Jump to content
Sign in to follow this  

Recommended Posts

Is there a good and in depth FM tutorial? I suck at 3d modeling and my photochop skills are terrible, but I do have a strong programming background and if anyone can show me some good literature on this I can get into FM work.

Share this post


Link to post
Share on other sites

There is a summary of the basic meanings of the coefficients, but Third Wire sims essentially use real world linear approximations for aerodynamics.

So the best way to learn is to actually study aerodynamics and then tinker with the flight models to grasp the concepts.

At a minimum, you need to be good with trig and algebra, though it doesn't hurt to understand calculus and differential equations.

 

So, to answer your question, there is no in depth FM tutorial unless you count the books available for learning to be an aerospace engineer.

 

The book at this link: http://www.amazon.com/Modern-Combat-Aircra...e/dp/0870214268

is an outstanding primer, but as it was written by a German, some of the examples use different symbols/notation than mentioned in the text or compared with American/English equations as used in TK's sims.

However, if you comprehend what is written, this book is like a bible to me, both for performance analysis and estimation of real world aircraft and for deriving flight models in TK's game engine.

While the book is not enough to allow you to start writing FMs from scratch, it should give you the insights you need to delve deeper into the world of flight modeling.

Share this post


Link to post
Share on other sites

Hmmm no wonder there are so few FM guys. It seems I have a lot of work to do. I always wondered what mach tables they were referring to in the inis. As if there was some secret reference graph or chart that they used to get the values from.

Share this post


Link to post
Share on other sites

TK has basically 2 types of aerodynamic co-efficients: simple constants and those that vary with some other parameter.

In reality, a particular co-efficient may depend on many parameters, but to keep things simple, TK chooses only one that he considers most significant.

The one exception I can think of is engine thrust, which varies with Mach and altitude.

Most others vary with either Mach or Alpha (angle-of-attack).

 

Lift, thrust, and drag calculations are not that difficult and are the ones that primarily determine performance such as max speed, ceiling, turn rate, climb rate, etc.

So if you focus on these, you can quickly reach a point where you can tune existing flight models to be much more accurate.

On the other hand, it is the stability and control variables that are the hardest to estimate or even tweak, yet are the most important in terms of the "feel" or character of the aircraft.

 

As an example, I created a high fidelity F-4B flight model for the service pack 2a version of SFP1.

I used a flight model editing tool I created to compare and tune TK's stock flight model to match the performance charts from the US Navy F-4B pilot's flight manual.

My tool (AIDE) is focused on lift, drag, thrust, and weight under steady state conditions such as level flight, a sustained climb, or a steady turn.

The results were very encouraging.

 

Years later, I stumbled onto NASA documents that gave me very accurate tables for some of the co-efficients such as zero lift drag (CD0).

It turned out that my estimate of CD0 was reasonably close, and the way the ingame performance of my flight model matched the Navy charts was somewhat impressive.

 

But, I never tweaked TK's stability numbers, so despite demonstrating a lot of the flight performance to very accurate levels, the "feel" may or may not be correct depending on how well TK estimated those parameters.

 

I got too busy with work and real life to fix the bugs that creeped into later versions of AIDE (causing crashes, especially if you open more than one FM at a time) as well as being overwhelmed by the rate at which TK changes the game's flight engine and stock FMs.

 

So, don't be discouraged from tweaking FMs.

Just be aware that it is a very complicated subject that can take quite a bit of time to learn and still take even more time after you feel like you know what your doing.

The small group of die-hard FM modders for this sim will help as much as they can, but I have been mostly out of the loop since my son was born in Nov 2006.

 

Good luck!

Share this post


Link to post
Share on other sites

Thanks for the encouragement. Would you mind letting me having a look over AIDE? It might help me get a handle on how it all works. The books looks great but for a starving college student, who already has a lot of books to buy the internet is my greatest ally. I think I am going to start by researching the math behind this (wiki of course!) and start messing with some inis.

Share this post


Link to post
Share on other sites

I wouldn't object to get my hands on AIDE's source code - just to see if we could work out a new version, or a new tool using AIDE's algorithms...

Share this post


Link to post
Share on other sites

That's why I'm asking for the sources - I'm a software developer after all...

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use, Privacy Policy, and We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue..