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I'll provide full equations once I've double checked them. Like I said, we did this research almost 3 years ago.It is the part on engine start that is where what 1505 does is shrouded in mystery and folklore. The functions of the other engine tables are well known, documented and fully understood. Any equations associated with that part would be very valuable.
Roy
Yes correct, CN1 is calculated using 1502, but the response is not instantaneous because a P function is applied to add some lag to it. Probably to simulate inertia.CN1 varies with CN2 as specified in 1502.
Corrected Thrust varies with CN1 and Mach as specified in 1506
Corrected fuel flow is a function of Corrected thrust and Thrust Specific Fuel Consumption
Corrected values are not used in the sim for performance computations, they are turned into real values as a function of Mach and altitude as described in my document in Resources.
Corrected does not mean exact, it is values that would occur at sea level static corrected using current Mach and altitude.
Engine performance is expressed in terms of what it would be when corrected to sea level ISA.
Roy
CN1 is not independent from CN2. CN1 is like mentioned calculated using 1502 and a P-controller / first order lag filter. (not sure what the best name for it is)It sounds like you are saying that CN1 can be independent from CN2 and I don't think that is the case.
Since TSFC is lbs fuel per lb thrust it certainly controls actual fuel flow. I have noticed that CFF sort of does its own thing and you cannot write values to it.
Roy
1505 affects spool rate, yes, but not by getting some kind of spool rate of change. It is a look-up table for a new target CN2.I don't think I agree with this.
I believe it is more like this:
1. 1503/1504 - Determine target CN2.
2. 1505 - Determine spool rate of change to achieve target CN2.
3. Adjust CN2 to target utilizing first order lag based on 1505 calculations.
4. 1502 - Determine CN1
I believe the only thing that 1505 actually controls is the spool rate between selected data points that correspond to CN2 values. But hey, what do I know.
Are you sure? I know about table 154B but that's found in the .air-file, however I can't find anything like that in aircraft.cfg while browsing the P3Dv4 SDK.Those tables are overrideable in newer versions of Prepar3D via aircraft.cfg entries.