航空宇宙英語：必須語彙とフレーズ

"lift coefficient"

A dimensionless number representing the lift generated by a wing relative to dynamic pressure and wing area

"The engineer increased the lift coefficient by modifying the camber of the aerofoil."

"angle of attack"

The angle between the chord line of a wing and the oncoming airflow

"At a high angle of attack, the aircraft risks entering a stall condition."

"drag polar"

A graph plotting lift coefficient against drag coefficient for an aerofoil across its operating range

"The drag polar revealed that the new wing design had significantly reduced induced drag."

"boundary layer"

The thin region of airflow near a surface where viscosity effects are significant

"Turbulent boundary layer transition was delayed by the riblet surface coating."

"Mach number"

The ratio of an object's speed to the local speed of sound

"The aircraft cruised at Mach 0.85, just below the critical Mach number."

"stall speed"

The minimum speed at which an aircraft can maintain level flight without stalling

"Deploying flaps lowers the stall speed and allows approach at a slower velocity."

"vortex generator"

A small aerodynamic device attached to a wing surface to delay flow separation

"Adding vortex generators to the nacelle improved engine inlet performance at high angles of attack."

"induced drag"

Drag created as a byproduct of lift generation due to wingtip vortices

"The winglet design reduced induced drag by fifteen percent during cruise."

"thrust-to-weight ratio"

The ratio of engine thrust to the total weight of the vehicle, indicating its ability to accelerate

"A thrust-to-weight ratio above one allows the rocket to lift off vertically."

"specific impulse"

A measure of propellant efficiency, expressed as thrust per unit of propellant mass flow rate

"Hydrogen-oxygen engines have a higher specific impulse than kerosene-based ones."

"turbofan bypass ratio"

The ratio of air bypassing the engine core to air passing through the core

"Modern widebody jets use high bypass ratio turbofans to achieve excellent fuel efficiency."

"afterburner"

A supplementary combustion system that injects fuel into exhaust gases for additional thrust

"The test pilot engaged the afterburner to accelerate through the transonic regime."

"combustion chamber"

The section of a jet or rocket engine where fuel mixes with oxidiser and burns

"Thermal coatings protect the combustion chamber walls from extreme temperatures."

"gimbal thrust vector"

A mechanism that tilts a rocket engine nozzle to steer the vehicle

"The launch vehicle uses gimbal thrust vector control for pitch and yaw during ascent."

"compressor stall"

A sudden disruption of airflow through a jet engine compressor causing a loss of thrust

"The crew performed an engine restart after a compressor stall at altitude."

"nozzle exit velocity"

The speed of exhaust gases leaving the engine nozzle, directly related to thrust

"Expanding the nozzle throat area increased nozzle exit velocity in the upper atmosphere."

"fatigue life"

The number of stress cycles a structural component can withstand before failure

"Stringent inspection intervals are set based on the fatigue life of the wing spar."

"stress concentration factor"

A dimensionless ratio indicating how much stress is amplified at a geometric discontinuity

"The cutout corner radius was increased to reduce the stress concentration factor."

"composite laminate"

A material made of multiple layers of fibre-reinforced polymer bonded together

"The fuselage panels are fabricated from carbon fibre composite laminate to save weight."

"flutter speed"

The minimum airspeed at which aerodynamic forces can cause self-sustaining structural oscillations

"Wind tunnel tests verified that the flutter speed exceeded the aircraft's dive speed limit."

"monocoque structure"

A structural design in which the outer skin carries most of the load rather than an internal frame

"The satellite launch adapter uses a monocoque structure to minimise mass."

"proof load test"

A structural test in which a component is loaded to a specified fraction of its ultimate load

"All main landing gear assemblies undergo a proof load test before installation."

"thermal gradient"

The rate of temperature change through a material or across a component

"The thermal gradient across the heat shield must remain within design limits during reentry."

"delamination"

The separation of layers in a composite material, causing loss of structural integrity

"Ultrasonic inspection detected delamination in the elevator composite panel."

"fly-by-wire"

A system that replaces conventional manual flight controls with an electronic interface

"The fly-by-wire system allows the computer to prevent the pilot from exceeding safe flight envelope limits."

