The link to the modified default A320 flight_model.cfg:
https://1drv.ms/u/s!AohwTJSZ0H8DgfVEOo_WUvCOykMFMg?e=CwgFn4
Steps to reproduce this error: 1. pre-compile an aircraft project 2. start
Sim 3. open project 4. load up the aircraft and note current value on
Aircraft Editor → Debug → Sim 5. do some changes to induced_flaps scalar
6. re-compile the project 7. resync on aircraft editor 8. compare value on
Aircraft Editor → Debug → Sim if calculation is correct according to changes
Hello @boufogre We spent some time running tests on the A320 with the
modifications you mentioned. The big difference between the target CD and the
final CD in this case has multiple causes. - The induced drag scalar set to 4
is kind of an aberrant value. Above 2, the normalization process will not be
accurate. It will match on the 2 reference points we consider (AOA 0° and 12°
AFAIK) but will have very different values everywhere else. A bit like this:
Instead of:
- What’s your elevator position
when you check your drag values? On the A320, the elevator has a big influence
on the drag. It will change the AOA where you have Cd0 and Cl0. - Finally,
keep in mind that you can’t just rely on the normalization to compensate for
the difference between target parameters and actual results. The normalization
helps a lot but it can’t do “miracles”. The first priority is to configure the
flight model so that it gives results as close as possible to target
parameters so that normalization only has some minor adjustments to perform.
What we are going to change: Aiming for SU10, we’re going to expose some
additional debug information and configuration parameters. - The drag debug
window will now show the polars so you have a better view of the match between
theoretical model and actual FM. It will also show when you have values that
we consider too extreme
will expose new parameters to configure normalization:
clcd_normalization_aoa_deg_low : Lower AOA at which the aircraft’s lift &
drag is normalised to the theory curve. clcd_normalization_aoa_deg_high :
Higher AOA at which the aircraft’s lift & drag is normalized to the theory
curve.
- We will expose newparameters to adjust the drag: wing_mindragincidence : Aircraft AOA at
which the wing’s parasitic drag is minimal. (Lift induced drag is always
minimal when lift is minimal). fuselage_mindragincidence : Aircraft AOA at
which the fuselage’s drag is minimal. We think all of this will greatly help
you. Let us know if you have any feedback. Regards, Sylvain