I'll Show You What Happens When Rockets Don't Have Fins

[@Cynthia_Cantrell]

I learned this lesson the hard way back in the 1970's, when one of my own highly modified rockets went sideways shortly after launch, causing all of us to run in different directions. At that point I went back and read all the info on "center of pressure" and "center of gravity" that I had come across before but didn't quite make sense. After the renegade launch however, the pieces started fitting together and I had an "a-HA!" moment. Physics - it's not just a good idea, it's THE LAW!

[@EstamosDe]

And what about your latest rockets? How did it go?

[@Cynthia_Cantrell]

@@EstamosDe I think it was many years before I did any rocketry after that - as a mentor for some young kids. We stuck to the kits and didn't try anything too dangerous - except perhaps for climbing quite high in a pine tree to retrieve a rocket.

[@bobthegoat7090]

If you are good at rockets, can you confirm something for me? He didn't explain why the center of pressure had to be lower in the video, so I would like to know if my guess is correct. Here is my guess: The center of gravity is like the point of rotation when the rocket wants to turn. When the center of pressure is lower, the drag will be higher on the part below center of gravity compared to the part above it, and thus it will be pushed back to the right orientation, if turned. So, it is a question of whither the point below the center of gravity produces more drag than the part above it. When the center of pressure is below the center of gravity, you are sure that the part below center of gravity will produce more drag.

[@ErickC]

I had a similar experience in Boy Scouts. I made my own 2-stage rocket design and was quite pleased with it. When it launched, it started doing corkscrews and impacted a wall at the school we were flying our rockets at (the wall was in the middle of the large grass field behind the school and presumably for bouncing a ball against). The rocket exploded into a bazillion pieces! I remember that people were offering their condolences. The truth is that I was a little annoyed that the rocket didn't work, but very pleased with the flaming wreckage that had scattered some distance in all directions. I remember saying "what you you apologizing for? That was awesome!" I think I was a demented little kid.

[@chrisfuller1268]

I did the same with a homebrew rocket we made with a multistage motor whose second stage was a bag of gasoline and firecrackers. We launched it from the back yard and time seemed to move very slowly as it headed for the house, barely clearing the roof. Fortunately, it landed in an empty road intersection.

[@tunguskalumberjack9987]

This is one of the only channels I know that 100% deserves it’s large subscriber count. Great content, and a great host!

[@Astromath]

If that's the case, you haven't yet seen most of the best (STEM) KZbinrs like 3Blue1Brown or PBS Spacetime

[@lazymass]

Ypu have a lot to discover then. Lucky you. Wish I was at that point.

[@everyweekmemes9178]

I'm so glad that he's not the type of underrated KZbinr that make Oscar worthy videos for 3000 views

[@rurutherussian]

Watch smartereveryday.

[@wesleymcdowellwm]

You need to watch veritasium

[@BrainfooTV]

This reminds me of one of my first crappy videos when I built foil rockets after being inspired by the king of random when Grant was at his best.( Bit of a copy of his style but I was learning) Without Grant Thompson I would never have been inspired to start KZbin and find my own niche, I will be forever grateful. It took me about 2 weeks to perfect the no fin match rocket, but to my knowledge still the easiest and furthest range of any match rocket.

[@domiepotato]

Now you make none lol

[@BrainfooTV]

@@domiepotato And? A bit like you..but successful lolz 😂

[@allensparks285]

Grant Thomson was an inspiration to many of us. I now have an arsonal.of clothespin guns because of his vids.It's good to hear he inspired you to go a step further.🤘

[@BrainfooTV]

@@allensparks285 Thanks, I think he helped a lot of people without even realising it. Nice legacy to leave.

[@joshuagibson2520]

Yeah, TKOR is awful these days. It's slowly dying.

[@atsumeru3245]

Missed an opportunity there for Kerbal Space Program 😭 e.g. to demonstrate one of the consequences of a finless rocket, with locked engines and no supporting thrusters. Learned it the hard way, to properly fin my core stages, and boosters, when they're needed. It's an excellent game for the channel viewers, and a bit of a shame it wasn't used here, but regardless, still a great and informative video!

[@AJD...]

Absolutely love Kerbal Space Program!

