Hola,

server crashed a while back and I wanted to bridge the downtime by programming something.
I got sick and tired of messing up my rocket runs in the Viggen because the QFE was not right, so the nerd inside me said "MAKE AN APP!"

github.com/AlexBrueckner/QFE_Calculator/releases

You can find the .apk under the releases tab. They are not yet verified and the app is not yet in the app store, so if you want to use it, you must enable the installation of foreign sources.

Here's a screenshot, not really much to say how to use it:
<div class="spoilwrapper" style="margin:5px 0;font-weight:normal;padding:4px 10px;background-color:#fff;border:1px solid #dbdbdb;border-radius:4px;color:#333333;"><div class="spoiltitle" style="margin:0;padding:0;width:100%;"><span class="spoilbtn" style="margin:2px 5px;text-transform:uppercase;font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:11px;font-weight:bold;display:block;cursor:pointer;color:#333;" data-show="{L_ABBC3_SPOILER_SHOW}" data-hide="{L_ABBC3_SPOILER_HIDE}">{L_ABBC3_SPOILER_SHOW}</span></div><div class="spoilcontent" style="color:#333333;display:none;padding:5px;border-top:1px solid #ccc;"> </div></div>

How to use: If you want the desktop version, download the .jar file and run it.
As for the Android version, browse the site on your phone and download the .apk then install it or transfer it there using a cable or something
It does not require any permissions, its simple arithmetics.
Enjoy...

There is, however, one thing I want to say before anything goes wrong. You most likely knew it but

<span style="font-family: Arial Black;">DO NOT USE THIS IN A REAL AIRPLANE!! ITS NOT DESIGNED FOR IT! DCS USE ONLY!!</span>

Update, July 13th 2017
Have been interested in trying out the JavaFx Framework for quite some time now. Here's the result:
<div class="spoilwrapper" style="margin:5px 0;font-weight:normal;padding:4px 10px;background-color:#fff;border:1px solid #dbdbdb;border-radius:4px;color:#333333;"><div class="spoiltitle" style="margin:0;padding:0;width:100%;"><span class="spoilbtn" style="margin:2px 5px;text-transform:uppercase;font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:11px;font-weight:bold;display:block;cursor:pointer;color:#333;" data-show="{L_ABBC3_SPOILER_SHOW}" data-hide="{L_ABBC3_SPOILER_HIDE}">{L_ABBC3_SPOILER_SHOW}</span></div><div class="spoilcontent" style="color:#333333;display:none;padding:5px;border-top:1px solid #ccc;"> </div></div>
github.com/AlexBrueckner/QFECalculator_JavaFx/releases
Confirmed to work on <span class="abbc3_strike" style="text-decoration: line-through">Winblows</span> Windows, can't speak for Linux and Mac. It SHOULD work, but I have concern about the Weblink in the image, as the way the code calls up the webbrowser is platform dependent. It checks if a certain Runtime for Windows can be used, if not it will open it in a way I could not yet test (Thanks Stackoverflow for the little segment).

Updated:
- Added landscape format
- Added shiny new F99th icon (Thanks Pyro!)
- Added a <span class="abbc3_strike" style="text-decoration: line-through">conscription notice</span> "Please visit f99th.com" Toast (Toasts are the little messages that pop up and fade out)
- Prevented editing the output field
- Elevation and Temperature may now be negative values
- Fixed computation. Typo combined with auto-complete caused the temperature value to be replaced with the elevation value resulting in QFEs being WAAAAAY of. Works properly now, tested and verified with a quick testing mission using preplanned waypoints (given inputs created almost identical outputs, we always have to keep minor rounding errors into account, but it sure is accurate enough to get these ARAKs on target)

<div class="spoilwrapper" style="margin:5px 0;font-weight:normal;padding:4px 10px;background-color:#fff;border:1px solid #dbdbdb;border-radius:4px;color:#333333;"><div class="spoiltitle" style="margin:0;padding:0;width:100%;"><span class="spoilbtn" style="margin:2px 5px;text-transform:uppercase;font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:11px;font-weight:bold;display:block;cursor:pointer;color:#333;" data-show="{L_ABBC3_SPOILER_SHOW}" data-hide="{L_ABBC3_SPOILER_HIDE}">{L_ABBC3_SPOILER_SHOW}</span></div><div class="spoilcontent" style="color:#333333;display:none;padding:5px;border-top:1px solid #ccc;"> </div></div>

Wow, good work sir! I don't have the Viggen, but I am going to download that App anyway.

Why thank you
If anyone else has ideas they want in an app, keep em coming.. Can develop on any platform except Apple (I won't pay THEM money so I can work and learn a new language )

I don't know what you're planning to do with it, but I updated the main post just to be safe

noice!!! i like it...especially 'dont use in real aircraft'
thanks

Thanks guys Appriciate that!

Update:
- Updated Layouts
- Included Radio Buttons for selection of units. If you choose Feet or Fahrenheit, the backend will convert them to meters (You will see your used units, but computation is still done with meters/celsius after converting)
- Made the image a button which will open the phones default browser and point to this website (Can be removed if not wanted - just give me a shout)

I need this!!! Just wish I wasn't an idiot and knew how to install or make it work.I have an android to boot.
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As for android you simply download the .apk file and open it. If it complains about "installation from unknown sources" you have to set this in your developer settings of the phone.