From: rdd@cactus.org (Robert Dorsett)
Subject: What is realism? (Re: Falcon MC Demo (at la)
Followup-To: rec.aviation.simulators
Organization: Capital Area Central Texas UNIX Society, Austin, Tx
Date: Mon, 23 Nov 1992 06:11:21 GMT

In article <1873.339.uupcb@pcb.batpad.lgb.ca.us> glen.kawano@pcb.batpad.lgb.ca.us (Glen Kawano)  writes:
>Hellcats does have a good frame rate, but the game itself is too simple
>and unrealistic. It's more of a simulator for the masses rather than a
>simulator for die-hard pilots.

Nope.  I'm a pilot, and a simulator enthusiast.  I've been playing them since
FS1, and have time in the real thing, too (707, 727, 747, A310, A320).  In my 
not so humble opinion, Hellcats has the best flying characteristics of the 
lot: it's the most like an airplane.  Its real contribution IS its 
sophisticated flight model (and nicely done graphics)


Once again, I'm taken aback by this intense desire of simulator players to 
somehow justify the investment in terms of realism.  Well, bad news: none
of them are particularly realistic.

Let's split it up by category:

1.  Flight dynamics.  

  o Does the simulator use a "real" flight model, based upon manufacturer 
    flight-test results, or does it use an approximation of that general 
    class of aircraft?  The REAL things are REAL expensive to acquire.

  o Does it take into account CG changes and wing sweep?  

  o High- or low-speed buffet?

  o Does it use a stability and control model, or is it a fudged-up ap-
    proximation, based upon a linear motion-frame, with fudge-factors for 
    airspeed and configuration, all "fine-tuned" to published performance
    capabilities?   Until a simulator starts using an S&C model, "fidelity" 
    probably shouldn't be used in the same sentence, at least with respect
    to flight dynamics.

  o Does it have a realistic atmosphere?  Does it take into account tem-
    perature and altitude effects on aircraft performance?

  o How well does it handle boundary conditions?  A lot of these games, like
    Hellcats, perform SUPERBLY "in-envelope," but mush out near the edges of
    the envelope, where the flight model is no longer accurate.

2.  Control.

  o Given the fact that airplanes must be trimmed, and that no interface 
    exists which displays either control forces *or* provides a credible
    option to trim away these forces, what does the manufacturer use?  Is
    this solution analogous to "FBW" interfaces in use on fighters and civil-
    ian aircraft?  If not, it had better be, to be considered "realistic."
    It's the only acceptable solution for personal computers.

  o How easy is it to land the airplane?  To borrow a page from Ron Wantajja,
    real pilots REALLY don't like to crash airplanes.  Give them a PC flight
    simulator, it should be as easy to control as a real airplane.  They 
    shouldn't have to re-study or learn new skills, just to land the airplane:
    the feedback offered by the airplane, the nature of that feedback, and
    external cues should all be satisfactory to land the airplane properly,
    EACH time.  No crashes.  "Flying" isn't the problem: it should be trans-
    parent to the user, to allow him to concentrate on the mission requirement
    (whether it's sight-seeing through a world database, or fighting enemy 
    MiG's or Zeros, or trying to maintain instrument-scan proficiency).

3.  Systems fidelity.

  o How well does the simulator handle systems?  Are the typical workload
    characteristics similar to a real airplane, or are they trimmed down,
    somehow, concentrating on just a component of the airplane?

  o How about instruments?  Does the simulator just show true airspeed (ala
    Falcon and MS-FS), or does it show indicated airspeed?  Is the "honesty"
    of the game designer such that they'll show what the user would see in
    a real airplane, and not just give a cheap "speed" thrill?  Does it sup-
    port a rotating compass card, or is it fixed "north," with a pointer
    showing you relative direction?