"inertial navigation system"

A self-contained navigation aid using accelerometers and gyroscopes to track position without external signals

"The inertial navigation system provided accurate positioning data when GPS was unavailable."

"FADEC"

Full Authority Digital Engine Control — a digital system that manages all aspects of engine performance

"The FADEC automatically adjusts fuel flow to maintain optimal thrust at each flight phase."

"redundant architecture"

A system design that includes duplicate components to ensure continued operation if one fails

"Triple redundant architecture in the flight control computer meets airworthiness certification requirements."

"avionics bay"

A pressurised or ventilated compartment housing electronic flight systems

"Technicians accessed the avionics bay to replace the faulty navigation processor."

"data bus"

A communication pathway linking avionics components and allowing data transfer

"The MIL-STD-1553 data bus connects all mission-critical avionics units on the aircraft."

"prognostics and health management"

A system framework that monitors component health to predict failures before they occur

"The prognostics and health management module flagged early-stage bearing wear in the gearbox."

"flight envelope protection"

Automated limits built into the flight control system to prevent the aircraft from exceeding safe operational boundaries

"Flight envelope protection prevented inadvertent overspeed during the steep descent."

"orbital insertion"

The process of placing a spacecraft into a target orbit by firing engines at a precise moment

"Orbital insertion was confirmed when telemetry showed the satellite in its planned geostationary transfer orbit."

"delta-v budget"

The total velocity change available to a spacecraft for manoeuvres throughout its mission

"Mission planners allocated sufficient delta-v budget for station-keeping over the satellite's fifteen-year life."

"attitude control"

The management of a spacecraft's orientation in space using thrusters, reaction wheels, or magnetic torquers

"Attitude control thrusters fired to align the solar panels toward the Sun."

"reentry corridor"

The narrow range of reentry angles that allows a spacecraft to return safely without burning up or bouncing off the atmosphere

"Mission control calculated that the capsule was within the reentry corridor to within 0.1 degrees."

"payload fairing"

The protective nose cone that shields a spacecraft from aerodynamic forces and heating during launch

"The payload fairing separated cleanly at 110 kilometres altitude, exposing the satellite to space."

"cold gas thruster"

A simple propulsion device that expels pressurised inert gas to provide small attitude adjustments

"Cold gas thrusters are used for fine positioning during proximity operations near the space station."

"launch window"

The specific time period during which a spacecraft can be launched to reach its target trajectory

"The launch window for the Mars mission was only twelve minutes long and occurred every two years."

"telemetry downlink"

The transmission of spacecraft health and performance data from the vehicle to a ground station

"Engineers monitored battery voltage through the telemetry downlink during eclipse periods."

"airworthiness directive"

A mandatory regulatory action issued by an aviation authority requiring specific corrective measures on an aircraft type

"An airworthiness directive was issued requiring inspection of all engine fuel lines within fifty flight hours."

"type certificate"

Official approval granted by an aviation authority confirming that an aircraft design meets regulatory safety standards

"The manufacturer received a type certificate for its new regional jet after years of flight testing."

"failure mode and effects analysis"

A systematic method for identifying potential failure modes and assessing their consequences

"The failure mode and effects analysis showed that a hydraulic leak would trigger a redundant backup system."

"design assurance level"

A classification (DAL A–E) defining the rigor required for software and hardware development based on the severity of a potential failure

"Flight-critical software must be developed to design assurance level A under DO-178C."

"continued airworthiness"

The ongoing maintenance and monitoring activities required to keep an aircraft safe throughout its service life

"The operator's continued airworthiness programme includes scheduled inspections and component life tracking."

"ground test article"

A physical hardware assembly used for structural or functional testing on the ground rather than in flight

"The ground test article was loaded to 150% of design limit load to validate the wing structure."

"mean time between failures"

A statistical measure of the average time a component operates between successive failures

"The actuator met its mean time between failures requirement of 20,000 flight hours."

"non-destructive testing"

Inspection techniques that evaluate a component's integrity without causing damage

"Non-destructive testing using X-ray and ultrasound found no cracks in the turbine blade."