[1] Unlike the 9-prefixed piston engine designations, the 109-series of reaction-thrust, turbojet, turboprop and rocket engine designation numbers' three-place numerical suffixes had no "firm adherence" to any one manufacturer.
Using this system, the famous BMW engine used in the Focke-Wulf Fw 190 would be known as the 9-801 (Piston(9)-BMW(8)Number(01)).
Engines produced before the RLM's designation system was set up are often listed using the same basic terminology.
So while the interwar Argus 10 engine can be referred to as the As 10, it is not correct to call it the 9–10, this designation was never applied.
The Luftwaffe also used engines from France, particularly the Gnôme-Rhône 14 cylinder series of radial engines for its Henschel Hs 129 (14M) ground attack aircraft and Messerschmitt Me 323 (14N) "Gigant" transporter.