For the correct functionality of a piston powered combustion engine, the camshaft must be able to control valves with precise timing to ensure proper fuel and air mixtures for ignition. To control valves, the camshaft relies on a component known as a lifter or tappet. In recent years, a component known as the roller lifter/tappet has begun to replace more conventional types due to their characteristics. As compared to alternative components such as the flat tappet assembly, the camshaft assembly roller lifter provides increased power advantages, smoother engine operations, and causes less friction between moving parts. As such, the roller lifter is an advantageous component for aircraft engines.
For the more traditional flat aircraft engine, the camshaft relies on lobes and other assembly parts in order to actuate intake and exhaust valves for engine operation. In order for the cam lobes to govern valves, they spin a component known as a lifter, which then acts through rocker arms to open and close valves. The point at which the lifter and the lobe meet is a flat surface, and the cam lobe swipes across this surface so that the lifter can spin. By replacing the flat tappet with a roller lifter
, the rounded shape allows for easier lifting over lobes so that less friction results from the movement. While being a small change to the entire assembly, the reduction to friction provided by such a configuration makes roller lifters very beneficial for use in automobiles. For aircraft, on the other hand, such concerns are not as common as the low friction characteristics of roller tappets may not be convincing enough for an operator to make the change.
For aircraft that have either Lycoming or Continental engines, however, spalling is a common concern that can affect the health and performance of the engine. Spalling is often the result of corrosion due to moisture, and cam and lifter components are highly at risk. If cam and lifter surfaces begin to corrode, high amounts of friction can result until lobes are completely removed. In such occurrences, the camshaft and engine assembly can rapidly lose performance.
While the roller lifter or tappet is just as susceptible to the forces of corrosion, its difference lies in the fact that the roller ball slides over the camshaft lobe rather than dragging along a face. As such, the degree to which the tapper is damaged due to friction and corrosion is less as compared to their flat tappet
counterparts. For performance, on the other hand, there is little change that warrants a complete switch if such characteristics are a primary concern. Nevertheless, many pilots have claimed to find benefits in the roller tappet
As a newer technology, roller lifters have a potential to become a standard with the improvements they offer to engine operations. Nevertheless, further industry testing will be required before more conclusive results can be found. As such, budgets, performance needs, and other factors may decide whether making the switch to the roller lifter is worth it for your particular aircraft and requirements.
At Jet Parts 360, we are a trusted distributor of aircraft parts and other aerospace components where customers can compare quotes for every aviation product we offer. Whether you are searching for a spring tappet
, shell tappet, tappet band lever, or another aircraft engine component, we can help you secure everything you need with competitive pricing. To begin the purchasing process at any time, customers may fill out and submit an Instant RFQ form as provided on our website. With the details we receive from your request, our team can quickly craft a personalized quote based on your individual needs and requirements. Experience why customers trust Jet Parts 360 for their operational needs today!