Baron Performance computes all the useful performance numbers for flight planning for Beechcraft Baron 55, 56, and 58 aircraft. It includes calculations for takeoff, landing, climb, cruise, descent, instrument procedures as well as emergencies. It also includes an interactive hold calculator, a risk analysis tool, one engine inoperative page, and a glide distance calculator that handles head and tailwinds.
Baron Performance is also available on iOS devices and as a WebApp (an App that runs in a browser) that runs on a variety of platforms (PC, Mac, tablets, phones). The Cloud Sync feature allows flight planning profiles entered on any device to be synchronized with your other devices when connected.
Baron Performance is a free, published-source development effort and has Apps and WebApps for other aircraft. See http://pohperformance.com for complete details.