The A2A Simulations Community

quick question for the team...goes for pretty much all your planes, i know they fly by the book with all settings, speeds, etc. but when you reduce prop pitch to top of the green arc, you just get that throatier, characteristic more powerful sound coming from the engine, and recommended emergency and takeoff settings usually call for max rpm, is this just audio, not actual performance? more simply put, more power with that little bit less rpm or not? thanks

That's exactly right, and you noticed it. When you pull the RPM back, you are taking a BIGGER bite of the air, and you are operating the engine at higher torque and "brake mean effective pressure" (BMEP) values. When the blades take a bigger bite, you will hear that, since our prop sounds are separate and unique sound files from our engine sounds. You will also hear that "throaty" sound, sort of like a Harley when you click it into high gear and motor on down the road. Yes, this IS more performance, not just "ear candy". These sound sets were VERY carefully tuned and if you listen closely you can hear the prop tone change independently of the engine tone, which makes for some very interesting and realistic sounds, especially during climb and cruise. There is actually a sweet spot (at or around optimum cruise) where the prop and engine sounds "synch up" and you get a beautiful, rumbling harmony.

These sounds were professionally recorded from an actual P-51D and the sound.cfg files and .wav files were engineered by professional musicians.

that's so awesome, truelly spectacular work. I'm still learning here...only a sophomore at embry-riddle, haven't gone through all the aerodynamics courses yet... question about full takeoff rpm? is this just more efficient at ground level for 100% prop pitch? if its more power at that sweet spot rpm, why knock it down a little when its needed most? gotta be better than, but why? thanks for the free answers, i dont have to dish out $44,000 a year for these classes!

For takeoff you want maximum horsepower and thrust, so maximum RPM is used along with a maximum allowable manifold pressure. For climb and cruise, you want to limit the RPM so as to allow the engine to run cooler and go longer between maintenance intervals, and of course burn less fuel. Higher BMEP/torque values with lower RPM usually provides better fuel economy, which is what you want for cruising.