Undulating speeds with AT throttle

[hjwalter]

Hi guys,

 

The engine power of quite a few of my aircraft undulates considerably between almost full power and idle when under auto-pilot/auto-throttle control. Probably a simple drag tweak somewhere but where ?

 

Thanks in advance for any welcome solutions.

Hans

[mrzippy]

Does it happen at all altitudes or only up near cruise altitude?

[tiger1962]

Hi guys,

 

The engine power of quite a few of my aircraft undulates considerably between almost full power and idle when under auto-pilot/auto-throttle control. Probably a simple drag tweak somewhere but where ?

 

Thanks in advance for any welcome solutions.

Hans

 

This could be caused by the fuel_flow_gain setting in the aircraft.cfg being too low, the default is usually 0.002, but this can be increased up to 0.6 (for the Maddog MD80 which had this issue too).

[hjwalter]

Yes, the fuel_flow_gain setting on the first problem plane I tested, was evidently (far) too low at 0.011. I increased it to 0.6 and that seems to have solved the problem. Thanks tiger1962.

 

Also thanks for your reaction mrzippy. The problem seemed to (have) show(n) itself at all altitudes, a little less during climb but far more pronounced at level flight.

 

Hans