 In addition, the XSB3U had fully retractable landing gear.The XSB3U-1 was delivered to Naval Air Station Anacostia for evaluation by the U.S. Navy in April 1936;, at the same time as its primary competitor, the XSB2U-1.Comparative testing of the two aircraft during 1936 proved the complete superiority of the monoplane configuration; on the same power, the SB2U-1 was faster despite being larger and heavier than the biplane.