Friedrichshafen FF.33 - version overview:
FF.33 - initial series with Mercedes D.I engines
FF.33a - D.II engines
FF.33b - Maybach engines, swapped observer and pilot positions
FF.33e - main production version with Benz B.III engines
FF.33f - scaled down fighter version, based on the FF.33e
FF.33h - modified production version of the FF.33f
FF.33j - modified version of the FF.33e
FF.33k - prototype version l
FF.33l - main fighter/survey version
FF.33s - training unarmed variant
FF.39 - development of the FF.33e with Benz Bz.IV engine
FF.49c - a high-volume reconnaissance version of the FF.39
FF.49b - serial bomber version of the FF.49c
FF.59a - another variant of the FF.39 with modified tail surfaces
FF.59b
FF.59c
C.I - ground variant FF.33l
Source:
http://en.wikipedia.org/wiki/Friedrichshafen_FF.33
FF.33 - initial series with Mercedes D.I engines
FF.33a - D.II engines
FF.33b - Maybach engines, swapped observer and pilot positions
FF.33e - main production version with Benz B.III engines
FF.33f - scaled down fighter version, based on the FF.33e
FF.33h - modified production version of the FF.33f
FF.33j - modified version of the FF.33e
FF.33k - prototype version l
FF.33l - main fighter/survey version
FF.33s - training unarmed variant
FF.39 - development of the FF.33e with Benz Bz.IV engine
FF.49c - a high-volume reconnaissance version of the FF.39
FF.49b - serial bomber version of the FF.49c
FF.59a - another variant of the FF.39 with modified tail surfaces
FF.59b
FF.59c
C.I - ground variant FF.33l
Source:
http://en.wikipedia.org/wiki/Friedrichshafen_FF.33