ANNOUNCEMENT: OpenRocket version 22.02 Final is now available for download

waltr

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Yeah , right! What about us that have no idea about coding, GitHub or how software is built. Where is the answer? This is not helpful at all. It's like telling us to find the answer in the Minitour's cave.
Even for some of us that knows coding it can be difficult to impossible to understand what someone else did.
Unless, there are Very Good comments in the code explaining how it works.
 

neil_w

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Feature request for the next round:

It would be super-awesome if there was a way to "comment out" components of a rocket. e.g., I could have different configurations of fins, nose cones, recovery devices, etc. all in one file, and just select or deselect them to be active in the sim. That way, I could compare different design elements all in one place. As far as I've figured out how to use OR so far, I can delete or modify something, but if I want to retain the old version, I have to save a new file. If I then make a change to some other component, I have to remember to go and manually propagate that change through all the desired versions of the file. If you're looking at differences in multiple components, it leads to an exponential increase in the number of files to be managed.

Would be way better if, when I wanted to try, say, a different fin design, or a parachute instead of a streamer, if I could just tell the program to ignore a component and use a different one, turning components on and off all within the same sim file.

Or is this already possible and I'm just not smart enough to have found the switches yet?
Not possible right now. I agree it would be nice, but it's potentially quite complicated to implement something like that.

We are looking into sensible ways to do something more limited, which is to have different component sets for different motor configurations, but it's probably not coming in the near future.
 

JoePfeiffer

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When OpenRocket is calculating spin for a rocket with canted fins, does it correct the fin angle of attack for the rocket's current (at that time step) rotation speed?
Checking.... it appears to be calculating drag and stability as if the fin weren't canted and the rocket wasn't rotating, and then calculating roll forces separately (so in that sense yes). I'm not seeing it applying the force required to spin it affecting acceleration (so in that sense no). I'd need to spend more time than I've got right now to be absolutely sure about the latter.

There's a pretty readable description in the technical docs at https://github.com/openrocket/openr...OpenRocket_technical_documentation-v13.05.pdf
 

boatgeek

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Checking.... it appears to be calculating drag and stability as if the fin weren't canted and the rocket wasn't rotating, and then calculating roll forces separately (so in that sense yes). I'm not seeing it applying the force required to spin it affecting acceleration (so in that sense no). I'd need to spend more time than I've got right now to be absolutely sure about the latter.

There's a pretty readable description in the technical docs at https://github.com/openrocket/openr...OpenRocket_technical_documentation-v13.05.pdf
Thanks for posting the documentation. Pages 37-40 make it clear that OR calculates a roll forcing moment and a roll damping moment. The roll forcing moment is calculated at zero rotation speed (a simple calculation), and the damping moment takes the current rotation speed into account (a much more complicated calculation that does some strip-wise integration). I think this would overestimate roll speeds since the forcing moment would be reduced as roll rate increases for a given speed. However, it may well not be worth adding the extra complexity to calculate a rotation-rate specific forcing moment.

Since this is kind of an edge case that may or may not give useful information (do we really need to know the rotation rate?), it's probably enough to know that OR [does or does not] overestimate the rotation rate.

I'll noodle around with sims from some of my spinning rocket designs and see what qualitative insights I can glean from that.
 

boatgeek

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OK, so here's some data from a 29mm diameter, 18mm motor mount rocket with trapezoidal fins at a 3-degree cant.
1678207020289.png
Angle of attack is nearly 90 degrees at ignition (makes sense from a slight side wind), and rapidly decreases. Roll doesn't start until the rocket clears the rod. The angle of attack goes to near zero during boost and coast (which is reasonable). Roll rate tracks velocity nearly exactly, which is about what you'd expect. It's not obvious from the scale of this chart, but the angle of attack never goes negative during coast. You would think that the AoA would be negative as the rotation slows down.
 

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JoePfeiffer

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AoA is the angle of attack of the rocket body, so this is expected.

I *think* the idea is that at equilibrium the roll forcing and damping cancel, not that they're both 0. So the rate it gets should be reasonably close to correct. Not a part of the code I've spent any time around, so I can't be sure.
 

boatgeek

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AoA is the angle of attack of the rocket body, so this is expected.

I *think* the idea is that at equilibrium the roll forcing and damping cancel, not that they're both 0. So the rate it gets should be reasonably close to correct. Not a part of the code I've spent any time around, so I can't be sure.
OK, that makes more sense for AoA. Thank you for the clarification.
 

SolarYellow

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I'm having a weird detail where the date modified for an .ork file shown in Windows Explorer is not updated when the .ork is modified and saved. A file I made changes to last night shows a last modified date of 01/14/2023, but when I open it, it includes the changes I made last night. Not really a problem, just confusing when I'm looking for the file I was working on recently.
 

thzero

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I'm having a weird detail where the date modified for an .ork file shown in Windows Explorer is not updated when the .ork is modified and saved. A file I made changes to last night shows a last modified date of 01/14/2023, but when I open it, it includes the changes I made last night. Not really a problem, just confusing when I'm looking for the file I was working on recently.

