Davtron
Model 655 - Five Function Indicator

Davtron's Model 655 is a computer based product that computes density altitude automatically. No longer does the pilot need to retrieve outside air temperature and pressure altitude, then enter this into a flight computer. The Model 655 measures outside air temperature, and accepts pressure altitude information from the blind encoder or encoding altimeter, then converts the information to a direct read-out of density altitude. The density altitude is computed using U.S. standard atmospheric tabulation. Take-off roll maximum rate of climb, and fuel consumption area all determined easily from density altitude and the aircraft's flight manual. A single push-button on Model 655 causes the digital display in automatic rotation to show its five functions of: Voltage Outside Air temperature (Fahrenheit), Outside Air temperature (Centigrade), and density altitude. When the radio master switch of the aircraft is first turned on, the Model 655 always reads out the aircraft voltage to the nearest tenth of a volt. A code letter E indicates it is in the voltage function (EMF). To display outside air temperature in degrees Fahrenheit, the button is pressed and the letter F appears to indicate this mode. The next press of the button displays C for outside air temperature in degrees Centigrade. The next function is indicated by the letter P, and now displays pressure altitude. Another press and the letter d appears displaying the density altitude. The indicator remains in the mode selected as long as the aircraft power is on. Any mode can be selected as fast as on can depress the switch. The mode selection will always sequence in the he same manner (F C P D E) as indicated on the instrument's face. The digital outside air temperature function replaces on the the most difficult to read instruments in the cockpit. The pilot may relate to outside air temperature in degrees Fahrenheit, then instantly change the display to degrees centigrade for the aircraft manual input, etc. The voltage function of the indicator allows the pilot to monitor the electrical system precisely. By monitoring the voltage he can anticipate a low voltage condition, unlike a warning light which tells only that this condition has already occurred. Also, the pilot can know with more accuracy that amount of capacity remaining in the battery. The voltage at which the battery is being charged is also of great importance, since over-charging can lead to excessive water loss and battery failure. In brief, the voltage function reveals valuable information which helps the pilot obtain more reliable and better service from the electrical system. Davtron 655 Displays the Following: -Outside Air Temperature (F) -Outside Air Temperature (C) -Pressure Altitude -Density Altitude -Aircraft Voltage