Firing the Flak 88mm on Mars - ballistics, history and worldbuilding

I calculate ballistic trajectories for the famous WW2 88mm Flak artillery piece on Mars. I also explain atmospheric drag and the Coriolis force. I touch on what projectiles would do on a fictional planet (worldbuilding).
Contents:
00:00 - Introduction
01:13 - Firing artillery
02:27 - Gravity
04:11 - Drag
07:08 - Coriolis force
11:41 - Worldbuilding
14:17 - Summary and tidbits
Sources:
[1] TM E9-369A Manual: www.lexpev.nl/downloads/tme936...
[2] Earth atmospheric density: www.engineeringtoolbox.com/st...
[3] Mars atmospheric density: www.grc.nasa.gov/www/k-12/Vir...
[4] Map plotting scripts by David Eccles: en.wikipedia.org/wiki/User:Gr...

[@ImprobableMatter]

A version of this video (and all my other educational ones) without background music is available on my DailyMotion: www.dailymotion.com/video/x88zs2z

[@danailvalov7246]

9:41 , its the opposite if im not wrong. the shell moving with the rotation of the earth will go less distance from its original point because that point is moving towards it. if shot away from earths rotation it will go further because the point from which it originated is going away from it.

[@derpythespy]

now do a version with SCHWERE GUSTAV cannon lol

[@BrettonFerguson]

Wouldn't you also need an oxidizer in the shell to make the propellant burn since there is almost no oxygen in Mars atmosphere?

[@derpythespy]

@@BrettonFerguson According to some sources, even in an environment where no oxygen is present, modern ammunition is able to fire due to them containing their own oxidizer, which is needed to trigger that explosion of gunpowder. or so i heard

[@BrettonFerguson]

@@derpythespy Yes some does. I think the 88 Flak used Diethylene glycol dinitrate powder for the propellant. However I don't know much about it, and all I can find about oxidizers is "Nitroorganics, such as DIETHYLENE GLYCOL DINITRATE, range from slight to strong oxidizing agents" So it definitely has some. I'm just not certain if it would fire the same in a zero oxygen environment. It seems like it would. It's not like on Earth oxygen is flowing into the barrel. We need to test this. Bring the 88 to the vacuum chamber sofort! Die Eroberung des Mars wird unser größter Sieg!

[@nevermindthegermans6242]

It had never even occurred to me that I would, for some reason, visit Mars without my trusty Flak 88.

[@michaelwoods2672]

While mars is extremely cold, I believe the very low air pressure would make it much harder to cool the weapon once you started firing it as most of the waste heat would be lost to passive convection on earth. So not only would it likely be difficult to get the gun to work at sub-artic temperatures, but you wouldn't be able to fire as many shells before it overheated and would have to wait a very long time for it to cool down again. You would be losing heat through contact with the freezing ground and starting from a much lower temperature, however, which would counteract the less significant air cooling at least a little. Thermal management would probably be a bit of a nightmare on Mars, with equipment at serious risk of overheating when it's operating at high power and underheating (for want of a better word) when it's at low power or idle.

[@TheAmericanCatholic]

This would be a disaster for machine guns

[@filipkossakowski2467]

This is a really interesting topic. Heating up is relatively easy as some electric heating mates or wires can be placed around the gun. As for cooling, I can imagine "water" jackets connected to a radiator dug into the ground. For stationary applications like AA guns, this should work nicely. Guns on Mars would also be much more potent weapons in comparison with rockets. Battleship-size cannons would be able to hit targets hundreds of kilometers away for a fraction of a missile price.

[@HappyBeezerStudios]

martian warfare would probably come up with fast switchable or multi barrel solution earlier than on earth.

[@jedihunter176]

I wonder how the guns in The Expanse solve that problem.

[@X4R2]

A relatively high-tech world could utilize geothermal powered heat pumps to cool the barrel. That is, install a coolant loop in the cold ground and hook it up to a heat exchanger welded to the barrel. They could optionally include a powered phase change heat pump to modulate and accelerate cooling. Installing the coolant loop into the ground may be difficult, considering frozen hard earth, but a potential design is a hollow hardened metal pile that can be hammered with tools or driven with controlled explosives.

[@kebman]

You'll be interested to know that I was on an exercise where the G3 (Norwegian version AG-3) was fired in -42 degrees Celsius. The biggest problem was the plastic butt-stock which would easily crack in such cold. The second problem was that the soldiers could never touch the butts-tock with their chins, lest they would instantly get severe "freeze burns." I just took photos during the thing, and it's some of my best photos to date. The lens froze solid as I kept working, so I had to thaw it on the AC of a running Gelenderwagen nearby (all cars were to be kept running in that cold).

[@a64738]

Was a short trip across the border from Neiden to Finland shopping and encuntered -40c there. Did not dare to stop the car engine and the steering froze on every straight line you drove where you had to use force to get the steering unstuck to make a turn... Lot of things stop working normally at such cold.

[@accelerationquanta5816]

Thank god for global warming. Disgusts me that earth can even get that cold.

