The RCV model engine brand was launched in 1998.The RCV is a 4 stroke engine which employs a rotating cylinder valve to control gas exchange to/from the cylinder. The cylinder/valve is rotated at half crank speed to allow a four stroke cycle (same as a cam shaft).

This is one of the original RCV engines which has the propeller bolted to the half speed cylinder. This allowed for a more streamlined shape and also enabled a larger prop to be used. 

This engine has not been run for many years. It was gummed up, but with a little heat and WD40 it turns over with reasonable compression. It will run but please assume it is a collectors item and not for practical use in a model aeroplane: these early RCVs had issues with overheating due to the small fin diameter.