SkewTLogPro vs AircraftPower S

SkewTLogPro gives you one-touch access to powerful skew-t log-p charts. View charts using your current GPS location, airport ID code or lat/lon. Each skew-t log-p chart provides a visual indication of temperature, dew point, winds aloft, and wind speed at various altitudes, as well as Current Radar, Airmets, Sigmets, and SkewT data charted, filtered by altitude. FEATURES: • NEW! View all Sigmet/Airmet on a map and filter by altitude • NEW! View SkewT data charted on a map with altitude filtering, shows potential warnings of Icing, Wind, and Visibility • Ability to view the lifted parcel line • Support for International Airport ICAO codes • View charts along your route using 'View Route' • Support for GFS for all locations outside the continental United States (Option in Settings) • View many values such as CAPE, LI, LCL, and many other options through settings • Save charts for offline use • View Skew T Log soundings by touching a location on a map • View skew-t log(p) charts using your current GPS location, airport identifier or latitude and longitude. • Scroll forward and backward to view past and forecast charts. • History list allows easy access to previously viewed locations. • Select how many previous and forecast hours are charted • Drag on the graph to view each point value • Double-tap to zoom in for more detail on the soundings. • Great for aviators, glider pilots and weather enthusiasts. An annual subscription is required to access these graphs and to use SkewTLogPro for $12.99 per year. Cancel anytime. Please view the End User License Agreement here: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

AircraftPower S is the iPhone version of my iPad app, AircraftPower. It is is an Aircraft Engine Performance App which uses a standard reciprocating engine performance model to calculate and display the sea level and altitude performance of 74 normally-aspirated Continental® engine models and 107 normally-aspirated Lycoming® engine models. A graphic display shows the engine performance chart and illustrates the manual construction method for determining altitude performance that we learned in ground school (and promptly forgot). As the user changes the input values for manifold pressure (or % rated power), rpm, pressure altitude (or indicated altitude & altimeter setting) and and outside air temperature, the power output and percent power (or manifold pressure required) are displayed, and dotted lines and colored dots in the graphic display follow the manual construction method. While the graphics aren't really necessary, they are instructive (and interesting) to watch. The user may choose english or metric units for altitude, temperature, manifold pressure, altimeter setting and power output (however, the graphic always uses english units), and may select default values for the inputs and the engine. The user can also choose to input the indicated altitude instead of the pressure altitude (the default), and choose to input the % rated power instead of the manifold pressure.