SDK Q&A Stream Feedback

I was one of the people asking during the end of the stream about if we will see improvements to the flight model in the future.

To be clear, I’m not trying to decrease the value of Asobo’s work and I really think that MSFS is an amazing product with a lot of potential for farther improvements and I’m really excited to see what’s coming next.

Regarding the flight model, an example of that is the incorrect simulation of leading edge lift devices, such as Krueger flaps or slats. They are presently simulated identically as trailing edge flaps when they actually have very different effects on the aerodynamics of the wing. Leading edge flaps will actually not change the lift vs AoA curve but rather increase the stall AoA, allowing to fly at lower speeds by increasing the AoA beyond the clean wing stall AoA, thus delaying the onset of the stall.
Trailing edge flaps will change the camber, shape and surface of the wing and thus increase the lift, changing the lift vs AoA curve by moving it upward on the graph, to put it simply. At the same time, the stall AoA of the wing with the deflected trailing edge flaps will be smaller or equal than the clean wing stall AoA.

Another example that comes to my mind is propeller drag. And I think that there must have been a tremendous misunderstanding between the developers and the community on the subject. As the devs said, there is a propeller drag parameter in the engine config file. But if I understand it correctly, this is the drag of the rotating propeller, when driven by the engine, acting along the propeller blade chord and slowing the propeller’s rotation (prop_cx in the engine config file, propeller section). What the community was talking about, was the drag of the propeller at rest ie not rotating, as what would happen during an engine failure after securing the failed engine. In that case, the propeller, if not feathered, would act as a big speed brake and the aircraft would experience a great amount of drag and glide for a given speed with a higher rate of descent and a more nose down attitude than the same plane with the prop feathered, which is basically the prop orienting its blades into the wind stream to decrease the drag. Tests were made by the community and there is no modelling of this. I have just tested it myself and propellers do not feather at all.

There is also the fact that the CoG changes position along the MAC when changing the sweep angle of the wing in the flight model config file, which shows improper simulation of swept wings which in turn affects the aircraft balance.

I’m just giving these examples at Asobo’s request during the Q&A, but here is a link to a topic which lists some of the most obvious issues at the moment with the flight model.

It has been 15 years since FSX was released and we have now an amazing opportunity for Asobo to fix many of the shortcuts that were taken years ago in the FS flight model.

I have to recognize that the modern flight model with the surface element distribution of the coefficients for the simulation makes it so much easier to design a credible flight model in a few steps and is my opinion a great step forward. However, many third party content producers want the ability to go beyond and bring a higher level of fidelity to their products. That’s why in the past some of them worked with external flight models.

If the MSFS development team were open to address these issues and work with the content producer to make a great flight model for MSFS, then there simply wouldn’t be a need for an external flight model at all!

To conclude, other pilots and I have voiced our comments about the flight model here and as it was mentioned during the stream that the flight model was developed with the help of pilots, then please take our comments into consideration.

About the SDK Q&A sessions, I think it’s a great tool for smaller developers and freeware developers to be kept in the loop of what are the latest developments about the SDK. Some sections are still very empty at the moment. I personally can’t wait to see the new platform that was announced.

Thank you for reading me!

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