[@chrisfuller1268]

Cool, I keep hearing about kerbal, I think ill buy a copy

[@tejasdixit4417]

@@chrisfuller1268 before you buy it, beware that it is a bit more complicated than usual games. The tutorial is essentially a physics lecture and is hideously long and you would need a lot of experience along with trial and errors just to make a rocket that doesn't immediately crash. So, it is great because it provides realism along with a real brain challenge, but not very reccomended if you are looking for something that gives instant results

[@Jeremy_Moro]

Remember that KSP requires a good PC but it will barely function on laptops (yes I tried it on my laptop)

[@Myndale]

@@tejasdixit4417 or they can just go watch a few Scott Manley videos and be in orbit in no time :)

[@scottmoe6700]

I've always wanted to make a rocket. 38 years old and have never tried it. Now that I'm a rocket scientist, i just might!

[@bunnykiller]

do it, there is quite a bit of satisfaction seeing something you designed and built take off at nearly the speed of sound and reach 10,000 feet. I did a 3" dia 6.75' long 2 stage that made it to 13,800 feet, it ran on a K-500 and a J-125. I made the electronics to fire the staging and chute ejection timer from scratch, custom built the rocket frames to handle the stresses, and it was done back in the mid 1980's ( when Tripoli had just a mere 550 members)...

[@chrisfuller1268]

Are you really a rocket scientist or engineering stuff going inside of a rocket/spacecraft? I worked at NASA for a decade designing spacecraft components, scientific instruments, training astronauts and operating instruments on-orbit and don't think I ever met a rocket scientist. I did work with a couple in defense applications, however.

[@luftwaffe_air_brigade]

@@chrisfuller1268 hello

[@emcllns]

This is one of those underrated bits of knowledge that when you have kids, you look like a genius.

[@jehru5]

Boots of knowledge are never underrated. They give +2 INT.

[@aviatornic2839]

@@jehru5 you're absolutely right, but I usually would rather just splurge for a thinking cap

[@Maxtherocketguy]

@@jehru5 lol I am 11 years old

[@not_available2395]

Definitely dad-knowledge!

[@MitzvosGolem1]

In marine architecture engineering "center of buoyancy vs center of gravity " a point called "meta center" where as center of gravity must be below center of buoyancy or ship/boat capsizes . Similar . Excellent 👍

[@determineddaaf3]

I think he also has a video where he mentions this actually. Pretty cool.

[@SmallSpoonBrigade]

Yes, and boats also tend to want to turn to put the side of the boat facing the wave if you're not careful.

[@zacrintoul]

Pretty much the exact same principal.

[@MitzvosGolem1]

@@zacrintoul below Mach 1 😂

[@J7Handle]

But the center of buoyancy moves as the ship/boat rocks in the water. If the boat’s hull is vertically sloped at the waterline, yes, it will capsize. Same if the slope is negative, like on a submarine or the stealth ship. But rowboats have a center of mass that is definitely above the center of buoyancy, and they don’t capsize because of the shape of the hull. Think: when the rowboat is on dry land, it’s effective center of buoyancy is at ground level, definitely below the center of mass, and the hull is completely curved. Based on what you said, the rowboat should tip over under these circumstances, but it doesn’t. Because as it rocks, the center of the normal force moves. Edit: self righting objects with round bottoms on dry land exist despite the fact that the “center of buoyancy” for objects on dry land can only be at ground level, certainly below the center of mass.

[@its_prince4real]

It's not just rockets you can see it with arrows as well 👍

[@westonding8953]

Just what I thought!

[@_Just_Another_Guy]

So do fish. Their dorsal and top fins help them keep balance and swim forward, even against strong water currents. Without these fins, the fish will just propel in any direction that the local water current is in.

[@0neIntangible]

Darts too?

[@randomfacer6306]

@@0neIntangible darts are some kind of arrows, so yes

[@whydoidodis6829]

yeah, thats why all the twigs that i shot used to go sideways :(

[@samjam77]

So that’s why all my rockets were dog water on kerbal space program

[@konoveldorada5990]

Scientist: *Fins don't affect rocket at all. It's just a decoration.* 100 years later, The Rocket Fish: *Fins go brrr.*

[@yerri5567]

Whats brrr?

