1669: Planespotting

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No, a hydroplane doesn't land on water--that's an aquaplane. A hydroplane is a plane that gets electric power from an onboard water reservoir with a tiny dam and turbines.
Title text: No, a hydroplane doesn't land on water--that's an aquaplane. A hydroplane is a plane that gets electric power from an onboard water reservoir with a tiny dam and turbines.


Cueball and a man with a hat are out planespotting, or aircraft spotting, a hobby where tracking the movement of aircraft allows plane fans to see as many different types of planes as possible. A knowledgeable spotter would just by the silhouette and maybe the engine sound of the plane be able to tell what type of plane it is, and may be rather proud of the fact, if he or she can tell this before one of the other spotters.

The plane in the comic is most likely a Bombardier Q400, a twin-engine regional turboprop with a T-tail as depicted.

The man with the hat asks Cueball to identify the airplane flying overhead. Cueball (or Randall qua the caption), who "assumes" he knows a lot about planes gives a long, nonsensical answer, proving that he does not. As mentioned in the caption he never actually checked if what he thought he knew was fact or fiction. As it turns out it is mainly fiction, but of course with some reference to real planes or vehicles. Due to the fact the characters are drawn in silhouette it is impossible to determine whether the character with the hat is Black Hat or White Hat or some other character.

  • Boeing: Boeing is a company that designs and builds aircraft, although not the Q400. It is one of the best known Aerospace companies in the world, so putting this in front is not a way of displaying any particular knowledge of planes.
  • Q404: The reference to Q404 is close to the Q400, which this likely is. 404 also refers to an error shown when a specific internet address or file is not found, or as in this case, the plane is not found!
  • Twin-engine: Twin-engine refers to aircraft with two engines, so at least Cueball got that right.
  • Quad band: Communication equipment that can use 4 different radio frequency bands is called quad band.
  • MiG: MiG is a Russian manufacturer of military aircraft, formerly the Mikoyan-and-Gurevich Design Bureau.
  • MIG-380: a type of welding equipment (metal inert gas, 380V). On the other hand A380 is an aircraft developed by Airbus.
  • Hybrid: A hybrid vehicle is able to use more than one distinct power source, typically an automobile that uses both a primary combustion engine and a secondary electric system. Boeing is currently working on a concept hybrid plane capable of using both electricity and natural gas.
  • Dual wield: Dual wielding is using two weapons, one in each hand. This is completely nonsensical in aviation -- even if we say that a pilot is "wielding" his aircraft, they would not personally wield two planes at once without remote controls for at least one, and it is equally ridiculous to imagine that the plane is dual-wielding anything.
  • Mk.: "Mk." (or Mark) is usually used to specify a model number using a Roman numeral. "Mk" is also phonetically close to Mach, a multiple of the speed of sound, often used to describe the speed of supersonic aircraft.
  • IVII : IVII is not a standard number in the Roman numeral system, under standard rules it would be written like VI = 6. On the other hand, it could be a mishmash way of writing "42", (IV = 4, II = 2) which could then make it a reference to the Answer to Life, The Universe, and Everything according to Douglas Adams' The Hitchhiker's Guide to the Galaxy, something referenced before in xkcd, for instance in 1608: Hoverboard if you got 42 coins. The correct way to say 42 in Roman numerals is XLII. The number could also be MI, or 1001, but this is unlikely.
  • Turbodiesel: Diesel engines are only rarely used in aircraft because of their low power-to-weight ratio. Turbo-diesel engines are much more common in cars and trucks. A Turboprop is a kind of aircraft turbine engine that sacrifices exhaust thrust for shaft drive.
  • 797: The Boeing 797 has never been produced, but a hoax design has been circulating the Internet since the mid-2000's.
  • Hydroplane: A hydroplane either refers to aquaplaning, a very undesirable activity of a wheeled vehicle crossing shallow water, or a type of boat for which hydroplaning is the desired mode of travel. The correct name for planes which can land on water is seaplane (US) or floatplane (UK), however the term hydroplane had been used in this meaning in the past; also in many languages such aircraft are named hydro (or some spelling variant of this Greek prefix) + whatever stands for plane, e.g. in Spanish, Italian, Portuguese, French, Czech, Slovak, Russian and others.

