March 31, 2009

It worked for Star Wars, frak it

So it worked for a fatally bad Lucas movie. I think it'd work for Battlestar Galactica too. I dunno about you, but Ron Moore's sudden "oh it's all the Divine and unknowable" turn, after four years of a good science fiction show with hard explanations, fair on made me sick. So if I wasn't so goddamn lazy, I'd either try it myself or set up a website appealing to those with skills.


I mean, seriously. You've got four years of footage. The first hour or so of the finale can probably stand fine on its own if you cut out a lot of the flashback crap-ola. The second hour? Yeah, well, here's your chance to show us you're not the white-flag-waving type, and try to actually give us some satisfaction. Pick some stuff Moore and co. didn't explain, and explain it. Personally I like the singularity->time travel option, a la B5's War Without End, but what do I know.

Seriously. Somebody. Save this series from sticking in my craw as the most ever let down by its ending piece of really awesome television in history. Please. I'm begging you.

Battlestar Galactica: The Real Frakkin' Finale would do fine.

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March 30, 2009

I Mourn me the B747

A while back, a colleague and I were adamant that the U.S.'s 'Next generation bomber' could and should be a militarized 747 variant. Our rationale was that it had similar carrying capacity in terms of cargo weight, was a well-understood and readily-available airframe, and offered ample volume for military systems to be added. In addition, the military already operated several 747s.

We heard many arguments about why it couldn't be done, but none that we really 'bought' - they all sounded like 'because we don't want to fly civvy air!' to us. However, recently I was speaking with an Air Force colonel who is also a B-52 pilot, and he offered the best-explained reasons it won't work.

The 747, as a civilian airliner, is a hollow tube of a monocoque fuselage designed to be pressurized during flight. In addition, the cylindrical nature of that fuselage is what allows it to evenly distribute the forces generated by said pressure across the structural members. A bomb bay, however, must by definition be at ambient pressure. It should be at such before opening in order to avoid sudden pressure changes, and of course it will be once it's opened.

The issue is that if you were to section off a part of that cylinder and move it 'outside' the pressurized area, then the load on the bulkhead separating it from pressure will tend to concentrate on structural points rather than evenly distributing - and this will cause difficulty making the airframe strong enough to perform properly. Even if it can bear the strain, the cycles of pressure differential during normal operation will lead to increased metal fatigue.

Weight and Balance
The weight of the weapons a bomber intends to dispense must be placed as close to the center of gravity (or, at least, the fore/aft balance line) as possible. That way the sudden change in the aircraft's weight profile while dropping ordnance is balanced. On the BUFF and other 'high-wing' bombers, the mainspar passes through the fuselage high enough that the bomb bay can be placed very close to if not directly astride the midpoint of the wings. This means that when the ordnance is released, the airplane lightens but does pitch up or down at all.

On a 747, however, the mainspar is low - it passes through the lower part of the fuselage in order to maximize cabin space. As a result, the bomb bay cannot be placed directly below the wing balance line, but can only be placed fore or aft of the mainspar, with consequent disruption to the aircraft balance.

In addition, airliners are built (my advisor says) to travel sedately and predictably from one place to another. While their airframes are designed to handle external stresses from turbulence, they are not built with the intention of the aircraft suddenly shifting its internal structural load as it dispenses ordnance. Again, you'd end up with metal fatigue or failure without significant changes to the airframe.

I mentioned the Evergreen Aviation 747 water bomber. He agreed that the water bomber could carry a cargo weight equivalent to ordnance, but pointed out that the tankage for this cargo could be aligned overtop the mainspar and the water dispensed from valves, not large bays. I checked their website, and yep, he's right - not only that, the dispense system is done via pressurizing the tank, so once it's empty it can be sealed and remains pressurized to avoid pressure differentials weakening the airframe.

Finally, the water bomber is intended to drop its cargo low and slow - around 400 to 800 feet, at a speed of 140 knots, or just 30% above stall speed. Thus, even if the tanks were not pressurized, there would be a negligible difference between internal and external pressure.

I'm almost convinced. :-) Not that I doubt him, but I still think there's a role for a commercial heavy-lift airframe in the bombing missions the U.S. has seen. The USSR once threatened to treat all Boeing airframes as enemy targets if the U.S. built weapon-carrying versions - at least, I've heard that from various pilots, although I can't immediately dig up a source - and whether true or not, it points out a problem of militarizing the 747 airframe. KAL-007 was shot down despite being obviously a transport, and various persons associated with the shootdown maintained that it was 'easy to convert a 747 into a reconnaissance platform.'


