Aircraft Cylinder and Exhaust Gas Temperature Indicating Systems

Reciprocating engines have served numerous types of aircraft since the first Wright Brothers flight. A complex collection of parts, reciprocating engines rely on the convergence of pistons and cylinders for the adequate combustion of fuel and air mixtures employed to drive propeller-powered aircraft. As fuel and air mixtures require combustion at certain temperatures, as well as the fact that an overabundance of heat can be detrimental to systems, it is important that there are components in place to monitor temperatures. These often come in the form of aircraft cylinder and exhaust gas temperature indicating systems, both of which monitor temperature conditions for the means of safety and performance.

The cylinder temperature indicating system of a piston-powered aircraft may vary, though most consist of an indicator, thermocouple, and electrical wiring. Near the firewall of the assembly, one of the thermocouple end leads is attached to the electrical wiring while the other end is connected to the cylinder. The thermocouple is typically designed with two different metals, such as constantan and iron, both of which are attached to one another through wiring. When there are differing temperatures present in the junction and the wiring connecting each metal, voltage is generated. A current is then relayed through the wires to reach the indicator, allowing for a temperature reading to be conducted.

When procuring a thermocouple for the temperature indicating system, such components may be a bayonet or gasket type. These components are then inserted within the hottest cylinder of the engine, that of which is found through a block test. For the installation of the bayonet variation, the knurled nut of the component is pushed down and turned clockwise until sufficient torque is reached. With gasket types, on the other hand, such components can be placed under the spark plug, replacing the conventional spark plug gasket. It is important to not cut off any of the lead even if it is too long. Instead, the extra length should be coiled and safely tied up. If installed correctly, the bayonet or gasket thermocouple end should allow for cylinder temperatures to be read with ease.

It is important to check the thermocouple regularly to see if it is secure, free from damage, or facing any other issues. The cover glass that is present on the cylinder head temperature indicator is one area that should be regularly inspected, such components facing the risk of slipping or cracking. The length of the wire can also become chafed or loose over time, especially if the wiring is very long and is coiled and tied down.

For measuring the temperature of exhaust gases, a thermocouple is placed in the stream of exhaust after the cylinder port. The thermocouple is then attached to the instrument panel, ensuring that pilots have the ability to properly adjust mixtures for the means of managing engine temperatures. Thermocouples are quite important for exhaust gas temperature, also providing the ability to monitor health conditions for efficiency and safety.

With the use of varying temperature indicating systems, pilots and personnel can better guarantee the proper operations of their aircraft. At NSN Supplies, we are unmatched in our capability to provide top-quality parts at competitive prices. Whether you need thermocouple, cylinder, or spark plug components, we invite you to browse our expansive inventory and request quotes for your comparisons. With our AS9120B, ISO 9001:2015, and FAA AC 00-56B certification and accreditation, we can guarantee top-quality parts that you can steadily rely on with ease. If you have any questions regarding our offered services or simply wish to kickstart the procurement process, fill out and submit an RFQ form today and a dedicated account manager will be in touch within 15 minutes or less.