While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
Honestly, nothing can compete with Litz's Applied ballistics app. the use of custom drag curves is unmatched by anyone in terms of accuracy especially through trans-sonic flight. Buy his book and it comes with a PC program.