Question

An A-6 Intruder is launched by catapult from the deck of the U.S.S. Nimitz aircraft carrier while the carrier is not moving and there is no wind. The airplane weighs 49,000 lbs and has a wing area of 529 ft2. The pilot sets the engines to the maximum thrust of 17,000 lbs (total for both engines; constant during takeoff). The catapult length is 400 ft. As the airplane leaves the catapult, its speed relative to the deck is 140 knots, which is 1.25Vstall. Assume that the drag and rolling resistance terms are negligible. What is the CLmax of the A-6 in takeoff configuration?

Answer 1

`CL_(max) = 2.182`

Step-by-step explanation:

Given that;

weight of the airplane = 49,000 lbs

wing area
`S_w` = 529 ft²

Thrust = 17000 lbs

Length of the catapult = 400 ft

Initial speed
`v_1` = 0

Final speed
`v_2 = 140 \ knots`

density
`\rho` = 0.002376 slugs/ft³

To find the
`V_(stall)`; we have:

`V_(stall)` =
`(140)/(1.25)`

`V_(stall)` = 112 knots

`V_(stall)` = 112 × 1.6878 ft/s

`V_(stall)` = 189.0336 ft/s

Weight W =
`(1)/(2) \rho *V^2_(stall) *S_w*CL_(max)`

`CL_(max) = (2 W)/(\rho * V^2_(stall)*S_w)`

`CL_(max) = (2 * 49000)/(0.002376 * 189.0336^2*529)`

`CL_(max) = 2.182`