4.  Powerplant.

  o How well-done is the powerplant?  Is it a "miracle" engine?  Does it
    experience altitude and temperature effects?  Are there failure modes
    for overtemp conditions?   Can you just set the engine to full-throttle
    and not worry about it, again?  Is its fuel consumption realistic?  How
    about slip-stream: is it a force-vector, ala a jet, or do you experience
    changes in lift from the propeller?  Does it take into account speed 
    effects, such as decreased net thrust at high airspeeds?

5.  The World (the logical definition).

  o Is the "world" the simulator flies in modelled on real-life locations?  
    Are roads and airports in the right places, relative to one another?  How
    well is sloping terrain handled?  How about mountains?  The real world
    *isn't* flat, dotted with pyramids...

6.  The Visuals (what you see).

  o How good are the visuals?  Are they distracting from the game, cartoon-
    land, or do they seem conducive to the game?  Night view or day view?
    City lights in the right densities in the right areas?

  o Is the perspective animation any good?  Do objects look like what you'd 
    see in real life, or do they "warp" as you fly around them?  Can you see
    an enemy MiG 100 miles away, as a big white dot, or do you have to find
    him using radar?

  o If it's a visual-based simulator (dogfighter, pleasure-craft, etc), 
    what proportion of the screen is devoted to the out-the-window view?  
    The more the better, the crisper the better.

7.  Genesis.

  o Where did the simulator evolve from?  Someone's Master's thesis on 
    graphical interfaces, or someone's desire to accurately model a real 
    airplane?  A bean counter's proposal to create and market a flight
    simulator, in an anonymous three-initial corporation?  These will all 
    have VERY strong influences on how well the simulator meets the above 
    requirements: aero engineering types will produce "realistic" airplanes, 
    probably with lousy visuals; computer science types will produce "eye in 
    space" simulations--but, since the vast majority of games come from the 
    latter orientation, not much more seems to be necessary to convey the 
    "game" effect, considering the accolades from the user community.

8.  The Game.

  o How important is all this to make the simulator an effective game?  If
    the objective is to let the user do a bit of role-playing, to make him
    play at being an F-16 pilot for a few hours, then all you need is a 
    convincing manual, sounds, and a central feature--a HUD.  If the objec-
    tive is flight training, then the actual fidelity of the instrumentation,
    systems, and flight dynamics becomes vastly more important.  When people 
    use buzzwords like "high fidelity," they're moving from the former to the 
    latter orientation: is this appropriate, or even desirable, when discussing
    games?


So, let's do a comparative evaluation of three highly "realistic" simulators:
Microsoft Flight Simulator 4.0, Hellcats, and Falcon.  We'll rate them from
0 (indicating low fidelity) to 10 (indicating high fidelity, what one would
find in a "professional" airline-quality general-purpose flight simulator 
(military flight simulators tend to be highly specialized, and believe it or
not, I hesitate at generalizing :-))).

1.  Flight dynamics.
	MS FS: 	2.  Linear-motion.
	Falcon: 2.  Linear-motion.
	Hellcats: 3.  Appears to use a S&C partial-derivative model.

2.  Control.
	MS FS: 1.  Very kludgy: control surface indicator takes on an 
             unacceptable importance in flying the simulator.
	Falcon: 3.  Doesn't appear to support the F-16's FBW modes (!)
	Hellcats: 5.  The S&C control model produces a very FBW feel: very 
             easy to control the airplane and concentrate on the game.

3.  Systems.
	MS FS: 2.  Nav only: no systems.
	Falcon: 3.  Good HUD, summarized secondary systems, non-existent
               tertiary systems.  Lack of tunable navaids major minus.
	Hellcats: 1.5.  Mostly nonexistent.  Fair to good instrumentation,

4.  Powerplant.
	MS FS: 2.
	Falcon: 2.
	Hellcats: 2.

5.  The World.
	MS FS: 3.
	Falcon: 2.
	Hellcats: 2.

6.  Genesis.
	MS FS: Graphics.
	Falcon: Game.
	Hellcats: ?

7.  Game.
	MS FS: 3.  Visual simulator.
	Falcon: 4.  HUD simulator.
	Hellcats: 6.  Classical ACM simulator.

On the basis of all this, I'm not prepared to call *any* of these "high-
fidelity" or realistic.  They all have their niches as effective games, 
though.

