real machine; actual device
Used in engineering, IT, and manufacturing to refer to a physical machine or device, as opposed to a model, simulation, or prototype.
We need testing on the actual device, not just simulations.
real aircraft; actual plane
Specifically refers to a real airplane or aircraft, often in contrast to a simulator or model. Common in aviation and military contexts.
The pilot underwent training on the actual aircraft.
We verified the new software on the actual device.
The manufacturer conducted tests on the actual new engine.
The pilot boarded the actual aircraft for the first time.
The rookie pilot underwent training on the real aircraft.
模型 is a scaled-down model or mockup, the opposite of 実機, which is the full-size, working real thing.
シミュレーター is a training simulator, contrasted with 実機, the actual physical machine or aircraft being simulated.
stand; base; platform; table; rack · setting (of a gem); mounting · stock (in grafting) · counter for machines and vehicles · level; mark; range; decade (of one's life) · tall building (with a fine view); observation platform · plateau; heights
Compound of 実 (じつ, 'real') + 機 (き, 'machine'). The reading じっき results from a common gemination (促音便) of じつき.