Flying a Cessna On Other Worlds: xkcd Gets Noticed By a Physics Professor

djl4570 writes "xkcd's 'What If' series consists of humorous takes on highly implausible but oddly interesting hypothetical physics questions, like how to cook a steak with heat from atmospheric re-entry. The most recent entry dealt with flying a Cessna on other planets and moons in the solar system. Mars: 'The tricky thing is that with so little atmosphere, to get any lift, you have to go fast. You need to approach Mach 1 just to get off the ground, and once you get moving, you have so much inertia that it’s hard to change course—if you turn, your plane rotates, but keeps moving in the original direction.' Venus: 'Unfortunately, X-Plane is not capable of simulating the hellish environment near the surface of Venus. But physics calculations give us an idea of what flight there would be like. The upshot is: Your plane would fly pretty well, except it would be on fire the whole time, and then it would stop flying, and then stop being a plane.' There are also a bunch of illustrations for flightpaths on various moons (crashpaths might be more apt), which drew the attention of physics professor Rhett Allain, who explained the math in further detail and provided more accurate paths."

Re:Not going anywhere...

[peragrin]

It is a cessna engine, it doesn't run on air but on money.

Mars plane by Boeing

[Anonymous Coward]

"plane would fly pretty well, except it would be on fire the whole time"

I think Boeing has a plane that meets part of the criteria already.

X-Plane

[Ichijo]

Your plane would fly pretty well, except it would be on fire the whole time, and then it would stop flying, and then stop being a plane.

It would be an X-Plane!

If your plane is on fire and not a plane anymore

[Lemming Mark]

If your plane is on fire and not a plane anymore then you are having a bad problem. You will not fly on Venus today.

Re:Wrong Professor is Wrong

[glwtta]

Not to mention when he says that Venus' upper atmosphere is "room temperature" - duh! rooms on Venus would have a very different temperature from Earth's rooms! What and idiot.

Re:Not going anywhere...

[Anonymous Coward]

You can't hand-waive away physics.

Sense of humor, on the other hand, is commonly waived.

Re:Not going anywhere...

[Warhawke]

FTFA: The motor is electric, and the fuel tanks are replaced with Li-Ion batteries. But I'll give you style points attempting to stifle scientific hypothetical inquiry and outside-of-the-box thinking with cynical non-imaginativism. Keep it up and you might win the scientific curmudgeon of the year award!

Re:Wrong Professor is Wrong

[Scarletdown]

They also didn't point out that if attempting to fly in the Sun's atmosphere, you may last longer if you do it at night. :P

Re:Not going anywhere...

[Anonymous Coward]

You must be great at parties.

Re:Mars plane by Boeing

[mrbester]

"on fire the whole time"

Typical. You go to all the trouble of flying a plane on Venus and all you get is petty criticism of minor teething troubles. There's no pleasing some people.

Re:Not going anywhere...

[Qzukk]

It it totally not believable in ANY context

Wow, you mean he's wrong and the Cessna would fly awesome and not just fall to the ground?

Our Cessna 172 isn’t up to the challenge. Launched from 1 km, it doesn’t build up enough speed to pull out of a dive, and plows into the Martian terrain at over 60 m/s (135 mph). If dropped from four or five kilometers, it could gain enough speed to pull up into a glide—at over half the speed of sound. The landing would not be survivable.

Glad we had you here to set things right. I'm going to get started on my plan to fly to Mars!