The Zeppelin-Staaken R.XV was an Imperial German bomber of World War I.
An incremental improvement to the Zeppelin-Staaken R.VI, this was one of a series of large strategic bombers called Riesenflugzeuge, intended to be less vulnerable than dirigibles in use at the time.
Almost identical to the R.XIV, the R.XV had a lighter airframe and more refined aerodynamics, in an effort to improve performance.
[2] Additional power was provided by a fifth engine mounted in the nose of the aircraft.
[1] Data from The German Giants[1]General characteristics Performance Armament