OpenRocket doesn't set the modification dates, that would be the low-level functionality in the Java Virtual Machine (JVM) that would be doing that in conjunction with the OS' file system APIs.

What version and what OS?
 

rocketgeek101

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I'm getting this error when I try to open a design file for a 4-stage rocket I've been dreaming up. File attached.

This happened to me last night as well and I ended up deleting the design file and just starting over but now it's happening again. My other .ork files open fine. I'm guessing it might be related to the large number of stages.
Screenshot 2023-03-13 at 2.42.33 PM.png
 

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thzero

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I'm getting this error when I try to open a design file for a 4-stage rocket I've been dreaming up. File attached.

This happened to me last night as well and I ended up deleting the design file and just starting over but now it's happening again. My other .ork files open fine. I'm guessing it might be related to the large number of stages.

<bodytube>
<name>Body Tube</name>
<preset type="BODY_TUBE" manufacturer="Rocketarium" partno="29mm Motor Mount tube 5.5"" digest="ef554285e8e7ab49e1bfc595ac240a5b"/>

That causes the malformed XML. Fix that and it should save/open. I manually fixed in the file and it opened.
 

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thzero

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<bodytube>
<name>Body Tube</name>
<preset type="BODY_TUBE" manufacturer="Rocketarium" partno="29mm Motor Mount tube 5.5"" digest="ef554285e8e7ab49e1bfc595ac240a5b"/>

That causes the malformed XML. Fix that and it should save/open. I manually fixed in the file and it opened.
FYI. the OR files are just zip files so can be opened with any Zip utility and then its just a text file with xml in it (even if its also named rocket.ork).
 

neil_w

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<bodytube>
<name>Body Tube</name>
<preset type="BODY_TUBE" manufacturer="Rocketarium" partno="29mm Motor Mount tube 5.5"" digest="ef554285e8e7ab49e1bfc595ac240a5b"/>

That causes the malformed XML. Fix that and it should save/open. I manually fixed in the file and it opened.
Ha, looks like the " in the partno is not being escaped properly. Will file an issue on that.
 

thzero

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Ha, looks like the " in the partno is not being escaped properly. Will file an issue on that.
Although really, I'd question the use of quotes or even single quotes in the attribute fields.

https://www.w3.org/TR/xml/#NT-AttValue

"To allow attribute values to contain both single and double quotes, the apostrophe or single-quote character (') may be represented as " &apos; ", and the double-quote character (") as " &quot; "."

But those are not good ideas for partNos one would think.
 

SiboVG

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Tha
I'm getting this error when I try to open a design file for a 4-stage rocket I've been dreaming up. File attached.

This happened to me last night as well and I ended up deleting the design file and just starting over but now it's happening again. My other .ork files open fine. I'm guessing it might be related to the large number of stages.
View attachment 568419
That's already been fixed some weeks ago.
 

Voyhager3

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I just realized that lately, my OR 22.02 has been saving my files as TMP files, rendering most of my files (since about a week ago) useless, does anyone else have this problem, or know what is going on?
 

JeffBigg

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Openrocket tip that may help others:

I just purchased a new laptop a few days ago and only installed version 22.02. So I don't know if this behavior was the same in the older versions.

Here is the situation, I'm just designed a new rocket, and built 20 different motor configurations for it. I go to the flight simulations tab and I am able to select and run all the simulations without any issue. Now for something strange. I select all of the simulations, and I want to edit them all as a group, and the edit simulation button is greyed out. (I usually do this to set launch rod/rail length depending on where I am launching and estimated winds for the day of the launch.) I thought it was possible to click edit in the old version.

Oddly enough, once I have all the simulations selected, I can press CTRL-E and edit all the sims as a group. I'm just wondering if there is a setting I need to change, or do I just need to get used to using the CTRL-E shortcut? I couldn't find anything about this in the documentation, and figured I would share it to help others.

Thanks for all the work on the new version. It has been really great.

Jeff
 
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This is awsom...

Just another big thanks to all having contributed to make this release come true!
I guess I can't even imgaine how much work that involves, and how much it helps all of us to be a better rocketeer.
I wish I could contribute, but I simply can't as not my area :)

Now it is downloaded and installed and I really look forward to start playing with it!
 

Winston

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Possible free form fin editing bug. I want to move the selected pint upward on the Y axis. Can't be done and the X,Y data field for that point can't be manually edited. Everything works as expected for all of the other points.
 

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Winston

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Possibly a bug in the freeform fin editor. Point selected in the attached image cannot be moved upward on the Y axis as desired nor can the X,Y data field for that point be edited manually. All other points act normal.
 

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neil_w

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That's a root edge point, locked at Y=0.

If you're hanging off the back of the body, a better way to do it is to move that point left until it's right at the back of the body, and then add another point to create the desired profile, e.g.:
1681924461167.png
 
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