Simviation Forums

Hi there,

I'm fairly new to flight sims and am currently playing FS2004. I see a lot of sites with add-on aircraft that look fantastic, but I'm not able to get any information on how these models perform when compared to the real thing.

How does FS2004 calculate the aircraft performance? Does it do it based on the surface of the model along with factors like weight, balance, etc. (I have no idea of the factors involved)? Or is there some recorded statistics that are approximated in creating new models?

Any thoughts?

This is an interesting post.

Basically, the visual model and the flight dynamics are two separate and independent things in flight simulator.

The better models, however, do try to simulate the flight dynamics of the real aircraft as close as possible, and there are examples of, say, Boeing B737 pilots taking on a flight and coming away suitably impressed.

Flight dynamics are a compromise between playability and accuracy.  You can't expect a $50-$80 "game" to accurately portray what a $77M aircraft does in real life.

Having said that, the  people that tweak the aircraft.cfg and *.air files perform magic.  The more serious ones delve into pilot operating manuals, and even get real-life pilots to "test" their creations.

A blanket statement cannot be said that all flightsim models are 'accurate' (or not).

Flight Simulator takes values entered into the aircraft.cfg and *.air files and internally calculates the flight characteristics at any given point.  If you review the annotated default models' aircraft.cfg files, you'll note the degree of information that is now being calculated and considered - weights, location of different data points, etc.

On the other hand, a program like X-plane DOES take the model geometry into consideration.  Real life aircraft home builders have been known to create a model for X-plane to preview the flight characteristics of their creations.

I see...

Is there:
1. Some site I can read that will give me a basic explination of the various parameters that go into FS2004 models (should I even bother to do this - all I really want is to be able to do "2." beow)?
2. Some site that reviews the models so that I'll know that the huge aircraft (eg. the C5 Galaxy) is not just a rehash of the Boeing 747-400?

Or am I asking for too much? I can see that there is definitely a lot of work being done and that they're mostly of the "labour of love" category. Also being a novice flight sim fan at best might not be sufficient skill to appreciate subtle differences.

Thanks.

All major flightsim sites (of which Simviation is, of course, the best) will have reviews.

It's a pity we can't get access to the Jane's archive...

Keep up the good work... I'm going to figure out how to fly the 747 without wrecking it mid-air... "too much stress" it's saying...

(no laughter please...)

Over at www.avhistory.org you can download Gerry's 1% spreadsheet which is used to construct .air files hopefully representing preformance within 1% of the actual. This is not 100% true but it does give a very good starting point and gives some insight to the active variables involved.

A lot of designers spend a many hours ( myself included) trying to get the best outcome for their model but it's never perfect. Like many things in life it's a compromise.

That is very true.

It takes months to complete an addon for the FS and CFS series. Many of us have to look into books, do a google search, look at pics, use barely-sufficient 3-view images, etc.

Look at my projects. I never drove a Porsche nor a Ferrari, but I am doing my best to make sure that they at least move around like a car. Problem is though, FS uses props and jet engines to deliver the thrust. FS never uses the tires to deliver the thrust. So, you can imagine the predicament that I am in right now.

Flight sims can only acheive a certain amount of realism.

Here is a summary of mine on the many sims that exist out there.

FS series: It's game engine calculates the values, which the user punches in, so that the visual flight models behaive according to the values [ex: wingspan, weight, engine specs, etc.]

Its drawbacks: The game engine's accuracy may be good enough for those who never flew a real plane, but it's not good enough for bigger uses [like testing out future real-life models]. This brings me to the next sim.

Bright sides: At least it's fun.

X-Plane series: Its game engine uses the visual models physical design [along with blade element theory] to calculate behavior in the skies.

Its drawbacks: It may be accurate enough for government work, but the system requirements are somewhat demanding than FS.

Bright sides: As long as you don't use a laptop to operate X-Plane, you're ok.

Orbiter Space Flight Simulator [OSFS] v 050116: It uses complex orbital mechanics to determine not only the behavior of the spaceships, but also the behavior of the planets and moons as well.

Its drawbacks: Making an addon for this sim requires a lot more knowledge than you might imagine. You even have to create your own modules if you want your addons to be extra special.

Bright side: At least there are a significant number of skilled OSFS fans out there that can help you.

However, this is just my opinion. You might think otherwise.