this is the basics on what a engine sounds like when its being tuned and what to listen for. im explaining mainly based on sound so youll have to watch the video a few times to know what to listen for.
in the vid im useing a magnum .46 xls with a 11x5/11x6 apc and 10x6 mas prop running wildcat 10% extra
tuneing the highspeed has more to do than just twisting the needle till the max and backing off a few clicks. you have to select the right prop or you are going to have overheat issues and deadsticks. the key it to learn when a engine is underproped/overproped and when its about right. remember in the air the prop unloads quite a bit, on the ground you want to be a of 12500 min and 14000 max to get the most power our of your engine (for the most part, it does depend on the engine).
for bushing engines the rpm numbers are totally different, so if you useing a os la, os fp, tt .42, ect then want to prop your engine around 10500-12000 on the ground