In the title text the concept of hydroplane is mixed up with other concepts, none of which has anything to do with airplanes:

  • Aquaplane: An aquaplane is a similar to a short surfboard, on which a person stands while the board is pulled by a speedboat. As noted with Hydroplane above, the term aquaplane is also used as a verb to describe the loss of traction of a wheeled vehicle at speed on a surface covered in shallow water. The correct name for a plane that lands on water (on purpose) is a seaplane.
  • Dam and turbines: Powering an aircraft with a miniature hydroelectric dam connected to an on-board reservoir is an absurdity. Hydroelectric plants derive power from the potential energy released by a mass of water as it falls. Because the plane is lifting the water reservoir in addition to its own weight, such a dam could never produce enough power. Ludicrously small hydroelectric power systems were previously considered in what if? "Faucet Power". In 2008, Randall discussed the more reasonable physics problem of whether an airplane would be capable of flight from a treadmill.

Only three weeks prior to this comic, 1660: Captain Speaking was released only with a drawing of a plane in the air, where the captain eventually finds out that his plane is probably a Boeing. Planespotting was later a part of 1910: Sky Spotters.


[Cueball and a man with a hat is seen in silhouette standing on the ground looking towards the sky. A fixed wing aircraft can be seen in the sky, also in silhouette.]
Man with hat: What's That Airplane?
Cueball:Oh, that's a Boeing Q404 twin-engine quad-band MIG-380 hybrid dual-wield Mk. IVII Turbodiesel 797 Hydroplane.
[Caption below the panel:]
I've always assumed I'm one of those people who knows a lot about planes, but I've never actually checked.

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Hybrid could also refer to hybrid airship dynastats which are a combination between a blimp and a lifting body airplane. HAV in England and Lockheed Martin have both flown prototypes in the last few years. https://en.wikipedia.org/wiki/Hybrid_Air_Vehicles_HAV-3 (talk) (please sign your comments with ~~~~)

How would one even pronounce "Mk. IVII"? IV is 4, VII is 7. I could see an argument for treating it as a really bizarre way to say 6. Or, if we treat it as two distinct digits (as opposed to a two-digit number), it could be either "1-7" or "4-2".

"Usage in ancient Rome varied greatly and remained inconsistent in medieval and modern times." But AFAIK each numeral only stood for a fixed amount, never for a "digit" (in the sense that its value could specify ones or tens depending on its position). So six ((5 - 1) + 1 + 1) is a plausible interpretation, though definitely not standard; but 17 or 42 would be treating Roman numerals as if they were Arabic. Huttarl (talk) 16:03, 18 April 2016 (UTC)
You're correct; in Roman numerals, there is not a concept of "this is an I, in the hundreds place, so it's really a 100". If you mean 100, that's always C. Hence the phrasing "two distinct digits (as opposed to a two-digit number). 14:16, 19 April 2016 (UTC)

I think that's actually MI, or 1001. 16:12, 18 April 2016 (UTC)

That was my first thought on reading it, too. Doesn't an underline and overline on a Roman numeral increase it by a factor of 10,000, or am I mis-recalling grade school? ---> 19:38 UTC, 18 April 2016
I read it as having too much space between strokes for it to be "MI" rather than "IVII", but poor penmanship is as likely as deliberate nonsense. In proper Roman Empire-era Roman numerals, the overline denotes "multiply by 1,000", but in English an overline/underline combo just means we're being fancy. 14:16, 19 April 2016 (UTC)

I assume there are other parts of this that are similarly nonsensical to people who know what Cueball thinks he's talking about. 14:43, 18 April 2016 (UTC)

When I first read the comic before the explanation I was assuming Cueball was roughly, and poorly, describing a Bombardier DHC-8. It is also known as a Q400 and is a twin-engine turboprop. The silhouette looks vaguely like it.R0hrshach (talk) 15:56, 18 April 2016 (UTC)
Wholeheartedly agreed on it being a DHC-8 version, which could be a Q400. The engine nacelles appear to extend behind the wing (unlike an ATR42/72 or Do328), and the T-tail eliminates a lot of other regional prop possibilities. It also ties in with Cueball calling it a "Q404". 17:07, 18 April 2016 (UTC)
As someone who's worked around "Dash 8's", I echo the Bombardier Q400 identification. The 400-series has the longest fuselage of the DHC-8 family and the aircraft illustrated looks longer than a DHC-8-300. It's definitely too long to be a DHC-8-100 or - 18:59, 20 April 2016 (UTC)

De Havilland Canada (which developed the Dash-8) did belong to Boeing between 1988 and 1992, during which time the aircraft was commonly referred to as the "Boeing Dash-8". The Q400 variant was developed after DHC was sold to Bombadier, however. So it is possible that a DHC-8 could, in fact, have been made by Boeing, just not the Q400 variant.