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March 19, 2009

War on Terror Update

Best use of counterterrorism funding ever.

Welcome to the world, Caesar Penn Boothe, and you're a New Yorker, you lucky sod.

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March 4, 2009

Movie Money Problems

So I was watching the Ocean's movies too many times, and listening to an excellent David Holmes track from the original, and I had had too much coffee at night. Anyway, I wondered - could Ocean's Eleven have managed to schlep $160 million in cash out of the Bellagio?

Well, a U.S. bill is 2.61" x 6.14" x 0.0043". So if you do the math, assuming $100 bills, you end up with around 65 cubic feet of money. Sure, nine guys could totally heft that, assuming those duffel bags held 3-4 cubic feet each.

The problem, though, is that each bill weighs around a gram. That means 10 kg/million (I think? hm, $100 x 10,000, yep, ok). That's 1600kg, and I don't think those guys could have hefted that amount out of the casino in one trip, nope nope.

If we assumed $1,000 bills, that comes down to a much more manageable 160kg, no problem for 9 guys.

The problem is that they don't make $1000 bills anymore. Shucks.

Update: Apparently someone at PageTutor was wondering along much the same lines.

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March 2, 2009

Safari 4 on OS X and Windows AD authentication

After a frustrating couple of days, I think I've figured out what bit me. Safari 4, or rather, a feature therein.

Background: At work, I use my iMac on our corporate network. This network uses Active Directory for all manner of tasks. At the time, my Mac was using local account authentication; however, I was running MS Office with Entourage, which was of course authenticating to our Exchange server. Our network had recently installed a web proxy filter, which required periodic (once per session, or less frequently) authentication to access the outside world. I'm also doing sub-rosa stuff with corkscrew to get SSH access out through the proxy server. So far, so good; all this stuff has been working for months.

Then I started getting locked out of my AD account. At first, this was hard to pin down, because everything I was using would cache credentials, so I would discover the next morning or after coming back from a system upgrade restart that I couldn't get mail. Highly annoying.

The AD server logs claimed that the auth request was coming from my machine's IP address, and was coming from MICROSOFT_AUTHENTICATION_PACKAGE or something close to that. Also, there would seem to be a string of failures in a row, resulting in a lockout - something between five and twenty tries, sometimes all within a second.

After a few days of fruitless troubleshooting (not using Entourage, not using my corkscrew hack, etc. etc.) I gave up and tried for a clean slate.

I switched my iMac over to authenticating against the AD domain, and as a result (because my local account had a different username than my domain account) I ended up with a new, clean account. All my work data was living in a fileserver folder anyway. I moved over a few plists in order to retain configs and license from some apps (BBEdit, Terminal, yadda). Just to be sure, I created a brand new Entourage profile (not copying over any office prefs) and put only my work email (not my personal accounts) on it.

Nope. I kept getting locked out. This was more annoying, because usually I'd figure this out when trying to get out of my (locked) screen saver - and it wouldn't exit, because the password had locked down.

Aha. I tried turning off the screen saver. Nope.

I went through my Apple keychain and deleted every entry that was from before the 'new account' switchover, and all entries with 'Microsoft' anywhere on them.

Nope. Still locked me out.

Then I thought really hard about what had changed on my computer. Yep. I'd installed the Safari 4 Beta.

So I downloaded the uninstaller (it comes with the installer) and backed out to Safari 3.

A couple of hours later, no lockouts.

Here's what I think was going on. Safari 4 had dutifully built me one of those 'Top Sites' walls, even though I told it I didn't want to see it unless I asked. However, I think Safari was still updating my various (ten to twenty) URLs from my Top Sites wall. And to do that, it needed to get through my corporate proxy authentication. As far as I could tell, it had not stuffed that credential anywhere into my main keychain - so it's possible it was storing it locally somewhere in the Safari app prefs.

It trying to update twenty 'Top Sites' would explain why sometimes the stupid lockout logs showed twenty password failures in close succession.

I can't prove this is what's going on. However, after dumping back to Safari 3, the problem seems to have gone away.

I would suggest, on the incredibly long chance anyone from Apple reads this, that Safari be smart enough to update its Top Sites in serial if there is an auth credential stored, and if it fails, to not try to update each site - because it will definitely lock you out. My AD server is set to five tries before lockout, within a short timeframe, I think.

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