Source for FMs

[Akmatov 1]

Cruising around reading posts and a thought occurred. Some folks discuss Flight Models as being more or less accurate. My question is, what is the source of peoples knowledge of what the accurate FMs are?

 

Other than a few replica aircraft there are no WW1 ac flying, as far as I know. So since no ac are available, the FM data must come from some text source and anecdotes of pilots who flew these ac. I'd be very interested to know where this info is available.

[Bullethead 12]

Cruising around reading posts and a thought occurred. Some folks discuss Flight Models as being more or less accurate. My question is, what is the source of peoples knowledge of what the accurate FMs are?

 

This is a question I'd like to know more about myself. But I have been able to piece some of it together, as a result of trying to make a new airplane for OFF. Here's how things seem to work to me (no doubt substantially wrong in a number of places....).

 

First off, the "flight model" apparently consists of 2 main parts. First off, each type of airplane has a number of data files that define its physical and flight characteristics. IOW, you can change 1 plane's data without affecting any of the others. This is where all your reseached info goes. The 2nd part is in the CFS3 engine, which interprets the data files for the various airplanes and uses that to make the airplanes move. Changes to this part affect all airplanes. I'd imagine OBD can tweak this part to some extent, or work around it somehow, but by and large this is probably pretty constant. IOW, it will always interpret the airplane data in pretty much the same way.

 

So..... The data files. The main one of these is the .AIR file, edited with the AirWrench program. This file is full of every real-world stat and performance figure you can imagine. It works kinda like a spreadsheet, in that if you change 1 value, it recalculates many of the others. Anyway, what you do is, you enter all sorts of the real-world values for the airplane into the various fields, it calculates others, and there you go.

 

In theory, this system should result in an airplane that flies in the game just like it did in real life. After all, the aerodynamic data are the same for both. However, this isn't the case because the CFS3 engine's interpretation of these data varies somewhat from how planes fly in reality. In fact, there are some real-world things that are just impossible for the CFS3 engine to do, such as (I've heard) making the Dr.I do a flat turn.

 

So at this point, you have to tweak the airplane's data away from realworld values to make it better match its real performance. For example, apparently one of the frequent things that needs tweaking is engine power, because even if you put in X hp at Y rpm, you don't get that in the game. I've heard it takes quite a lot of testing and tweaking just to get the speeds and climbs correct, let alone the handling characteristics. Eventually, you will reach a point of closest approximation to what the real plane could do, but can't get it anybetter.

 

At the bottom line, therefore, you research the airplane and decide what its various physical and aerodynamic values were, based on which sources you like. You use that as a starting point in the game, then try to get those chosen values out of the plane by giving it different values as needed.

 

This is a process I'm not looking forward to with my plane

[+Polovski 460]

There is no real central location of authoritative WW1 flight model information. It's available by a lot of research, and in many locations, documents, books, internet, etc all in pieces.

Many have incomplete, or conflicting info. Many modern craft may be similar but often have several differences, including materials or engines etc from the real deal but may give some useful indicators of how the real craft flew. Also modern craft are not flown under war conditions or stresses so again hard to quantify - also aircraft could be adjusted and managed in the field differently.

 

Some test reports can be flawed for example some British tests of captured German aircraft could be skewed by use of incorrect fuel type.

 

Many tests reports have for example figures noted for "top" airspeed but only at a certain altitude and in fact turns out not to be the top speed but the only reported speed at a certain alt.

 

Several tests I have seen for some craft have several large differences in performance even day by day during the testing - could be due to weather, pilot, or some other issue.

 

As you say there are various pilot anecdotes and test flight reports some excellent to be found in various books and references. and more modern reports in books such as Frank Tallman's Flying the Old Planes (these are often replicas). Some very recent efforts are extremely well done though.

 

With all the inconstancies all you can do is gather all you can, study, read all the reports and come to a conclusion.

Some craft may be almost fully documented and you can calculate mostly others have very little skimpy information and is very difficult.

[Akmatov 1]

Thanks for the insight. Your comments were very helpful.

 

I seem to remember that one important issue with these planes was rigging - are all the wires set to the right tension, at any given moment. So day to day, and I would assume hour to hour, performance might be different because the shape of the aircraft could be subtly different.

[cptroyce 0]

Having had many, many, many, many, many ,many, many, many, many, hours devoted to RB3 FM building, IMHO...the process is to research as much as you can as to how these great craft flew (pilot reports, data, etc.). Then get the FM editor program Air Wrench and A/C editor-two excellent programs that lend themselves to CFS generated files-learn about the aviation parameters that they can alter, and then try and duplicate the behavior that your research has described. It is an absolutely wonderful endevour that will "alienate you" from those you love, but at the end of the day, you will have created something that may endure for a long time and be used by 100's of fellow enthusiasts around the world!

 

Regards,

Royce

 

PS- "Back in the day", there weren't programs like Airwrench and A/C Editor...these programs allow you to alter sim a/c down to the "n'th degree" I believe.

Edited February 12, 2010 by cptroyce