Fuel flow returns a negative value for (some) negative path angles

TUDelft-CNS-ATM / openap

Open Aircraft Performance Model and Python Toolkit

https://openap.dev

GNU Lesser General Public License v3.0

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Fuel flow returns a negative value for (some) negative path angles #1

Closed obbe79 closed 5 years ago

obbe79 commented 5 years ago

Hi, I'm using your library to calculate fuel flow for A320. However for some negative values of the path angle I get negative values of the fuel flow.

This is what I do:

ff = FuelFlow(ac='A320', eng='CFM56-5B4')
ff.enroute(mass=60000, tas=301, alt=34200, path_angle=-2.1)

>>  -0.00615753894796707

Is this an issue or am I using your library in an incorrect way?

Thank you.

junzis commented 5 years ago

This was indeed a bug. The thrust should not become negative, but the idle thrust at the minimum. It's fixed now in bee774d.