NASA Glenn · Guide to Aeronautics
NASA Glenn · Retrieved 2026-09-05
Educational reference; original Owl summariesPROPULSION
Jet thrust & momentum
FLIGHT SCIENCE / CONCEPT REFERENCE
SCIENCEConditions & principles
An engine produces thrust by changing the momentum of the airflow and through exit pressure forces.
REFERENCE COVERAGE3 / 3 editorial sections
PROVENANCE1 linked source
LAST RETRIEVED2026-09-05
Editorial section coverage describes the article structure, not scientific validation or completeness.
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Source editions
NASA Glenn · Guide to Aeronautics ↗Edition / snapshot: Reference snapshot, September 2026Retrieved: 2026-09-05
Retrieval dates record when Owl obtained the data; they are not publication dates or proof that a specification is current. Where the edition contains only a snapshot date, the original publication date is not recorded.
01
Mechanism
A control-volume balance compares incoming and outgoing momentum. A pressure difference between the nozzle exit and ambient air also contributes.
02
Aircraft response
Net thrust differs from gross exhaust thrust because the incoming air has momentum. Thrust changes with operating and ambient conditions.
03
Context & interpretation
The simplified single-stream equation below neglects fuel mass flow. Turbofans require accounting for both core and bypass streams.
Physical relationship
F ≈ ṁ (Ve − V0) + (pe − p0) Aeṁ: air mass flow; Ve and V0: exit and incoming speed; Ae: nozzle exit area.
Sources & context
Educational explanation of physical mechanisms. Aircraft-specific procedures, limitations and current weather information are separate references.