摘要 |
The invention comprises a tachometer for aircraft for determining engine operating parameters from magneto signals from right and left magnetos. A signal conditioning circuit receives ignition signals from at least one magneto and modifies the ignition signals to provide a right and left train of input pulses for the microprocessor. The microprocessor follows a stored program to develop filtered quantitites depicting right rpm, and left rpm for respective right and left engines, or right and left magnetos of a single engine. The maximum rpm achieved during operation is also stored, along with the difference between the right and left rpms, the change in rpm over a period of time, and average rpm of two engines. A mode switch selects from right rpm, left rpm, maximum rpm, difference rpm, change in rpm over time, and average rpm for display on the display means. A method for calculating highly accurate engine RPM is disclosed. The displayed information is used by the aircraft mechanic and/or pilot to diagnose aircraft engine and instrument performance.
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