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Guest Totalbeginner

744 Engine spool now less realistic!

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Guest Totalbeginner

I am curious to know why the engine spool timings were adjusted in SP 2.1 so that they are now less realistic? At thrust reduction it takes nearly 5 seconds for the engines to spool down and the time delay now triggers 4 x EICAS warnings for N1 limits.What was the reason for this?Regards,Martin Neep

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Martin,I'd be interested to know what leads you to believe this isn't realistic?


Mark Adeane - NZWN
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4 x EICAS warnings for N1 limits is definitely not normal on the real aircraft. Are your EEC's in NORM?Try setting your joystick throttle not so far forward for takeoff (i.e. forward enough to stop the levers throttling back during thrust hold on takeoff, but not enough to not trigger the limit warnings).Cheers.Q> イアン

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Guest Totalbeginner

This is not a takeoff issue, it happens during the climb-out.At the THR reduction ALT the Target N1 changes to CLB and the engines start (very slowly) to spool down. Then for a brief moment, a caution message is displayed (N1 limits), before being extinguished when the N1 matches the demanded N1.Does anybody else have this problem with SP 2.1?By the way, I've used all three engine varients PW, GE, RR and the problem occurs on all three.Martin

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"This is not a takeoff issue, it happens during the climb-out.At the THR reduction ALT the Target N1 changes to CLB and the engines start (very slowly) to spool down. Then for a brief moment, a caution message is displayed (N1 limits), before being extinguished when the N1 matches the demanded N1."I think you've misunderstood me, Martin.If you set your joystick thrust for takeoff (and don't move it afterwards), then it will be in the same position as the takeoff position at thrust reduction height. There may be interference from your joystick preventing the thrust from decreasing in a timely manner (although I don't know why you would get any messages, irrespective of the time taken to spool down).How do you set your thrust for takeoff?Cheers.Q>

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The flap 5 thrust reduction is slower then normal, the change in engine pitch should be almost instant but this is not a PMDG Issue as far as I'm aware? it's a FS limitation, low end spool is faster then normal and high end spool is slower then normal. Not the best example -


Rob Prest

 

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Guest Totalbeginner

Ok, I've done some tests and it's definitely not caused by the throttle on my yoke. I've performed a takeoff using just the keyboard ( with my yoke disabled) and the same things happens. Are you using FSX with SP 2.1?I totally agree with the last comment regardng spool times. Spool-up lag should be least noticeable between 70% N1 and above. With the greatest lag occuring between Idle and 40 % N1. But in the case of FS, and god knows why, this is reversed!I don't know if this is related, but when performing a normal takeoff (this only happens when TOGA is used) shortly after rotation, at the moment the main gear unstick, the throttles retard very briefly? Again, this is not related to my yoke, because I've tested it with the yoke disabled. However, if I manually set takeoff N1 and DO NOT press the TOGA switch, it doesn't happen? However, my first problem occurs all the time?Can anyone from PMDG shed some light. This is starting to sound like a problem that only I am having.Martin

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Interesting... None of the engine indicators are showing overspeed. Is N2 or N3 overspeeding?Cheers.Q>

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EPR is 1.46 and CLB 1 limit is 1.45 so that should trigger a warning right?Rob


Rob Prest

 

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I see the same thing. Nothing to do with the throttle on my stick.I think a couple of things were broken in this update. See my thread on the fuel cross-feed problem (I'm fairly sure it isn't an operational problem). I don't remember this caution before the update.Best regards,Robin.

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Ah OK now I think I know what you're talking about. I saw this just last week when I flew a near-empty 744F out of Zurich, I had blasted off at TOGA thrust (for a bit of fun you see), but with CLB-2 selected as the climb limit during my preflight there was a larger than normal 'gap' between the two limits. I noticed the same EICAS indication for about 2-3 seconds seconds during reduction.For me at least, The message seems to trigger only when the differential between TO and CLB is greater than usual.Q is this not possible in the RW even with greater differences between TO and CLB thrust limits?As a side note, launching a near-empty 744F with TOGA thrust, CLB, and no speed restrictions below 10,000 feet is a heck of a fun (if unrealistic) ride. The accel is so great that it's a challenge to clean up the flaps on schedule as the aircraft gains momentum so fast! Highly recommended for those who want a little fun in their routine, plus moving that fast so close to the ground is a bit of a 747-only privilege in the commercial airliner stakes so make the most of the speed rush!


Mark Adeane - NZWN
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Rob, the messages you see should only apply to rpm, not EPR, either on the RB211 or GE. These messages only appear if you exceed the red lines on the scales, not when you go over the current thrust mode limit.I think we need to consult the PMDG programming experts on this one ;)Cheers.Q> Ян

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Maybe completely unhelpful...but every now and again when levelling out to initial CRZ ALT, I get the ENG 1,2,3,4 RPM LIM message or some similar-sounding message (can't quite remember exact message). It flashes for a second and is gone. Just seems to be a little harmless of quirk of this simulation.


Rudy Fidao

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