Early in production planning it was decided to make it always be winter with snow on the ground and frost on the windows. This was to prevent problems with continuity and to allow the episodes to be shown in any order. Since much of the filming was done in the summer the actors had to wear coats and act cold even when the temperature was over 90 degrees F.
The show was still very popular in its final season on the air. However, it was caught up in the "rural purge" that took place just before the 1971-1972 television season. The main reason it was canceled was due to the fact that it was felt that the show mainly appealed to rural audiences and older people in much the same way that shows like The Beverly Hillbillies (1962), Green Acres (1965) and Hee Haw (1969) were.
'Ivan Dixon (I)' ('Kinch') left the series at the end of the fifth season (the only regular cast member to do so), stating that he was fed up with the posturings of Bob Crane, Werner Klemperer and Richard Dawson. He was replaced by Kenneth Washington for the final 24 episodes. Also, there was no mention of what happened to Kinch following Dixon's departure.
The black and white pilot episode originally included a Russian character who was played by Leonid Kinskey. Kinksey refused to continue with the series because he became uncomfortable with having Nazi characters starring in a comedy.
The car seen leaving the camp in the opening credits and from time to time during the series is a Mercedes model G4 Parade Car. The six-wheeled, three-axle vehicle had four wheel drive on the rear wheels (6 x 4) and was popular among the German Military elite.
Richard Dawson stated that when he got the part of Newkirk, Mike Dann (then president of CBS) asked him to use a Cockney accent, rather than his native Liverpool accent. Dann believed that the Cockney accent would sound more familiar to American viewers.
The Stalag 13 outdoor set was located at the NW corner of the Forty Acres back lot in Culver City, CA, near Lucerne Ave. and Higuera St., SE corner. After the series cancellation, the set was used in the Mission: Impossible: Trial by Fury (1968) episode where it doubled as a South American prison. It was also used as Medical Camp 9 in the Nazi sexploitation thriller Ilsa: She Wolf of the SS (1975), during the filming of which it was burned. The back lot was then bulldozed in 1976 and is now an industrial park. The location was previously used for the Tara plantation facade in Gone with the Wind (1939).
The show was famous for recycling actors in different roles. For example: William Christopher (best known as Father Mulcahy on M.A.S.H) played a POW, a German soldier and a British flier. Harold J. Stone played both an American agent and a German General. Antoinette Bower played Berlin Betty, a German scientist and an underground agent.
The ornate helmet that sits on the desk of Col. Klink, Werner Klemperer is a pre-WW1 Prussian army Pickelhaube (Spiked Helmet), possibly a family heirloom as it is clearly one of his most prized possessions. As the helmet used in the show differs in several respects from museum examples it is probably a replica produced by the props department and not an actual antique.
The standard rifle of the German army in WW2 was the Mauser K98, but the rifle carried by Sgt. Hans Schultz (John Banner) and most of the other German guards at Luft Stalag 13 is actually a U.S. military issue Krag Jorgensen rifle. The Krag Jorgensen, used by the U.S. military in the early 1900s, was most likely substituted for the Mauser due to its abundant availability as cheap war surplus in the U.S. and its general resemblance to the Mauser rifle.
Cynthia Lynn who played Klink's secretary "Helga" in the first two seasons was replaced by Sigrid Valdis who played "Hilda" at the insistence of Bob Crane after Valdis began dating (and later married) Crane.
Another recurring character was Burkhalter's sister Frau Gertrude Linkmeyer, usually played by Kathleen Freeman, but on one occasion, in the fourth year, by Alice Ghostley, who also appeared in a final season episode as the wife of a Nazi field marshal.
The sign outside Barracks 2 translates to English as : "Forbidden: 1. Strict orders have been given to the German Troops around Brussels to shoot any civilian cyclist. 2. People who, after the fifteenth of December, are still in possession of carrier pigeons as well as other persons who, by signals or any other means, cause annoyance to German military interests will be judged by court martial." It is dated December 13, 1944 and signed by General H. Heinrichs (who shares the same initials as the show's art director Howard Hollander).
Among the recurring characters who appeared on the show were female French resistance fighter Tiger (played by Arlene Martel), Marya the White Russian (played by Nita Talbot) and the bumbling R.A.F. officer Colonel Crittendon (played by Bernard Fox).
In the German dubbed version, very often the salute "Heil Hitler" was changed to "Heil Kräuter!" (literally translated: medicinal herb). - Also, when the show alluded to actual bombing and killing, the dialog was often modified as well. For instance, when the Americans destroyed a munitions factory, the German version made it a toilet paper factory. And when Sgt. Schulz reported the Allies having bombed Hamburg, it was revised to the Royal Air Force dropping candy as a "propaganda maneuver".
The series was originally supposed to take place in a regular American prison. But creators Bernard Fein and Albert S. Ruddy rewrote the script when they heard that NBC was developing the pilot Campo 44 (1967) which took place in an Italian POW camp.
The various secret code names that Colonel Hogan & his outfit used were fairy tale names of "Papa Bear", "Goldilocks", and "Little Red Riding Hood". Colonel Hogan's codename was "Goldilocks" in the series debut, contacting an underwater submarine in Hogan's Heroes: The Informer (1965).
General Burkhalter's staff car was actually an American hybrid with a Mercedes Benz logo on it. Col. Klink's staff car was a 1936 Mercedes 260D, although in some episodes it was the Pullman limousine model while in others it was the standard model.
2 Cast members never called by only their first name were African-American actors: Kenneth Washington as Sergeant Richard Baker (Season 6). and 'Ivan Dixon (I)' as Sergeant James 'Kinch' Kinchloe (Seasons 1-5).
Among the 6 seasons, of 168 episodes, as they originally televised, seasons 1, 2 & 5 (88 episodes) were on Friday evenings. Seasons 3 & 4 (56 episodes) were on Saturday evenings & Season 6's 24 episodes were on Sunday evenings.
For the first several seasons the "snow" on the roofs and on the ground was actually salt. By the fourth season much of the snow on the roofs had been replaced by patches of white paint. By the sixth season all the patches of snow on the roofs and many of the patches of snow on the ground, especially in the high traffic areas, were also just paint.
Colonel, Bob Hogan's test & fake name, to test new POW's that may become possible double agents for Nazi's and report Hogan's secret group of heroes, to Stalig 13, was Major Campbell. The name was mentioned twice in the series' debut, on Friday, September 17th, 1965.
Cast who were never seen in women's clothing were the two African-American actors: Kenneth Washington, with role of Sergeant Richard Baker, (Season 6), were 'Ivan Dixon (I)', as Sergeant James Kinchloe (Seasons 1-5), and Colonel, Wilhelm Klink, acted by Werner Klemperer, through out the series.
German film distributor KirchGruppe acquired the rights to Hogan's Heroes, but did not broadcast it for many years due to fears that it would offend viewers. It was first broadcast on German television in 1992, but the program failed to connect with viewers. However, after the dialogue was rewritten make the characters look even more foolish (which ensured that the viewers understood the characters were caricatures), the show became successful.