Using KSP to simulate the flight of a model rocket

[MetricKerbalist]

Hi everyone,

I am quite interested in model rocketry — high-, mid-, and low-powered rocketry (but especially high-powered model rocketry).  I am a member of the National Association of Rocketry, in fact.

One of the purposes for my wanting to learn Kerbal Space Program is to apply it to understanding the flight of model rockets.  Not to misunderstand.  Excellent software packages exist to simulate the flight of model rockets, and two widely used packages are OpenRocket (open source) and RockSim (proprietary).  Still, these packages -- especially wonderful in designing model rockets -- have limitations in simulating their flight.

I believe that KSP can fill some of the gaps found in model-rocket simulation software.

Two things in particular that I currently would like to investigate are using canted engines to try to induce spin to the flight of a model rocket.  I would also like to see how changing the number of fins, and also canting the fins, changes the flight behavior of a model rocket.

I understand that one can play KSP in three different modes: Sandbox, Science, and Career.

Since one of the first things that I want to do with KSP is to simulate the flight of a model rocket, would Sandbox mode provide a realistic model-rocket simulation?  As I understand it, Science mode would not be the way to go to start building rockets.  So do I need to use Career mode?  The problem with Career mode for my immediate purposes, as I understand it, is that I would have to build up quite a few qualifications to start constructing rockets.  Or am I wrong in that?

I must say that I find KSP quite daunting to use.  I have started to go through the training tutorials for Career mode.  I can build the rockets alright, but getting the hang of orbital maneuvers is so far not going well.

To conclude, therefore, let me summarize my questions:

 

• Does using Sandbox mode provide as realistic a flight experience as Career mode does?
• If I used Career mode, could I build a rocket without needing to earn qualifications?  For the moment, I don’t need to engage in fancy orbital maneuvers, docking, or landing.  I just want to examine the behavior of a rocket as it lifts off, burns out its solid fuel, coasts to apogee, ejects its parachute, and drifts back to land.

Thank you for your consideration.

Stanley

 

Edited June 3, 2021 by MetricKerbalist
Typo

[Suyash - Jevaria]

Try out the base game in career mode to get the lay of the land and understand the concepts then try Realism Overhaul and RSS. If you need help with the the transition to RO PM me.

[FleshJeb]

The physics is the same in all modes. Sandbox is what you want if you just want to play with physics and engineering without restrictions.

It will be good for experimenting with general concepts, but you won't be able to for example, specify the angling and size of a fin and have those numbers carry over to real life.

Even modding KSP to be as realistic as possible won't get you usable data, as it's not a simulator. The aerodynamics in particular are very basic.

[AHHans]

What do you plan to learn from your KSP "simulation"?

As already mentioned by @FleshJeb the aerodynamics simulation of KSP is rather basic. It is good for teaching general concepts of aerodynamic stability but don't expect it to faithfully represent the behavior of a real rocket.

So if you want to get an idea of the difference in the flight profile of a rotating vs. a non-rotating rocket, then you can use KSP for that. You can also have a look at the differences between having angled fins vs. angled exhaust. But any details like the amount of rotation to aim for or a good angle for the fins or rocket motors are not well represented by KSP.
And that ignores other practical considerations: e.g. you'll never get the ropes of a parachute tangled in KSP, because that just isn't simulated.

In order to "learn KSP" I'd suggest to just forget about the model rockets for a while and just play the game. I'd suggest to start career mode because the contracts give you some guidance on what you may want to try next, but career mode can be grindy if that is an issue then try science mode.

[cubinator]

I think OpenRocket and Rasaero are better if you want to simulate the flight profile of an actual model rocket. 

[Klapaucius]

If you want to learn KSP, I would suggest finding a good tutorial series. Though a bit older, I think this series is incredibly good. I learned from it after a lot of frustration and I cannot recommend it enough. It uses Science Mode to teach, and while I play almost exclusively in Sandbox mode, it is a very good way to learn.

 

[MetricKerbalist]

Hi Klapaucius,

Thank you for the link.  I will watch the videos.

Stanley

[Kerbart]

On 6/2/2021 at 11:57 PM, MetricKerbalist said:

• Does using Sandbox mode provide as realistic a flight experience as Career mode does?
• If I used Career mode, could I build a rocket without needing to earn qualifications?  For the moment, I don’t need to engage in fancy orbital maneuvers, docking, or landing.  I just want to examine the behavior of a rocket as it lifts off, burns out its solid fuel, coasts to apogee, ejects its parachute, and drifts back to land.

There's no difference in the physics between  the various modes.

Career provides a challenge that some find lacking in sandbox: by starting with limited resources one has to "earn" their way into an all-out space program. While career mode does make it easier to get started by eliminating being overwhelmed by choices, it's really not intended as a learning mode (it would have been named "learning mode") as some pretty important parts are locked up in the Tech Tree. If you want to learn the game, using the tutorials and experimenting in Sandbox will likely lead to faster results. Career might be more satisfying by giving a feeling of accomplishment though but that's not always someone's goal.

[Klapaucius]

3 hours ago, Kerbart said:

There's no difference in the physics between  the various modes.

Career provides a challenge that some find lacking in sandbox: by starting with limited resources one has to "earn" their way into an all-out space program. While career mode does make it easier to get started by eliminating being overwhelmed by choices, it's really not intended as a learning mode (it would have been named "learning mode") as some pretty important parts are locked up in the Tech Tree. If you want to learn the game, using the tutorials and experimenting in Sandbox will likely lead to faster results. Career might be more satisfying by giving a feeling of accomplishment though but that's not always someone's goal.

I actually think career is quite difficult to learn in because you are:

1. Building aircraft early on with some of the worst landing gear available.

2. Trying to learn to build without necessarily having the skills to even fly anything yet.

 

I found it much more useful to take some of the better stock craft and learn the control basics with them before I started creating my own. Also, when you do start building, especially aircraft, sandbox offers you parts that are higher in the tech tree but make it far easier to build your first plane.

 

[Kerbart]

11 minutes ago, Klapaucius said:

I actually think career is quite difficult to learn in because you are:

(...)

I agree that learning the game through Career is a really bad idea but I wasn't in a particular mood to get flamed by Career fans.