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Improving Glider Realism: Difference between revisions
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→Variometer: gave formula for TE reading
(→IGC file logger: everytrail.com and gpsvisualizer.com links) |
(→Variometer: gave formula for TE reading) |
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* ''Total energy compensation''. If the glider is climbing, a factor can be subtracted from the indicated lift if the glider is decelerating, and the reverse during descent. So if the glider is neither accelerating or decelerating the absolute rate of climb (or sink) will be shown. | * ''Total energy compensation''. If the glider is climbing, a factor can be subtracted from the indicated lift if the glider is decelerating, and the reverse during descent. So if the glider is neither accelerating or decelerating the absolute rate of climb (or sink) will be shown. | ||
** Potential energy = mass x G x height (or height = energy / (mass x G)) | |||
** Kinetic energy = 0.5 x mass x velocity squared | |||
** if in time period 't' the glider goes from height 'h1'..'h2' and speed 'v1'..'v2': | |||
** uncompensated vario reading = (h2-h1)/t | |||
** TE adjustment = height the glider would have gained if it hadn't accelerated | |||
** = (change in kinetic energy / (mass x G)) | |||
** = (0.5 * mass * v2^2 - 0.5 * mass * v1^2) / (mass x G) | |||
** = (v2^2 - v1^2) / 2G where G = 9.81 meters per second per second | |||
** TE reading = uncompensated reading + TE adjustment | |||
** '''TE reading = (h2-h1)/t + (v2^2 - v1^2) / 19.62''' | |||
** (all units meters, seconds, meters per second) | |||
* ''Netto compensation''. The design sink rate of the glider at the current airspeed is added to the total energy vario reading, so the variometer actually displays the vertical rate of the air outside the glider. For a perfectly compensated instrument, the vario will show zero in still air regardless of the airspeed of the aircraft | * ''Netto compensation''. The design sink rate of the glider at the current airspeed is added to the total energy vario reading, so the variometer actually displays the vertical rate of the air outside the glider. For a perfectly compensated instrument, the vario will show zero in still air regardless of the airspeed of the aircraft | ||