I'm using FG since several years as a user and not a developer, and mostly played with several aircraft to learn IFR without being a real life pilot.
A couple of years later, I'm now a real life glider pilot, and I'm now using FG to simulate some cross country flights, with XCSoar running on a smartphone attached to FG over a NMEA/UDP connection; so I'm using a real flight calculator attached to the flight simulator, and I encounter some abnormal behaviors with the ASK21 glider. I also fly time to times a real ASK21 in my local club.
- - Air-brakes performance seems to be very low in for this model : in landing conditions (ie between 88 and 100km/h IAS, 1.3xVso, depending on load) with full opened air-brakes, the descent rate stays very low (-2 or -3 m/s instead of at least -4m/s). I don't have any reference value in a flight manual, but according to Sailplane Rule Book from EASA :
It must be shown that the sailplane has a glide slope not flatter than one in seven at a speed of 1.3 VSo
with air brakes extended at maximum weight.
Taking 90km/h as approach IAS, this means at least -3.6m/s must be observed to be compliant with EASA regulation. The current ASK21 model in Flightgear is almost impossible to land correctly using the regular traffic pattern used for gliders, without any additional maneuvers (increase IAS while full air-brakes in order to temporary increase the descent rate, and catch up the nominal glide slope).
- descent rate mostly stays between 0 and -1m/s on transitions even at IAS > 120km/h which is not compliant with the official polar from the flight manual. The XCsoar attached computer gives crazy values for glide ratio during transitions in still air, like 50 or 60 [metric]. According to the polar from the flight manual, this could not exceed about 40 with a small load).
I would be happy to help in tuning this aircraft model properly into a more realist simulation, but I don't really know where to start.. any help from the community would be welcome
Thanks,
Thomas.