There are so many things wrong about this comic. .42 (talk) 14:53, 18 April 2016 (UTC)

Maybe I'm totally off base, but this reminds me of something called "Vaynespotting". In League of Legends, there's a character named Shauna Vayne. She has an extremely high skill-ceiling and skill-floor. Vaynespotting is a minigame where other players receive imaginary points for calling out a bad Vayne player when that player makes aggressive maneuvers, but doesn't have the skill to pull it off. Thefance (talk) 15:38, 18 April 2016 (UTC)

Is that black hat or white hat? 15:10, 18 April 2016 (UTC)

Probably White Hat, but it is impossible to say. Have corrected explanation Kynde (talk) 16:11, 18 April 2016 (UTC)
Yes, I think that it is White Hat. Just in terms of personality, most encounters with BH end up with some sort of sadistic remark, whereas WH is sometimes used just as a foil character.RedHatGuy68 (talk) 02:17, 20 April 2016 (UTC)

Fixed the title text explanation regarding the hydroelectric plant. The water going over the dam still falls down (reservoir -> dam -> out of the plane?), but lifting the water in the plane would take more energy than the plant would produce. 17:02, 18 April 2016 (UTC)

To me this comic looks like a clear reference to the "user agent" property of a browser notorious for being long, nonsensical and bearing little relationship to the version and the type of browser the client actually uses. E.g. In my Chromium this value is: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/49.0.2623.108 Chrome/49.0.2623.108 Safari/537.36. 17:46, 18 April 2016 (UTC)

The user agent string is not SUPPOSED to say what browser you HAVE, but what your browser is capable of doing. For start, Mozilla/ means that it's graphics browser, just like Netscape 4. Gecko means that authors of engine did read the HTML specifications (as authors of Gecko did), as opposed to authors of older versions of Internet Explorer (older than 7). It's because user agent string is only thing server knows about browser and therefore uses it to choose what version of page (and bug workarounds) it's supposed to use. And because some servers never update their definitions, every new browser needs to ADD his own strings to strings of some already existing browser instead of replacing them. -- Hkmaly (talk) 14:16, 19 April 2016 (UTC)

Dual Wielding could easily refer to the fact the plane has two engines or possibly four if it is dual wielding engine sets. I feel the current explanation of that line item is a little lacking. ( 17:52, 18 April 2016 (UTC))

Then please update the explanation :-) Kynde (talk) 17:58, 18 April 2016 (UTC)
I read "hybrid dual-wield" as being at least partly a combined reference to RPG and MMO games. Hybrid classes are those that are half-way between melee combat and non-melee combat classes, and are often characterized by agility, accompanied by "dual wielding" one-handed weapons (as opposed to using a single larger weapon based on strength). (talk) (please sign your comments with ~~~~)

I originally read that as "Dual Weld", as in 'using a dual welder', which made no sense since it would be absolutely irrelevant (a dual welder can mean either a welding machine that operates on 120/240V or one that operates in both gas/gasless mode.) Ralfoide (talk) 16:40, 19 April 2016 (UTC)

I understood the Mig-380 part as a mix, an Airbus-380 but made by Mig. I'm not sure if I explained myself properly...NeoRaist (talk) 18:15, 18 April 2016 (UTC)

Some reference on "planetspotting" by Kepler? 18:43, 19 April 2016 (UTC)

"What's that planet?" "That's Sid Meier's Taupe Netherlands PILF #14!" .42 (talk) 20:27, 19 April 2016 (UTC)
It's NEW Netherlands! ;) Elektrizikekswerk (talk) 08:50, 20 April 2016 (UTC)

Well done guys! I have finals, so I didn't check xkcd until now. Loand Behold! An in depth explanation for every part of this joke, which I originally understood none of. With dry humour on the side To Boot! Gold Stars All Around!NotLock (talk) 04:55, 20 April 2016 (UTC)

"Most flights are on auto-pilot for hours at a time, and the pilots serve primarily for takeoff, landing, and emergencies." As someone who works in aviation, this is a common misconception, particularly the part about the pilot being just there for emergencies. Yes, autopilot is overwhelmingly used, but even routine flights have dozens of decisions that need to be made and minor issues to face. A pilot can be very busy even with advanced horizontal and vertical navigation engaged talking to ATC, responding to ATC commands, adjusting the route through navigation, handling weather, etc. In reality the autopilot, similar to an adaptive cruise control on a car, does not make the pilot useless or oblivious, but instead it simplifies things that should be easy, like following a chosen route at a constant speed. Since this sentence doesn't blend well with the rest of the paragraph, I suggest it just be deleted. (talk) (please sign your comments with ~~~~)