sentences:  There are two known surviving engines, one of 1100 cc and the other the 1500 cc unit at the Shuttleworth museum at Old Warden, although there may be others.Note that the Blackburne engines are not related to the Blackburn Aircraft Company (founded by Robert Blackburn), even though the Blackburn Bluebird was a Blackburn aircraft with a Blackburne engine.The De Havilland DH53 Humming Bird was a 1923 ultra-light plane, the first two initially powered by Douglas engines, but they changed to Blackburne engines to get improved reliability .