TruAirspeed vs performify

TruAirspeed is a True Airspeed Calculator for the iPhone and iPad. It's a bit different from other true airspeed calculators, in which the pressure altitude is an input. This requires resetting the altimeter to the standard sea level pressure of 29.92"Hg to read the pressure altitude. With TruAirspeed, you input the indicated altitude and the Kollsman window's pressure setting — the app then calculates the pressure altitude, density altitude, true airspeed and mach number for you. The calculations involved take full account of compressibility effects, but not shock waves, so it's limited to subsonic, non-transonic flight only. You have a choice of units for inputs and results, and you may choose either a calculator-style keypad (top row: 7-8-9) or a telephone-style keypad (top row: 1-2-3). You may also set a correction factor for your bird's airspeed indicator/pitot-static system, if you know it (mine is 0.95).

performify! - Calculations derived from the manufacturer's AFMs. Reverse engineered mathematical equations so that you don't have to draw, interpolate or calculate yourself! - Efficient workflow in mind. Designed for the pilot to make quick decisions or play with the numbers! - Widgets! - Automatically derived parameters, based on location and local weather - Dark Mode! - Add a preferred margin to every calculation! - Add a favourite aircraft variant for every aircraft make, to get started quicker. - Currently supports landing and take-off performance calculations. More to come! - Currently supports a number of aircraft such as: - Antonov AN2 - Cessna 152, 172, 172 R&S - Piper PA28-181 - Robin DR400/140B, DR400/180 - Tecnam P2008JC - More to come! IMPORTANT: !! DO NOT USE FOR PLANNING PURPOSES !! Reason: performify is not a certified or approved application by any organization or authority. Please do not use this app for planning purposes. Always cross verify the results with your AFM! By downloading this app you confirm that you use all calculations AT YOUR OWN RISK. Always check with the AFM. The developer nor the publisher are responsible for any damage caused by the use of the calculations." Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/