09/15/2006. Remarks by Johan Visschedijk: "The RF-4 was designed by René Fournier, three aircraft were built by Alpavia at Gap-Tallard Aérodrome, Gap, Provance-Alpes-Côte d'Azur, France. At Dahlemer Binz Flugplatz, near Blankenheim, Nordrhein-Westfalen, Germany, Sportavia-Pützer was formed to produce the aircraft in quantity as RF-4D (D denoting Deutschland, Germany) and 155 (c/n 4004 to 4158) were built."