Only Coanda unsuccessful in the entire Timeline of aircraft engine development Quite strange   I have noticed that the entire timeline of aircraft development ranging from  to  has a single engine labeled as unsuccessful All other motors are considered successful also many o them are in the same situation as Coanda More some engines never left the drawing board being years later developed by other inventors in efficient motors with major modifications  I will delete the epithet unsuccessful because I consider it was not placed in good faith Coanda power plant itself was built worked and it was an original design