Пионер
Я еще маленький.., я только учусь...
Не могу понять почему счетчик наработки на тахометре за месяц показал 19 часов, а счетчик ELAPSED TIME показал 28 часов. По моим подсчетам наработка около 20 часов. А что тогда означает цифра 28 часов?
В электронном журнале Direct approach propeller (4th Quarter 2011), который издает Cessna, в статье Time Recording я думаю, что есть ответ на Ваш вопрос:
&The mechanical recording tachometers typically installed in single engine Cessna airplanes are calibrated for the cruise RPM of the installation. The tachometer calculates time in service by mechanically dividing the accumulated number of engine revolutions by the cruise revolutions per hour for which it is calibrated. Therefore, it will record one hour of operation if the engine is operated for one hour at the calibrated cruise RPM. However, if the engine is operated at 75% of the calibrated cruise RPM for one hour, the instrument will record 45 minutes of operation.
An hour meter records time when an electric circuit is present. While power and ground are applied to the instrument, a small electromagnet winds a spring that powers the clock every few seconds. When an aircraft equipped with an hour meter is shut down, the clock can sometimes be heard making its last few ticks, ready to be wound next time power is applied.
Current production 172, 182, 206 and the majority of Cessna out of production single engine aircraft use an oil pressure switch to power the mechanical hour meter. In order for the instrument to record hours, the master switch must be “ON” and the engine oil pressure must be at a sufficient level to activate the oil pressure switch.