sentences:  The RR300 retains the look and layout of the Model 250 from which it is derived.The RR300 is the second attempt to develop a lower-rated version of the Model 250-C20, coming 20 years after the 350 shp Allison Model 225 of 1987.The five-seat Robinson R66 light helicopter features the RR300 as a turboshaft engine, Robinson having originally intended on utilizing the standard Model 250-C20.