Marqtholomew

Lately I’ve been working on a web-based application for creating and sharing quizzes, using Google App Engine. Tammy and I took a UNIX class over the summer, and I wrote the program so we could prepare for our final exam, but I had other uses in mind for it, primarily that of a means of keeping aviation knowledge fresh in my mind. It was also a good excuse to learn a new development framework, and served as something fun to build.

The app is called quizlink, and it is available at quizlink.appspot.com. You have to login to your google account to use it, since it keeps track of your scores and your responses to each question, so you can review what you need to improve on. Only you have access to your scores, and you can delete old sessions if you don’t want to look at them any more. You can make your own quizzes, and when you think other people could benefit from one of your quizzes, you can publish it to a public directory where others can take it. You can also make comments on questions if want to challenge the answer or make a correction; the comment will appear on the quiz author’s main page. There’s also an “auto quiz” which will ask you questions from your various quizzes. It’s pretty basic stuff, and is a pretty minimal user interface, since I’m not much into web design.

I’ve been working on some aviation-related quizzes, and Tammy made one on music history. Feel free to create and share your own quizzes (please don’t publish “test” quizzes though). The code is in python (as all GAE apps are), and is available on google code.

I’m preparing for a flight to Friday Harbor tomorrow, and I’ve been following the weather forecast carefully over the past week. The forecast along my route of flight has been good, until I checked the national weather service’s graphical area forecast of the pacific northwest:

The NWS seems to be forecasting a super-thunderstorm of apocalyptic proportions which will cover the entire northwest around 5pm PDT tomorrow, accompanied by heavy rainfall. Apparently Utah will be spared from its wrath, as the superstorm will be precisely confined to the Idaho side of the border. Is it just a glitch in the NWS software, or cause to repent?

There’s a site called SkyVector.com that provides free access to scanned aeronautical sectional charts through a user interface similar to google maps. The maps also overlay routine weather observations (METAR) and provide detailed airport/runway information.

But here’s the cool part–they’ve recently added the ability to compute course headings and distances between points on the sectional chart and assemble a flight plan from the points. You just right-click anywhere on the sectional chart, select a waypoint, and repeat until you’ve created a list of waypoints defining your flight plan.

*A disclaimer indicates that the feature is “not for navigation.” Nevertheless it is still a useful tool for rough high-level planning, as it is much more convenient than a plotter for getting an idea of how much distance the flight will cover. I’ll continue to use my flight planning software and the paper sectionals for my actual planning and navigation, but it does seem that SkyVector.com is moving their service in the direction of a software package fit for actual flight planning.

I finally got around to packaging up my Weight and Balance program for the Pocket PC, and it is now available for download. The product page describes the program and has a few screen shots. I recently added a fuel calculator feature to the program which allows you to specify how many gallons of fuel you’ll have at takeoff, how many gallons will be consumed en route, and it will calculate the takeoff and landing fuel weights. I have been using it before all of my flights to compute the takeoff and landing weight and balance figures so it has undergone some real-world testing. Although it does have pretty decent unit test coverage I certainly make no claim that it is defect-free, so exercise caution and common sense when using this program for actual calculations. Let me know if you discover any problems, or have any requests for additional features.

Update: Marcware W&B has been reviewed on AviationReviews.com! See the review here.

This evening I added another command to the SMS Service for retriving winds aloft forecast data from the National Weather Service. The command is “FD”, which is the product code for the textual winds aloft forecast. You can query the service with the code for a major airport, and the service will reply with the wind direction, wind speed, and temperature for each altitude. The response for the command “FD PDX” might look like this:

So at 6000 feet, the wind is blowing from 270 at 20 knots, and the temperature is 4 degrees C. At 9000 feet the wind is coming from 250 at 33 knots, and the temperature has dropped to 2 degrees. They don’t give the temperature at 3000 feet.

See the SMS Services page for more information on this command.

I have a strange need to be constantly aware of the current weather conditions at the local airports, even if I have no intentions of flying any time soon. I found myself calling the Automated Surface Observation Station (ASOS) at Hillsboro Airport multiple times throughout the day and tying up the phone line, which led me to build a SMS service so I could get the same information through text messages. I started out with the METAR and TAF commands, allowing me to obtain routine weather observations and terminal aerodrome forecasts.

Last night I added a non-aviation related command for retrieving video game ratings from Gamespot. To try it out, just send this text message to sms(-at-)marqtholomew.com:

REVIEW ZELDA WINDWAKER

A minute or so later you will get this reply:

The “9.3″ is the gamespot rating on a scale of 1-10, and is followed by their short synopsis. Very useful for those times when you’re in the video game aisle and desperately need to make an impulse purchase.

I also put together a page that describes the supported commands and gives examples on how to use them. The service is implemented as a python script scheduled to run every minute in a cron job. The script processes the messages and issues replies to the sender’s address.

I’ve been working on a program for the Pocket PC to perform aircraft weight and balance calculations, implemented in C# using version 1.1 of the Mobile .NET Framework. There are plenty of programs available that do this, but they all had little usability quirks and few had all of the features I was looking for: a graphical CG envelope, takeoff and landing fuel calculations, and multiple airplane profiles.

You start out by creating a new airplane profile, then configuring the center of gravity limits from the chart in the Pilot’s Operating Handbook. Then you enter the actual weight and arm values for each station (including Takeoff and Landing fuel weights), and hit the “Calc” button. A screen appears that shows the values for the Takeoff, Landing, and Zero-Fuel center of gravity at the top, and plots the values in the graphical envelope. If any of the center of gravity values are out of the limits, they will appear in  red .

At the moment there are still a few features I’d like to implement before I make it publicly available, such as the ability to specify moments instead of just arm values for each station. I’ll probably put together a product page in the next few weeks. In the interim it’s been a useful tool for speeding up the pre-flight calculations!

What I need now is a good name for the program. “Weight and Balance” is terribly unoriginal (but it is descriptive!).