[@prich0382]

@@yerri5567 It's a meme

[@yerri5567]

@@prich0382 What does brrr in the meme mean?

[@prich0382]

@@yerri5567 So you know the A10 Warthog? It's got a Gatling gun basically that goes *brrrt?* Well take that concept that apply it to other fast things, like money printer go *brrrrr* which I think is the original or whatever fast occuring things

[@yerri5567]

@@prich0382 Ahhh okok thanks!

[@GooogleGoglee]

I want more videos and explanations about this field and matters! Good one

[@ddogthepimp]

Tf?

[@fisher402]

I've learned so much from this channel

[@I_LoveWriting]

Same here

[@guycha0s380]

Same

[@guycha0s380]

Whoththo

[@Sad_VoBo]

thanks so much... you explain everything so clearly and make everything so interesting :)

[@rgbii2]

When I was a kid building rockets, once we found the center of gravity, we'd put a string around that spot and hold it with tape. Then we'd spin it around over our heads, letting the string out till it was a few feet. If the nose took the lead as we wanted, the center of preasure was behind the center of gravity and it was ready to fly. Just needed to repeat the test if you made any modifications to weight or shape. If you didn't, you got a quick reminder when you launched it :)

[@mikefochtman7164]

We did the same, swinging it by a string.

[@Ozzy3333333]

Be sure to have it loaded ready to fly with a new motor. It works great and is quick.

[@chrisladouceur4093]

Gets much more difficult when you start trying to swing 7’ tall high power rocket around ;) but definitely a great quick and dirty test for low power rockets like the ones flown in parks

[@Svelix]

Much easier and faster way to find the center of gravity: balance the object on 2 fingers or 2 sticks or something and move those 2 fingers/things towards each other. Where they meet is your center of gravity.

[@runic6452]

that can only be done on simple surfaces, like the most famous one, the pencil. however when the mass is unbalanced (ex. you put one of those eraser attachments onto one side) you can't really gauge the total mass and thus also the center of gravity unless you balance it further out onto the "attachment." by concept it just might work cuz it sounds logical but practical applications are of course more complex. i'm not a physicist or something btw, just a regular worker who's fascinated by how things get easier if you understand them more lol

[@Svelix]

@@runic6452 Actually it does work even with unbalanced masses! Try it with a broom, that is quite obvious unbalanced, and you will see it works there, too. The point at which it fails is quite obviously when the surface you are balancing it on changes, e.g. when the center of gravity is somewhere where the fins of the rocket are attached. But for the examples in this video it would have worked perfectly.

[@vibaj16]

@@runic6452 It still works if the mass is unbalanced. It works due to friction: if one finger is holding more mass than the other, the other finger should come towards it, and that happens because the finger holding more mass will therefore have more friction with the object, so it won't move until the other finger has more friction. This method won't work (or at least will be a lot more difficult to use) with an object that doesn't have a more or less one dimensional bottom.

[@Saruman1000]

You’re an absolute mad lad. I can’t believe how many ideas you have for videos without watering down the quality. Everything you put out is genuinely interesting and entertaining and you make like a video a day…

[@3DPDK]

The trick to the shadow method is to account for the total fin area. The shape drawn only accounts for two fins so the tail end is slightly light causing the center of pressure to move forward. At model scales you can just eyeball an extra amount, 1/2 the length of the fin, on the end of the fin profile on each side. With the actual Estes rocket we used to add a few metal washers to the bottom of the nose cone to bring the CG really far forward.

[@glenncurry3041]

What if the shadow was created by spinning the model and drawing the furthest points at any point in the rotation? This would also include any other deformities.

[@3DPDK]

@@glenncurry3041 Imagine if you had four (or more) fins. Even rotating the model you still will only account for two fins. Since this method is to let gravity simulate the effect of wind pressure, your silhouette profile needs the total surface area (weight) of all fins to be accounted for, and in the correct lateral position along the centerline. A 4 fin rocket silhouette would have fins twice as wide as the actual model. Another way would be to cut out the correct number of fins and lay them on a finless silhouette at it's base.