[@TheZebinator]

@@accelerationquanta5816 ⭐

[@hosmerhomeboy]

Having done construction work at these temperatures, I can tell you that all sorts of problems occur. Wood cracks and splits sometimes, airnailers get condensation which builds up and locks the safety open, allowing them to just keep going off. Steel is brittle and breaks. The ground is like iron. Machines have far more mechanical problems. Trucks often have battery issues. When anything encounters groundwater, it is instantly frozen. The leather aprons we wear turn hard and can cut you. The nails become difficult to handle with any type of glove that is useful. Often they simply freeze together in a ball. Any metal you touch will tear off your skin. Everything hurts more. Extension cords are brittle and stiff. And that's all just for starters.

[@WhenDoesTheVideoActuallyStart]

@@accelerationquanta5816 I wish you a merry 50°C summer

[@mixer5557]

"I took ballistics in school, fascinating subject. Things go up, things go down!"

[@13deadghosts]

12:04 If Warthunder ever introduces a Mars map, I will be a better shot there with my Flakbus thanks to you :D What a great video to stumble upon, have a nice day and greetings from Germany :)

[@Ghostmaxi1337]

There was a Space event.

[@HailAzathoth]

Now imagine the range of a 456 mm naval cannon on mars....

[@user-qi6pv9jh7o]

Or Dora.

[@asandax6]

It'll probably just go to orbit

[@EgnachHelton]

Paris Gun

[@brunos6599]

@@EgnachHelton Who was in paris?

[@EgnachHelton]

@@brunos6599 it's a huge German railway artillery that can hit Paris from Germany.

[@fokjohnpainkiller]

This channel is such a gem. I'm in the process of watching all the previous videos to the fusion reactor one and I'm just stunned at how simple the Coriolis effect explanation was.

[@mikedrop4421]

Me too. The computer explanation was top notch.

[@badmonkey2468]

yup this really is good work

[@MightyElemental]

this went waaaaay more into detail than I expected

[@Wizard_Pepsi]

Everyone who has a physics degree: "Trust me, it gets worse."

[@Revelations-cp6if]

I was taught manual cannon gunnery during my time at Fort Sill. Watching this video, especially the parts about compensating for the earth's rotation and air density, gave me a lot of flashbacks of the instruction lol. Awesome video, I really enjoyed it.

[@rosecityrower]

I would think that in a near vacuum like on mars, muzzle velocity should be higher, as the shell doesn't have to push air down the barrel as it travels.

[@ImprobableMatter]

Totally true, I mention it at the very end: didn't have the time to simulate it, and would need to make some assumptions.

[@zazugee]

it would yes, but not too much, because the pressure of the expanding gas is order of magnitude higher than ambient pressure usually chamber pressure will be in the 2000 bar range so,

[@miguellopez3392]

@zazugee take into acount that the air infront of the cannon compresses to higher pressure as the shell tries shoving it out, the only disadvantage I can think of is that it may make the shell faster relative to the burning expanding gas/propellent making it less efficient in building pressure behind the shell.

[@iivin4233]

I'm thinking the viscosity of the fluids inside guns' recoil tubes would cause problems. These recoil devices often work by compressing air with that oil. The lack of atmospheric pressure may make the those air vessels leakier. The cold of Mars could turn the fluids compressing that air solid or thicken them or possibly cause their constituent ingredients to separate. I'm not an engineer though so I have many questions about what specifically Mars would do to recoil mechanisms. Thinking about small arms brings to mind issues of metal fatigue, the muzzle velocity issue you brought up, how well the friction of feet could keep person from being blown off of them by their own weapon. Air cooling too. What even happens with that? Is it better on Mars because of the temperature gradient, or is it worse because there is less air to conduct that heat? Ray guns. That's the Martian way of war I say.

[@alexanderray77]

@@ImprobableMatterThe channel ‘Smarter Every Day’ has a series where they built a supersonic baseball cannon. It utilised a partial vacuum in the barrel to significantly increase muzzle velocity.

[@Luke-mr4ew]

Have you tried watching The Expanse? It pays attention to these sort of effects making its worlds feel incredibly lived in. Even something as trivial as pouring a drink when living on the inside of a spinning asteroid causes a Coriolis effect

[@ireneuszpyc6684]

you're very wrong: I have read the first novel (Leviathan Wakes) - it's full of nonsense (from scientific point of view)

[@Xandros999]

@@ireneuszpyc6684 Even if the books are full of nonsense, he's talking about the show.

[@meisterproper8304]

@@ireneuszpyc6684 can you give examples?

[@ireneuszpyc6684]

@@meisterproper8304 many paragraphs can be written about it; an alien molecule mutates a teenage girl's body: and then while she's half-conscious, she's steering a space ship, which has such an acceleration that no human space ships can keep up; Leviatan Wakes can be compared with Wakanda (Black Panther) franchise

[@meisterproper8304]

@@ireneuszpyc6684 well, it's still science fiction. Overall the franchise tries pretty hard to make sense. It explores stuff like 1. The effects of gravity being absent or reduced, leading to humans who can't live on earth anymore 2. Mars marines training in increased gravity to simulate fights on earth. 3. Producing artificial gravity on space ships by building them like towers 4. High automatisation on earth leading to the vast majority of people being unemployed and relying on the government 5. Effects of G-forces on the body during combat manoeuvres That's just what i can remember from the top of my head

[@democratie_et_esprit_critique]

If anyone is wondering what is the hidden text, at the end of the video: “One could say that their dictatorial ways are worthly of the original operators of the Flak 88”

