In this story, a small band of Foundation partisans fly around the Galaxy, trying to escape from the mysterious, star-conquering mutant called the Mule, and alternately trying to find some way to defeat him. More than once it repeats the prior story's point that hyperspace jumps are not feasible close in to a planetary mass:
It was when Toran had left [planet] Kalgan sufficiently far in the rear to attempt his first interstellar jump, that Captain Pritcher's face first creased slightly... [Book Two, p. 150]
With cold-eyed calm, Toran drove a protesting vessel from the vicinity of one star to that of another. If the neighborhood of great mass made an interstellar jump erratic and difficult, it also made the enemy detection devices useless or nearly so... [Book Two, p. 217]
Then we get our longest description to date of the calculation procedure required for interstellar jumps:
The stars begin to cluster closely when the core of the Galaxy is penetrated. Gravitational fields begin to overlap at intensities sufficient to introduce perturbations in an interstellar jump that cannot be overlooked.
Toran became aware of that when a jump landed their ship in the full glare of a red giant which clutched viciously, and whose grip was loosed, then wrenched apart, only after twelve sleepless, soul-battering hours.
With charts limited in scope, and an experience not at all fully developed, either operationally or mathematically, Toran resigned himself to days of careful planning between jumps.
It became a community project of a sort. Ebling Mis checked Toran's mathematics and Bayta tested possible routes, by the various generalized methods, for the presence of real solutions. Even Magnifico was put to work on the calculating machine for routine computations, a type of work, which, once explained, was a source of great amusement to him and at which he was surprisingly proficient.
So at the end of a month, or nearly, Bayta was able to survey the red line that wormed its way through the ship's trimensional model of the Galactic Lens halfway to its center, and say with Satiric relish, "You know what it looks like. It looks like a ten-foot earth-worm with a terrific case of indigestion. Eventually, you'll land us back in Haven."
"I will," growled Toran, with a fierce rustle of his chart, "if you don't shut up."
"And at that," continued Bayta, "there is probably a route right through, straight as a meridian of longitude."
"Yeah? Well, in the first place, dimwit, it probably took five hundred ships five hundred years to work out that route by hit-and-miss, and my lousy half-credit charts don't give it. Besides, maybe those straight routes are a good thing to avoid. They're probably choked up with ships..." [Book Two, p. 221-222]
Most of this scene speaks for itself: The 1940's style approach to solving engineering problems with (rustling) paper charts, various mathematical methods employed by the operators, real-versus-not-real solutions, and simplistic calculating machines (that, apparently, a court jester such as that represented by Magnifico might conceivably use). Again, we see that even in possession of charts (albeit apparently poor ones in this case), the pilot must still perform intricate calculations prior to any jump. The 500-ships-and-years background to developing the navigational charts is interesting. But for our purposes, perhaps the most salient point is that here we see the first note on the time frame for these calculations: "days of careful planning between jumps", which is the same as that used in the Star Frontiers: Knight Hawks game. At least for closely-packed star systems near the galactic core -- which itself also matches the SFKH campaign setting (actually the very first thing ever said about the game: "Near the center of a great spiral galaxy, where stars are much closer together than Earth's sun and its neighbors, a Human race developed..."; Star Frontiers Basic Game inside cover).
A little while later, the group debates how it is that the Mule can apparently still be tracking their ship across interstellar space, when after a half-galaxy of flight they still encounter a ship of his men:
"Followed?" hooted Bayta. "Through hyperspace?"Now, one significant point here is that apparently one's real-space direction of travel determines the course of one's hyperspace trip, or is at least correlated with it -- not terribly surprising, but nice to have it confirmed here in how the characters discuss possibly being tracked. But the far more intriguing thing is the phrase "building up take-off speed", which is the one and only whisper of a hint in the Foundation stories that one needs to achieve a certain velocity before making a hyperspace jump. If that's correct, then it would in fact give some kind of precedent (perhaps) for the Knight Hawks mechanic of accelerating to a given fixed jump speed (namely 1% of light). Or maybe that was just a sloppy way of referring to the need to get a certain distance away from any large solar or planetary mass -- a point which is made far more clearly and consistently then needing a certain speed. The reader may need to make up his or her own mind on exactly what is being said in this short passage.
Ebling Mis interposed wearily, "That can be done -- given a good ship and a great pilot. But the possibility doesn't impress me."
"I haven't been masking my trail," insisted Toran. "I've been building up take-off speed on the straight. A blind man could have calculated our route."
"The blazes he could," cried Bayta. "With the cock-eyed jumps you are making, observing our initial direction doesn't mean a thing. We came out of the jump wrong-end forwards more than once." [Book Two, p. 226]