Reusing parts from the 747 makes sense, but I am a bit surprised that they are using the 747 engines. I thought that they were not efficient enough for modern planes.
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If they are the same as the 747-8 they would be very modern engines.
18 posted on 05/31/2017 3:55:59 PM PDT by Moonman62
(Make America Great Again!)
The engines are probably from an older generation of 747. In what seems like a clever cost reduction strategy Stratolaunch bought a couple of used 747s and scavenged the engines, landing gear, etc. from them