Contra rotating propellers is nothing really new. The oldest plane, which comes into my mind, is one version of the experimental Heinkel He-177 bomber of WWII, the "Ural Bomber", which never entered service.
The widest use, I think, is the Tupolev Tu-20 Bear bomber and its cousins Tu-95 and Tu-114. Also French (and British?) Navy had a carrier based single engine fighter plane some 30-40 years back - don't remember its name right now. And the Avro Schackleton, didn't it have contra rotating propellers too? - maybe I remember wrong.
It is really surprising that it hasn't been more widely used, especially on powerful single engine aircrafts. It would eliminate the asymmetric gyro effects which has killed a lot of good pilots over the years.
My guess is that it was too expensive, too heavy, and probably too maintenance intensive for use where they could really have made a difference, on WWII and later single engine propeller fighter planes.
On the four engined Tu-20 Bear and AN-22 I think that the reason for contra rotating propellers was somewhat different. To get rid of those 15,000 HP a single propeller would be much larger in diameter and call for extremely long landing gear legs, and besides that it would be difficult to keep the blade tips at subsonic speed. They probably didn't mind the extreme noise of supersonic propeller tips, but the efficiency of a propeller going supersonic is much inferiour to one going subsonic.
Only one plane has - to my knowledge - been designed to fly with a supersonic propeller, The Republic YF-84H - a turboprop version of the famous F-84F Thunderstreak fighter. That project was cancelled. I have read that one major reason for the cancelation was that the noise was absolutely unbearable, even when mixing with other fighter planes with afterburner.
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs