I just got back from my mountain flying trip; 5 days to Colorado and back. Lots to say about the trip. One thing I learned first hand was how different it is flying a plane on a 100° day at 9000 feet. It's a little alarming when the plane keeps lumbering down the runway and never wants to take off. Heck, at Telluride we took advantage of the fact the airport is up on a plateau; as soon as you clear the fence you can drop down 1000' into the canyon.

The key idea is density altitude, a measure of air thickness. Little piston airplanes don't fly well in thin air. We need air molecules under the wings to generate lift, oxygen to burn fuel, and airflow to cool the engine. For takeoffs and landings the thicker the air the better: a Cessna 182 needs only 645' of runway to get airborne at sea level but at the highest airport in the US it needs 1430'. Field elevation is the most important thing driving density altitude, but pressure, temperature, and humidity also matter.

At sea level when it's 15°C and 29.92inHg density altitude is roughly 0'. On a warm 30°C day it goes to 1800'. When we took off yesterday from the lowest airport in the US it was so damn hot in Death Valley that it was like being at 2600', despite the airport being at -200'. 10°C is roughly 1000' in density altitude. Hot mountain summers require careful attention to plane performance.

The nice thing about flying is you can go directly between airports; no following roads. But pilots often choose a more complex route to avoid mountains and in instrument conditions pilots have to follow specific airways. There's no signs in the sky, how do we navigate?

Pilotage and dead reckoning are the most elemental navigation. Pilotage just means "looking down", trying to figure out where you are by matching what you see on the ground to what's on your chart. It's remarkably difficult, particularly high up, but following roads and recognizing unusual landmarks works OK. Dead reckoning is the art of guessing where you are by what direction you've been going. It's pretty unreliable, particularly because of winds aloft, but it can give you some idea where you are.

Beacons are the historical source of airplane navigation. A VOR radio beacon tells you the bearing to a known station on your chart; cross-checking two VORs (or using DME) gives you location to a pretty precise point. Earlier beacons include NDBs, four course ranges, and beacon lights (map, current operation in Montana). The drawback to beacon navigation is you only learn your position relative to some fixed, expensive-to-maintain equipment. Also it's generally only easy to fly directly to or from a beacon, hard to fly any path.

Area navigation is the simplest way to know where you are, X marks the spot. Everyone knows GPS, it makes airplane navigation very simple. Predecessors to GPS include LORAN (RIP) and good ol' sextants, used until the 1970s. An interesting alternative is inertial navigation, in active use today in commercial aircraft and quite accurate as long as you can occasionally correct the accumulated errors with some other reference.

I pretty much always navigate via GPS: plug in the course and fly the purple line. But GPS can and does fail, so it's important to stay current with other forms of navigation. Pilotage is fun and keeps you busy long boring flights. VORs are still an important part of IFR flying. But honestly, GPS is so great it's hard to use anything else.

I have the arrogance of having worked at Google; I thought I knew all there was about Internet technology leadership. But I've overlooked Facebook; they're doing some very impressive tech. And Facebook's openness gives them some mindshare over Google.

Pingdom just posted a roundup of Facebook technologies that's worth reading. Load balancers, distributed datastores, scaleable logging, etc: a lot of good systems technology. Many of their systems tools are available open source; a lot of startups I talk to are using various parts of Facebook's tech. Google has plenty of open source too but they tend to keep the server systems proprietary. If you want a distributed datastore today you may read the BigTable paper but you're going to be using Facebook's Cassandra.

Facebook's API strategy is also impressive. They own the American social network: if you're building something using social relationships it's really tempting to do it inside Facebook. (Or as one startup friend of mine put it, "Facebook is layer 8 of the Internet".) People have complained about how awkward the earlier Facebook APIs have been to use. But the Facebook Graph API is the new hotness and it's nicely designed. I'm particularly struck by how it's typeless, all data objects in Facebook have a unique 64 bit id and they're all accessed via URLs like https://graph.facebook.com/649745863. I'm liking this flat REST+JSON design.

I've finally gotten to use my pilot's license for what I originally planned: actually going places! As a student I was on a short leash and since getting my ticket it's been hard to line up a plane rental, good weather, and the right mood to go somewhere. But this week has been great: 1000nm of flying, 10 hours.

Monday was a big flight I'd been anticipating for weeks: taking Ken up to Grant's Pass, Oregon to pick up his plane. My first time out of state, my first time over real mountains, and my first time flying over 10,000 feet. The route we took following I-5 never requires you go over 7000' or so, but that's still serious terrain and you get within a few miles of Mt. Shasta, a volcano at 14,200. Unfortunately we weren't able to land in Oregon because there were clouds below us, but I dropped Ken off in Redding to rent a car. Frustratingly the weather cleared an hour later!

