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Karl419

747-400 Engine Types

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Ok. Question for the team who created the PMDG 747.

Your 747-400 is currently offered with 3 different engine types: RR, GE & PW.

Now, this should go without saying but, we all know that all three engines operate differently. Agreed? No two engines are the same. Each has different values in all respects.

Now, I won't be mad, but I want to know from the PMDG 747-400 team: "Are the three different engine types (GE, PW & RR) actually PROPERLY simulated on the 747-400? I'm not talking about look, aesthetics, etc. I'm talking fuel consumption values, thrust, capacity, etc."

Like I said, I won't be upset if the answer is no, I just want a completely honest answer. It's very difficult to properly flan a flight for the Queen if the values for the actual aircraft do not agree with the values you are trying to plan with.

I'm not talking about just offering the liveries with various engine types (i.e. United comes with PW, Lufthansa comes with GE, etc.). I'm talking actual real proper values.

I love flying the 747. One of the greatest aircraft mankind has ever created, I believe. I thank you for your extensive work on her and the beautiful product you have created. Thanks again.

All the best!

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Now, I won't be mad, but I want to know from the PMDG 747-400 team: "Are the three different engine types (GE, PW & RR) actually PROPERLY simulated on the 747-400? I'm not talking about look, aesthetics, etc. I'm talking fuel consumption values, thrust, capacity, etc."

 

Your answer is here:

http://forum.avsim.net/topic/245757-b744-engine-simulation-one-or-three/#entry1553716

 

 

 


You missed the meaning of this line.static_thrust = 58000.0 //Lbs, nominal SLS adjusted thru EECPeople commenting know what EEC is ? Or what the word nominal SLS thrust implies ?The 744 does indeed have 3 engines types with different thrust limits. This is handled internally by the math, adapted to and fooling FS. CHeck it yourself. Load a 744 at MTOW and try RR, GE and PW engines. Rates of climb are different (least powerful RR, most powerful PW). You need the latest versions ofcourse or the -F model.I suggest simmers spend more time enjoying (and learning about) a very carefully tuned aircraft model rather than trying to unravel mysteries which are not there. This is not your average mickey-mouse sim dont treat it like one.Vangelis

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there is no easy answer and has you have read it was a long debate.

 

the only engine combo used for developping and by developpers was the pax version with CF6 engines.

 

the rest is cosmetic even on the FMS.

 

there are differences for each frame and engine and that is the reason some operators use a kind or another ones, the pw4062 is maybe a little more powerful but at the end you don t use the max of the engine or you wont fly a lot ...

 

all the best.

 

Phil

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As far as I know, when the -400F was released, and the service pack to, they updated the displays to show the EPR ratings and three shafts in the case of the RR engine, but they also said in the document that they now properly simulated all three engine variants, but they also said that operationally the differences between them are not that big.   You will notice different EPR readings for example between the RR and PW engines on the same power settings.

 

I stand to be corrected though...

 

Kind regards

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http://forums1.avsim.net/topic/117459-attention-to-pmdg-team-on-flightplanning-side-if-any-help-come/

 

Posted 23 April 2006 - 04:52 PM

We used data from the Boeing Company.This is good as a reference for starters : _747-400_OM_TBC_C_040501_QRH_B6P.pdfNovember 1 2003 / Ref. D6-30151-400Chapter PI / Section 11 for MAX/OPT ALTBest Regards,Vangelis===================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com=====================================

 

maybe it had changed since but this is the info i got.

 

Phil


As far as I know, when the -400F was released, and the service pack to, they updated the displays to show the EPR ratings and three shafts in the case of the RR engine, but they also said in the document that they now properly simulated all three engine variants, but they also said that operationally the differences between them are not that big.   You will notice different EPR readings for example between the RR and PW engines on the same power settings.

 

I stand to be corrected though...

 

Kind regards

Werner there are differences between any of the frame but will an actual simulator be able to simulate the 3 to 5% i dont know ..

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Werner there are differences between any of the frame but will an actual simulator be able to simulate the 3 to 5% i dont know ..

 

Can't argue with that lol.   Maybe a real world 747 skipper that has flown the different engine types can give some information on this.   Interesting discussion anyways...

 

Kind regards

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there is no easy answer and has you have read it was a long debate.

 

the only engine combo used for developping and by developpers was the pax version with CF6 engines.

 

the rest is cosmetic even on the FMS.

 

there are differences for each frame and engine and that is the reason some operators use a kind or another ones, the pw4062 is maybe a little more powerful but at the end you don t use the max of the engine or you wont fly a lot ...

 

all the best.

 

Phil

It may be cosmetic, but the end result is a convincing and accurate RR, PW and GE simulation. This subsequent post by Vasngelis in the very same thread you quoted from explains how this is achieved:

 

OK I'll bite :) static_thrust is just a mutliplier for the non-dimensional thrust engine curve(s) in the airfile for a specific set of TAT, mach, N1. Note that static_thrust does not imply MAX thrust. This depdends on the aforementioned engine curves. N1 in turn depends on ambient pressure (delta), throttle position, mach and TAT (as defined in other airfile tables). If [a] one knows how the FS engine (thrust) model works for each set of conditions the airfile is carefully tuned and [c] has a significant amount of data for engine indications per type (for sets of conditions) then one can both move the FS throttle to produce as much thrust as exactly required on one hand, while on the other producing custom engine data (outside FS) for the EICAS that correspond precisely to a specific engine type. In other words : a virtual engine in the panel with correct thrust from the FS intrenal model (necessary for modelling performance). Takes a bit of time but evidently do-able.Best,Vangelis PS. Manual not my thing !

 

http://forum.avsim.net/topic/245757-b744-engine-simulation-one-or-three/#entry1553748

 

Correct thrust for the engine type means the sim flies right and correct EICAS indications means it looks right. Not to mention they sound right due to different sound models. The only thing he doesn't mention is whether spool up time differences are modelled.

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