But don't take my word for it.  Try several simple tests, yourself, the first
things I do with any new simulator:

1.  Stall it.  Try to spin it.

2.  Fly as high as you can.  
    o Note how it behaves at altitude.  
    o Try loaded (high-G) maneuvering.  Any sign of buffeting?  
    o How high can you fly?
    o What happens when you get there?  Does the airplane remain controllable,
      just mushing out to 0 rate of climb?  Can you "bounce" against an 
      absolute ceiling at full throttle, 70 degrees pitch?  Do you stall out
      and fall 30,000' before regaining control?  How closely do you need to
      follow a climb airspeed?  
    o Can you get higher by "zooming" (diving, then pulling up with increased 
      airspeed) than in a steady-state climb?
    o Do you see a varying (decreasing) rate of climb, with altitude?

3.  See how it handles with high-G maneuvering (Break up?  Black out?).

4.  Cross-check your VOR (or map) locations with airspeed at sea level and
    20,000'.  If they're the same, the simulator either doesn't account for 
    an atmosphere (evidenced by a constant rate of climb at a set airspeed),
    or is displaying only "true airspeed." (the problem here is that it makes 
    it much more difficult to fly precisely).

5.  Land it.  
    o Did you succeed on the first try?  If not, something's wrong: anybody 
      can land an airplane: there should be enough feedback to let you know
      when you're screwing up, and you should be able to retain control, go 
      back, and try again.
    o Stabilized on the approach, do you see any phugoids (slight oscillations 
      of the view, caused by the stability characteristics of the airplane)?  
      These should exist, but not be distracting or affect the approach..

6.  What happens when you move your input device?  
    o Is there any "damping" at high speeds, or does it pull 30G turns at 
      the flick of a wrist?  
    o Do you have to use the keyboard to control the airplane?

7.  How does it feel when you turn?
    o Are you getting enough feedback from your instruments and the visual
      to feel like you're controlling the airplane properly, or do you have
      a maddening compulsion to do a 360 degree turn in five seconds, in a 
      modelled Cessna 182?  In lack of inertia, there should be other cues
      to discourage over-controlling or rough controlling.

"Too much of a perfectionist," you'll say.  Not really.  I'm not asking
for component-level modelling of engine valves: just a decent simulation
from the *pilot's* perspective.  Some degree of realistic modelling is 
unavoidable: a lot can be done with "smoke and mirrors," just like it always 
has been (*especially* in the Real Thing).

A high-fidelity simulator IS possible on contemporary high-performance 
computers, which greatly outperform most of the computers driving real flight 
simulators in the 1970's.  None of these things are unreasoanble to expect--
EXCEPT a manufacturer-originated S&C flight model, perhaps.  But Hellcats is 
alleged to use a homebrew S&C flight model; so does Azuresoft's Elite (but 
there are abrupt envelope limits, there).  

The technology's moving in the right direction, but probably won't come from 
"established," mainstream software houses.  Spectrum seems to just barely 
muddle along; BAO & company have had Flight Simulator technology for over 12 
years, but just now, *barely* have a decent flight model--and the basic game, 
from a playability viewpoint, is almost unchanged since 1982's FS2.  If it
makes you truckloads of money, don't change the concept! 

None of these GAMES, though, quite fit the bill, but what chafes my hide is
that the publishers (and their satisfied customers!) will make the most of 
the product's "reputation" for *realism* to try to enhance sales (and then 
try to DEFEND this nonsense).  I say: let them put their money where their 
mouths are, and produce simulators which actually live up to the hype.  But 
we won't see this, as long as they can get away with marketable, "low-tech" 
solutions (which are MUCH cheaper to implement: just the cost of coding, no 
need to spend several times that amount developing flight and systems models).  







---
Robert Dorsett
rdd@cactus.org
...cs.utexas.edu!cactus.org!rdd
Newsgroups: comp.sys.mac.games