Today's flight was a classic lunch run to Santa Maria. Nothing too challenging, but a good long distance and a pleasant trip to somewhere different. I finally got what I've been looking for; getting bored in the cockpit. I need to start bringing friends with me on trips like this. (Feel free to ask!)

Next week Ken and I are going with a CFI on a group flight to Colorado, 5 days of challenging mountain flying. If the weather allows we'll be doing things like flying through Independence Pass, where the low spot is at 12,093'. And then next month we're flying to OshKosh for AirVenture, probably three days there and three days back again. It's not particularly cheap, fast, or convenient, but it's fun to fly yourself.

Apparently it's a masturbation simulator.

I'm sad to have learned that Steve Dyer has passed away. Steve was an old friend from Boston and from soc.motss, the gay and lesbian Usenet group I frequented around 1989-1996. We haven't talked in years, but his generous social and Internet life have had a big impact on my life.

Steve was an old Unix and Internet hacker, in the center of net technology and culture in the early 80s. He founded net.motss in 1983, our own little place on Usenet for gay culture. That culture became an important part of many people's lives. Motss was my window on to the gay world when I was in college, a wider place full of intelligent people from all sorts of backgrounds. I wouldn't have met a whole lot of friends without motss, including my partner Ken. Later Steve also founded the Bears Mailing List which was instrumental in defining a subculture for gay men who were unrepresented in mainstream gay culture.

Internet communities always seem to have people like Steve: someone who creates places for a group, who does the organization and the shaping. Steve was particularly good at connecting socially, every motsser I know has a fond story of a casual gathering at Steve's house where they could finally meet motssers in person. Steve was a particular joy face-to-face because of the mirthful twinkle in his eye, friendly and wicked-smart and very generous to people. I regret now we hadn't spoken in some 10 years, I'm sad he's gone.

The Eye-Fi is good hardware. It's a magic SD card that you put in an ordinary digital camera to give it WiFi capability. With the Eye-Fi your camera will automatically and wirelessly upload photos to your computer, sharing sites like Flickr or Facebook, printing sites like Wal-Mart. It'll even upload video to Youtube. I bought it solely to physically avoid plugging my camera in to a computer; I'd been using the crappy iPhone camera for photos because it was simpler to upload from.

But what Eye-Fi really is is a marvel of tiny WiFi engineering. Buried in a standard SD card the size of one fingerjoint is a WiFi adapter with an antenna powerful enough to work from inside a camera. All powered off the camera's battery. It's kind of crazy that cameras don't have WiFi themselves, but Eye-Fi's solution works pretty well.

But what's really exciting about Eye-Fi is what else you could do with it other than photography. GPS trackers. Cell phones. Game consoles. Basically any device that has a storage interface could be given WiFi capability. Sadly, Eye-Fi has focussed their product specifically on the photo market and is not hacker friendly, so you can't actually do anything other than cameras with the hardware. Too bad.

The basic Eye-Fi goes for $50; compare $12 for an equivalent non-wireless card. At that price the only drawback is that the Eye-Fi may shorten camera battery life. The other caveat is there's a confusing proliferation of products. It all seems to be basically the same hardware, but the fancier versions will upload to public WiFi hotspots and geotag photos. Between the artificial product differentiation and the closed platform it feels a bit like they don't know how to make enough money selling the basic thing. But that's OK, because the base product is great.

You know the old joke about Playboy magazine, about how he "reads it for the articles"? It's funny because it's true. That's what Butt Magazine is like, only instead of cheesy airbrushed naked chicks paired with faux-sophisticate culture it's slightly gritty naked guys with faux-casual sophisticated culture. It feels like a well produced zine, with a very personal editorial slant. Instead of the usual hairless-youth or bearish-30something mindless gay crap it's more hipster, nerdy.

Butt started as a magazine published in Amsterdam in 2001. What's remarkable about it are the interviews: Casey Spooner, Matmos, Michael Stipe, Martin DeGville (Sigue Sigue Sputnik). Fashion and art too: Marc Jacobs, Roger Payne, Matthias Vriens, Gus Van Sant, Edmund White (a particularly good one). Some straight out porn: Peter Berlin and Bruce LaBruce. I also love their random other interviews: Julian Ganio "the gereontophile poster boy of the London scene", Perez Hilton, Gore Vidal. Their interview style is very personal, simultaneously casual and way more revealing than the usual garbage. It's thoughtful journalism. The photos are good too, particularly the non-porny erotic shots, although their insistence of publishing on pink newsprint makes it hard to really enjoy the detail.

Sadly, Butt is going on a bit of sabbatical so now isn't a great time to subscribe. I can strongly recommend the Butt Book, though, a compilation of the best articles from the first 17 issues. The main website is interesting too, they've gone a bit bloggy.

I've mostly gotten bored with being gay. Gay overculture doesn't interest me, it's too vapid and too cruising focussed. Butt reminds me of the interesting part of being a sexual outsider.