Vallejo Metal Colour - Engine 4 Colour Acrylic Paint Set (AV77604)Metallic colors for painting radial or linear aircraft engines. Metallic colors for painting radial or linear aircraft engines. The colors included in the set can be used as a base for painting most of the radial or linear engines of any period. For this tutorial the Oberursel engine of the WWI is used as an example. It is recommended to use photographic references for the color combination most suitable for our model.