Hobbs meter

Hobbs meter is a generic trademark for devices used in aviation to measure the time that an aircraft is in use.

The meters typically display hours and tenths of an hour, but there are several ways in which the meter may be activated: For general aviation, "Hobbs time" is usually recorded in the pilot's log book, and many fixed-base operators that rent airplanes charge an hourly rate based on Hobbs time.

Many organizations, such as flying clubs, charge by tach time so as to differentiate themselves from fixed-base operators as 10–20% less time recorded makes it 10–20% cheaper to fly (if the hourly rate is the same).

In the case where flying clubs use tach time, many will charge a "dry rate", requiring the renter to pay for fuel on top of the hourly tach time rate.

The Hobbs meter is named after John Weston Hobbs (1889–1968), who in 1938 founded the company named after him in Springfield, Illinois, which manufactured the first electrically wound clocks for vehicle use.