- Basic statistics on the airplane's size and configuration
- Engine thrust and fuel performance throughout the flight envelope (including max, military and part power conditions)
- The airplane's drag polar, including the effects of stores drag, Mach number, and g-loads
A central element of this simulation will be the predicted engine performance. For many of the jet engines now flying, performance information is readily published at static, sea level conditions. Such statistics as maximum and military (or dry) thrust, specific fuel consumption, overall pressure ratio, fan pressure ratio, bypass ratio, and air flow are all published for many of the engines developed during the 1980s and in the decades before. These statistics provide a basis for extrapolating engine performance across to other design conditions. Again, the objective here is not to precisely simulate everything that goes on inside of a modern jet engine, or to design its components. We are not seeking that level of detail. Moreover, any functional limitations - such as maximum pressure limits - will be unknown. But such an extrapolation will allow an engineer to draw some conclusions regarding how the engine, and aircraft, will perform across a broad variety of flight conditions.
Building on this successful experience, we can assemble a similar simulation for the F110-GE-100 engine, which equips the Block 40 F-16C. Like the F100, statistics are publicly available for overall pressure ratio, fan pressure ratio, bypass ratio, air flow, and specific fuel consumption. Unlike the F100, there is no publicly referenced value for the burner exit temperature - but we know that the F110 was a contemporary of the F100, employing similar technologies, and that the burner temperatures must be of similar magnitude. There is therefore sufficient detail to develop an analytic model for this engine.
Combining this collection of airframe statistics, projected engine performance, and drag polar data, we can begin to perform an example mission profile assessment - in this instance for a hi-lo-hi mission. Comparing between the published and predicted combat radius of the aircraft, we can see that the two values are in close agreement - with a predicted value of 770 nm compared to 760 nm from the published literature. This comparison further affirms that with sufficient aircraft and engine data, and some fundamental design relations, we can draw some fairly accurate projections for the mission capabilities of a particular aircraft.
This assessment however, only touches on the mission profile capabilities of the airplane. To complete the complementary performance assessments for this aircraft, we would need to be able to assess the effects of flight conditions on the drag polar of the aircraft. This includes Mach number effects (for which published data does exist), and g-load effects. The latter data is more difficult to come by, since it is not an area of particular concern for commercial aircraft. There is, however, at least one published resource - again coming from NASA - that documents the effects of g-loading on the drag polars of the F-15, F-16 and F/A-18, allowing us to calibrate prediction methods for these effects.
In summation, there is a broad body of published data for both aircraft and engine operation, available for many of the aicraft flying today. Even many Soviet aircraft, once shrouded in secrecy, have come into public view with the fall of the Berlin Wall - drive by the Russian manufacturers as they seek to secure export sales. Significantly, this same data is not readily available for some of the most recent aircraft flying today. Many of the basic statistics for both the airframe and engine of the F-22 and F-35 remain unpublished, to prevent a potential adversary from performing precisely the type of analytic studies that are illustrated here.