EPR Formula

[jspan_com 0]

Hi All,I want to use the XML variable (a:var) TURB ENG1 PRESSURE RATIO and have tried different codes without any success. This code is for a turboprop engine (ATR42), example:(A:TURB ENG1 PRESSURE RATIO,percent) Result is that the indication starts on 100 %. By changing to this code:(A:TURB ENG1 PRESSURE RATIO,percent) 65536 / 100 *the result is almost zero. Help on this one is appreciated!Another interesting "issue" is the way MSFS calculates hPA or millibars versus inches HG. According to the Gauges Tutorial by Dai Griffiths MSFS sets 29.92 in HG equal to 1013.2 mb, while the correct value should be 1013.25. I have set this calculation in an XML Altimeter like this:%((A:Kohlsman setting hg,mbar) 1.0000493485984998026056060007896 *)%!04.0f!and it seem to work fine related to the in HG values.Best regardsJan H. Sorensenwww.jspanels.com

[Guest HartmannH]

I don't know the answer for your question, but for what do you need an EPR value on an ATR panel???

[jspan_com 0]

Hi Hans,I most probably have got it wrong then, since you are asking :-). The purpose of this gauge is the NH NL indication (pressure ??). If you can inform me what kind of (XML) variable to be used here it would be fine!Best regardsJan H. Sorensenwww.jspanels.com

[Guest airhead]

Jan,Sorry to muck up your posting with no helpful info for your question, but just wanted to say that I followed the link to your site and your ATR42 panel looks really great. Nice job with the gauge and panel bitmaps! One of the best I've seen, IMHO. Nice looking model too.

[Guest Douglas K]

>I most probably have got it wrong then, since you are asking . The purpose of this gauge is the NH NL indication (pressure ??). If you can inform me what kind of (XML) variable to be used here it would be fine!:)

[jspan_com 0]

Hi Douglas,Thanks for your help and for the most useful information on the ATR42 engines :-).The TURB ENG (1&2) CORRECTED N1 a:vars work fine both in FS2002 and FS9.Best regardsJan H. Sorensenwww.jspanels.com

[Guest JeanLuc_]

Thank you for this invaluable information! If Hans in the post above is the Hans on the development team of the ATR42, then I guess you contributed to save the day for this next ATR42 payware release! Thanks!

[Guest HartmannH]

Looks like Jean-Luc didn't sleep too well last night... @Jan: sorry that I didn't answer earlier. I just didn't look into this forum. Anyway Douglas said everything that has to be said about the NH/NL indications. Another way to solve this would be to use the normal N2 variable and correct it by using a non-linearity table. My knowledge about the XML stuff is pretty small, but if nl-tables work in XML like they do in C, it should be easy to do.

[Guest JeanLuc_]

Hi Hans! Are you the Hans working on the upcoming announced for Christmas ATR? here is from yours: "for what do you need an EPR value on an ATR panel???" and from the answers, it looked like to me there was some very good info for you! In any case:"We were looking for the best developers we could find for this package. Obviously, when we wanted a great panel, we looked to members of Dreamfleet to help us out."So don't take any of my comments in consideration! there are definitely not worth it!! It is not better than:http://www.simforums.com/forums/forum_post...p?TID=4963&PN=1Best,

[jspan_com 0]

>Looks like Jean-Luc didn't sleep too well last night... >>@Jan: sorry that I didn't answer earlier. I just didn't look>into this forum. Anyway Douglas said everything that has to be>said about the NH/NL indications. Another way to solve this>would be to use the normal N2 variable and correct it by using>a non-linearity table. My knowledge about the XML stuff is>pretty small, but if nl-tables work in XML like they do in C,>it should be easy to do.Hi Hans,No problems :-). Thanks to all who have been very helpful during the development of the ATR42 project, which by the way is far from finished yet! A new article has just been posted on my web site (address below) with some screenshots of the 2D panels, among them the new engine gauges on the center panel. Best regardsJan H. Sorensenwww.jspanels.com

[Guest Ian_K]

This is from a JT8D SS EPR data for A B727 and may give you some ideas. There are lots of graphics on the AvHistory Decode Forum.Ian EPR vs N1 - Takeoff and Go-Around OAT F -65 -58 -40 -22 -4 14 32 50 68 86 104 122 130 C -54 *C -50 -40 *C -30 -20 *C -10 0 *C 10 20 *C 30 40 *C 50 54 *C EPR Target N1 Percent 2.3 2.30 91 92 94 95 97 99 101 103 105 106 108 110 111 2.2 2.20 87 88 90 92 94 95 97 99 101 102 104 106 107 2.1 2.10 84 85 87 88 90 92 94 95 97 99 100 102 102 2.0 2.00 81 82 84 85 87 89 90 92 94 95 97 98 99 1.9 1.90 78 79 81 83 84 86 88 89 91 92 94 95 96 1.8 1.80 76 77 78 80 82 84 85 87 88 90 91 92 93 23.10.16 1.7 1.70 74 75 76 78 79 81 82 84 85 87 88 89 90

[jspan_com 0]

@ Ian,Thank you for the JT8D SS EPR data, which will be useful for future Jet Aircraft projects :-). As said before on this tread, the ATR42 engines does not use EPR, but rather NH, NL and NP data.Best regardsJan H. Sorensenwww.jspanels.com