The 140RX is a great engine . . arguably one of the best made.

A friend has one in a 4.7kg Integral, and it flys with authority . . no problem with power. Big Top Hats, Humpty's, stall turns are really quite impressive with it. It would probably struggle with a rolling vertical 'S' on a windy day . . but VERY adequate.

The "Aussie Icon", Tom Prosser still uses one (I believe) and is hard to beat on any given day.

Jason Shulman flew one in a John Payne designed Cyclone (owned by Henry Hutchinson - pic below) . . and won the Aust. Nats and Aust. Masters with it over fantastic pilots with great equipment, the likes of Alf Pye, Bill Bloodworth, Steve Coram, Chris Swain, etc. using OS200's, YS170's, Hackers, and Plettenbergs . .

So my guess it is far from a thing of the past. Probably more a case of matching an airframe to the motor. One combination I remember seeing was the OXAI Austral X with the OS140RX . . EXCELLENT performance.

Cheers, JB