[@glenncurry3041]

@@3DPDK Interesting. I am totally new at this. It would seem there would be a quantity/ density of fins that would at some point be the same as just a bulge in the cylinder? Which compared to an ever multiplying surface area of each, would suddenly drop to just that increased girth? And that could reduce at higher air speeds as laminar flow got wider on each surface?

[@3DPDK]

@@glenncurry3041 This actually works. It works with even pressure in 360°. Not so much a bulge, but more of a flare; like the bell of a horn in the tail end of the rocket. The cons are that it applies a constant resistance or drag even if the rocket is flying straight into the air stream, and at high speeds it creates a huge amount of turbulence in the exhaust stream. The problems on a model rocket is being able to make the shape without adding a lot of tail weight, as in 3D printing it, and difficulty with launch wire clearance. Both problems are solvable, but the constant drag limits rocket altitude.

[@fgbhrl4907]

This is such a cool practical demonstration. Congrats. KSP helped me realize these concepts, but this feels so much more "real".

[@presidentgamingz]

i play SFS 💀

[@unXpectedM]

I have always been interested in rockets but the sheer maths involved in rocket science always made my head hurt. This video helped me understand the basics of design principles of rockets. Thank you very much The Action Lab, loved this video.

[@xcbrr50]

You should try out Kerbal Space Program if you havent played it yet.

[@unXpectedM]

@@xcbrr50 Thanks, I'll try that. And that's a great name you got there

[@mastershooter64]

Lol there's nothing called "rocket science", it's aerospace engineering. Also the math used is actually pretty simple, like 90% of the math is literally just multivariable calc and linear algebra and some ODEs and fourier analysis. That's about it really. And the mathematics is actually really fun!! There's so much good stuff on youtube to learn that math. (Dr. Trefor Bazett on youtube, you can learn the calculus and ODEs stuff. And Gilbert Strang lectures on linear algebra on youtube also buy a good book on those subjects too!) You can easily learn it mate, anyone can! don't get intimidated by it, math is actually really beautiful once you actually start learning it

[@gasun1274]

the math used in aeronautics are some of the most straightforward

[@joyl7842]

8:10 boosters are not at all what you are describing. What you are describing are maneuvering thrusters.

[@SylviaRustyFae]

9:50 I mean yes, but at this pt we are all merely Theoretical Rocket Scientists. We need to go out and make the rockets ourselves to become Practical Rocket Scientists.

[@benuscore8780]

But at least in theory, theory and practice are the same...

[@westonding8953]

How would you account for multistage rockets? When are fins entirely unneeded?

[@scottstewart9154]

this is a great video, I teach 4H kids model rocketry and you gave me good examples of why rockets need fins and explanation of center of pressure and gravity

[@Myrddnn]

If you have the means, show them both fin type rockets as well as the gimballing engine types (SpaceX)....

[@walkermitchell4444]

Stewart😜

[@jurrione]

Why don't they give rockets spin like a bullet or an arrow? For un-manned flight ofcourse. Or maybe not. Give the cabin counterspin, and all shoud be smooth sailing.

[@calvinatdrifterstudio8438]

When I was a kid, all my weird rocket inventions didn't make it very far before spiraling. If I had this video back then, I would probably be in jail or something as a teenager 😂😂

[@Leo_prods]

I love your videos im your biggest fan

[@TheTechAdmin]

9:48 Congratulations, you've now caused thousands of people to experience the Dunning-Kruger effect.

[@35_sankalpshirodkar68]

Guys he is hiding the truth , is.. The rocket will suffocate without fins.

[@bunnykiller]

and the fun thing about it all... the CG moves forward as the motor burns making the rocket even more stable... so, when doing the CG testing, do it with the motor you plan to use or else the CG may be behind the CP and once it comes off of the rod it will go wacky...

[@DrDeFord]

Shadow method doesn’t account for aerodynamic coefficients. Will you be doing a follow up on bullet stability vs rocket stability (spin stabilization/gyroscopic forces vs this Cp vs Cg explanation)?

[@sharonsabu365]

Putting rocket scientist in my resume. I don't know why people say it's hard.

[@specialkender]

Jeeesus man 4M subscribers! I am so happy for you, when i came to the channel back in the days it was small but i was like "This guy got it"

[@demarcuscousinsthe65th]

It is for stabilization

[@A._Meroy]

Thank you for the explanation, that was a very impressive demonstration. Now I'm sure I can build better rockets in KSP.

