Full-size Saturn V simulation in OpenRocket

Sampo

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I decided to test the limits of OpenRocket by simulating a full-size Saturn V rocket in it. I wrote an article on the project for our club magazine (in Finnish).

The results were reasonably good, considering OpenRocket doesn't do full spherical coordinates and the rocket flew at over 20 Mach. In OpenRocket the design reached an altitude of 152 km, while the true orbital altitude was 191 km. (The curvature of Earth at that distance is ~300km.) The rocket's speed profile matches reality quite well, though it remains 20% too low. The acceleration is very close to reality especially during the first stage.

kuva-1.png
kuva-2.png

(Flight profile, velocity and acceleration. Dashed line simulated, solid line reality.)

Because I wanted to simulate a real flight where the rocket is actively controlled, I added a script to the simulation which forced the orientation and speed vector direction to be that of the real flight. OpenRocket was left to simulate the acceleration, speed and position of the rocket. (If you want to try this yourself, for security reasons you need to manually re-enable the script in Simulation Options --> Javascript script.)

You can find the article (in Finnish), the ORK design and necessary engine definition file at https://www.sats-saff.fi/node/106

Below are a few images from the design. I had to use a slightly modified OpenRocket version to create the images, as the default version does not expect the 3D models to be so large.

rendered.jpg

saturn-v-2.jpg

saturn-v-4.jpg
 

Sampo

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Here's a screenshot I took for the article. (The real-time simulation results are bogus, since they don't use the script doing the active control.)

screenshot.jpg
 

K'Tesh

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Very Nice! I've thought about trying to sim various real life rockets... Hadn't thought about going quite that big.
 

Cabernut

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Really cool Sampo. Makes sense to control the orientation since the real rocket isn't passively guided like ours are.

I'm telling ya though, we're just a hair away from connecting simulation data with that nice Photo Studio. Press play and watch it go!
 

Zeus-cat

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Does OR simulate the rocket hitting the dome when it gets high enough? You hoax-deniers and round-earther types really crack me up.

Seriously, good job.
 

ksaves2

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Does OR simulate the rocket hitting the dome when it gets high enough? You hoax-deniers and round-earther types really crack me up.

Seriously, good job.

You mean flat-earther types? I really don't know what deniers would be doing on this site since most of us take immense pleasure when Buzz Aldrin popped that guy in the face that hassled him about the moon mission. Kurt
 

Spurkey

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Look at that, it's even over 1.0 calibers for stability. Must be all the weight for the LEM that helps it out. ;);) What a fantastic project, thanks for sharing it and thanks for all your work on OpenRocket!
 

snrkl

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Here's a screenshot I took for the article. (The real-time simulation results are bogus, since they don't use the script doing the active control.)

screenshot.jpg

But where did you put the launch lugs?!?!

8-p
 

Answer

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Here's a screenshot I took for the article. (The real-time simulation results are bogus, since they don't use the script doing the active control.)

screenshot.jpg



That’s quite impressive. I’m a student in aerospace engineering and I’m interested in the possibility to expand OpenRocket to the world of heavy rockets. Is there an English version of the article? Have you created also a 3D simulator?
 

RGClark

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I decided to test the limits of OpenRocket by simulating a full-size Saturn V rocket in it. I wrote an article on the project for our club magazine (in Finnish).

The results were reasonably good, considering OpenRocket doesn't do full spherical coordinates and the rocket flew at over 20 Mach. In OpenRocket the design reached an altitude of 152 km, while the true orbital altitude was 191 km. (The curvature of Earth at that distance is ~300km.) The rocket's speed profile matches reality quite well, though it remains 20% too low. The acceleration is very close to reality especially during the first stage.
...

Did you include the fact that in the flat Earth approximation the gravitational force is effectively reduced by the centrifugal force, i.e., by M*V2/R?


Bob Clark
 

RobVG

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I know this is an old thread but I was wondering about the stability being negative 1 on the file?
It flies but does that mean stability is not a factor in OR?
 

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