The Mid Ocean - Time to Arrive equation calculates the amount of time needed to go between a location (lat/lon) and one of the airports in the pull-down list based upon the calculated distance and the ground speed.

Description

The Solar Impulse vehicle is flying from Nagoya, Japan on the island of Honshu to Hawaii.  This calculator lets the user enter a latitude and longitude for the current location of the aircraft and a ground speed.  With this, and assuming that the flight plan is a great circle arc between points (shortest distance on a globe:sphere), this equation calculates the approximate amount of time needed to get to the selected airport.  The latitude and longitude of the following airports are pre-entered into this equation:

These airports are the main airports listed in Hawaii, the home port of Nagoya in case the craft has to turn back, and the abandoned airfields at Midway Island and Johnston Atoll.

Ground Speed

Ground speed is usually different than flight speed.  The Solar Impulse aircraft cruises at an airspeed of 43 mph (70 km/h).  Based on the wind speed and its direction, the ground speed is greatly effected, going faster with a tailwind and slower with a headwind.  See the Ground Speed equation for details. 

See Also

• Mid Ocean Distance - Calculates the distance from the current location to the selected airport.
• Ground Speed - Calculates the ground speed based on air speed and azimuth and velocity of wind speed.