Flying with Machine Guns?

http://blog.wolfram.com/2014/12/05/flying-with-machine-guns/

by lelf • 12 years ago

156 68 12 years ago

blog.wolfram.com

unchocked• 12 years ago

Relevant video at 0:24 https://www.youtube.com/watch?v=FRp3S8OOeZc

prestonbriggs• 12 years ago

An alternative video: https://www.youtube.com/watch?v=uKOrpyO0z48

monksy• 12 years ago

I'm going to file this under: I've always wanted to know this, but never knew I did.

dietrichepp2• 12 years ago

There is a jet aircraft, the A-10, with a gun so powerful that it provides more thrust than the jet engines.

Gracana• 12 years ago

"The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN), which is slightly more than the output of one of the A-10's two TF34 engines (9,065 lbf / 40.3 kN each). While this recoil force is significant, in practice a cannon fire burst only slows the aircraft a few miles per hour in level flight"

Source: http://en.wikipedia.org/wiki/GAU-8_Avenger

digi_owl5• 12 years ago

And then thanks to a certain XKCD what if article: https://what-if.xkcd.com/21/

We learn about a certain russian gun: https://en.wikipedia.org/wiki/Gryazev-Shipunov_GSh-6-30

That can apparently produce 40G of recoil force...

Towards the end of it all, it is starting to look like the premise of a certain mobile game: https://play.google.com/store/apps/details?id=com.halfbrick....

abfan1127• 12 years ago

It also used to produce so much oxygen-free gas that the engines would flame-out. The engines were modified to deal with it. Its in the same wikipedia article.

Audiophilip• 12 years ago

Some guys used exactly this effect to land the A-10C on an aircraft carrier in a flight simulator: https://www.youtube.com/watch?v=fteYkPabLTA Very entertaining.

winslow2• 12 years ago

XKCD did a whole article along with the math about this topic specifically. Great read.

https://what-if.xkcd.com/21/

speeder• 12 years ago

It is written on this article that the article was inspired by the XKCD post.

winslow2• 12 years ago

Ahh I didn't catch that at first look. I love when people break down absurd things like this in myth busters style.

digi_owl5• 12 years ago

https://what-if.xkcd.com/imgs/a/21/jetpack_speeding.png

Best part.

HCIdivision17• 12 years ago

I've just realized that it's curious how the cop pulled him over. Pretty sure tanks aren't fast enough or durable enough to make pursuit, and unless he stops firing while changing lanes, he likely strafed the cop getting off the road.

Frankly, I think the scenario is just too unbelievable. Perhaps a souped-up SWAT van clad with ablative plating and 12 inch thick laminated windshields, but definitely not just some ordinary cruiser.

acadien• 12 years ago

Reminds me of that Neal Stephenson book, Anathema, that had a space ship that was propelled by setting off nuclear bombs just outside its hull.

necubi• 12 years ago

He didn't make that up. As crazy as it sounds, NASA considered exactly that idea in the 1950s: http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsi....

digi_owl5• 12 years ago

Well it was the 50s. Both sides of the cold war tried to come up with various uses of nuclear power. From civilian cars to military strategic bombers. Never mind using nukes to dig harbors...

https://en.wikipedia.org/wiki/Project_Chariot

And would it surprise anyone that a champion of this project was Edward Teller?

CurtMonash2• 12 years ago

Niven & Pournelle's Footfall also had an Orion-type ship. It was a desperation tactic on the part of the overmatched Earthlings, but it worked.

antimagic• 12 years ago

If I remember currectly, the Fthip dropships used a similar (but cleaner) pulse technology. They even claimed to have taught us the trick...

marktangotango• 12 years ago

Ha! Great reference, iirc the humans put a pusher plate under a battle ship (uss missouri?), launched into orbit and pummeled the aliens. I also recall something about fighter craft and 16 inch cannons. Great read.

joshcrews• 12 years ago

I think someone could have a hit building a flappy-bird clone off this concept.

noobermin• 12 years ago

I was thinking of a sort of violent version of _Up_, in which Carl launches his house by shooting an assortment of machine guns attached to the bottom his house to propel it upwards instead of using balloons.

sp332• 12 years ago

In the game Jetpack Joyride, you start with a "machine gun jetpack". http://jetpackjoyride.wikia.com/wiki/Machine_Gun_Jetpack

ajuc• 12 years ago

There's this old split-screen real-time worms clone called liero, it has rifle weapon that allows this in-game.

They play with reload times set to 0, so this is a little extreme, but just to give an idea:

https://www.youtube.com/watch?v=C6rfXFyssbE#t=695

This game is great BTW, very playable, strange that nobody did html5 online clone.

moron4hire• 12 years ago

Ooooooh, give me about a week and your wish will be my command.

darsham• 12 years ago

He's playing against the ridiculously bad AI in that video. Here's the more impressive "mortars only" style in the LieroX remake:

https://www.youtube.com/watch?v=kx3ivYFY4ig#t=67

I had a couple of years at uni where we played this on LAN in one of the computer labs during every lunch break. We even made some maps!

lmm3• 12 years ago

Maybe not html5, but teeworlds is a free clone with modern graphics and network play.

bra-ket• 12 years ago

that's the idea behind Project Orion (nuclear propulsion): http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propul...

nickpinkston• 12 years ago

Great reference! A thermonuclear explosion drive - not elegant, but damn would that be a sight to behold!