[@Unassuming_Gay]

lmao

[@nikolatasev4948]

Quite interesting. I was about to mention that the muzzle velocity would be larger due to the lower pressure in front of the projectile, but you mentioned it at the end! Another thing is that the barrel would need to be stronger, because the pressure difference between the inside and outside would be larger - but 1 atmosphere among hundreds would probably not be as important. We already have a low-gravity high-pressure body in our Solar System - Titan. A human could fly using his own muscle power there. Another interesting consequence of low gravity I have rarely seen discussed in fantasy/sci-fi would be lower grip. When you start running you depend on the grip on your feet. Lower gravity means lower force pushing you down. You would need to lean forward more, but even then it would be much easier to slip if you push back too hard. So you could jump higher, possibly run faster, but gain speed slower. Unless you can push yourself away from a vertical obstacle, you would have a harder time dodging things. On a higher gravity world cars would have much harder time managing inclines, but could take turns at a much greater speed. The downforce we get here by spoilers they get simply from gravity.

[@44R0Ndin]

So cars on Titan might have aerodynamic features intended to create downforce as a simple "that's just how we need to build them here to make them work right" kind of thing. And on low or micro-gravity worlds and space stations (such as inside a habitat where a small amount of "gravity" force is provided by rotating the habitat at a slow speed), wheeled vehicles could probably use permanent magnets in the tires to create the needed downforce to ensure stable turning and handling at reasonable speeds. IIRC the carts on the "generation ship"-cum space station operate with magnets in the tires for this reason. However, if you do manage to overcome that downforce, the vehicle is gonna float off into free space until it finds something to stick to. Of course, this leads to an interesting method of preventing these vehicles from going where you don't want them to, just set up a moving band of magnets in the floor combined with a lower traction non-magnetic surface such as UHMWPE polymer to physically catch and drag the vehicles away from where they're not wanted no matter what the propulsion systems of that vehicle have to say to the contrary, without having them become disconnected from the flooring system.

[@saelesbonsazse9919]

OVER 9000!!! Man, I laughed out loud!! Amazing!!

[@krzysztofnawrocki9958]

seems to be a great, new up-and-comming channel. keep it up!

[@jauntyjaun]

this must be one of the coolest video titles on youtube

[@gregwilliamson3001]

Thank you for going to the effort of doing these equations. This is something I have always assumed since my teens, but have never come across answers anywhere near this interesting and helpful. 👍🏻

[@richardmarkham8369]

Interesting stuff. I use a program called Hawke Chairgun to work out drop and dift of airgun pellets. Amazing how much a tiny bit of crosswind will ruin a shot! Thanks for explaining Coriolis effect too. I will see if my mate, an ex gunnery instructor, remembers teaching this!

[@RavensEagle]

This is an absolutely amazing visual on explaining ballistics. Thank you for this video.

[@Zedul]

My grimdark fantasy novels are set in a baroque period, with early muskets -- since my world is 1.33x the size of the earth (but less density), it has 1.15x the mass and hence gravity. I consider this with all ship battles, artillery, arrows, et., and even the weight of many longer weapons like spears, pikes, halberds, etc. I also think about how gunpowder would work in a world with a slightly different atmosphere and gravity, and I still need to sit down and work out all the appropriate cycles with two moons...

[@matthieugeorgelin5671]

If it has 1.33 times the volume and 1.15 times the mass, it only gets about 1.046 the gravity at the surface. This would barely change a thing. Variations in the gravitationnal field of earth can already be of 5% depending on the rocks composition beneath you and the proximity of mountains or such. Don't overthink it, it's basically the same as it is on Earth. Now if it's 1.33 the diameter of Earth, the gravity is actually lower than Earth for 1.15 the mass. Gravity at surface for a constant average density is a linear function of the diameter/radius, as gravitationnal force is a x² function and volume (therefore mass) a x^3 one.

[@Zedul]

@@matthieugeorgelin5671 Thank you so much. Years ago, while taking physics for my engineering degree, I realized that the ocean waves would be larger on my planet. I lost those notes, and I could not figure out how I calculated those waves - this probably explains some of that.

[@matthieugeorgelin5671]

@@Zedul Ah yes, the waves could indeed be higher. Waves are really complicated stuff that involves a lot of fluid mecanics, but you can assume if gravity is the only thing that changes, they will be higher overall.

[@iotaje1]

One interesting thing to take away from that video is that on mars, artillery can hit you almost a continent away. This means artillery would never need to move, can be built into fortified cities whose entire purpose is to feed the gun to lob bombs at another city thousands of kilometers away.

[@hztn]

I was mistakenly clickbaited somehow thinking about theoretical project of sending a superhuge artillery shell from Earth to Mars. But found an entertainment scientific basics, which every artillerist must know (also a snipers too), and listened to the end with pleasure. Thanks!

[@Choochificational]

keep it up man, this stuff is fantastic

[@TheLadderman]

Really awesome video, I love ballistics and worldbuilding. I was about to subscribe when I realized I already was lmao. It looks like I subbed because of your breakdown of Helion. I do hope you make more videos on this kind of stuff, because I absolutely love the technical side of worldbuilding.

[@cabanford]

A very random, but extremely well done and interesting video 🙂

[@stevenwilgus8982]

Odd but extremely fascinating topic. Kept me engaged the entire time....well done!