[@zacrintoul]

Technically extending the rocket body would shift the center of pressure forward more than the center of gravity. Aka making it less stable. This is especially the case since your motor and motor mount is in the back. Usually little model rockets just have a parachute in the front.

[@EchoLostAvakin]

How about show us something that's isn't obvious.. edit - that being said, i do like your videos and I'm just being a miserable sod.. but lot of your vids are just common sense

[@man15h]

@The action lab why 0:20 will there be less air resistance, when there's more area? I don't understand, larger the area more contact with air and more drag?

[@man15h]

I know I'm wrong and there aren't any square facing rockets or of any other shape, but I just can't understand this line, this explanation

[@RajasPuranik]

simply play kerbal space program to understand the whole thing ezily but in pain

[@paprikar]

true

[@malayali_here]

Him : "if no fins, rocket will go side ways" Me : "Then, launch your finless rocket side ways. It may go up😁🙄" Him : "You're now officially rocket 🚀scientist"

[@ericwazhung]

Never thought I might say I'm a rocket scientist! This was far more interesting than I expected. But now I'm filled with questions! The sideways-in-the-wind aspect is surprisingly crystal-clear; Why, then, don't they, say, have two thrusters, one at each end, and redirected at a 90degree angle...? If it wants to fly sideways, why force otherwise? And that center of pressure method seems confusing; What would happen if the tailfins were replaced by a cone?

[@ChucksSEADnDEAD]

If you try to fly with thrust on both ends, the rocket will break at the middle. It's like a soda or beer can after it's empty, to crush it top to bottom requires some strength to make the sides collapse. But press on an empty can from the sides, and it folds easily. You want rockets to be light for performance, if you make the sides thick enough to not get damaged, the rocket will be very heavy.

[@ericwazhung]

@@ChucksSEADnDEAD Oh, interesting! That's a good way to explain it, too, crushing a can.

[@vdinh143]

Not only that but the wind pressure would now be quite a bit higher as well, since the long side will naturally want to face the oncoming pressure.

[@gummybeef978]

I have a small and probably a dumb question. But when you put extra weight in the back of the rocket to move the center of mass, wasn't the center of progression moving as well, just in the opposite direction, Because it get's harder for the air to push that extra weight? PS sorry for bad spelling.

[@conradleonard]

Ah yes CG > CP for positive stability... fond memories of the classic Handbook of Model Rocketry by G H Stine; still available today in 7th edition!

[@JoshiJi05]

I had a question, how do firework rockets manage to go up pretty straight without any fins or pivoting engines?

[@dmk_games]

The stick hanging along the side and down the back puts the centre of pressure (centre of drag) behind the centre of mass.

[@ngotranhoanhson5987]

its central gravity is close to the nose cone

[@exoc1]

Remove the stick next time :p (or don't)

[@JoshiJi05]

@@dmk_games Ahhh I get it..thanks!

[@JoshiJi05]

I thought it had something to do with it spinning really fast, creating some sort of gyroscopic stabilisation

[@sniper7269]

"Largest area vs perimeter -> least air resistance" kinda the opposite, that gives the greatest air resistance for given perimeter, so that's disadvantage. BUT. What largest area takes as disadvantage, it gives as advantage in the way that it allows for largest volume for given material (if we're talking cylinder-like shapes, or else sphere is the largest volume).

[@kymcainday6677]

When I saw the thumbnail and the title, I initially thought "ah, I already know what the rocket fins are for; for stabilisation." I was about to skip it when I thought, "wait, maybe there is something I don't know just yet" so I clicked it. I already know about the concept of airplane about how they fly, the airfoil, the CG, flaps, ailerons and other controls like Thrust Vectoring. What I didn't know is the Center of Gravity should also be applied on rockets, and the center of pressure is new to me. It's worth the click. Thanks a lot.

[@man15h]

@The Action lab **Fine I'm dumb, pls explain like I'm 5, or 10** 0:20 why more area is good???

[@MUTHU_KRISHNAN_K]

Sir, Why rocket should be built with high internal pressure? What if centre of gravity and centre of pressure are in same point? Can we use more or less than 3 no.of fins?

