Aircraft rating system

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Revision as of 04:05, 29 May 2014 by Johan G (talk | contribs) (Some rephrasing of the initial section; Heading levels; +cat: Aircraft enhancement; etc)
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Aircraft rating and status as indicated in FGRun.

The aircraft rating system is an attempt to help you find the aircraft your looking for among the hundreds of aircraft available for FlightGear. This is done by providing a quick objective way to rate aircraft. This was discussed in some detail on the -dev mailing list in December 2010.

The rating system gives an aircraft a 0–5 score in four areas - FDM, systems, cockpit and external model. These ratings can then be encoded in the aircraft -set.xml file from where they can be picked up by launchers, web pages etc. The sum of the scores in the four criteria provides an overall 0–20 score, which can be mapped to a textual overall aircraft status.

Rating criteria

Flight Dynamics Model (FDM)

  • 0: None, or using FDM from other aircraft
  • 1: JSBSim Aeromatic or YASim geometric model used without tuning. Flaps modeled.
  • 2: FDM tuned for cruise configuration.
  • 3: FDM tuned for rate of climb and cruise Pilot Operating Handbook (PoH) performance numbers
  • 4: FDM matches PoH in 90% of configurations
  • 5: FDM matches PoH and most known test data.

Systems

  • 0: No controllable systems: engine is always on, generic radio,
  • 1: Generic engine start/stop (}}s), correct size/number of fuel tanks, generic (untuned) autopilot, working flaps/gear
  • 2: Working electrical system, fuel feed cockpit controls, stable autopilot
  • 3: Accurate startup procedure, tuned autopilot with cockpit controls matching real aircraft systems, generic failure modelling (Vne, +ve/-ve G, gear limits). No unrealistic systems.
  • 4: Primary aircraft-specific systems modelled (aero-tow, radar, GPWS, weapons, external stores). User able to follow normal PoH checklists (e.g. startup, shutdown) in entirety
  • 5: Some aircraft-specific failure modes implemented (e.g. flame-out, inverted engine limitations). Some emergency procedures implemented (RAT, emergency gear release), able to follow some emergency PoH checklists in entirety.

Obviously some aircraft (e.g. glider) have fewer systems than other (e.g. and airliner). If your aircraft does not have a given system, ignore it for the purposes of rating. E.g. a glider does not need a stable autopilot for a 2 rating.

Furthermore, for a 3 or above, the aircraft should not implement systems not present in the real aircraft (e.g. flaps if none present IRL). The exception to this is an autopilot accessed through the menu (considered useful for flight testing purposes).

Cockpit

  • 0: No cockpit
  • 1: 2D panel, no cockpit.
  • 2: 2D panel in 3D cockpit, or incomplete 3D panel
  • 3: 3D panel and cockpit
  • 4: 3D panel and accurately modelled 3D cockpit, plain texturing. Hotspots for majority of controls.
  • 5: 3D panel and accurately modelled 3D cockpit with photo-realistic texturing.

External Model

  • 0: None
  • 1: Simple 3D model, no animations
  • 2: Accurate 3D model with animated control surfaces (elevator, aileron, rudder, flaps)
  • 3: Accurate 3D model with animated control surfaces, gear detailing (retraction, rotation), prop
  • 4: Accurate 3D model with animated control surfaces, gear, prop, livery support (if applicable).
  • 5: Highly accurate 3D model (down to minor components such as control rods), with animated control surfaces, gear, prop, livery support, tyre smoke, shader effects.

Objectively differentiating between a 4 and a 5 is very difficult. As a guideline, a "5" model is as realistic as possible given the available rendering technology.

Note  The difference between a 3 and a 4 seems to be just the livery support. I propose to add "detailed parts (realistic lights, exhausts, airing)" for a 4

(you are free to remove this NOTE after reviewed this proposition)

Overall status

Sum the ratings of the 4 criteria, to produce an overall score from 0 to 20.

This maps to overall status as follows:

Encoding the rating

In the -set.xml file

The ratings should be encoded in the -set.xml file for the aircraft, under <sim> as follows.

<status>early production</status>
<rating>
 <FDM type="int">5</FDM>
 <systems type="int">4</systems>
 <cockpit type="int">3</cockpit>
 <model type="int">3</model>
</rating>

In aircraft articles on the wiki

Status ratings can be (optionally) included in an aircraft's wiki article. Please note that those posted on the wiki are only used by the wiki itself and do not substitue the rating in -set.xml, as described above!

The overall status is auto-calculated and will be displayed. Remove the |status = line if you use the official system and add the following lines, each with a rating on a scale of 0 to 5. See Template:Infobox Aircraft for more info.

...
| status-fdm     = 5
| status-systems = 4
| status-cockpit = 3
| status-model   = 3
...

You can find the current wiki aircraft pages within each status level via the aircraft status category page.

Related content

External links

Some topics on the FlightGear forum related to the background of the aircraft status: