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cmp

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Hello everybody, I am new to this forum and started using Open Rocket recently. I need to add a motor to the database and the references to how to do this in this forum are quite old and are not working for me. I got a test file from the Cesaroni website and placed it in C:\Users\UserId\AppData\Roaming\Open Rocket\Thrust Curves folder - it does not appear in the motor selection screen. I tried 7unzipping the jar file but under \datafiles\thrustcurves there is a single file with extension ser which I understand is a binary file. Opening the file in a text editor I can see it contains motor data but that was not what I expected. Is there a way to add additional motors to the database that I am missing?
 

neil_w

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Presumably the motor file you have from CTI is an RSE or ENG file. If not, you can almost certainly obtain the necessary file from Thrustcurve.org.

I don't recommend adding motors to that particular folder (and I plan to update the OR docs accordingly). Rather, create a folder on your machine where you will store new motor files (I put it on Dropbox so it's available from both machines I use OR on). Put your motor file in that folder, and then go to Edit->Preferences and set the folder where the motor files are stored. Restart OR and your motor will be available in it.
 

cmp

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Thank you! Yes, the .eng motor curve came from ThrustCurve.org. I had already added it to a folder in C:\User\HPR\ThrustCurves. This is in Windows 10. It still does not show in the selection list. I am assuming other people are using Windows 10.
 

neil_w

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Thank you! Yes, the .eng motor curve came from ThrustCurve.org. I had already added it to a folder in C:\User\HPR\ThrustCurves. This is in Windows 10. It still does not show in the selection list. I am assuming other people are using Windows 10.
If you set your preferences to point to that folder, restarted OR, and it still doesn't show, then I don't know the issue. Can you point me to the exact ENG file you're using?
 

cmp

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Thanks! I am trying to add Cesaroni_40960O8000-P.eng I got from ThrustCurves.org. The largest motor in the delivered OR database has a total impulse of around 21000Ns, I was trying to see how high a single stage rocket would go in OR.
 

Jay Rairigh

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When you use the 'add' button the whole filename is entered into the 'User-defined thrust curves' field but apparently only the folder path is needed here.

cmp, have tried using the Add button to make sure you have correct path?
 

cmp

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Thanks for the suggestions! I tried adding the filename, close OR and reopen and it still did not show. Also, when you use the Add Button it stops at the directory level. It should show at the bottom of the list since it has the highest total impulse and I am sorting it by that field.
 

cmp

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Also, in case anybody is wondering, the inner tube is long and wide enough to contain the motor case - I have seen it filter out diameters wider than the tube - neat design!
 

neil_w

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You only need the path name, not the file. You're specifying a folder where files will be stored, not the files themselves.

I tried the files and they work for me. In the motor selection dialog, make sure you have the filters for Total Impulse and motor dimensions set correctly:
1609696708953.png

(or you can uncheck "Limit motor diameter to mount diameter").
 

neil_w

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Actually I take that back... the files didn't work for me because the O8000 was already in the OR database. Please check your filter settings and look again.
 

cmp

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Ah, interesting. Does your database have other O class motors? Mine has none, it stops at N. I am on 15.03.
 

neil_w

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This is also 15.03.
1609711931736.png

Can you post a screenshot of your "select motor" dialog (the whole thing)?
 

cmp

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So, there seem to be several sources of OR out there. I got a jar file from the openrocket.info set. It has the same size file as the one from sourceforge.net. There is another source, github. The download file there is a zipped file. In it the motor database file is dated 12/21/2020. Do you know where you got yours from?
 

cmp

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Oh, I had not seen your response about the diameter. You got it! Thank you!
 

DeltaVee

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If the file is already in the database, there are a few ways to trick it however the key here is to know if the motor designation has multiple entries. The top of the sheet (if there are multiple entries) will have an active dropdown arrow on the rhs of the motor designation field. For example, you will see that there is more than one entry for motors like the AT F50 and F62. If the motor you are interested in only has a single entry in the drop-down, add the .eng version of the file... then what you do is you append to the file name "_1" just in front of the .eng.

Evidently the multi-entry drop down is enabled via the .eng files (afaict the rse files won't do the same but I have not tried it.) If there are already multi entries, then you would likely add _2 .engor _3.eng etc. (so these examples would be: AeroTech_F50_2.eng... I wanted a new G77 thrustcurve and found I had to add it as AeroTech_G77_2.eng because the current one already had two entries!) IF i had I examined what is in the OR source and found out how this "works". IOW if you see two items in the drop-down you'd use _2 for your new file of an existing entry. If the dropdown is inactive (i.e. only ONE entry) you use _1....

So If you have an updated thrust curve you can add it to the stable by determining what _N.eng to use.


1609727171925.png



BTW I've managed to figure out how to strip out the engine list in OR without recompiling the code and have all the curves as files... Anyone interested?
 
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neil_w

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BTW I've managed to figure out how to strip out the engine list in OR without recompiling the code and have all the curves as files... Anyone interested?
All the motor files are taken directly from thrustcurve.org, so I'm not sure if there's value in stripping them out....
 

DeltaVee

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All the motor files are taken directly from thrustcurve.org, so I'm not sure if there's value in stripping them out....
Someone on another thread asked about that because they felt it would be easier to manage the addition of curves not to mention the elimination of those that are no longer sold or certified. In this case the idea here is that instead of having an unchangeable list of motors, you have complete control over the management of them... still have all the original data files from the source.... it's just easier for me to mess with it this way.
 
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DeltaVee

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@neil_w Is there a link to the thrustcurve motor data to import into OR?
The thrust curves in OpenRocket come from ThrustCurve.org as @neil_w pointed out... however they are compiled into an object that is part of the code. The only way to "import" is either 1) drop them into the folder where OR looks for more thrust curves or 2) recompile the curves into the serialized object in the jar file (thrustcurves.ser happens to be the file name).

The problem with option 1 is that no internal thrust curve is replaced by that method... and if the name of the file is the same as when it was compiled, it won't update or add it.... My prior post describes to some degree, ,the rules one would follow in order to add an updated curve to one that exists. That's why I changed the way my jar file works... my OR has no built in thrust curves, and the ones that are compiled into the single object exists as separate files in a specified folder on my system... I can add or replace or eliminate at my discretion.

As far as downloads go, you can download by individual file once you search for/zero in on a particular motor... I've never found a link that would allow the download of all the curves in one zip file... doesn't mean it's not there somewhere however.
 

rickus

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I just wanted to jump in here and say thank you for all the good information. I too had been struggling with adding new motors to OR. The posts from neil_w were especially helpful. Again, thank you!
 
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