Bonus points for EMPing vast swaths of the launch region.

arethuza2• 12 years ago

"but damn would that be a sight to behold"

I imagine it would be quite something to experience as well!

NoMoreNicksLeft• 12 years ago

Not all nuclear detonations cause EMP. It requires a particular set of circumstances.

prezjordan• 12 years ago

Great way to use up all those nukes we have lying around.

mirkules• 12 years ago

My first thought was a space propulsion drive based on machine guns, much like ion propulsion. If humanity decided to get rid of all firearms (ha!), we could probably send them to space and drive a few spacecraft cheaply, easily and for a very long time (there are a lot more bullets than nuclear weapons)

Thermonuclear propulsion, as cool as it is, would be very powerful but uncontrolled acceleration, whereas a firearms-based drive could be controlled a lot more.

It would be fun if someone did a comparison on how long, fast and far nuclear versus bullet drives would get us in space.

AceJohnny22• 12 years ago

The article directly refers to Munroe's What-If article, and Munroe is pretty clear that he relies heavily on Wolfram Alpha for his calculations (see end of "Falling With Helium" [1])

So it's rather amusing to me that things are coming full circle, and that Worlfram's guys are now using Munroe's topic to demonstrate SystemModeler, another Wolfram product.

[1] https://what-if.xkcd.com/62/

mintplant• 12 years ago

The page you linked says that he normally uses Mathematica, and fell back to Wolfram|Alpha for that piece when it started locking up.

While researching this article, I managed to lock up my copy of Mathematica several times on balloon-related differential equations, and subsequently got my IP address banned from Wolfram|Alpha for making too many requests.

AceJohnny22• 12 years ago

That was an example. If you have to be pedant, then here are his other references to it:

https://www.google.com/search?q=wolfram%20site%3Awhat-if.xkc...

Compare with his (currently) 2 references to Mathematica: https://www.google.com/search?q=mathematica+site%3Awhat-if.x...

lmartel• 12 years ago

Mathematica and Wolfram|Alpha are developed by the same company, if you weren't aware.

soneca• 12 years ago

trivia about flying on helium balloons:

"In 1982, Larry Walters flew across Los Angeles in a lawn chair lifted by weather balloons, eventually reaching several miles in altitude. After passing through LAX airspace, he descended by shooting some of the balloons with a pellet gun."

In Brazil, a priest doing a gimmick to raise some funds to his church went on flying with helium balloons. He was drifted to the ocean by the wind and didn't know how to return. He did took a phone and a GPS device. But he didn't know how to use the GPS he took to tell people his location. He died.

source: http://en.wikipedia.org/wiki/Adelir_Ant%C3%B4nio_de_Carli

speeq• 12 years ago

"In 1982, Larry Walters flew across Los Angeles in a lawn chair lifted by weather balloons..."

I watched an old episode of MythBusters last night on YouTube where they tested exactly that, it was Season 1 Episode 3 - if anyone is interested.

ademarre• 12 years ago

There's also the wonderful Australian romantic comedy film Danny Deckchair. Danny flies away from his problems in a deckchair-balloon aircraft.

http://www.imdb.com/title/tt0337960/

lutorm2• 12 years ago

He seems to make it unnecessarily complicated. Average thrust (momentum flux) is m_bullet x v_muzzle x fire rate, which needs to be higher than m_rocket x g for it to work.

dietrichepp2• 12 years ago

The point here is to advertise Mathematica, not to solve a problem.

damoncali• 12 years ago

Trivia: the rifle's momentum comes not only from (M_bullet x V_bullet), but also significantly from (M_gunpowder x V_gunpowder). The burnt gunpowder is often 1/3 to 1/2 the weight of the bullet, and traveling faster than the bullet.

cmsmith• 12 years ago

This analysis and the xkcd one linked below both neglect the concept of staging - which could get you higher. As a first order try you could replace the human on the bed of guns with a smaller bed of guns supporting a squirrel - now you're twice as high! Of course at that point there is nothing stopping you from reaching the moon except for your gun budget and how much unobtanium you can get for the bed connecting structure.

lmm3• 12 years ago

Come now, everyone knows you use asparagus staging for this kind of thing. What happens when you start jettisoning empty machine guns as you go?

maxerickson• 12 years ago

The ammunition mass is a more effective way of increasing your stored energy than extra rifles, so it is at least addressed implicitly in the section that examines the ammo to carry (1 gun with 2 bullets obviously beats 2 guns with single bullets, I guess more complicated situations would follow).

You always want to fly with the minimum number of guns necessary to provide your desired thrust and then as much ammo in addition to that.

lmm3• 12 years ago

Yeah, but the optimal amount of thrust need decreases as your mass decreases.

xasos• 12 years ago

There is a game that puts this into concept called Jetpack Joyride (made by creators of Fruit Ninja): https://appsto.re/us/TybrB.i.

My physics class actually did a lab report to find the relationship between the # of bullets and distance propelled in the air with the game. While it was nowhere near as accurate as this simulation, it was definitely interesting to see the results.

bitwize• 12 years ago

An automatic-fire weapon in Cave Story also allows you to fly by firing it downward (though there is a separate jet pack item available as well).

Flying with Machine Guns?

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