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Fig. 10. Scaling of maximum force output (A) and ratio of total piston cross
sectional area to stroke length (B) in relation to motor mass over the entire
size range of piston engines. The vertical dashed line indicates the crossing
point of the scaling fits for Group 1 (dashed line) and Group 2 (solid line)
motors. Maximum force output (N), motor mass (kg), total piston area/stroke
length (m2 -1).