04/30/2015. Remarks by Ron Smith: "The first special variant of the Cessna 310 to be marketed was the high performance Riley 65 and its related developments, the Riley Rocket, Turbostream and Super 310. Jack M. Riley purchased a number of Cessna 310 aircraft and modified them to such an extent that they were certificated as a separate type. Structural modifications were introduced to strengthen the type, reflecting the higher performance available.
The most evident and externally visible change for the Riley 65 was to replace Cessna's over-wing augmentor exhaust system with a system fitted below each engine nacelle. The other distinguishing features of the type were an additional third window on each side at the rear of the cabin and the introduction of a one piece windscreen. 20 gal (76 l) auxiliary tanks were installed in the rear of each engine nacelle.
The Riley 65 was a contemporary of Cessna's 310D which was fitted with 260 hp Continental IO-470-D engines. The Riley 65 was offered with either 240 hp O-470-D or 260 hp IO-470-M engines. There was a great emphasis on quality of finish and this was reflected in higher cruising speeds. Maximum takeoff weight was 4,830 lb (2,191 kg) and an empty weight of 3,000 lb (1,361 kg) was quoted.
The UK distributor, Keegan Aviation claimed that the 240 hp Riley 65 had similar performance to the Cessna 310D. This was backed up with a cruise speed of 225 mph (362 kmh) at 75% power; slightly faster than that of the more powerful 260 hp Cessna 310D. The 260 hp Riley 65 model was 10 mph (16 kmh) faster again. A climb rate of 1,800 ft (549 m)/min was quoted. The UK sales price was, surprisingly, significantly less than that of the Cessna 310D.
An eye-catching sales slogan was that the Riley 65 could 'fly faster on one engine than a Piper Apache on two'. The under-wing exhausts resulted in a much quieter cabin, assisted by the use of sound absorbing materials in the cabin."