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il86

RFP high altitude performance

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I am a bit confused having recently aquired PMDG's 747-400 "Queen of the Skies". This product with maximum fuel/passengers/cargo starts to have a great deal of dfficulty climbing above FL20. This contrasts with VMAX's RFP (a 747-200) which easily sustains 500fpm above FL30 all the way up to FL39. Another product CLS's 747 Flite model seems to agree with RFP altough it tends to slow down less at FL39 (all these comparisons are at maximum fuel/passengers/cargo) and also uses less fuel. Boeing's 747-200 has lower weight as well as lower performance compared to the later 747-400 which has more weight and the potential for more fuel but also more powerful engines. I am just surprised by such a large difference in climb performance. Step clmbs seem unecessary with the 747-200 as its velocity appears to be considerably less affected than the 747-400 which starts to slow down noticeably if there are no steps. So is the high altitude/high load performance of RFP wrong or was the 747-200 able to climb much more easily at high altitude/high load than the 747-400 ?

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I think the RFP is wrong in this, as one should burn off fuel to step climb.

Its been a long time, I remember adjusting the airfile for this long ago, but dont have it at hand.

 

The CLS has way to much power imho.

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Hi Johan,

 

I had read that many real world pilots consider RFP to be a very accurate representation of the 747-200. The CLS version I am less critical of as it is for casual simmers. If you are correct then it seems a little odd that VMAX would go to all the trouble of systems modelling accuracy as well as all the detail in their 240 page manual only to make the engines over powered. I wonder if anyone has a more realistic airfile for VMAX's 747-200

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I don't remember fully, but I believe step climb was needed due to heavy weight in real life. I think the PMDG is more correct in this (at MTOW!)

Maybe it was in FS2002 where it worked as advertised, and in FS2004 the file needed adjustments.

 

Anyhow, RFP is hopelessly outdated now, and I miss the bird. Since I only fly VC now, what gives me more immersion and a more realistic view on landing, there is no other option.

 

I fly a lot in the PMDG747 for FS9, and like it a lot, but miss the -200. Time to move on I think.

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My RFP is the CD box version. I see it was released as freeware as V2. I will download this and see if that makes any difference re. climb performance. I know the V2 version starts cold and dark (one of my pet hates with an add on) but I'll just copy the cfg/air files. If that fails then I'll risk life and limb fiddling with the air file and drag/lift ratios which I'll have to do a bit of research or copy from somewhere. I am surprised no-one has done an FSX/P3D version of the 747-200 in detail. For some reason obscure light aircraft or military aircraft seem much more of a priority.

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