Aircraft Weight Estimation
How can you evaluate aircraft designs for maximum takeoff weight, fuel consumption or maneuverability, if the component weight data is not available? This example uses a weight estimation method to derive the mass properties from aircraft geometry and a few design variables.
Two models of a Boeing 737-800, one with known mass properties and the other with estimated mass properties, are compared.
This example compares the flight of a Boeing 737-800 for a 3 h 15 min flight with its known mass properties (mass, inertia tensor and center of mass location) and mass properties that are estimated by using the weight estimation method found in the Aircraft library.
Compare Fuel Consumption
In this particular case, the weight estimation method resulted in a slightly underestimated weight, leading to smaller throttle demand and smaller fuel consumption.
The top plot shows the mass of the consumed fuel with known and estimated mass properties. The middle plot shows the masses of the entire aircraft and the fuel left inside the tanks. The last plot shows the throttle positions of the engines.
Response to Design Constraints
Both the aircraft fulfill the constraints set on the load factor and dynamic pressure during the flight. The values of the constraints are used for the weight estimation method and thereby will also affect the estimated mass properties.
The top plot shows the load factors of the Boeing 737-800 with known and estimated mass properties and the constraint set for maximum load factor. The bottom plot shows the dynamic pressures and the constraint set for maximum dynamic pressure.