Creating two mode engine - PatPL/Generic-Engines GitHub Wiki
As of 0.7 you can create engines with two engine modes (Like Rapier from stock). This tutorial will show you how to create your own multimode engine using the example of RD-701
First, create a new engine, mark it as active and set Polymorphism to 'Multimode Master'. Then enter values of the primary mode of the engine.
Next, either create another engine or duplicate the previous engine. Set its Polymorphism to 'Multimode Slave' and set previous engine as its master. You might have noticed, that some values were greyed out. They can't be changed, and will inherit master's values.
Keep in mind, contrary to 'Multiconfig Master' engine, 'Multimode Master' engine can only have one 'Multimode Slave' engine.
Then, export the engines. If you encounter any validation errors, Press 'Validate' to see a list of the errors. You can't export engine list with validation errors.
The engine should show up in game. You can toggle the mode using 'Toggle Mode' button. Automatic switching doesn't work.