^Well the 3 years might be at a certain speed. After all a car uses it's fuel more efficently at certain speeds. As for fuel that's what the Busssard collectors to allow partial refuelling to take place whilst moving through space. But for sure at times they just wrote what sound good. 4 billin miles per second sounds really fast, it's not until you actually work it out thats 21 000 times the light that you run into a problem. I.e at those speeds it would take Voyager about 40 months to return home
The sustainable top speeds they are talking about is measured in less than a dozen hours, maybe less than 5 hours, hell it could be how long they can sustain that speed for one hour. Otherwise why the frakk would they spend most of their time lolling about at warp 4?
Not necessarily - because, as pointed out, the word "sustainable" was never used to describe the speed of our hero ship. Instead, Stadi used "stable" and Janeway used "top" as their definers for the cruising speed of the ship. Timo Saloniemi
It is 'The Calculus' that views that this sustainable is not a surge. 'The Calculus' follows Triginometry which follows simple Algebra and this follows simple Arithmetic. It is simple arithmetic that states Voyagers cruise speed (which is 3000 light speed) it would take 25 years to complete the journey, but they must have comparable stop-overs to replenish systems. Throughout the series it was sometimes evident their was something wrong with Voyager's speed- like they had a bad motor that made them fly through jello . and this shouldn't be forgotten-- This is Janeway's statement in 'Caretaker'-- JANEWAY: We're alone in an uncharted part of the galaxy. We have already made some friends here, and some enemies. We have no idea of the dangers we're going to face, but one thing is clear. Both crews are going to have to work together if we're to survive. That's why Commander Chakotay and I have agreed that this should be one crew. A Starfleet crew. And as the only Starfleet vessel assigned to the Delta Quadrant, we'll continue to follow our directive to seek out new worlds and explore space. But our primary goal is clear. Even at maximum speeds, it would take seventy five years to reach the Federation, but I'm not willing to settle for that. There's another entity like the Caretaker out there somewhere who has the ability to get us there a lot faster. We'll be looking for her, and we'll be looking for wormholes, spatial rifts, or new technologies to help us. Somewhere along this journey, we'll find a way back. Mister Paris, set a course for home.
And please don't give me a Columbian neck tie in my sleep, all you big handsome Maquis out there. Although using the word "assigned" (to the DQ) really makes me think that Seven was closer to the mark than she gave herself credit for in he Voyager Conspiracy.