I would think that most useful info for a player in Aces High would be this: establish a 60 degree bank, at 200MPH IAS, 250MPH and 300MPH, and see how long in seconds it would be required to make a 180 degree turn! Looks to me like that info would be the most useful in ACM's. Same thing with spilt "S", or an Immelmann turn. Not sure, but how quickly one could turn into an opponent would be of some value in ACM's.
FLS and I both were explaining those numbers that are most useful. There are actually three turn performance numbers that are most important to a fighter pilot in ACM. These are sustained and instantaneous turns rates and turn radius all of which can be pulled from the EM diagram.
On the EM diagram I posted (we’ll only talk the P-51 for simplicity), the left hand red line is the lift limit line. Go to the left of this and you'll stall. The upper line is your G limit line. Pull more than this and you'll damage your ride (or, in AH, you'll black out). The middle red line is the P
s=0 line. Spelled out that's the “Specific Excess Power equals Zero” line and it divides the chart between excess engine power and insufficient engine power. If you’re anywhere on that line you can keep doing what you’re doing without climbing or descending. Above the line you have less power available for sustained performance and below the line you have more power available. Your best sustained turns are where this line intersects the lift limit line and your best instantaneous turn occurs at corner velocity where the lift limit line intersects maximum G limit line. At any point you can follow the radius lines on the chart to determine turn radius for that particular combination of G and speed.
You can see that the P-51D’s best sustained level turn is at 170mph which gives you an 18 degrees per second turn rate at about 2.7G and an 800ft turn radius. Anything below the P
s=0 line gives you less sustained turn performance but what you would find is you have more power than you need for a sustained level turn. If you pull to the edge of stall at say, 125mph, that excess power means that you will start out turning at about 10DPS (just draw a vertical line from 125mph to where it intersects the lift limit line) but will gradually accelerate to your best sustained turn at 170 giving you improved sustained turn performance. This part is particularly interesting in that many people mistakenly believe that the slower you are the tighter you can turn but look at the radius for 125mph, it’s 1000ft while at your best sustained turn speed of 170mph the radius has decreased to 800ft.
Above the P
s=0 line you can see that pulling to the edge of stall (the lift limit line) gives you a greater turn rate and even smaller radius. This is due to the greater G available as a result of your speed but you don’t have the power to sustain this turn (you’re above the P
s=0 line) and you’ll rapidly decelerate so, since you can’t sustain the turn rate, it's called instantaneous turn rate. Say that your speed is 225mph. If you pull hard at that speed you can see that your instantaneous turn rate is 25dps (just follow the 225mph line up to where it intersects the lift limit line again) with a turn radius of about 760 ft. That higher turn rate is a direct result of having more G available to you, in this case, about 4.5G but since you don't have the power to overcome the induced drag created by pulling all those G's you'll decelerate rapidly along the lift limit line right down to your best sustained turn speed of 170mph.
Your absolute best instantaneous turn performance is where the lift limit line intersects the G limit. Increasing G increases your turn rate and decreases your radius but only up to the G limit. You can only pull the maximum amount of G that the airplane can handle otherwise you’ll break your ride (or black out). That’s why corner is the best turn rate and smallest radius you’ll ever get (that’s for an actual turn, not a maneuver like a vertical rudder reversal). For the Pony you can see that corner is about 255mph giving you almost 32dps at 6G with about a 750ft radius. That turn rate is almost twice what you can sustain unless you’re in a descending turn. If you stay level, you’ll ride the lift limit line right back down to 170mph. If you’re faster than 255mph aircraft performance is limited by the airframe’s G limit and again, from the chart, you can see that your turn rate is less than at corner and your radius rapidly increases.
So, to go back to your comment, the most important numbers to know you can get from this chart. Your best sustained turn rate, corner velocity and turn radius.
