= Rocket Engines =

Contemplating the expansion ratio and mach number of miscellaneous high-expansion rocket engines.  The mach number is from Figure 3.1 on page 39 of Sutton, assuming a specific heat ratio of 1.3:

||                         || ratio || mach ||
|| Saturn V first stage F1 || 16.1  || 4.01 ||
|| Saturn V 2nd/3rd J2     || 27.5  || 4.50 ||
|| Apollo SM AJ10-137      || 62.5  || 5.31 ||
|| Shuttle SSME RS-25      || 77.5  || 5.53 ||
|| SpaceX Merlin Vacuum 1C || 14.5  || 3.91 ||
|| SpaceX Merlin Vacuum 1D || 165   || 6.36 ||
||<-3>||
||<-3>||
|| Laser Ablation Thrust   || 2.95  || 2.50 ||
||<-3> from Phipps and Michaelis 1994; can we do better? ||

note = Atlas sustainer was central engine used after the two outer booster engines were jettisoned.