What kind of indicating system is used to measure oil temperature in a small, single-engine GA airplane?

What kind of indicating system is used to measure oil temperature in a small, single-engine GA airplane?

• A. A sealed system in which a bulb partially filled with a highly volatile liquid is installed inside the oil strainer, with the bulb connected to a pressure gauge
• B. An electronic resistance temperature detector
• C. A digital memory device
• D. A fiber-optic thermometer

Answer: (A)

Oil temperature in many small single-engine GA airplanes is shown with a sealed bulb that contains a highly volatile liquid and is placed in the oil path (in the oil strainer). This bulb is connected to a pressure gauge. As the oil heats up, the volatile liquid vaporizes, increasing the pressure inside the sealed system. That pressure change is transmitted to the gauge, which is calibrated to indicate oil temperature. It’s a simple, passive, mechanical indicator that doesn’t require electrical power. Other technologies like electronic resistance sensors, digital memory devices, or fiber-optic thermometers exist, but they’re not the traditional indicating system described here.

Oil temperature in many small single-engine GA airplanes is shown with a sealed bulb that contains a highly volatile liquid and is placed in the oil path (in the oil strainer). This bulb is connected to a pressure gauge. As the oil heats up, the volatile liquid vaporizes, increasing the pressure inside the sealed system. That pressure change is transmitted to the gauge, which is calibrated to indicate oil temperature. It’s a simple, passive, mechanical indicator that doesn’t require electrical power. Other technologies like electronic resistance sensors, digital memory devices, or fiber-optic thermometers exist, but they’re not the traditional indicating system described here.