Open up flight model for customization and/or natively support external flight models

Although MSFS’s blade element theory based flight model, in most regards, is
regarded as superior to those of other consumer simulators, it is still
lacking or incorrect in quite a few areas. Among these, include ground
friction/handling, supporting multiple flaps/slats configuration and proper
flap auto-retract behavior, finer control over multiple speedbrakes and
separate individual speedbrake deflection angles, lift coefficient behavior
for slats, complete control over icing effect on aerodynamic model, and so
forth. Furthermore, there are countless configurations presented by unique
aircraft which may be outside of the scope of Asobo’s work simply due to the
amount of time needed to support them - such as supporting 3 separate ailerons
per each wing on the A380 (which uses it for load alleviation), supporting
multiple vertical stabilizers or horizontal stabilizers on aircraft that use
them, supporting unique configurations such as ruddervators or elevons,
canards, supersonic flight, etc. Rather than make issues for each of these
unique edge cases, which may just be deferred to the backlog for months or
years (and can indefinitely delay aircraft that rely on them), it would be
beneficial to either open up the flight model system for 3rd party developers
to modify as they see fit, or create a native API in which 3rd party devs can
easily incorporate an external flight model while still being able to use
blade element theory.

I’m fairly sure there isn’t any blade element theory going on in the flight
model. Additionally, your assertion that MSFS’s flight model is “regarded as
superior to those of other consumer simulators” is simply false. There is a
reason NASA, Beta Technologies, Airbus, etc have used that other consumer
simulator in the design of real-world aircraft and would never even consider
using MSFS for that purpose. It’s flight model is unquestionably better. It’s
important that Asobo are aware of this, because unconcious incompetence
doesn’t help anyone. You can’t fix something if you don’t know it’s broken.
That little rant aside, I agree with all of your points; the current flight
model API is very limited allowing the definition of only a limited subset of
aircraft.

It does use blade element model - take a look through all the equations here:
https://docs.flightsimulator.com/html/index.htm#t=Additional_Information%2FFlight_Model_Physics.htm
However, it has a way to go, and I wish it would be prioritized above
everything else once the Xbox version is released. That, and being more
transparent about new changes and upcoming plans to the flight model - it’s
probably the one area we don’t get much feedback, if at all, from Asobo in our
communications.

Mmm, I was just taking Seb at his word; I remember him saying quite
unequivocally when asked about the flight model pre-release “it’s not blade
element theory”

And whose word are you taking that Airbus uses X-plane in their design
process? NASA may have used it for looking at potential designs for flying
drones, etc on other planets, but they don’t generally design aircraft.

Just checked - indeed he mentions it’s not blade element theory. Regardless, I
still wish there was more communication and documentation regarding the flight
model, and the ability for developers to modify the core logic as there are
many faults in it, even nearly a year after the sim first released.

This would also enable custom VTOL designs. Even if MS/Asobo adds an official
helicopter flight model, I don’t think they will ever provide a generic flight
model that can cover all combinations of multirotor and tilting mechanisms
used by those creative eVTOL designs popping up everywhere. This could also
open up the FS platform to serious training applications that need tight
control over their flight models. Would simply supporting the already
specified “External Sim” SimConnect API be sufficient?
http://www.prepar3d.com/SDKv3/LearningCenter/utilities/simconnect/simconnect.html#ExternalSimOverview

Discussion on which sims flight profiling system is better is not relevant.
What IS relevant is that MSFS’ system is broken in a lot of ways (as per
above). Having the ability to make our own “sections” on this would be a boon
and helpful to all devs… not just 3PD’s…

In addition to the external sim simconnect API, there should be some API to
get data for the forces acting on all the 640 surface elements. Here is the
documentation mentioning that:

FYI, our FM is based on the same approach. We call it “surface elements model”
in the documentation but it’s the same logic. :slight_smile: