The SP-1 was Bowlus' sixteenth glider, and was test flown at Lindbergh Field in San Diego in January, 1929.

[2] The SP-1 received two nicknames, the first "Old Number 16" as the sixteenth Bowlus glider, and "Paperwing" because its wing rib webs were fabricated from craft paper.

[4] The aircraft originally had a 44 ft (13.4 m) span wing with a USA 35-A airfoil with conventional aileron control and landing wheels for the rough dirt surface at Lindbergh Field.

[5] The wing was later redesigned to include tip-ailerons, extending the wingspan to 47 ft (14.3 m).

[16][17][18][19][20] Many variants patterned from the Bowlus SP-1 through Bowlus S-1000 series were constructed, including the Silver King by Harland Ross, and the Nighthawk, a sailplane flown by William A. Cocke to a world endurance record of 21 hours 34 minutes in 1931.