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FlyBoyMike

NGX performance anomalies

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Hi Everyone,Hoping someone might be able to give me a bit of advice. I've recently come across a strange problem particularly with the -700 where after takeoff and on the climb out to cruise (say FL380) and after transition altitude the rate of climb becomes very slow and often the FMC will calculate a T/C distance of well over 200nm. My flights typically range from between 400-600nm to the destination and a climb rate this low will typically either a. only leave me with a very short distance to T/D or b. for a shorter range flight may not even be able to reach cruise altitude.This also happens regardless of the CI that I use but my typical values are between 60 and eighty. The FMC calculated speed for climbing also can never be reached when this happens. The only other thing I can think of is that it might have something to do with the total GW of my aircraft after takeoff.

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Hi there,Do you fly online? There's a bug when using FSInn weather on Vatsim (I'm not sure if this was reported with other weather engines). For some reason air temperature increases when you get higher, thus decreasing engine performance resulting in very poor rates of climb. In that case solution is using different software for weather generation.Also be aware that your rate of climb will decrease when using higher CI. 60 is pretty much i think, although it shouldn't affect performance as much as you describe.

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This sounds like a weather issue. What is the OAT when experiencing this issue and at what altitude? Are you using real weather or FSInn as mentioned above?Ninja'd

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Hi guys,Yes I do fly online and have just recently installed FSInn (I was previously using SquawkBox for a little bit but it's really unstable on my setup and causes the whole sim to crash to desktop quite frequently).I haven't actually played around with the options too much but is it possible to turn off the FSInn weather system and revert back to the FSX weather if this is what's causing the problem? I'm not too keen to go back to SquawkBox due to the stability issues I have.

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I haven't actually played around with the options too much but is it possible to turn off the FSInn weather system and revert back to the FSX weather if this is what's causing the problem? I'm not too keen to go back to SquawkBox due to the stability issues I have.
Yes, it's possible. And I'd reccomend freeware FSrealWX lite instead of FSX default weather engine.

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Thanks for the tips guys! :)I've just gone and installed FSRealWX and works really well, much nicer than default FSX weather. I've also turned off the weather updating in FSInn and after taking my -700 for another spin seems to have helped.I'll keep an eye on to it to see if the problem pops up again but hopefully it won'tCheers.

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Had the same issue, it's definetly FSInn's weather over FL200? issue in which temperature goes up instead of down. What you end up with is 20+°C at cruise which kills engine performance. Disable FSInn's control over your weather entirely (or click the CAVOK button).

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IIRC the IC values for the NG are much lower at the range of 20 to 30...
One of the common misconceptions on this forum, is right next to the tripple channel autoland discussion.While these values are more TYPICAL for the 737 NOWADAYS, it is by no means in any way required to fly the NG with these CI.The NG(X) CAN and WILL accept anything from 0 to 200/500 (depending on FMC software) and it CAN and WILL fly the VNAV path perfectly with ANY of those settings, barring some outside influence such as unforecast winds, or anti-ice usage. Regardless what some will tell you.It is NEVER a case that the aircraft is misperforming just because you put a "wrong" "too high" CI in the FMC, it is practically always a software bug (high idle, FSInn weather bug, etc) or user error (incorrect forecast entry, incorrect VNAV constraints usage).It is theoretically possible that NGX VNAV CALC could be buggy at high CI, but i have flown with CI of everything in between low 20s to 200, as well as policy maximum speed cruise&descent, and never ever had any problem with the VNAV.I am not saying that you George are not understanding CI/VNAV or misinterpreting it, but it is common.

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