[@AA-dn8dj]

Wow this is amazing! I remember a conversation several years ago on a weapons forum on how a lower gravity planet with less atmosphere being a long shot's dreamland due to there being significantly less drag from air resistance and thus less variability due to wind(depending on planet). Shooting 1 moa at 5 miles would be less of a dream and more of a reality for dedicated antimaterial cannons.

[@Geezer_Gun]

Very interesting subject. Edger Rice Burroughs did address some aspects of a fantasy Mars in the John Carter series, albeit wrong assumptions. On another point, spin of projectiles, rpm, spin stabilization, etc. powder type, weight, temp, burn rate, are all factors to think about. Lots to think about. Thank you for bringing brain power to KZbin.

[@DSlyde]

I don't know why this was suggested to me now, but it was an excellent video. Loved the world building bent to a physics problem.

[@andrewcockburn3227]

I once had an assignment to describe the physics of H.G. Wells’, “War of the Worlds” and I attempted to describe the ballistics of the Martian cylinders being shot towards Earth. I wish I had been able to describe the process as clearly as this video.

[@SW-qr8qe]

Good work, keep making videos!

[@nuklearkhaos115]

This Video immediately made me think of the book War of the Worlds by H.G.Wells; in which the martian's craft are cylindrical shaped objects fired from what are basically massive cannons.

[@handlethisshitainttwitternigga]

one of the few actually interesting algorithm recommendations. thinking i wont see another on the same level like this again.

[@Fanny-Fanny]

This was really, really good. Subscribed!

[@keithbyrne1]

Great work, nice channel

[@jasonfernando7352]

Awesome... i really enjoy ur work, could you add more sort of calculations in upcoming vids such as how to calculate the drag coefficient of bullet. And thank you for making youtube quite interesting again. This is some real quality content.

[@DanielDaCat]

Your voice reminds me of Dune's scene where Paul is looking at stuff from Arrakis in his quarters. Very pleasing to listen to.

[@kirawr8064]

"Over 9000 thousaaaand" 🤣🤣🤣just great

[@TiSnDd]

"over nine thousand!", Absolutely brilliant video, I liked the explanations and everything else :).

[@JackMott]

My grandather was one of the people calculating those ballistic trajectories on the first computers. He never seemed to think it was a big deal, mentioned it offhand in his 80s. And I was a computer science student!

[@wolfgang4488]

wow, this is a great video!

[@MemeMarine]

I'd like to know how ballistics would be affected on a ringworld or hollow planet - would the geometry make shooting artillery substantially different?

[@pyramear5414]

If you have a hollow planet (a big hollow sphere) there would be no gravity on the inside of the sphere as gravitational forces cancel out (assuming constant density of the planetary shell and that it doesn't have a seperate core). This would lead to an area of atmosphere, but no gravity, so you can imagine objects getting stuck in the middle just floating in air.

[@zuthalsoraniz6764]

A Niven ring is large enough that the only effect from being under spin gravity would be that the Eötvös effect is opposite - shooting spinwise increases the apparent gravity on the shell and thus makes its trajectory lower and shorter, and vice versa. It gets really interesting if you instead situate the exercise in a O'Neill Cylinder. At a radius in the low to mid tens of km, the tangential velocity would be of the same order of magnitude as the shell velocity, which means that inertial effects become very significant, leading to quite weird trajectories.

[@Sekir80]

Great video! Props for the pronunciation of Eötvös, almost correct!

[@holandreas]

Really cool video! I think what might be missing to make the two graphs in 15:40 fully overlap is the influence of wind velocity.

[@WildBillCox13]

1st class content. Liked and shared.

[@OceansideSpiderHouse]

My brain translated the video's title to "Firing (up)on Mars" and within that instant I remember the famous line of Dr. Samuel Hayden: "You can't just shoot a hole into the surface of Mars."

[@gentlydirking4912]

Wow that was really interesting! I came in thinking "firing on mars" meant like, firing AT mars.. I think because I heard some trivia recently about the USSR firing at venus one time. Really liked the worldbuilding segment, I've been getting back into worldbuilding after finding a podcast on it. This gave me some great knowledge to consider, cheers

[@zelda_smile]

how could the ussr fire at a planet?

[@olivermarden2433]

The video I didn't know I needed

[@markus4925]

Great video 👍 thx

[@shadowraven3253]

Just to note here that I get this recommended out of the blue without watching anything like it one year after release and am pissed that it only shows now!!!

[@edwardgreenough1686]

Excellent video. Please read the three body problem or ball lightning. The author is excellent at creating sci-fi worlds exploring life govened by slightly altered scientific and engineering principles.

[@StephenGillie]

Those titles are very vague, as both are widely studied phenomena. Fun fact: Lagrangian points are solutions to the 3-body problem.

[@tolbryntheix4135]

@@StephenGillie I think he meant the books that go by that name.

[@StephenGillie]

@@tolbryntheix4135 Good luck finding them among all of the other books on those topics. SEO has changed Google from a friend into an enemy. Will AI save them?

[@saktisukmapersada1799]

youtube recommendation at 3am is wild and i like it

[@DeprivalAllStar]

Very Good, i like more pls

[@PutitinDaramen]

this is pretty cool.

[@Rationalific]

Interesting and informative video! Vegeta would be proud.

