Dear Hesham,
Mr. Marjánek is an aeronautical engineer and worked for many years at Orličan Choceň (formerly the Beneš-Mráz factory), among other places. He had the opportunity to look into the archives of the Beneš-Mráz company, so he has more information at his disposal than is available in the archives of the National Technical Museum in Prague... As I wrote in my previous post, it was quite common at Beneš-Mráz for several different types of aircraft to be developed under one model number.
