Remarks: The B737 was the first short hall jet to have power plants mounted under the wings due to the use of the fatter B707 fuselage cross-section when compared to the T-tailed DC-9, 1-11 and Caravelle et al. As can be seen here from the prototype (ex N73700) the series 100 was very short and rear mounting studies resulted in disturbed airflow due to the close proximity of the wing's trailing edges. In order to offer the airlines faster turn around times the engines were mounted hard up against the underside of the wing which kept the aircraft both low to the ground and clear of the boarding access. Although hard mounting was a relatively straight forward technical issue for the designers to solve, they nonetheless had to ensure that, for safety, the turbine sections would be kept aft of the wing's rear spars and this is what gave the first generation 737s their characteristic long power plant housings.
Remarks: We were extremely lucky to catch a real Boeing 737-100! And all the way from Peru as well. Aero Continente's OB-1736 is baking in the sun at Tucson. Picture scanned from paper-print.
