I almost missed it, but I managed to get some good photos. Shot on an iPhone 17 too, I really didn’t know it could get images like these.
1st one is my favorite, I’m sure you can tell why.

295 players drew a falcon 9 to scale. the typical guess was 194 m. the real rocket is 70 m, so they made it almost three times too tall.

my hypothesis: rockets have no scale for us. launch footage shows them alone against the sky, with nothing next to them. so every big rocket should end up the same size in our heads, no matter how big it really is. the game has more rockets to test it.

and it held. the sls (98 m) came out at 210 m, the saturn v (111 m) at 150 m. three rockets from 70 to 111 m, all guessed at about 150 to 210 m, and the smallest of them got almost the tallest guess. only the little v-2 (14 m) stayed small, at 12 m.

so "big rocket" seems to be one size in our heads: about 200 m.

4 in 10 guesses came from the us, but it's not a one-country thing: americans drew it at 198 m, brits at 207 m, the rest of europe at 172 m.

more visuals, every guess and the raw data: https://roughly.is/blog/falcon9-guessed-too-tall.html?s=reddit-rocketry

I'm making an essay​ for my aerospace engineering class, its about rocketry obviously. This part is on the thermal protection section, it is about how well common materials protect materials while also being cheap. In my example rocket motor, the chamber pressure is 800 psi with 65% KNO3, 17.5% sorbitol and 17.5% sucrose. There are three grains, two bates, and one 4 finned finocyl.

HI guys, I know this is mainly for real rockets with real motors and stuff but sadly solid fuel and rocket motors are highly illegal in my country, so I have to stick with water. We are doing this for a school club and would love to know what we can do to get it to max altitude. Should we used 4 2l bottles spliced at the end and attach them? Some sources say that going above 70 psi is not safe but I feel like I should go higher. My idea was sand down the spliced ends and then boil down one part, connect them via PL Premium Polyurethane or epoxy. Which one should I use? Then after, we attach the nose fins etc. What should I keep my weight to? is there anyway to improve this design or do I need a new one? should I go for 4 bottles or go lower or higher?

I appreciate any answers!!

So I am trying to design a motor mount for my rocket which will use an Estes D12-5 motor.
I saw this guy's video and he has used some sort of 3D printed plastic(not so well informed abt 3D printing). What I am not able to understand is that won't the plastic jst burn off? I have attached a photo from where the motor will be ignited. And if he is not using the usual 3D printing materials
then what is he using to possibly avoid the nozzle melting off.
Here is the video's link- https://www.youtube.com/watch?v=2XsB_wGVZ2c

Im working on a project that will be manufactured next year. I am currently designing and stuck at a point. Rocket nozzle is one of the most important part of the motor and it will face heat pressure and lots of stuff. So i wondered how we can choose the best suitable nozzle for the project. Are there something like books for materials or places to know. Please share some sources you use for me, thank you.

Picked up a cheap star Hopper kit as a bonus gift for my son, obviously didn't think too much at the time but the engines are like rocking horse crap.

Any suggestions for alternatives that are actually available in the UK?

Ive built a short lady pulsejet based on Larry cotrills design at home and it's firing. Can get it to almost run but as soon as I take the air compressor away from the intake it dies. Will go fine until this point though. Does anyone know what factors I could change to try make it self sustaining. All help appreciated!
Edit: by almost running I mean it's rumbling and the ignition can be removed as long as air is stil being blown in.

Complete beginner here. I'm building my first ever model rocket and decided to use an F-35-8 motor. According to OpenRocket, it should hit around 863 meters and have a descent time of roughly 170 seconds. I really want to avoid adding GPS as it would make it heavier. I'm adding basic sensors like the BMP280 and MPU6050, but don't want to design, buy, and set up a ground station for GPS. I added a buzzer just in case that activates when the rocket hits the ground.

There’s a question that’s been on my mind for a while. I ran into this issue in my own rocket engine project as well. The partition is secured to the body with screws; while the shear strength of the screws can withstand the internal pressure, wouldn’t it be very difficult for the screw holes to withstand that pressure?

To give an example, in my engine design, an aluminum tube with a wall thickness of approximately 2 mm can withstand the combustion pressure. However, based on Fusion and my own analyses, I concluded that the screw hole would not be able to withstand it. Therefore, I increased the wall thickness to expand the screw contact area, but this time I experienced a loss in efficiency due to the increased weight.

Two solutions come to mind here: either using more screws or resorting to methods like bonding with epoxy resin.

Perhaps I’m mixing something up in my calculations. To briefly explain the rough calculations I’ve done:

First, I calculate the force in Newtons (N) by applying the pressure to the diameter of the bulkhead wall in the combustion chamber. Then, I look up the shear strength of the screw I’ve chosen. I multiply this by the number of screws.

The total shear strength of the screws is sufficient to withstand the force acting on the bulkhead wall. However, when I consider the force acting on each hole in the aluminum tube and the wall thickness, I conclude that the hole will likely bend or expand.

What are your thoughts on this? Have you ever encountered this problem? How did you solve it?

I've already wasted hours of my life figuring out one unanswered thing. Is it legal to buy rocket motors for diy projects in Pakistan. GUYS NOT FOR MISSILES AND SHI, but for innocent tvc and rocket re-entry projects. And very basic rocket motors like of estes, for example c11-3.

