Originally Posted by Silberfuchs
"The Space Shuttle definitely accelerates more quickly from the launch pad (twice as quickly as the Saturn V)"
The more rapid liftoff for the shuttle was due to higher initial thrust-to-weight ratio, but this changed vs the Saturn V during the ascent.
From a thrust standpoint, the Saturn V sea-level liftoff thrust on Apollo 15 was 7.823 million lbf (34.8 MN), which increased with altitude to a peak of 9.18 million lbf (40.8 MN) at T+135 seconds. The engines were not throttled; this was due to increasing nozzle efficiency as ambient pressure dropped:
Image:SaturnVThrust2.jpg - from the Schools Wikipedia
The shuttle liftoff thrust was about 6.78 million lbf (30.16 MN). The SRBs underwent significant throttling over their approx. 120 sec firing time, as can be seen in this graph. This throttling was not dynamic but designed in by controlling propellant surface area:
https://en.wikipedia.org/wiki/Space_...Srbthrust2.svg
Like the Saturn V, the shuttle SRB and SSME engines improved with altitude, but they both throttled back around Max Q, roughly T+60 sec. Despite improving nozzle efficiency with altitude, the SRB throttle schedule probably meant the peak vehicle thrust was at liftoff not at altitude like the Saturn V. So comparing peak thrust to peak thrust, it was about 6.78 million lbf vs about 9.18 million lbf.
Despite the slower start, at higher altitudes the Saturn V accelerated more rapidly, reaching a peak of 3.8 g just before 1st stage cutoff.
Of course the ultimate goal is delivering a payload. On Apollo 15 the Saturn V delivered a payload of 140,930 kg (310,697 lbs) to low earth orbit. The heaviest shuttle payload was about 23,586 kg (52,000 lbs).
It would have taken six shuttle launches to deliver to LEO the same useful payload as a single Saturn V.