No Russian synchronization gears went into production before the 1917 Revolution – although experiments by Victor Dibovski in 1915 contributed to the later British Scarff-Dibovski gear (described above), and another naval officer, G.I. Lavrov, also designed a gear that was fitted to the unsuccessful Sikorsky S-16. French and British designs licence-built in Russia used the Alkan-Hamy or Birkigt gears.