1:32 Gnome 9 Delta

The Greek alphabet in a list of engines

The Seguin brothers introduced a nomenclature by Greek letters for their rotary engines, and thanks to that a modeler can place a type before starting to count cylinders. The Omega stood at the beginning of the series, the Lambda added output while keeping the same seven cylinders, and the Delta meant a step to a nine-cylinder star. More cylinders carried more power strokes per revolution, the running smoothed out and the unit pulled heavier airframes than the designs of 1909 could manage.

How a rotary engine worked

What does not move on it is the crankshaft; the block of cylinders turns together with the propeller. The cooling was thereby solved of its own accord, because every cylinder flies through its own stream of air and the water circuit, the radiator and the piping fall away, that is kilograms no prewar aircraft could afford. The pilot paid the price for it: the rotating mass resisted every change of direction and the lubricant went out through the exhaust straight into the open cockpit. The supply of fuel was reckoned at an hour and a half of flight.

The set in 1:32

A nine-cylinder is markedly denser than a seven-cylinder, and that is exactly what shows on the finished piece if the cowling stays open or is taken off altogether. The resin parts capture the heads, the finning and the valve gear; they are assembled with cyanoacrylate glue, the only thing resin responds to. Before painting it is necessary to wash the castings and let them dry out properly, otherwise the paint will not hold on the remains of mold release. It pays to seat the cylinder star dry and try whether the cowling fits over it.