[@yoongzy]

People who played Kerbal Space Program before: I'm kind of a rocket scientist myself

[@michaelarbach]

I wonder if the lasko fan company ever imagined their products would be used for rocket science wind tunnel testing.. lol

[@KK-mo9df]

The title sounds like a threat

[@TKC_]

As a kid I used to just check model rockets by spinning them around me with a string attached at the cg outside. So basically your fan method, but without the fan. Putting a motor in is important since it’s weight in the back. You could get a rocket to take off unstable tumble then stabilize halfway through the burn and dart in a random direction from the change in cg as the fuel burns.

[@zacrintoul]

I always thought those were the most entertaining. And then you can track down the maker and sternly ask them why the didn't properly verify the physics before launch. Lol

[@kevinhacken9801]

This would have been useful back when I started KSP. That and knowing about struts.

[@LeonardoUlhoa]

It'll be great if Kerbal Space Program use this video to explain center of mass and pressure!

[@jbj7799]

**Kerbal Space Program players gained no new knowledge from this video**

[@Viki-zo1bc]

I'm officially a rocket scientist now! Thanks for the certification. See you at the launch 👋

[@tyranttitanium5721]

I've played enough Kerbal Space Program to know where this is going

[@hardhits1]

Now im gonna apply for a job and say this guy made me an official rocket scientist

[@yousfhr1726]

Thanx for the info, now if you don't mind I'm going to build my own rocket . See you🚀

[@man15h]

@The action lab why 0:20 will there be less air resistance, when there's more area? I don't understand, larger the area more contact with air and more drag?

[@stargazer7408]

Exactly!!

[@man15h]

​@@stargazer7408 so ??? why what I didn't get it

[@ggre55]

Just play Kerbal space program and you'll be a rocket scientist i learned a lot from there

[@RickSjoerds]

Can you send me my certificate of being a rocket scientist? I wanna apply for a job 😃

[@vaibhavgupta1897]

Seeing the thumbnail and reading the title.. I frickin got scared for a second 😳

[@Kris.G]

Kerbal Space Program taught me what happens when you don't put fins on rockets.

[@pranavmohan6109]

Now I shall go and build a rocket and hope that it doesn’t crash into my house 🥲

[@sean_vikoren]

You are one of thubers that just keeps getting better. You (and team) are awesome. And you are appreciated.

[@mardeandwayne]

No wonder my Kerbal space rockets kept flipping over on ascent

[@constance_012]

As a Besiege player, this is definitely a video I want.

[@KurimuzonTaiyo]

ngl I understood this at the beginning of the video. But this is just excellent explanation

[@nigeljohnson9820]

How do you compensate for the change in the CG as the fuel is used up?

[@Comedy_baap]

Next Time In Diwali I will add fins on my Rocket 🚀🇮🇳👍

[@neelakandan.v.m2991]

I think this is the reason why arrows have fletching. To fly straight .

[@SFSALi]

>}=====> 🔹️ 🔸️ But this is not because of the fins. In fact, a rocket's center of gravity is toward the front end. And the center of air resistance is in its rear part. It would also work if you made the Cone heavy. >}=====> 🔸️ 🔹️

[@ryangemini24]

When I saw the title I thought this was a video from Not what you think lol

[@aviatornic2839]

Another banger video I can watch with younger cousins

[@ShiranaiOki]

Now I know how to build better rockets in Kerbal! xD

[@mastershooter64]

Thrust vector control: _Am I a joke to you?_

[@readtruth6670]

Same exact principle used in making arrows.

[@likithstochastic]

Brilliantly explained! Center of pressure is just like center of gravity, except that, it doesn't differentiate between regions of different mass densities, but rather depends on the cross sectional shape as seen from the direction of the wind.

[@duggydo]

The same principle can be applied to keep trailers from swaying. If the center of gravity is behind the trailer's axle, it will sway when you pull it. The axles are where the upward force is applied to lift the trailer so it acts like a center of pressure.

[@toastrecon]

Interesting. I was just wondering if that trailer stability situation was related, and it is!

