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March 17th, 2019

xfoil

Friday we ate dinner at Holy Frijoles. This neighborhood Tex/Mex place makes excellent chicken enchiladas verde. 

Saturday morning I got up early and drove to Carrollton, about a half an hour away. I stopped first on the Carrollton Blue Trail. This sidewalk path runs by a small town lake and continues by some open spaces and trees. I counted some 20+ species of birds during a 40 minute walk. I recognized everything I saw, except that I am still internally debating if the bird I listed as a Savannah Sparrow is in fact a Song Sparrow.

Then I headed to the Dallas Makerspace for the North Texas Linux Users Group meeting. I had not been to one of their meetings in a year or two. I have never been a regular attendee, but only go once in a while. When I first arrived, the group was all looking at a program used by a new visitor called xfoil.

I had never heard of xfoil It is a bit of software that allows one to design airfoils. Apparently, this bit of free and open software saved the aeronautics industry substantial sums, as the resulting virtual airfoils are much cheaper to utilize than physical windtunnels. The users' group offers a service in which they help visitors put Linux on their computers. This visitor wanted help getting a dual-boot install so that he could run xfoil in Linux.

While we had some downtime, I installed xfoil on my computer, as it was in my Linux distribution's Linux repository (i.e., collection of free software set up for easy download-and-install). The nice man who brought in xfoil showed me how to define an airfoil (it turned out to be a handful of coordinate commands on a 180 degree x.y axis).  We could get it to load, but we could not get it to render (a command called ppar showed the airfoil). It looks as if my system was missing a font. The same specifications worked on someone else's Fedora computer.
The aircraft enthusiast kindly explained to me at length the genesis of xfoil, which was surprisingly interesting.

At home, I tried to get xfoil to work and to render an airfoil. My home laptop seemed to have the font that my 12" travel laptop lacks. I took the specifications for an airfoil for a wind turbine (by a company called Bergey) and altered some of the coordinates substantially. The result was an "airfoil" that looked a bit like a sail crossed with a caterpillar. I like drawing in x,y, but should do a more precise job.I like xfoil because it reminds me of Logo, a simple programming language with allows one to move a turtle (the cursor) along an x,y and even z axis. I did not use xfoil's more advanced features having to do with drag, lift and this or that coefficient, just as I never program in Logo beyond a few dozen commands. The program did warn me in effect that my airfoil did not look very aerodynamic. I like succeeding at quests to get things to work that are complete non-sequiturs.

After the meeting, most of us went to Taco Bueno to have lunch and chat. These were all guys, and good guys, mostly a decade or so older than I am. They were, as tech hobbyists often are (but I am not) avid ham radio buffs. One fellow, also named Bob, explained how he flew bomber missions during Vietnam as an Air Force navigator after his graduation from college. I had spoken with Bob before, and know his hobby is using computers to build organs that sound like pipe organs. He is a good guy, like me more a user than a programmer. During lunch he made some political statements contrary to my own political views. I was irritated, a bit, by this injection of political stuff into a nice lunch, but more irritated that I spent time trying to rebut his positions. He's a good guy, though, and I'll see him at another meeting, where I hope we talk virtual pipe organs.

I stopped by PetSmart on my way home to pick up Beatrice's food. Because it has a measure of weigh control in it, this food is the equivalent of doggie prescription medicine. Apparently, some people buy dogfood with weight control features for the wrong reasons.
In the late afternoon, I took Beatrice on a walk in lovely weather. She loved being outdoors but I noticed that she took the turn at the elementary school that cuts our walk short by half. I saw a Brown-Headed Cowbird, which will be the 60th species on my eBird list.

I had left my SD card in my camera at home by mistake, so I rummaged to find the right kind of USB cord to move my sparrow photos from camera to computer. Then I puzzled once more on the sparrow ID issue, as the photos looked Savannah Sparrow-ish but lacked the yellow lore characteristic of that species.  I am intrigued, by the way, with how many cords I own in life.

We ate dinner at Tokyo Joe's, where I had a bowl of chicken and vegetables. We also went to PetSmart to do an exchange, as I had accidentally gotten R/D food instead of W/D food.

The deaths in New Zealand at the hands of a terrorist of at least 50 people who were worshipping in a mosque in Christchurch is so sad. I hope that a concerted effort is made to root out terror cells of white supremacists and to improve security. for mosques, schools, chuches and other public gatherings. It is all very sad.

The college admission bribery scandal still resonates with me. I hope the FBI exposes any further participants in this situation. I continue to be struck by the wiretap allegedly of a lawyer with a nationally-prominent New York firm who proclaimed to the government informant that he was not bothered by the moral issue involved at all.

I want to walk, to get practical things done, and to read my book today. I started reading "A Perfect Explanation" by Eleanor Anstruther, after finishing "My Name is Carey" by Martin L. Shoemaker. I heard from actor Joe Marsh on Twitter after I complimented his excellent job on the audiobook of "Cousin Phillis".














from Dreamwidth, because two posts of the same text are twice as nice

adding to the count

In the mid-morning I walked in Shawnee Park. I saw my first Field Sparrow and my first Harris's Sparrow of the year. After church, I drove to Chicken Express, where I ate catfish and green beans with a dinner roll. 

After lunch I walked in Suncreek Park in Allen. I saw my first Golden-Crowned Kinglet of the year. My best pictures today were of an Eastern Phoebe in Suncreek Park and of a Northern Flicker in Shawnee Park.

In the mid-afternoon, I worked on making my car more tidy. I made some progress, but  did not finish. Then I took Beatrice for a walk. For the second day in a row, she opted to take the "shorter route" in which we deviate from the park to the elementary school beside the park rather than walking around the park pond. During that walk, I saw my first Common Grackles of the year.

We ate home-made pizza with goat cheese and parmesan cheese, which was very good. I plan to read my book tonight, get a good night's sleep and then have a productive week this coming week.




from Dreamwidth, because two posts of the same text are twice as nice