[@s.jackson502]

I never in my life contemplated, "hmm, what about space howitzers?" and yet here I am fascinated by the info and presentation. Well done. Way to suck in the WW2 nerds, u clever bastard!

[@marcelthevirginian1656]

They say learning should be a fun experience for the students. Please teach more science with Flak 88s and Panther Gs.

[@empty5013]

one interesting thing you didn't touch on, it would be much harder to use artillery at close range since aiming high to avoid obstacles would result in unusably long trajectories. you can of course get around this by lowering your propellant load, which might be an interesting thing in a setting like that, close quarters combat can use low velocity artillery, but you can blow up a city from half a continent away with high velocity artillery. maybe they would figure out MAD faster than we did in such a setting.

[@lc1138]

Thank you very much !

[@mvmcali6900]

I never like when we call cureolus a force. I think it's better when we call it an effect . You can bring a ball on merry-go-round with a friend and see it in action

[@ImprobableMatter]

Fair enough. I did make it clear that it is sometimes called a "fictitious force".

[@bo_bb1442]

I think we need to pay thanks to the brave men who travelled to mars to test all of this in the first few video clips.

[@tg13fire]

Omg I'm in the Canadian artillery and a conversation years ago about shooting a howitzer on the moon and seeing if it would enter orbit and land back on the gun from the rear. We never finished the debate

[@cornkobmansanto17]

Super cool

[@SimonAmazingClarke]

Very interesting

[@NoahSpurrier]

Fun stuff!

[@brianhirt5027]

I love this video. I'm always thinking of how unique physics shapes a story narrative. For instance, I'd love to write a high action drama set around the equivalent of something between the Dakar & the america's cup but set in Venus's upper atmostphere. Hypoithetically you could hold a race around the equator in an 'air yacht'. The dense lower atmosphere would theoretically allow for an airship that would, I think, look a lot more like an airplane in some ways, and a ship in other ways. A TRUE AIR-SHIP. The same concept of displacement holds true as would some concepts of lift & fluid dynamics. High stakes drama. Every ounce of weight would have to be calculated for. The unique fluid dynamics would allow for something like 'boost sails' that could be deployed to gain acceleration, but at a great risk of a crosswind flipping you vertically so you plummeted to your death in the inferno below. ANY Failure equals death. Body unrecoverable. Due to the atmospheric effects radio telemetry could be haphazard. There would be a lot of opportunity to eliminate competetors very directly with no way of proving it wasn't mechanical failure. Say, a race held once a century, with a substantial prize making it the risk worth it. An X-prize style contest between the various system colonies alongside the national representation from the declinining population old terra. A reward of, say, a hundred year contract to build autonomous crafts harvesting Jupiter & saturns vast rich gas feilds to be compressd for the outsystem bound colony ships at each giants L4 & L5 (like 624 Hektor) 'filling station' with each centurian winning design. The kind of contract that ciould make or break a financially struggling colonies. High stakes stuff, running the gas stations of the interstellar future, i'd think. Love to hear your thoughts. THis is just a speculative outline i've dallied with for years.

[@hedgehog3180]

I think one interesting possibility would be that the side to the west or "upstream" in the rotation of the planet would have a decisive advantage in artillery duels. When we're talking about several km in range difference then that is enough to actually matter since there will be some sort of engineering limit to the range of artillery. It'd be a similar sort of advantage to being upwind from the enemy in an age of sail naval battle or having the high ground. Armies might seek to maneuver to put themselves west of their enemy, this mutual maneuvering might mean that most battles would take place along a North-South axis. Something kinda similar has happened irl where armies fighting at dawn would seek to position themselves with the sun at their back to blind their enemies.

[@sevenodonata]

Easy subscription! :D

[@blas_de_lezo7375]

science to improve fantasy or scifi worldbuilding I LOVE IT! more!

[@BonkerzGamer119]

this video is strangely all my interests: world building, ww2 and math/science

[@milobem4458]

Coriolis effect does not depend on the azimuth of fire, only the location. All moving objects in the North Hemisphere are deflected to right. If you fire north it will deflect to east. If you fire east it will deflect to south, etc.

[@ImprobableMatter]

Not if you're shooting east or west. If you don't believe my explanation, how about this one: "For the Northern Hemisphere, if you shoot North or South of the target you will likely hit right of it. ... Shooting in the East will result in a high hit and shooting West results in a low hit." Source: www.laxrange.com/explaining-coriolis-effect/

[@milobem4458]

@@ImprobableMatter Sorry but shooting range in LA is not a source for laws of physics. Their website reproduces a very common misunderstanding of the Coriolis effect, because of the usual intuitive explanation. In reality, Eotvos effect is an additional one, but Coriolis still shows in all directions. When shooting north, only horizontal component of the Coriolis effect manifests. When shooting east, we still get a horizontal Coriolis, and additionally a vertical Eotvos. Wikipedia article has a paragraph about ballistics with the complete set of the equations. Eotvos is strongest at the equator and null at the poles, while the Coriolis is the opposite. When firing horizontally in LA, Eotvos about two times stronger than Coriolis. In northern Europe is close to the opposite. en.wikipedia.org/wiki/Coriolis_force#Ballistic_trajectories

[@ImprobableMatter]

@@milobem4458 OK, then maybe I don't understand what you mean. The equations in the Wikipedia have an azimuthal component, agreed? In any case, I used the general formula for motion in a rotating frame (something like at the top of that Wiki article) for the calculations I presented.

