The aircraft was completed and first flew on 5 July 1948, only nine weeks after construction had begun.

[1] The prototype had been ordered by Bill Frutchy of Elmira, New York and the aircraft was available for him to fly it in the second half of the US Nationals.

[4][5] A 1-23, flown by William Ivans, set a world altitude record for gliders on 30 December 1950, reaching a height of 42,089 ft (12,840 m).

[6] 1-23Ds were flown by Paul McCready to win the 1953 US Nationals and to set a distance record of 455.5 miles (733 km) by Joe Lincoln.

[9] Data from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II[16]General characteristics Performance