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Guest David Ketchum

Engine spool up times - FS9 VS FSX PMDG 747

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Guest David Ketchum

Hi,I've noticed that in the FS9 version of the 747 the engines come up to initial takeoff setting stabilization RPM of 70 percent N1 fairly quickly. In the FSX version, the engines seems to spool up a little slower under the same circumstances.I also note that in the FS9 version, full takeoff power is almost always realized at or before 80 knots groundspeed, but in the FSX version at heavier weights, full takeoff power sometimes isn't seen until past 80 knots.I thought the '80 knots' callout by the F/O was to verify that all engines were at takeoff power and that throttle hold mode was engaged, but I may be confused (not unusual for me). :)No huge deal either way, just trying to understand everything a little better. I wonder which version of the 747 is the most realistic. Thanks!-David W. Ketchum

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I could be wrong (probably am) but I seem to remember this being discussed at one point. You might try a search and see what you come up with.Sorry I couldn't be more helpful, but I don't know the answers. :)


Mike Roth

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>> but in the FSX version at heavier weights, full takeoff power >> sometimes isn't seen until past 80 knots.*heavier* weights? Are you sure that is not *lighter* weights?I'd expect it to be more of a problem when you're light, as it should accelerate quicker.Best regards,Robin.

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The engines need to be initially EPR stabilized, TOGA depressed and HOLD (indicating throttle servo disconnect) annunciated on the FMAs BEFORE before 65kts GS. The 80kt call is to emphasize the transition from low speed to high speed for the T/O roll- and force focus on the fact that an abort now is much more of an event than before 80 kts.Unfortunately I do not have a lot of experience with the FSX version, but in hundreds of hours of FS9 flight, the time-line seems appropriate but slightly slower in reaching final THR REF EPR than RW.Best-Carl F. Avari-Cooper BAW0225http://online.vatsimindicators.net/980091/523.png| XP Pro SP3 - FSGS System Unification | 2 x APC UPS | Coolermaster Stacker 830 SE | Gigabyte P35 DS3R | e8500 @ 4gHz | Tuniq Tower 120 | EVGA 8800GT 512MB | Sony 40" Bravia XBR | Creative X-Fi Fatal1ty | Bose Companion 5 | 2 x 1 GB Corsair XMS2 | 2 x 320GB WD Caviar RAID 0 | Corsair HX620W PS | CH Products Yoke-Pedals-Throttle Quadrant | Aerosoft 747MCP-EFIS-EICAS |


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Carl Avari-Cooper

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