To: RayChuang88; NorthMountain
Easy answer: they are used as flying engine test platforms. The upper picture is a plane that belongs to GE Aero Engines, and the bottom one is a plane belonging to Rolls-Royce. But did you notice the really odd thing about the GE 747-121 testbed? It has 3 P&W JT9D engines not GE CF6's. The plane was owned by GE Capital when Pan Am went into bankruptcy.
41 posted on
08/31/2016 10:13:35 AM PDT by
Paleo Conservative
(Just because you're paranoid doesn't mean they're not really out to get you.)
To: Paleo Conservative
OK ... Some more slightly beyond usual 747 pictures. <.P
![](https://theaviationist.com/wp-content/uploads/2012/05/lg3.jpg)
WTF? Another engine test, I suppose ...
![](http://1.bp.blogspot.com/_FPQYMhernsQ/TJEfxVgrG5I/AAAAAAAAAYM/LFMzdwpnkS4/s1600/strangest+planes_forangelsonly033.jpg)
Airborne LASER.
![](http://www.nasa.gov/sites/default/files/images/728037main_ED10-0182-04c.jpg)
SOFIA infrared telescope
![](https://upload.wikimedia.org/wikipedia/commons/a/a2/Boeing_747-400LCF.jpg)
Parts hauler for the 787 program
45 posted on
08/31/2016 10:29:21 AM PDT by
NorthMountain
(Hillary Clinton: corrupt unreliable negligent traitor)
To: Paleo Conservative
I think because it was an ex-Pan Am plane, GE Aero Engines decided NOT to replace the original JT9D engines because it would have required replacing a lot of hydraulic, fuel delivery and electrical systems to accommodate the CF6-50 engine. I believe that plane is still active, and will soon have a GE9X prototype engine mounted to test the engine for the upcoming Boeing 777-8 and 777-9 airliners.
46 posted on
08/31/2016 10:29:31 AM PDT by
RayChuang88
(FairTax: America's economic cure)
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