Specifications

CT Corsair Final Report May 2, 2014

An F4U-4 Corsair Plane Model was purchased from A2A; a software add-on company. The file

is from their “Aircraft Factory” line and includes F4U-4 A, B, C and D models. By installing the

provided executable, a 3D Corsair airplane is loaded into the program with skins, dashboards and

expected flight characteristics.

5 Kinematic Analysis for Motor Selection

5.1 Theory

The original prototype’s induction motors are 1hp. These motors were replaced in later

commercial models as they tended to overheat with prolonged use

. The overheating occurs

when motor’s proper duty cycle is exceeded. When the duty cycle is exceeded, the motor does

not have enough time to cool the between cycles

. The induction motors obtained by the Phase I

team are 0.5hp induction motors with a 90° offset on the output shaft and were also non-braking,

which rendered them not an option for the Phase II design. To obtain reasonable torque

requirements, a free body analysis was performed on the mechanical system which includes a

derivation of the central spring constant, the forces experienced by the cam’s arm and the

required output angular velocity.

5.2 Free Body Analysis: Spring Coefficient

Due to the presence of the central universal joint, the spring cannot act in lateral z-direction

compression or tension. For the derivation of the spring constant, it is assumed that the only

motion the experienced by the spring is a rotational motion about the central pivot point

. It is

assumed that the spring constant can be derived by assuming the right side of the pivot point

provides upward force, while the left side of the spring applies a downward, tilting force which

restores the platform to a neutral flat position. The free body diagram of the platform is shown in

Figure 13. The central spring and universal joint is depicted in red and the platform in teal.

Knowledge from statics

can be used to describe the moment about the pivot point. This

involves the spring and tilting forces, which can be summed and set equal to zero.

Figure 12. Central universal joint and spring motion

Figure 13. Free Body Diagram for Calculating Spring Coefficient