The Vertical Valve RCV (VRCV) is the high performance/higher cost version of the RCV engine.
The VRCV engine employs a separate rotary valve and a fixed cylinder. This improves the thermal characteristics of the engine and reduces cost.
In the VRCV the valve is coaxial with the cylinder. This gives the most efficient breathing for the engine allowing maximum performance.
The VRCV geometry also enables the most compact and therefore efficient combustion chamber shape to be employed. This optimises heavy fuel operation.
Because the valve is in line with the cylinder this means it is rotating at 90 degrees to the crank. A more complex valve drive is therefore required between the crank and valve. This drive generally involves a bevel gear to transfer the drive through 90 degrees.
Typical power densities for the VRCV between 80-100bhp litre.
The primary application areas for the VRCV are high performance UAV engines where performance and efficiency are paramount, and cost is less critical.