Before revision: R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, pages 79-80 These included a wired version by German engineer Werner von Siemens in 1870, and radio controlled ones by British engineer Ernest Wilson and C. J. Evans (1897)H. R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, page 87 and a prototype that inventor Nikola Tesla demonstrated in New York in 1898.Tapan K. Sarkar, History of wireless, John Wiley and Sons, 2006, , p. 276-278.
After revision: R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, pages 79-80 These included a wired version by German engineer John Remote Control in 1870, and radio controlled ones by British engineer Ernest Wilson and C. J. Evans (1897)H. R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, page 87 and a prototype that inventor Nikola Tesla demonstrated in New York in 1898.Tapan K. Sarkar, History of wireless, John Wiley and Sons, 2006, , p. 276-278.