[4][5] It was originally ordered as the Siemens-Schuckert G.I prior to the German Inspectorate of Flying Troops (the Idflieg) adopting the "R" classification for multi-engine aircraft in late 1915.
[8] The main undercarriage consisted of divided units, each of which carried dual wheels, and the tail was supported by a pair of tailwheels.
[2] They ended this flight prematurely because of overheating in the gearboxes,[2] and subsequent tests revealed other defects such as excessive vibration in the drive system.
[6] Although damaged in transit, the R.I was repaired and was assigned to the Riesenflugzeugersatzabteilung (Rea — "giant aircraft support unit") as a trainer from mid 1916 to 1918 — possibly even to the Armistice.
These serials were changed on 13 July 1915 to G.33/15 - G.38/15, for unknown reasons and again on 6 November 1915 to R.2/15 - R.7/15 in the R (Riesenflugzeug - giant aircraft) series, adopting the R.II to R.VII designations.