[@eventhorizon7846]

You missed one key thing about rockets Center of Thrust : Basically where all of your thrusters forces meet and must face the center of mass or the rocket goes flying off in a random direction. Space Shuttles had their thrusters at an angle to have the center of thrust point towards the center of mass.

[@hafizuddinmohdlowhim8426]

He explains the aerodynamics part dude. Thrust is not relevant because this is aerodynamics balance and not attitude control system.

[@KronosGodwisen]

Kites and center of pressure would be a good video.

[@jonathandill3557]

The ancient Chinese rocket design with just a stick 7x the length of the motor could be an interesting test. In high school, sometimes I'd take a model rocket motor and just tape a long stick to it like a bottle rocket, not the best or most efficient, but flew surprisingly straight. There are modern firework rockets with this design and usually a cone on the top.

[@swapnilbandgar8730]

thank you for making us Rocket Scientist in just 10 min...

[@gyropyro]

Hey, Great Video, can you also please explain how air to air missiles fly in the air without wings?

[@formerfofcastudent7470]

My guess is engine gimbals like he said but I didn’t take any of my time to actually research it so take it with a grain of salt

[@CharlesB147]

Hey, so I had an interesting question: We saw what happens when your COG is above your COP, and what happens when it's below, but what happens when your center of gravity and center of pressure are at the same exact spot, by such a method as adding just enough weight to make the COG equal the COP? Would the rocket still fly off sideways, or would it stay straight?

[@A._Meroy]

I'd say it would stay straight, provided that no other forces disturb the trajectory. But any disturbance could cause the rocket to spin sideways, and the spin wouldn't be stabilized by the aerodynamics so that it would keep on spinning. This is probably not a thing you would want in reality. Furthermore, unless all of the fuel sits exactly at the COG, burning fuel would shift the COG quite a bit during flight. You probably want to ensure that the COG is above the COP on both full and empty rocket.

[@CharlesB147]

@@A._Meroy Fair enough. Didn't think about the shift of fuel during the actual flight trajectory. It also might not affect a model rocket where the fuel is a somewhat negligible part of the weight, but I could understand the difference of the hydrogen and oxygen on board an actual rocket as being much heavier!

[@neeldher2982]

"Rocket without fins is a knuckleball"

[@jebus456]

Did someone start playing KSP?

[@firasnizam]

Great, thanks for sharing this valuable info

[@Psychology0009]

What about bullets fired from guns?

[@leolipasti]

"C'mon, guys, it's not rocket science"

[@Blackmark52]

"You're now all officially rocket scientists." Until gimbles and finless rockets, the science was as old as arrow fletching.

[@RichSanDiego1969]

Your rocket didn't have any fuel

[@crazyme7825]

Fins are for stability and adjustments

[@بوفارسبونورا-ص7ه]

لماذا الرصاصة ليس لديها زعانف ؟ Why does the bullet have no fins ?

[@spynorbays]

Guns have spiral grooves in their barrels called rifling, they make the bullet spin very fast as it leaves the barrel. Bullets are stable in the air because of their spin.

[@treadless_co]

hey Action Lab, I wonder if you could do a video on coefficient of friction being larger than 1 with some metals (copper, aluminum). Cheers!

[@MrJdubs14]

Great video! Minor point, but air resistance, or drag, is partially a function of medium density, velocity, and cross sectional area. I believe maximizing cross sectional area actually increases the drag, but your second reason for pressure stability is great. Maximal cross sectional area also maximizes volume/load and decreases costs for wall materials. Think about the drag on a sheet of paper traveling laterally (i.e. as a magic carpet). It will exhibit negligible drag. But it also won't be able to carry anything as it has virtually no volume.

[@Theimtheimtheim]

I think the cross sectional area is fixed, as you need to carry a certain amount of fuel. then the drag would be smallest for a cylinder, as less perimeter means less contact with the air around it 😅 But I agree, could've been said more clearly... Like a circle minimizes the perimeter for a fixed area, not that it maximizes the are for a fixed perimeter...

[@Otoma]

Kerbal Space Program Tutorial!

[@karthikeyanak9460]

I am learning a lot from his videos

[@FormerlyKnownAsAndrew]

Great video. I enjoyed this👍🏾

[@nic5894]

Have you ever seen a fly chase light?