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OpenRocket

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Re: OpenRocket

#101

Post by simgt »

hermitcrab wrote: post #32

We used OpenRocket for designing our rocket for UK youth rocketry competition UKROC[1]. It is great for getting a 'spherical cow in a vaccuum' idea of likely altitude with different motors, centre of pressure, center of mass etc. But it obviously doesn't take account of detailed aerodynamics etc and we found the maximum altitude estimates were about 15% too high. But it was still very useful. [1] UKROC is an amazing…

I can't find the French competition, ironic given that the front page of ukroc is full of French gov officials... Could you share the name if you have it?

Re: OpenRocket

#102

Post by wiseowise »

alexpopow wrote: post #95

What about misuse for weapon development? Does the project not massively cut R&D costs (hence lowering the entry hurdle) for potentially malicious actors on the planet?

Even if it does, you need industry to have any meaningful impact. And a big army with distributed attack nodes.

Re: OpenRocket

#103

Post by teraro »

simgt wrote: post #101
hermitcrab wrote: post #32

We used OpenRocket for designing our rocket for UK youth rocketry competition UKROC[1]. It is great for getting a 'spherical cow in a vaccuum' idea of likely altitude with different motors, centre of pressure, center of mass etc. But it obviously doesn't take account of detailed aerodynamics etc and we found the maximum altitude estimates were about 15% too high. But it was still very useful. [1] UKROC is an amazing…

I can't find the French competition, ironic given that the front page of ukroc is full of French gov officials... Could you share the name if you have it?

The biggest one is C'space: https://cnes-edu-cspace.com/cspace-2025-en/

There is also the European Rocketry Challenge in Portugal: https://euroc.pt/

Re: OpenRocket

#104

Post by teraro »

There is also the rocketpy framework. https://docs.rocketpy.org/en/latest/index.html

Essentially it can do the same thing as openrocket, but in python. You can even go as far as to simulate liquid fueled rockets during flight, modeling for example how the depleting tank influences the center of mass. My student rocketry team used this for the flight simulation of our Ethanol/Liquid Oxygen rocket which flew to over 5km

Re: OpenRocket

#105

Post by notahacker »

teraro wrote: post #103
simgt wrote: post #101

Earlier quoted context omitted.

I can't find the French competition, ironic given that the front page of ukroc is full of French gov officials... Could you share the name if you have it?

The biggest one is C'space: https://cnes-edu-cspace.com/cspace-2025-en/ There is also the European Rocketry Challenge in Portugal: https://euroc.pt/

And for older students in the UK there's https://race2space.org.uk/

Re: OpenRocket

#106

Post by hrmtst93837 »

altruios wrote: post #8
mitchbob wrote: post #2

The miracle of 3D printing. First ghost guns, and now ghost rockets. Will be curious to see what prediction markets will have for these.

you get some good, you get some bad. Building a rocket shell is probably just fine: you need to fuel yet - that you can't 3D print. probably fine... Overall 3d printing is a lot more than ghost guns and ghost rockets. That the conversation dominates this small sub-section reeks of 'think-of-the-children' screeching that hides explicit power grabs in regulation and surveillance with the main intent seemingly to be 'en…

[flagged]

Re: OpenRocket

#107

Post by zamadatix »

dotancohen wrote: post #83
zamadatix wrote: post #37

Earlier quoted context omitted.

Distance is usually the wrong measure in space. Something like delta-v will give you a much better scaling as once you manage to get something to orbit the rest is actually a lot closer than it would seem on the ground. Not to say the effort somehow becomes peanuts, cheap, or easy... but the jump in delta-v needed to go from "100 km vertical ascent" to "hit the moon 350,000 km away" is more like a ~6-7x increase than…

Everything you've said is correct, but Delta-V scales logarithmicly with fuel load - you need to carry the new fuel. So for purpose of discussing altitude (a valid way to look at getting to the moon) the size of the rocket, and the fuel expended, does in fact grow much closer to linearly. I think I'll go land on Mun and Minmus now...

What I actually started with was comparing Electron to the current bos.space rocket and seeing the relationship was nowhere near linear. The above is the largest component of why I could think of but there is always more than 1 thing going in.

Re: OpenRocket

#108

Post by sandworm101 »

plugger wrote: post #78
hermitcrab wrote: post #32

We used OpenRocket for designing our rocket for UK youth rocketry competition UKROC[1]. It is great for getting a 'spherical cow in a vaccuum' idea of likely altitude with different motors, centre of pressure, center of mass etc. But it obviously doesn't take account of detailed aerodynamics etc and we found the maximum altitude estimates were about 15% too high. But it was still very useful. [1] UKROC is an amazing…

> we found the maximum altitude estimates were about 15% too high. this often happens when the wrong rocket finish is selected. Everyone chooses a polished finish when in actuality they've just sprayed the thing with paint. Skin drag is real.

They also seem to be treating rockets as rigid bodies. Flex of parts is real at these accelerations but the calculations get into supercomputer territory very quickly. All the math is questionable if, at any given moment, your rocket isnt actually straight.

Look into the physics of archery, which has similar accellerations albeit of a narrower tube. The choice between a heavier/stronger arrow v a lighter/flexible shaft is the entire game.

Re: OpenRocket

#109

Post by hermitcrab »

simgt wrote: post #101
hermitcrab wrote: post #32

We used OpenRocket for designing our rocket for UK youth rocketry competition UKROC[1]. It is great for getting a 'spherical cow in a vaccuum' idea of likely altitude with different motors, centre of pressure, center of mass etc. But it obviously doesn't take account of detailed aerodynamics etc and we found the maximum altitude estimates were about 15% too high. But it was still very useful. [1] UKROC is an amazing…

I can't find the French competition, ironic given that the front page of ukroc is full of French gov officials... Could you share the name if you have it?

The French and Japanese competitions seems to be rather low-key compared to the UK and US competitions. The winner of the French schools is mentioned here:

https://www.safran-group.com/news/have-you-heard-about-rocke...

Maybe you can contact the school and find out more?

Re: OpenRocket

#110

Post by hermitcrab »

teraro wrote: post #104

There is also the rocketpy framework. https://docs.rocketpy.org/en/latest/index.html Essentially it can do the same thing as openrocket, but in python. You can even go as far as to simulate liquid fueled rockets during flight, modeling for example how the depleting tank influences the center of mass. My student rocketry team used this for the flight simulation of our Ethanol/Liquid Oxygen rocket which flew to over 5k…

>My student rocketry team used this for the flight simulation of our Ethanol/Liquid Oxygen rocket which flew to over 5km

Cool. Is there more information on their rocket or a video?

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