The Fairey P.24 Monarch was a British experimental 2,000 hp (1,490 kW) class H-24 aircraft engine designed and built by Fairey in the late 1930s. The engine did not go into production.The P.24 Monarch was a 24-cylinder development of the H-16 layout version of the Prince, designed by chief engine designer Captain A.G. Forsyth. Similar in layout to the Napier Dagger, the cylinders were arranged vertically in two blocks, driving contra-rotating propellers using separate shafts and gears. Like the smaller Prince engine, one bank of cylinders could be stopped in flight with the other still driving its own propeller, an idea that was reused much later in the Armstrong Siddeley Double Mamba turboprop.The idea came from the desire to deliver twin-engine power with twin-engine reliability in a single engine installation for naval use. A twin-engined aircraft would take up more space on an aircraft carrier. With two power blocks a failure in one of them would not necessarily lead to complete loss of engine power. This is just the model, meaning you still have to put an engine inside it.