[@milobem4458]

@@ImprobableMatter But we are talking about this component: Az = 2w * Vx * sin(lat) which means all objects deviate to right, depending on the horizontal velocity and latitude. This is what most people call Coriolis force. Eotvos effect is described by the component: Ay = 2w * Vx * cos(lat) * sin(az) the other components describe effects of vertical velocity Vy (which doesn't apply in an urban shooting range, but they do in indirect fire artillery), and cross-range velocity Vz (which comes into play in long range artillery)

[@ImprobableMatter]

​@@milobem4458 OK, so the way Wikipedia defines it in the ballistics section is confusing. Look at the original definition with F'= on the left hand side. Ignore the first and last terms, as it explains these are the Euler force and centrifugal force. We have F'=-2m(omega x v'), where I am using x for the cross product. The angular velocity omega is a vector from the center of the Earth out through the North pole. Now, imagine v' is East or West, so it is perpendicular to omega. Apply the right hand rule for the cross product and it is strictly perpendicular to both - up or down. I believe I am right and that the wording of the ballistics part with regards to "downrange" and so on is confusing. Furthermore, I coded the full Coriolis force into the simulations and it agrees with what I am saying.

[@knightning3521]

wow i just discovered your channel. i would have loved an estimation of the additional range gained due to the larger effective force on the projectile due to lower air pressure.

[@ImprobableMatter]

I wish KZbin had a better text discussion. This is something best discussed out of a video, plus people more knowledgeable about the barrel pressure can give me some pointers.

[@frankwalder3608]

Your video is one of the most informative and thought provoking I have yet seen on KZbin. I am currently working on a fictitious world for a science fiction novel. It has about half the gravity of Earth, and about twice the atmospheric density. Would the world's(it is a moon of a gas giant) average surface temperature of -200° C, and high radiation, especially X-Rays, and Cosmic Rays make a difference for that 88mm Flak gun? Would the world(moon) being tidally locked to the gas giant make a difference? Finally, its atmosphere is primarily hydrogen and helium. Would that change any of the equation compared to Earth's oxygen-nitrogen, or Mars' carbon dioxide?

[@ImprobableMatter]

Glad you enjoyed it! A few things: half the gravity and double the (surface) atmospheric density of Earth is perfectly possible. A couple of implications which jump out, however; with so much atmosphere, it is likely that the surface temperature would be higher. Mars is cold because it has a thin atmosphere, though a H/He mix would not be as insulating as a corresponding atmosphere containing CO2, for example. I do not readily have the tools to get the opacity (which is what determines to what degree the atmosphere would blanket the moon), but it's something to think about. Then again, the planet+moon could be really far from the host star(s), or the latter could be very dim. The atmosphere would be a great protection against x-rays and other cosmic radiation - they should be absorbed even more than on Earth. As for ballistics: the barrel velocity would be slightly lower than on Earth, because of the higher pressure pushing back as the gun fires. Someone pointed out in the comments that cooling would be a problem with as little atmosphere as Mars; for this moon, that should not be a problem. Other than being affected by the differing drag/gravity effects as mentioned in the video, there should not be many other changes to ballistics. I assume that the tidal effects make the sidereal day quite long, meaning the Coriolis effects should be minimal.

[@nemofunf9862]

Glad we got that off the table.

[@user-bm2qf6qw4z]

I guess you can't just ignore the curvature of planet: shell would fly about 3° longitude. Great work. Thanks.

[@domesday1535]

to know if the cold would interfere with the weapon's function you would need to know some properties of the steel used. Particularly the coefficient of thermal expansion and DBTT and tensile properties at those temperatures. The first two failure points that come to mind would be either the bore shinking and seizing the round, or the barrel outright exploding and fragmenting due to the different material properties at low temperature

[@bloodypommelstudios7144]

Would it be easier to dodge projectiles on a low gravity world though? Sure you can jump higher but that just puts you on a predictable ballistic trajectory and conversely ducking would be slower. With lower gravity you also have lower friction so lateral and angular acceleration would be more difficult. This isn't to say you couldn't have some interesting effects regarding mobility though. Off the top of my head human powered flight with medieval technology, parachuting with much smaller backpacks Using wings to run up walls, depending on air pressure having easily survivable terminal velocity. It would also change a lot of regular movement considerably for example needing running around a corner would require you to practically lean over sideways to stop centrifugal force throwing you over.

[@ImprobableMatter]

Really good points.

[@Navak_]

now this is the niche content i want

[@THE_ONLY_REAL_WAFFLE]

Nice

[@LNgKhoi]

Another interesting random recommendation popped up on KZbin. This reminds me that a few weeks ago, I had an idea of a sword whose density is so dense that it visibly attracts stuff around it. I talked with some guys and made physical problems to determine its... "probable" weight -- some guys even calculated the energy output for its average swing.

[@floseatyard8063]

If that sword was so dense and had that much mass (it attracts objects by gravity) which means that it would have more gravity THAN THE EARTH the sword would just fall out of the users hand and crash into the earths core if you are talking realistically

[@LNgKhoi]

@@floseatyard8063 Hm, good point. Now I wanna see what happens

[@floseatyard8063]

@Lưu Nguyên Khôi yeah you don't have to be realistic anyway, it's your story.

