2. (40 points) The F-35B (Joint strike fighter) is a vertical takeoff and landing (VTOL) jet aircraft. It achieves this capability using a combination of a lift fan and a thrust vectoring nozzle as shown in Fig. 2a. Schematic of a lift fan system is shown in Fig. 2b. The engine torque is shown as M. Circular bevel gears are used to transmit the engine torque to the lift fan shaft (d-e). The engine shaft (a-b) is connected to a clutch that can be used to disengage the lift fan during cruise. The dimensions of the components are shown in the figure. Use G to denote the shear modulus of the shaft material. (a) Compute the engine torque M that is needed to achieve a lift fan torque T. (b) Compute the maximum shear stress in the clutch in terms of M. (c) Find Q (d) Find o , ab the angle of twist at b relative to a. ad' the angle of twist at d relative to a. Fig 2a Fig 2b Bevel gear 4D+ 0.5L = Lift fan torque T P e Lift fan Engine X 5D 3D 2D 2D C b a M Clutch