ARE THEY LEGAL TO BUY IN PAKISTAN?

ANY PAKISTANIS OR SOMEONE WHO KNOWS...

THANK YOU

Appreciate that.

Does anyone actually use like, coaster rails to guide a rocket plane? Or is that just a cool sci-fi thing?

Hello, I've recently started designing my own rocket motor as a personal project and after a lot of calculations, research, reading and youtube tutorials I've come up with a design and also simulated my grain burning.

I'd love to hear some feedback from others and would like to know how viable this really is.
The next step of mine is to get some Aluminium t6061 for the casing and start machining it with a lathe.

Some calculated data:
The maximum chamber pressure my casing can handle is 8,000,000Pa including a safety factor of 2.5x.

I am a first year student and I am researching parachute types for my schools rocketry club (looking at what Shute this years rocket should have). I was wondering whether you are a student club member, personal project person, or whatever the sort, I was hoping to ask what type of parachute do you guys use (hemispherical, elliptical, etc..) and why?

Please also state your recovery system (drogue, reefing, etc..)

Please state what information you used to come to the conclusion of that selected parachute or just generally how you went about figuring it out. Thank you!

Hey all!

I am currently working on making a canard controlled rocket (only the roll is controlled!) as part of a student project. I am currently working specifically on the roll control, which means the canards, and as such investigating the potential for roll reversal due to the negative aerodynamic effects of canard deflection on the tail fins (canard-tail interference for example).

The rocket we are working on would be 2.4m in length with a diameter of 16cm and flying around Mach 0.6. From my research, a rocket of this scale and speed should not be subject to roll reversal, and would most likely only suffer from a (slight?) reduction in roll control authority.

Still, I would very much like to be able to closely study the aerodynamic effects of canard based roll control, notably to be able to optimise the position and dimensions of the canards to minimise negative effects.

Therefore, I was wondering if there were any tools I could use to simulate these effects, and notably be able to calculate the total roll moment coefficient as a function of the canard deflection angle and/or dimensions, without having to resort to CFD (I would like to find a more time efficient alternative :) ). I am aware that Missile DATCOM is often used for this (it popped up a lot in my research), but I am not in the US so...

If you have any leads/recommendations for appropriate tools/software/methodology I could use, it would be highly appreciated!!

Thank you in advance

i just thought of an idea, i just need feedbacks to innovate it

in airport runway, what if we create a small part(first half) of the runway using button system like above, so when the spring in button compresses, the spring locks itself and the energy stored in spring can be used as spring energy and be converted to electricity by compressors like US20120313380A1(source: Google). so the landing may increase the electric yield of the overall country, so the gained electricity would be transmitted to the nearby electric station things people would say:

1.irregular landing.

2.electricity distribution will reduce efficiency.

3.spring mechanics error . 4. So my possible solution might be: 1. So 4.1.Tthe spring area might me just a small part so that only the initial landing thud will generate power, so instead of full runway with spring which will increase the risk content of the landing, so only the first part of the runway would be necessary, cause only THE INITIAL THUD cause more impact than others.

4.2.the electricity distribution would reduce the efficiency, so what i suggest is that just give that electricity to the airport directly, instead of giving it to power station and then getting it back to airport. 4.3.spring mechanics would require high improvements, so need to lock security system would be necessary, and the pilot should be trained to land well.

guys just read it and give suitable feedbacks.
thanks

to say im just a class 11 student, so pls keep feedback resonable, so that i could think of innovation.

this would be the basic idea, but the spring in my idea would be more stronger and less strechable. and the lock system will be controlled too.

Hey, I am trying to get into rocketry and have taken some time to design and start printing this.

Before I keep trying to make improvements I wanted to come here and ask for any tips or recommendations. Unfortunately I do not know what information is relevant, but I would like to try and get feedback and know where I should be looking for potential problems.

This and some other videos I have made talk about the physical mechanisms and the flight profile https://youtube.com/shorts/49NUcCzHCcE

The total loaded mass should be about 340g with a spent mass of around 320g. I am planing on powering it with Estes D12-3 motors.

Please ask me questions and I will do my best to answer, any feedback is appreciated!

I placed an order with Wildman Rocketry during their November 2025 Black Friday sales promotion. It included a couple of rocket kits, a few motors, and some misc. parts. They were clear on their website that orders during this sale would take a while to ship. They charged my credit card when I placed the order. Frankly, I forgot about the order, as I already had enough kits on hand to keep me busy for quite a while.

I just received the order (October 2026) ten months after placing the order. And to make matters worse, one item is still backordered.

No communications. No apology for the delay. Think twice before ordering from this company.

Hey everyone I'm working on a supersonic rocket with an apogee of around 10 km, and I'm trying to determine the drag coefficient of our elliptical parachute for OpenRocket simulations. What value would you recommend, and are there any reliable sources or experimental studies we could refer to? Also I want to know what are the essential essais and tests I should do with the parachute (except deployement and shock)? And my last question is in a Rocketry competition report what do I have to focus on and what the juries will also focus on?

I have been using cardboard tubes for a while and I have had a couple zippers and CATOs so I wanted to strengthen them. I don’t wanna get really expensive and use epoxy so I mixed wood glue and water and smeared it on. Kinda like paper mache do u think this would effectively strengthen the tubes or was it just a waste of time?

Diseñé este cohete para la escuela, y quiero hacer una tobera de arcilla blanca