[@rags417]

There is actually a computer game called Interplanetary in whihc players fling giant asteroids and rockets at each other within a solar system. The game is simple and somewhat unrealistic (they don't have computers to calculate these trajectories ?) but it it is fun watching players aim for one planet and hit another !

[@ImprobableMatter]

It's on my Steam wishlist, I believe. Haven't checked it for a while...

[@jamespike5161]

FASCINATING SUBJECT. Things go up, things come down!

[@StephenGillie]

Bringing John Carter into the ballistic age! Mars and Earth have about the same amount of CO2 in the air. But Mars doesn't have all of the dioxygen and dinitrogen.

[@Matygos]

From knowing the mass and muzzle speed of the bullet and approximating the volume of the chamber and barrel you can calculate the pressure curve that has to form there to deliver that amount of energy. Or putting it both earth and mars atmospheric pressure into one equation could theoretically cancel the guns pressure out so you would just get how many times would it go faster.

[@ImprobableMatter]

That is true, but I don't think it's possible to uniquely identify the pressure curve (multiple curves would yield the final known muzzle velocity). Some assumptions have to be made, or better yet additional information could be found to constrain the problem, e.g. the maximum barrel pressure.

[@fuzielectron5172]

Seem the thumbnail, one minute in and the nerd in me is hooked.

[@Valkija]

This is extremely interesting stuff! This is the first video of yours I've stumbled across and I am so glad I did - this is exactly the kind of thing I like to think about when approaching my worldbuilding. I'm working on a setting in which the planet is earth-like in most aspects except it is twice the size yet half the mass. The force of gravity on this world would remain the same as on Earth, but presumably this means the effect of the curvature of the world would be much less pronounced. In addition, with days of similar length to those on Earth the planet's spin must be faster, causing the coriolis and eatvos effects to become much more pronounced. Am I right to assume this would mean that the geographical location of artillery pieces would be much more important a factor in ballistic calculations, but that they may be slightly more predictable at longer ranges because of the reduced curvature?

[@ImprobableMatter]

If the days are the same length, the Coriolis effect would be the same too (it depends on the period of rotation, not radius). With the planet curving away slower, the range would be slightly smaller. Assuming air density is the same (there would have to be a larger total amount of air), things should be fairly similar. With less curvature, there may be some important climatic effects; the Coriolis force is part of the reason that China is wet and fertile and the Sahara is not.

[@Valkija]

@@ImprobableMatter Thanks so much for the insights! You're right, I totally interpreted it wrong! That's a really interesting point about the climate effects, thats something I'll need to build in - which is perfect, I'm at just the right stage to make those sorts of considerations!

[@matthewsmith5104]

You touch briefly on an interesting concept when it comes to the environment influencing technological development. On a world with weaker gravity but a thicker atmosphere, flight would be much much easier and likely developed technologically much earlier, relative to how long it took us to figure it out. Imagine some of the concepts of powered flight dreamt up by da Vinci, except they could actually work in the 1400s. It would have completely altered the timeline of progress.

[@mlamazigh5398]

Amazigh video

[@dougsundseth6904]

Since it seems that you're trying for a certain rigor: Unless fired at precisely the escape velocity, a shell in a vacuum will not follow a parabolic course. Instead it will follow an elliptical course (if below the escape velocity) or a hyperbolic course (if above the escape velocity). The ellipse (the normal case for anything larger than an asteroid) would be that of the orbit the shell would enter if you assumed a point-mass at the center of mass of the planet, and would of course intersect the surface of the planet. At short ranges, a parabola is a reasonable approximation of the elliptical course, though. Also, as your range increases and your planet size decreases, the approximation of the surface being planar becomes less correct. Here, the longest ranged shells would be impacting some 10° around the surface of the planet (assuming my quick estimates are close), which would significantly increase the calculated range.

[@htomerif]

I used to work on (among other things) firing solution computers for the field artillery. In addition to early computers being used to calculate firing solution tables, more advanced early computers and huge computational resources even today are used for weather prediction, that data being disseminated to the field firing solution computers I used to work on. I don't think its possible or practical to use any kind of curve-fitting to accurately aim a modern piece of field artillery at long range. For mortars or direct-fire of artillery against materiel targets, tables are fine, but for everything on the range of miles, firing solutions have to be voxel calculated with the weather data and the appropriate differential equations. We do get some people trying to incorporate actual science or physics or math into fantasy settings with questionable results. The 40k "depleted deuterium" rounds come to mind. There was a Star Trek TNG book though I remember reading as a kid that did have a piece of artillery in it which was a trap: it fired a round that went around the planet it was on and hit its operator. Again, not realistic if it were aimable in any way.

