Sunday, September 27, 2009

iPhone for Pilots - ThinkDigits

ThinkDigits is a great application if you're a pilot. What's more, it's the brainchild of a very smart guy in Melbourne - made in Australia! Initially it's hard to describe what ThinkDigits is, partly because it's an entirely new class of application as far as I can tell.
I think the best way to describe ThinkDigits is as a "mind-mapping calculator". You create mind maps which are actually "flows" of calculations or "calculation models". This is quite interesting in itself because it lays out the logic of solving the problem in a visual fashion so that you can think through it. What's more it's easier to audit than an Excel spreadsheet and easier to use.
The simplest way to show you what ThinkDigits does is to work through an example. My first example is calculating crosswind component - let's imagine you get the ATIS and think "ooh that's a big number". You'll more than likely be interested in knowing the crosswind component. There are of course rules of thumb for doing that and the whizz wheel but ThinkDigits does it pretty nicely as well.
First I created three "bubbles" to take the data inputs: Rwy direction; wind direction; and wind speed. You create these bubbles by typing a number in the keypad and then dragging the result to the page. Then you can format and label the bubble. In order to update the value in a bubble you simply type a new value in the keypad and drag it over your existing bubble.
OK we've now got our data values, now we want to calculate the answer, which in this case is the crosswind component.There are a number of steps to do in order to get there. ThinkDigits has a wide range of functions built in, including trig functions. My first step was to created a simple "calculation bubble" which subtracted rwy direction from wind direction. To do this I "dragged" the function key across to the page and in the menu that popped up I selected the function (subtraction) and the various format options I wanted. Once the calculation bubble was ready I simply dragged wind direction across to it and when the bubble "pulsed" I released the wind direction bubble. A window opened and I selected which "slot" in the calculation I wanted that value to fit into (the first one). I did the same for the rwy direction but attached it to the second slot. The calculation bubble now showed me the "relative" wind direction. Next I created a new calculation bubble to convert the relative wind direction in degrees into radians. This was simply a matter of creating the bubble, selecting the radians function and connecting my last calculation bubble as the input. Each calculation bubble shows the current result of the calculation it's doing.
Next step was to calculate the sine of the relative wind direction - another calculation bubble and join the radians bubble to it. Finally a cacluation bubble for the "answer". This bubble is labelled "Crosswind" and it takes the wind strength and the sine of the relative wind direction and multiplies them. Giving a crosswind component in knots with negative values for left crosswinds.
I like it because I now have a little visual calculation page that doesn't strain my tiny mind. I have bubbles for each of the three required inputs and I simply put the values into those bubbles and I get my answer.

What you can't see in this screenshot is the the intermediate bubbles that calculate relative wind direction, convert it to radians and calculate the sine. They are all there - you can see the connectors running off the page - and you can scroll to them with one flick if needed!
I've constructed a similar page for headwind/tailwind component and I'm working on one for density altitude.
The punch line to a long winded story is that I really like Thinkdigits. It appeals to my visual nature, it's much more powerful than you first think and it is simple to use. What's more it now has a facility that allows you to share your models with other ThinkDigits users. You can find ThinkDigits in the app store and their homepage is here.

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