Yves Guillaume's formulas

I am currently planning on making a modified FDE for the TDS 737-800 and SkySpirit 777-300, using Yves flight dynamics document and formulas, but here's the problem: Some of these ask for Records in the .AIR file which are represented as graphs (i use AirEd 1.52 to open these). For example:


It is asking for the R1541 table. Which value should i use in this formula? and if that table is not present in the .AIR file (yes, some planes dont use certain tables), what value should be used instead?

Roy Holmes

Resource contributor
1541 is one of a group of records that effectively remove the role of 1101. If you start with an existing air file you can bet it is probably in an old form with a lot of unused or obsolete Records. !541 is not a table as such, but a group of individual pitch derivatives.

Aired is not my tool of choice. AAM is better if you just want to change some values. A big problem though is replacing or modifying tables. What works for me is to use Air Update and do a dump of the air file. This will spell out the tables in a form where you can easily edit them or load them in excel to see what their graph looks like. You can extract a table edit it then update the air file using the update function. That is the quickest and most certain way to deal with tables.

Having updated the file I use AirWiz to see how it affects the airplane performance. In an AirWiz session you can fine tune individual coefficients. For example if you are certain your engine data is correct you can change the drag coefficients and immediately see how that changes top speed. Once I am happy with the changes, I'll make the permanent change in AAM and save it there. AirWiz has a fixed structure that it saves and AAM will do what you want. AirWiz has saved me hours of flight test and is far more accurate at showing results.

Yves document is excellent but I'm not sure what part is can play in developing or testing an air file. The sim applies the formulae and that is what you should study rather than the derivation of the individual derivatives.