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Windmilling Engine start

At 25000 feet and 320 KIAS, you should see a N1 RPM of 22% and a N2 RPM of 31%. (+/- 3% for each N indication)

(The 18% for N2 at 20000 ft and 320 KIAS is most likely a typo. 28% N2 would be much more logical.)


And you're working on a 727 panel? For FSX and Tom Ruth's model per chance?
 
Yes, that is clear for me! And my gauge show this values.
The right question would be:
At what N2 would be the windmill start successful? For 300 KIAS N2 from 21 to 33?
And what does the line 3 mean? Are this minimum N1 or N2 for engine start.

I have got an AOM, but there is also only this table with no further explanations.

This panel is written in XML of course using Doug's sound-, config- and dump gauges.
Bitmaps are from the Richard Probst-panel. For Elec-, Hydr-, Pneu- panel i took some fotos from a B727 simulator.
I use Ericks old B727ADV. FS9. But sooner or later i will change to FSX.

Edi
 
This post deals with in-flight starting of a CFM56 on a 737:
http://www.pprune.org/2204836-post3.html

It says that you need at least 15% N2 to relight the engine core without using the starter and seeing as the default starter spools N2 up to 20%, the latter value seems to be a good treshhold to work within MSFS' limitations. So any speed-altitude combination in the chart that yields at least 20% N2 is a good basis for relighting a JT8D in FS9. MSFS doesn't model windmilling (or does it?), so you will have to work around that. For FSX, I'd suggest implementing a windmilling logic using XMLTool's "Set A: var" functionality.
Any speed-altitude combination in the chart that yields less than 20% N2 would require use of the engine starter. On the JT8D, the starter is pneumatic and thus would require bleed air from one of the running engines to work (see the Tin Mouse 737 panel), but unless you've modeled a pneumatic starter, simply engaging the default (electrical) starter will be enough to make the dead engine turn again.
 
Thanks for the link but i found it some times ago.
Windmill start is programmed in XML using the starter under certain condition, proper N2 ,starter switch to flight , proper voltage.

According to the AOM non-normal procedures engine flameout, enginestart is only explained with windmilling. So i think airstart with crossbleed is not possible. And so it is programmed.

Edi
 
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