Don't remember who said it but the B-S/F 17 name is pretty silly.
Some dummy- "Well, it kinda looks like a B-17 but we need something that sounds more science fictiony..."
Other dummy- "How about B- S/F 17? Eh? Get it? S/F for science fiction... "
First dummy- "We're done here. Lunch!"
Super-fortress. Stratofortress. Starfortress. It makes sense. Oh wait, no it doesn't...