Turbojet Architecture – Does the Compressor Need a Turbine? Evaluate the statement: 'A turbo-jet does not require a turbine to drive the compressor.' State whether it is correct for practical turbojet engines.

Introduction / Context:
Understanding the flow of energy within air-breathing propulsion systems distinguishes ramjets, turbojets, turbofans, and turboshafts. The key question is whether the compressor has a mechanical power source and what component provides it in a turbojet.

Given Data / Assumptions:

• A conventional turbojet comprises an inlet, compressor, combustor, turbine, and exhaust nozzle.
• Steady operation at design conditions is considered.
• Ramjets (no compressor) are a different class of engine.

Concept / Approach:

In a turbojet, the turbine extracts part of the hot gas enthalpy downstream of the combustor. The extracted shaft power drives the compressor via a concentric shaft; the remaining exhaust kinetic energy produces thrust through the nozzle. Without the turbine, the compressor would have no mechanical drive and could not maintain the required pressure ratio, so sustained turbojet operation would be impossible. By contrast, ramjets rely on vehicle forward speed and inlet compression, not on a rotating compressor; therefore, they have no turbine either. But the statement as written about turbojets is incorrect.

Step-by-Step Solution:

Verification / Alternative check:

Any standard turbojet schematic shows a mechanically linked compressor–turbine spool. Engine performance maps further imply turbine work closely matches compressor work at steady operation.

Why Other Options Are Wrong:

Afterburners do not drive compressors. Supersonic flight does not eliminate compressor power needs. The note about ramjets is true for ramjets, but irrelevant to turbojets.

Common Pitfalls:

Confusing turbojets with ramjets/scramjets; assuming inlet ram compression suffices to replace a compressor.

Final Answer:

False