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[conquergl]

Boeing 727 and Boeing 737, as well as McDonnell Douglas DC-9 aircraft, made use of Pratt and Whitney JT8D engines. The air flow rate through these engines is 143 kg/s. The inlet velocity is 220 m/s and the exhaust velocity is 650 m/s. After the aircraft touches down, vanes are actuated to produce reverse thrust to aid deceleration and hence shorten the landing distance as shown in the sketch above. Determine the reverse thrust on aircraft with reverse thruster deployed (actuated).

 

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To determine the reverse thrust on the aircraft with the reverse thruster deployed, we need to consider the change in momentum of the air passing through the engine during reverse thrust.

Given data:

• Air flow rate through the engine, ṁ = 143 kg/s
• Inlet velocity, V1 = 220 m/s
• Exhaust velocity, V2 = 650 m/s

The momentum change of the air passing through the engine during reverse thrust can be calculated using the momentum equation:

ΔP = ṁ * (V2 - V1)

Substitute the given values into the equation:

ΔP = 143 kg/s * (650 m/s - 220 m/s)
ΔP = 143 kg/s * 430 m/s
ΔP = 61490 Ns

Therefore, the reverse thrust on the aircraft with the reverse thruster deployed is 61490 Ns.