13-09-2020, 02:53 AM
An article in Autocar 30.7.65 gave the Cd for an RP as .608 (cf .35 for typical modern) The cross section of my compact Javelin (less wide than a Minor!) is 22 sq ft. The Austin is taller and 7 inches more narrow but does not narrow at the topr. Assuming 18 sq ft the air resistance at 50 mph is over 9hp! So air resistance certainly predominates. Would also seem to dispel the oft quoted 10 bhp as max power for engines of those years, a notion which caused a near riot here years ago.