Last time I watched Robotech was in 1997-1998. In 2001-2002, I skimmed the DVD releases. In 2001, I re-read the full set of novels. So it's been a while....
What happened to the fold engine in the SDF-1? The original one vanished at that first fold. I seem to recall the engine was "stolen" by either the SDF3 (or latter SDF6, maybe), or the Tirolians (Rem, Zor?), in the future (or past, after time travel). And wasn't there another fold drive that disappeared? SDF3, maybe?
I just don't remember.
///////////////////////////////////////////////
UPDATE:
Okay, I found a Robotech site with a timeline. I was right. The SDF-3 had it's spacefold engine taken during End of Circle, when it went back in time. The Regis stole the SDF-3 engine as it was leaving, so the SDF-3 steals the SDF-1 engine across time (because they knew it was going to disappear). Self-fulfilling prophecy.
///////////////////////////////////////////////
Of course, Shadow Chronicles is pretty liberal with the old scripts Macek laid out, and the novels by the two authors using the McKinney nom de plume, so we can now consider such things elseworlds... Maybe...
Reading over those timelines, I forgot how sinister Haydon IV was.
//////////////////////////////////////////////
I miss the old days of the alt.fan.robotech newsgroup (mid/late 1990s). Had some great discussion there. Enjoyed reading and conversing with that professor at Rice. He was famous for his efforts to further the science, fandom and stories of the show. He's even quote in some novels.