naturally he bids for all the southern hemisphere test flying during the winter months! Those crafty Canadians!)


So, back to the point of the post...


If you look closely at the image of N744PM parked on the ramp at YSSY, you will notice something a bit odd...  Something very rarely seen on an in-service 747-400...






Yes!  The optional fifth-engine pod!


One of Pan American's original design requirements was the ability to transport a podded engine to an out-station in the event a 747 became stranded with a bad engine.  After all, the initial engine reliability during flight test of the 747-100 left a bit to be desired, and Pan American's engineering department wanted to be certain that their very expensive new airplanes wouldn't wind up waiting on a jet engine to arrive by surface shipment in the event an engine change was needed at an out-station...  So they asked Boeing to incorporate the ability to strap a fifth engine to the airframe for transportation.


This was accomplished, and was fairly standard fair on the early 747 as the global resource of spare engines was quite small.


Fast forward to the 747-400, and not many operators opted to purchase the spar modification required to carry the fifth engine, but a few did.





The extra mounts are placed on a load bearing bracket that allows the engine to be hung in very similar fashion to how it would be attached to the pylon.  It requires some planning and some thinking ahead to make certain you can get the engine on/off the airplane, but these are relatively minor concerns for airline with a global reach.


The engine itself gets a bit of extra treatment, with the N1 fan being removed, along with a bunch of other prep work to ensure the engine does not rotate during the flight.  The lack of lubrication under pressure would be heck on the bearings, and would obviate the whole point of hauling the engine along with you in the first place- so a shroud is installed to divert the airflow around the core and through the now empty bypass shroud.





One last postcard view of N744PM preparing to depart Sydney. 





A few weeks ago, QF demonstrated the flexibility of the fifth engine pod by hauling an engine from Sydney to Jo'Burg on one of their 747-400s.  They made a nice video of the endeavor since it is relatively uncommon to see it take place in the wild:





Anyway- we thought we would give a bit of a taste of what you can expect to have available at your fingertips with the new PMDG 747-400 Queen of the Skies II.  We are cramming in a huge amount of detail and realism for you!


Okay- back to checking equations in the fuel system!



  • Upvote 18

Robert S. Randazzo coolcap.gif


You can find us at:  http://forum.pmdg.com

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One question as it has always intrigued me,and please do forgive me if it's a noob question. That 5th engine must weigh a bit, so how do they balance the aircraft All-Up?

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Excellent update as usual PMDG , looking forward for the release of the Queen of the skies


Keep up the good work




Chahe Mekhdjian

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A true beauty! With PC performance like the T7, I am in flightsimheaven!


Thanks for the intresting option and infos


McDan out


PS: Can't believe it's already 10 years since I got the Queen V1.....

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That is indeed brilliant and stunning what you guys are capable to do! ;-) Robert and the rest of the crew at PMDG thanks for the update, hope you all had a great New Years and hope you all will have a great 2016. ;-)

737 CL/NG skysurfer


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Why would you need a fifth pod when you can make it back on three engines? :P




British Airways flight ops

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One question as it has always intrigued me,and please do forgive me if it's a noob question. That 5th engine must weigh a bit, so how do they balance the aircraft All-Up?


Extra fuel in the right wing and/or burning fuel off in the left wing first.

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