本帖最后由 LJQC 于 2012-1-12 16:27 编辑
F风 发表于 2012-1-12 15:24 
BMS直接用的某个拿分析用的F-16的数据，据说低于跨音速的气动做的不错，跨音速和超音速不行，不过任何一个 ...
这点我们都知道～～BMS4所使用的NASA TP 1538中的各种力矩系数（包括Cm、Cn、Cl等）只有0.6马赫下的数据，他们把这用在了整个飞行包线上。但BMS4用的HFFM数据（包括CL、CD、CY、推力数据等）把0马赫到2.2马赫都包含了进去。
The Aerodynamic Data
The aerodynamic data used in this NASA simulation were derived from low-speed wing static and dynamic (force oscillation) wind-tunnel tests of sub-scale models of the F-16 in wind-tunnel facilities at the NASA Ames and Langley research Centers.
There are 6 “global” aerodynamic coefficients to completely describe a model:
The Forces:
·CL : Lift Coefficient (reference airflow)
·CD : Drag Coefficient (reference airflow)
·CY : Y-Axis Force Coefficient (reference body)
The Moments:
·Cm : pitching moment
·Cn : yawing moment
·Cl : rolling moment
The NASA performed wind tunnel testing to evaluate all those parameters in a maximum of possible conditions (static and dynamic). However those testing have been performed at mach 0.6 equivalents--which would have been totally insufficient for our model dedicated to fly in the whole flight envelope.
Thankfully, HFFM data were retro engineered from real performance charts, which means HFFM data included CL and CD for the whole flight envelope (mach 0 to mach 2.2).
For the moments coefficients, no other data other than mach 0.6 wind tunnel testing were available. However, because of the FLCS, the pitch/roll/yaw behavior is fully controlled artificially across the whole flight envelope. We can say that using mach 0.6 moments coefficient for the whole flight envelope will not make the flight model deviate from the real too much. Indeed, from mach 0 to mach 0.9, the moments coefficient do not evolve that much and above mach 0.9, it is clear that the model evolves in a very low AOA envelope and therefore the pitching/rolling/yawing reactions of the model are much governed via the FLCS than from the pure aerodynamics coefficient.
Finally it has been chosen to use:
·HFFM data for CL/CD (and Thrust)
·NASA data for all other coefficients.
The association of HFFM and NASA data certainly ensures a very high level of F-16 simulation accuracy through the whole flight envelope.
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发表于 2012-1-12 15:11:00
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