[ACE-OF-ACES]

Originally Posted by swift

The results of a calculation (what you call maths) is only as good as its data.

Correction..

The 6DOF math (what you call thumb rules) is more than adequate to simulate flight!

And the 'data' that the 6DOF math uses has nothing to do with any of the real world performance data (ROC, TSPA, etc). The 'data' the 6DOF math uses is coefficients only. That is to say the 6DOF math for a P51 is the same as that for a Bf109, what makes a P51 a P51 is the coefficients loaded into the 6DOF equation. That is to say, no where do you 'load' say the ROC or TSPA values from a WWII performance test.

The only time you make use of the WWII performance data is in the validation of the 'outputs' of the 6DOF math and the corsponding coefficients selected.

That is to say the math never changes, only the coefficients.

Basically they can get a good set of coefficients to use based off the geometry of the plane (CL, CD, mass, wing loading, etc). Than they 'tweak' the coefficients until the outputs of the equations match the real world data. As part of all this the power plant (engine) is also simulated and is one of the inputs to the 6DOF (thrust) equation.

Originally Posted by swift

Also there are equations and equations. Some are highly approxamtive and only thump rules for quick estimates, others may be closer to reality but also very complicated and requiring a lot of divers input data.

The more complicated versions were an issue back in the early 90s.. Where games like AOTP made use of fixed point math, in that the floating point processors were just not fast enough to do the complex calculations in real time. Mater of fact back then they were even limited to a 3DOF flight model, but than around 1995 a flight sim called Pacific Air War 1942 came out, that was one of if not the first PC flight sim to implement a 6DOF flight model, it still used fixed point math. These days there is no need for fixed point math and thus no need to use the simplified versions of the 6DOF flight model equations.

Originally Posted by swift

I would agree to use mathematical relationships to deduce aircraft behaviour if we had enough reliable data or data at all for input into the equation and some reliable data to verify the results.

Who wouldn't?

Originally Posted by swift

My guess is the data we would need to calculate it is not available.

Depends on which data your referring too.. As noted above, a good estimate of the 6DOF coefficients can be derived from the planes geometry. Actually the hard part to simulate is the engine! In that many of those records do not exist and no good way to derive them from looking at the dementions of the engine.

Originally Posted by swift

I mean what would be great if we had all the aerodynamic coefficients as a function of Mach number and angle of attack and the corresponding reference area for each plane.

As noted above, if they have enough info to draw the plane in 3D, then they have enough info to derive many if not all the coefficients for the 6DOF FM.. What is lacking in the power plant info (thrust)

Originally Posted by swift

"Equations" deducing turn performance from the wing loading, sorry, this is far from anything near accurate.

Disagree 100%

Originally Posted by swift

I would not like to have the fm built on this kind of thump rules. Then I'd rather prefer anecdotical evidence.

To each his own than