:-lol

Most maintenance schedules on reciprocating engines is done based on tachometer time.

Actually, the hobbs meter is ONLY used for tracking real time (clock time). It is NOT normally used for maintenance purposes.Engine tachometer time is used for maintenance requirements including 100 hour inspections, annual inspections, TSO's, AD's, or other engine maintenance requirements.Hobbs meters were originally installed in many aircraft to track the amount of "Real-Time" being flown on the aircraft.Engine tach time is close to clock-time but is not the same. As engine RPM varies, so does the rate at which the tach meter changes.This means that if you flew the airplane for 1-hour of your watch, engine tach time may only measure say 0.9 hours of running time.This is why most rental FBO's charge based of hobbs time as opposed to tach time. Also, pilots normally prefer to log their flight time based on the hobbs meter as oppossed to the tachometer for the engine(s). In multi-engine airplanes, tach time often don't match and vary for each engine.When I log my flight time, I use the hobbs meter or my watch if a hobbs meter is not available in the airplane that I am flying.If I were to use tach time, I would be shorting myself some legally loggable flight time.But for maintenance issues, the hobbs meter is normally not referenced to meet the FAR requirements. However, if hobbs time was used for maintenance, it would normally mean that maintenece is being done at shorter intervals, than if the tachometer was used.This doesn't mean that hobbs meter times can't be used to schedule maintenance, it's just not normally the prefered method to determine maintenace intervals for most aircraft operators.Happy Simming!Scott :-)ATP/CFII - KCOS, in the real avaition world.

Despite the lack of a dedicated gauge, this plane is a joy to fly. Once you get the feel of the throttles down, it is fast,stable as a rock on final and has one of the nicest 2-d panels around. Well worth the $$$ in my opinion.

>This doesn't mean that hobbs meter times can't be used to>schedule maintenance, it's just not normally the prefered>method to determine maintenace intervals for most aircraft>operators.>My airplane doesn't have a tach meter, because I didn't put one in. The Hobb's will be the total time counter, and it runs off the oil pressure switch.L.Adamson --- Van's RV6A (experimental homebuilt catagory)