At every point at some point in simple planes you would of been in the same slump I have wether it be a lack of innovation or downloads etc one thing stood put for me that no one pays attention to engines! They are the driving force behind every aircraft though are very underrated in the game overlooked if you will I spent 10 months trying to come up with my own engines and have found an easy way to make realistic reliable and high quality custom made engines
1. Creating the internals first
1. Start by selecting a existing engine
2. XML mod it to 35Xor most aircraft that are Boeing 737 A320 sized adjust it to your liking as this will determine the power output of your engine
3. Attach a piston which will spin the fan blade assembly
4. Main blade assembly personally I use the 2.2x width and 75 inch blade diameter for midsized aircraft engines as I find it to be the best between size and being compact though this can be adjusted
5. Attack 2 inlets either at the top and bottom of your existing engine or to the left or right of your engine this will ensure optimal airflow throughout the engines components
Next Step Designing The Engine Cowling (Housing)
This is crucial for fitting your engine into as well as for looks so your engine looks good to say the least
1. Start with a glass material and increase its thickness to 100 making it lighter and more durable than regular fuselage materials
2. Design it to size so that it encompasses the fan blade assembly
Adjust your width and height of the opening of your glass fuselage to Aline the size of your fan blade assembly
The rear is up to you in how you want to design the encasing wether it tapers off etc it’s all up to you and why engine design is so rewarding in simple planes
3. Fit your engine using the connection system or adjustment systems this can be finicky but will eventually click together to form your engine

And there you have it a comprehensive guide to make amazing high performance engines in simple planes I’d love to see people’s engine designs after following this guide if you tag me below you can share your engine or ask for help if needed enjoy