10/31/2007. This Gulfstream has been modified by Lockheed Georgia for the NASA Propfan Test Assessment program. The aircraft’s powerplant on the left wing was jointly developed by Hamilton Standard (propeller), Allison (6,000 shp 501-M78 industrial turbine) and Rohr (modified P-3 Orion engine cowling). A 2,100 lb (953 kg) static balance boom was fitted to the right wingtip and a 0.375 in (95 mm) was mounted over the fuselage adjacent to the propfan in case a blade failed. The first flight with the propfan operating was made on March 28, 1987.