Well, yes and no. Of course, they are just reciprocating engines like any else. What is somewhat different to some other engines is that they are RPM-limited by load to a relatively narrow operational range. The designer essentially knows that the engine runs, for instance, in between 2000 and 3000 RPM always when it is under considerable load (never higher), that it is always operated at or above certain operating temperatures, that the RPM is changed smoothly, and say, that it is not used for engine braking but is under good loading when at speed. And so on. Then you can simplify and optimize ignition and valve timings, cooling, crank journal lubrication and whatnot. Material properties, fatigue and all that sort is of course just like with any other engine of similar metallurgy.WB_FlashOver wrote:1) A reciprocating piston engine, is a reciprocating piston engine, is a reciprocating piston engine. Sure there are many differences with stroke, bore, valve train layout, etc, etc. I understand now that airplane engines are created differently.
That is one thing, but there is more into it. Using higher power reduces the time you spend at high power setting, low airspeed combination with your air cooled engines. Also, with many aircraft engines, if you are not using the maximum power, you are not allowing for the full-rich takeoff power fuel mixture, which is often achieved by specific enriching function enabled by throttle moving to the full.WB_FlashOver wrote:2) I was always under the assumption that using full takeoff power is for safety sake, "Don't dilly dally, get her airborne".
Well, they are neither, but more like pre-plotted settings where the engines and the airplane operates more or less as designer wanted, and in a predictable way. Usually there are little reasons to invent one's own settings, if not for a specific purpose. (There are some few exceptions of course, and even some flight manuals give settings that...well, are rather interesting.)WB_FlashOver wrote:I also thought that the listed climb and cruise settings were considered to be the max, or do not exceed, settings. Not "use these or expect failure" settings.
-Esa