Asking because this is about to come up in the game I’m running. Magic carpets have specific movement rates listed, but overland travel distances for flyers is also doubled. If the magic carpet is pursuing a mounted rider and both have the same movement rate by round, how would that work? Is the carpet actually twice as fast as the horse, even though they may have the same movement rates?
The assumption on overland movement is
1) There is micro-terrain, too small to be modeled on a wilderness map, that precludes travel on foot from going in truly straight lines and which imposes costs in endurance and time
2) Flying is more efficient in terms of energy use per mile, as a result of gliding, soaring, etc., so that flyers are less fatigued and can maintain a higher relative rate of travel over time
Neither of these matters in the short term, where minor deviations from straight lines are moot and distances are too short for the endurance differences to matter.
Therefore over *short distances* the flying carpet and the mounted rider have the same actual speed but over long distances the flying carpet will cover twice as much ground per day.
Note the difference in relative speed implied by the three movement rates:
Running per combat round - 240 yards per round is (240/1760) x (3600 / 10) 49 mph.
Walking per combat round - 80 yards per round is (80/1760) x (3600 / 10) 16mph.
Walking per day - 48 miles per day / 8 hours is 6mph.
Note that the rules provide a limit for how far a character can sustain his walking speed per round (characters can only remain active for 5 turns out of 6 and suffer a -1 penalty thereafter until they rest) and how long they can sustain their wilderness rate (8 hours per day; they can force march for 4 hours for an extra 50% of their movement rate at a -1 penalty until they rest.)
But the rules don't provide a limit for how far a character can sustain his running speed. So let's sort that out.
In real life, a quarter horse can gallop full-out at 50mph for a quarter-mile (hence the name). A quarter mile is 440 yards; at 240 yards per round, that is about 2 rounds of full speed.
The great racehorse Secretariat traveled a mile-and-a-half in 2.5 minutes, for an effective movement rate of 176 yards per round, or approximately 180 yards per round. Secretariat is certainly a DEX 18 light horse (movement rate 300') so we can see that over time frames of minutes his movement speed has dropped to 60% of his maximum.
Similarly, the world record for human sprinters is about 9.75 seconds for 100 yards and about 19.5 seconds for 200 yards, but about 45 seconds for 400 yards - so again we see basically full speed for 2 combat rounds (20 seconds) and then a drop off, with the next 200 yards taking 12.25 seconds each, or 25% more time.
The world record for the mile is 3:43 and 7:58 for the two mile. That is, 21 combat rounds to go 1760 yards or 83 yards per round, and 48 rounds to go 3520 yards, or 73 rounds per yard - respectively 70% and 60% of maximum speed.
The world record for the marathon is 2h2m, or 42,240 yards in 732 rounds, or 57 rounds per yard - about 50% of maximum speed.
From the above we might rule that for land-based travel:
- In round 1 and 2, full running rate applies
- From round 3 to round 5, running speed drops to 75%
- From round 5 to round 20, running speed drops to 66%
- From round 21 to 2 hours, running speed drops to 50%
To make Endurance proficiency meaningful, we will rule that a character suffers a -1 penalty to throws starting on round 3, or starting on round 21 with Endurance.
The mounted rider can thus escape the flying carpet over short distances (500 yards or so) but will thereafter slowly be caught.