General newbie questions

[CBris]

OK, so I should know better. I've been hooked!

I just twiddled with a small aerobatic biplane using AirWrench and the SDK. The results on the Pitts are very satisfying to me.

Now I want to do more but I am confused by all the "unnecessary" junk (?) that AirWrench puts in the config and maybe by the unnecessary duplication of info between the "air" and the "cfg"

So.... what is a better tool to look at the "air" with? One that also doesn't come with a "no commercial" use clause...

I mean... how do microsoft create their air files? There's not much obvious about that in the SDK.

Aren't there any other sensible editors around?

[fliger747]

The cfg file can be edited with any text editor (ie. wordpad). The Airfile can be opened with something such as Aired, however many of the tables are in Hex...

Even with those tools the contents are of some import. Jerry has gone to great lengths, starting with his workbook system, to use the physics of aerodynamics to attempt to bring some relevence to the created airfiles to the charcteristics of the actual aircraft. This has been continued through Airwrench. To create for example a prop table by hand might be a formidible task!

Note that the MS stock airfiles are not always the last word in accuracy for the aircraft involved. As the folks who designed the sim, they have computer access to all of the mathematical modeling involved. All that said, I have worked with them a bit on some things and am of the opinion that they are good computer geeks, but not as knowledgable about some areas of aviation as they might think.

If you want to do this stuff by hand, there are no silver bullets!

Good Luck!

[CBris]

Thanks Fliger, for your answer. I agree on Jerry's workbook and AirWrench - they are good stuff, but unfortunately his license does not allow commercial use and I am discovering a couple of paywares are using "airwrenched" air files.

Not good

So I was looking for some tool - any tool - which can open and be used to read or edit the stuff. There's not even the slightest hint in the SDK. I used to do the math myself years ago, so I am not worried about a silver bullet. I just need to refresh a lot of memory

Do I even need to alter or create an air file - the SDK gives a lot of good stuff for the config. Which takes priority at runtime? the cfg or the air? Looking at the AirWrench tables there is a lot of overlap.

Questions, questions... I have the knowledge but not the tools...

I'll keep digging

[sparks]

how do microsoft create their air files?

Microsoft uses assembler language macros to build air files. Same concept as the update.txt file output by the flight model workbook.

Thanks Fliger, for your answer. I agree on Jerry's workbook and AirWrench - they are good stuff, but unfortunately his license does not allow commercial use and I am discovering a couple of paywares are using "airwrenched" air files.

Not good

A commercial license can be negotiated for AirWrench, but only one developer has done so - and his products are not yet on the market.

AirWrench air files are watermarked and can be easily identified with the right software. Perhaps it's time to release that software.

There's not even the slightest hint in the SDK

People, the truth is out there. You just haven't looked in the right places...

Which takes priority at runtime? the cfg or the air?

The cfg file. Much of the air file data is obsolete and ignored by FSX. Unless it's missing from the cfg file, in which case FSX will transfer the data from the air file to the cfg file.

[fliger747]

Another editing program out there (still?) in Aircraft Airfile Manager which does present the tables in a graphical manner and has the points editable by insertion of base ten numbers into the edit boxes to adjust the curves.

One of the more important aspects of all of this is controlled and accurate test flying with examination of all parameters.

T.

[sparks]

Aircraft Airfile Manager seems to have been abandoned by it's author, but was released as freeware and can be downloaded here:

http://pagesperso-orange.fr/hsors/fsairfile.html

[CBris]

Thanks - for info: Vista 64 does not like AAM, AirEd looks like the sort of thing I recall. A long numbered table with appropriate values... The Work Book is OK too.

One thing about airwrench is strange. After I saved a pretty workable air file, I reloaded it later and found a lot of the dimensions have changed. Does the air file edit itself to the config?

[CBris]

Ah - a posting overlap

It has actually been ages since I last plotted polars and worked out mach numbers for money... Seriously - I got paid to do those sums... I was in the army and training was paid :d and since leaving "school" I haven't touched a lift coefficient since.

Another "wishlist" thought is that we could input the wing shapes too. For example: look at the difference between a Lysander wing and a Spitfire wing.

But never mind. I am getting to where I want to be. Not too sure about wanting to break down the machine code though (may the fleas of a thousand camels be visited upon MS for being so painfully obscure. An Exel table would have done nicely thank you!)

And thanks to you people for keeping me hooked! I know I will perfect this simple stuff really soon.

By the way - I am a believer in the Newtonian theory of flight, Bernoulli just sucks - Newton reacts

:costumes:

For more whys about that, visit my hero's lecture (link below). I was knocked down by my teachers when I said Bernoulli didn't do enough. But like many people who only think they "know better" they wouldn't consider fresh though. So it was like a breath of fresh air when this guy Anderson came along with his lectures on flight and vindicated all us Newtonians.

http://vmsstreamer1.fnal.gov/Lecture...rson/vf001.htm

(It's a great lecture on understanding flight - it's quite long, but it will open your eyes. Don't keep it to yourselves)

[sparks]

Regarding wing shapes - it's up to the author of the flight dynamics files to understand how wing shapes affect lift vs AoA, oswald efficiency, stability coefficients, etc. FS was designed so these calculations can be performed off-line to reduce the processing load on the CPU at runtime. FS hasn't changed under the covers all that much since FS98. I'm having a hard time remembering - what the fastest PC in 1998?

[CBris]

what the fastest PC in 1998?

386, 486? I can't remember when I got my first Entipum 3 (Blue man group advert came out first), but I think that was in 2000.

I actually bought my first notebook before I bought a PC. That was a 386 Librex in around 93. But I stayed on Amiga until '96. Sublogic simming until then...

Gods! I just Wikipedia'd my first computer after the Texas Instruments scientific programmable calculator... It was an Atari 800XL. 35 years ago!

[fliger747]

Aside from the baisic max CL values etc, the wing lift curves can be hand tweaked. Flight sim/actual airfoil charcteristics can be closely duplicated. Other things that require much testing and tweaking are such issues as HP/thrust vrs varying power/rpm settings for supercharged engines. Also known flight charcteristics ar often described in a rather imprecise manner and reflect the opinion of the tester more than anything else. The 1944 Joint Fighter conf (available as a reprint) gives some idea of the vareity of opinions that may be encountered on any given aircraft.

The AFSD stand alone utility by Herve Sors is a good testing program for many parameters. Sparks also has a test panel on his website.

Good Luck! T.

[CBris]

I also had some great tips from Jerry Beckwith too - now I understand his work more.

The fact that MS didn't use truly real world aircraft engineering practices with the CofG had me flummoxed for a while. But I think I can handle it all enough for private use now. That's if I am not painting...

Thanks all for the many words of wisdom.

[pilotwing]

Can the Aircraft Airfile Manager be used for CFS3?