In 1972, the "Scorpion II" was introduced with an OMC 125 horsepower, 2 cycle engine which provided the added power to fly two lightweight people in cool, low density altitude environments. But despite all the improvements, overhaul times on the major components were still not up to the desired levels.

In 1974, the company embarked on a major redesign of the helicopter once more with the end goal of reducing the amount of maintenance time required per every hour of flight. The first, and most important, item to be addressed was the elimination of the inefficient 2 cycle engine. The company realized that there would never be a way to sufficiently dampen the excessive vibration and low torque associated with this type of engine. The vibration was found to cause rapid wear in various parts and had a tendency to cause cracks in airframe and drive systems.

Unable to find an engine manufacturer to make their 4-cycle engine suitable for the helicopter, RotorWay set forth on an aspect of the company that is unique to this day - producing their own engine. Called the RotorWay RW 133, this 4-cycle, 4-stroke engine now had the added power and torque the company was looking for. The RW 133 had a cruise speed of 128km/h with a range of 190km and a useful load of 190kg.

Later versions of the company's engines, the RW 145 and RW 152, represented continuous improvements made by RotorWay. These predecessors of the RI 162F engine helped make today's product possible. Nearly everything on the engine (and most of the kit) was produced in-house. From the cast rockers to the crankshaft and rod forgings, the RotorWay brand stood for excellence.

With a two-place helicopter available, RotorWay was able to begin instructing customers on how to fly their aircraft. Done at Scorpion Sky Center in Tempe, Arizona, this new program would remain an invaluable customer service tool from that point on.

www.rotorway.com

In 1958, B.J.Schramm set up a company to market a single-seat amateur-built helicopter known as the Schramm "Javelin". This machine had a tubular steel structure with a formed aluminium body shell and was powered by a 75kW Mercury powerboat engine. It first flew in August 1965. Schramm subsequently redesigned the "Javelin" as the "Scorpion", and he formed Rotorway Aircraft Inc. to market kits for this revised version, and claimed that 250 were flying by 1970. The "Scorpion Too" followed, and this had an expanded fuselage structure with a two-seat fibreglass cabin enclosure and a 105kW Evinrude marine engine.

R.Simpson "Airlife's Helicopter and Rotorcraft", 1998