Fixing FS9 EPR

[airforce2]

Pete;

Is there any way that you could put a feature into FSUIPC 3.xx that would allow a programmer to write an EPR value to an FSUIPC offset and have that value poked into FS9's extern data table (overriding the flawed FS-derived value)? As you know, the EPR computations in FS9 are hard broken...but there's a lot known on how to derive valid EPR values from other parameters such as CN1. In an ideal world, each panel developer would do this, but the world isn't ideal. I'd like to be able to write a piggyback program to compute and write valid EPR data that would override the FS value and be retrieved when a lookup of the FS EPR value is performed by otherwise salvageable panels like the CaptainSim 707/727 for example.

Anyway, I figured if anyone could work that sort of magic it'd be you.

Happy Holidays from sunny central Chile!

[Pete Dowson]

Is there any way that you could put a feature into FSUIPC 3.xx that would allow a programmer to write an EPR value to an FSUIPC offset and have that value poked into FS9's extern data table (overriding the flawed FS-derived value)?

No, not in any way that any such value won't get immediately overwritten by FS's simulation engine on the next computation frame. It is a result, not an input.

As you know, the EPR computations in FS9 are hard broken.

No, I don't know that? Where is this published? What is the error?

I'd like to be able to write a piggyback program to compute and write valid EPR data that would override the FS value and be retrieved when a lookup of the FS EPR value is performed by otherwise salvageable panels like the CaptainSim 707/727 for example.

Why not write your own gauge to replace the one in your favourite aircraft, then? If this is a well-known fault in FS, why haven't the competent aircraft makers fixed it in the gauges? The gauge code doesn't have to use the value exactly as provided, it can do as it wants.

Regards

Pete

[airforce2]

Hi Pete;

Yes, it's true that FS9 does not compute EPR in any meaningful way...EPR values coming from the FS9 FDE engine are generally nonsensical...like seeing 1.6 EPR at idle on the ground. Much has been written on the topic in the AvHistory.org FDE forums among others. Indeed, some competent panel programmers do in fact get it right with custom programming in their gauges...PMDG, Dreamfleet, even my own gauge work in the TinMouse II 737 (shameless plug alert!). But I'd love to be able to divert the indirection in FS, making it write the flawed EPR values to some unused corner of the data area, and replacing the data at the address used to access EPR with externally generated data in lieu of the flawed EPR values that are being read from FS by a number of otherwise decent panels written by guys that simply didn't get that part right.

Anyway, the project at hand right now is to make a working EPR gauge for the JT3D-7 in the CaptainSim 707...they, unfortunately, use a single massive multigauge panel (the entire main panel is a single gauge) that doesn't lend itself to replacing one errant gauge, and they are utterly hopeless when it comes to fixing things once they consider a product to be close enough to done.

Cheers

[Pete Dowson]

EPR values coming from the FS9 FDE engine are generally nonsensical...like seeing 1.6 EPR at idle on the ground.

Really? Shows how long it has been since I flew a 'plane which used EPR. In FS2002 and before I seem to remember things being fine.

If such an essential value is so much up the creek, why hasn't there ever been any request that I've seen at all in the three years of FS2004? Very strange!

... I'd love to be able to divert the indirection in FS, making it write the flawed EPR values to some unused corner of the data area, and replacing the data at the address used to access EPR with externally generated data in lieu of the flawed EPR values that are being read from FS by a number of otherwise decent panels written by guys that simply didn't get that part right.

There's no way of altering the internal values, but I suppose a methods coud be provided to prevent FSUIPC populating whichever offset it is you are thinking of, allowing other values to be written there for other FSUIPC clients to read.

But surely after more than three years of FS2004 now is not really the time to be making such basic changes. Have you checked FSX?

Regards

Pete