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IfikratisK

Disagreement of TOPER and PMDG

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Hi all,

I face a problem with TOPER for the 777-200LR. As you can see in the picture, TOPER advises to use an assumed temperature of 70C but the V speeds are in complete disagreement with PMDG's calculation. I have also put TOPCAT , where it gives 50C instead and its V speeds are much closer to the PMDG. If I select 50C in the FMC, then the V speeds of TOPCAT match PMDG's prediction too.

So, my question is why TOPER is giving wrong V speeds and more assumed temperature? Is this a bug?

Untitled.png

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Hello and thank you for providing me with this information.

First I would like to address the "TO-1" de-rate option. It seems to be a bit buggy at the moment, so I would have to look into it.

When it comes to TOPCAT, from what I can see in the screenshot it is calculating "V" speeds up to 50deg assumed temperature. TOPER and CDU are desplay for 70deg.

Kind regards,

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Thank you sir for the reply, really appreciate that you keep working on improving the TOPER tool.

Regarding your comment for TOPCAT, yes it seems this is the maximum it gives for this calculation. But I'm am not mistaken, I have seen higher assumed temperatures, like 65C. It seems to find an optimum at 50C. Instead TOPER gives 70C for the same derate, however the speeds are quite off.

Thank you for looking at it, and I look forward for your future update regarding this. : )

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On 3/8/2018 at 6:02 PM, IfikratisK said:

Thank you sir for the reply, really appreciate that you keep working on improving the TOPER tool.

Regarding your comment for TOPCAT, yes it seems this is the maximum it gives for this calculation. But I'm am not mistaken, I have seen higher assumed temperatures, like 65C. It seems to find an optimum at 50C. Instead TOPER gives 70C for the same derate, however the speeds are quite off.

Thank you for looking at it, and I look forward for your future update regarding this. : )

Thank you kindly for your feedback and help in improving TOPER.
I will do a manual calculation and check the speeds for the given parameters.

Kind regards,

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