[@rayotoxi1509]

125mm smoothbore gun next would be intresting

[@putzak]

Next do Schwerer Gustav on Jupiter

[@WildBillCox13]

I'm with you on world design. My PatchWorld series is based on my understanding of planetary mechanics, geophysics, cultural anthropology, and the problems attendant to sustaining a reasonable ecology and history inclusive of magic as a potential source of work done in the world. I began the series when it occurred to me that writers write themselves into corners when they design worlds and cultures on the fly. I'm not looking at you, Rowling, but I might as well. Suspending disbelief is easier when the writer is a bit of an explainer as well. Integrating disparate elements without testing their compatibility is, to specify, bad writing. I developed several brand new approaches in result. It's given my novels the sense of comprehensive reason that I believe almost all the rest lack. Also, I never write a story, I never tell a hero's journey or append to my ideas any of that pre-fab approach. I create a world and its geology, its humancentric situations, its cultural history, then assemble characters by means of their backgrounds coinciding, and through their eyes chronicle the successive events. I don't design characters or use them to tell a story. That's for comic book writers and penny dreadful hacks. In fact, PatchWorld began as my Isekai . . . only I showed how it could happen, why characters from different worlds might collide, how majic works if it obeys existing physical laws (there ain't no free lunch, and etc). The world and its place in time and space took up the first year. Since then, I wrote 12 serial novels and never had to check my backtrail for compatibility. I already understood all the components. The gestalt was a pleasure to work in. 4 years, 12 novels of 60K words each, later, I consider PatchWorld to be a worthy artwork. All of it hangs together. I wrote it so nerds would now what to expect, once they knew the parameters. I made the heroes believable characters, their backstories significant. I eschewed purpose built storyline devices or props.

[@PelemusMcSoy]

If a thinner atmosphere means a higher muzzle velocity and a lower gravity means greater range, then I believe smaller arms (like pistols or PDWs) could be more common: ~The guns and ammo would be even lighter to carry (even lighter so on a lower gravity planet). Soldiers would be able to carry more gear before feeling weighed down, have an easier time carrying massive weapons, or simply move faster if carrying the same weight in gear. Plus, they'd be cheaper to produce. ~The increased muzzle velocity would increase the damage potential of the rounds, so smaller rounds could potentially have the same stopping power as the current rounds used by militaries. ~Increased ranges means pistols wouldn't just be a last line of defense (the effective range of a soldier's pistol is said to be "when the enemy is too close to use your rifle"), and shorter barreled weapons would be sniper rifles (which pairs perfectly with lighter gun, lighter rounds, and greater range). Of course if an Earth solider came to their planet, our military guns would likely be seen as massive overkill, but then again there is no kill like overkill!

[@CZ350tuner]

"Muzzle Velocity is fixed" - Actually, in real life, muzzle velocity is a variable, due to various chaotic physical influences, such as propellant condition & burn rate, gun barrel cleanliness, individual shell drive band sealing, etc. This is why some shells fall short or bounce off armour well within their capabilities.

[@PBnFlash]

I'm working on a fiction where I could see using this in an interesting way but I'm struggling a little bit with the math. It takes place on a space elevator with ~ -1G of gravity (Cable material is no issue due to sci-fi magic) Does the much larger sphere reduce this effect to near zero on the Flak cannon scale?

[@ImprobableMatter]

Not sure I understand the premise - is the elevator going really fast? Are you concerned with tension on the cable, or a gun fight inside it?

[@PBnFlash]

@@ImprobableMatter The elevator is held in tension, anchored to the ground at ~2x geostationary orbit. Since it is linked to the ground it will rotate with the earth and create illusionary gravity pointing away from the earth. Like spinning a bucket full of water on a string. My intuition are the effects would be more pronounced, but the large radius may cancel it out almost entirely at the flak scale. Shooting a flak north would probably not show any real Coriolis effect.

[@ImprobableMatter]

@@PBnFlash There are two effects not to be confused. When you spin a bucket of water, a teacup ride, or a centrifuge, you are experiencing centrifugal force. Indeed, people at the equator are doing so now, slightly reducing their weight. Rockets are usually launched from equatorial sites for this reason. If you look at a description of centrifugal force, you will see that it does indeed increase with radius (distance from the axis of rotation). Note that, if the elevator is stationary, the occupants are not in freefall and will still be somewhat pinned to the floor by gravity. Look up the formula for the force of gravity and centrifugal force - Wikipedia will do and seems to have some worked examples. The above holds if the elevator is stationary. The Coriolis effect applies to moving objects such as the Flak shell.

[@zevstewart8607]

This video taught me that even educated people cant help but say OVER 9000!!!!!! I feel validated

[@colemiller2149]

In a fantasy setting I'm using there's gravity magic which can affect the apparent weight (force experienced from gravity) on an object. This effect is far from simple to manifest but you could theoretically have a small super aerodynamic super light bullet all of a sudden weigh as much as a truck if enchanted properly

[@CaptainCarrotzz]

Thanks for the video, very interesting. Would the muzzle velocity change by being fired in a near vacuum?

[@ImprobableMatter]

Yes, it would be higher. I mention at the end that I didn't try to calculate the difference because I'm missing some data.

[@CaptainCarrotzz]

My mistake, thank you!

[@George10767]

This reminds me of Hitler's V3 weapon, intended to fire shells from northern France to London. That project was never completed, but Saddam Hussein started construction of a similar weapon to fire shells from western Iraq to Israel. (The Israelies forcibly cancelled it). The V3 had a very long barrel (perhaps 100 metres long) supported up the side of a hill. It had explosive charges (perhaps about a dozen) up its entire length which detonated in rapid succession. So the shell had an enormous muzzle velocity. It might be possible to launch a projectile into low Earth orbit from such a system.