Sikorsky S-72 Sikorsky S-72 The Sikorsky S-72 was an experimental hybrid helicopter/fixed-wing aircraft developed by helicopter manufacturer Sikorsky Aircraft. The Rotor Systems Research Aircraft (RSRA) was developed by Sikorsky for NASA and the Army. The RSRA was developed to allow the inflight measurement of helicopter rotor characteristics. The airframe was developed using an existing Sikorsky S-61 main rotor, an S-61 roller gearbox, and a highly modified Sikorsky S-67 airframe. The RSRA could be fitted with TF34 turbofans and wings to allow compound helicopter configurations to be experimentally investigated at speeds up to . In addition, it could fly as a fixed-wing aircraft
Sikorsky S-10 Sikorsky S-10 The Sikorsky S-10 was a Russian Empiren military twin-float seaplane that served with the Baltic Fleet from the summer of 1913 to 1915. After Igor Sikorsky built the successful Sikorsky S-6 for the Russian military, he tried to build another successful aircraft for them. The S-10 was a modified S-6B built by the Russo-Baltic Carriage Factory. Approximately sixteen production versions of the S-10 were built. It had a less powerful engine and generally weaker structure than the S-6. They had either an 80 HP Gnome Monosoupape or a 100 HP Argus Motoren engine. Some were deployed on the