ANNOUNCEMENT: The OpenRocket 22.02 Beta Period is now finished

[Charles_McG]

If I had my work laptop with me, I could submit one myself (the GitHub verification to my personal email gets eaten by my host’s spam monster - and I’ve forgotten the password already. The consequence of depending on the cache.)

I posted here so it would be more visible. Maybe I’m an outlier.

 

[neil_w]

If I had my work laptop with me, I could submit one myself (the GitHub verification to my personal email gets eaten by my host’s spam monster - and I’ve forgotten the password already. The consequence of depending on the cache.)

I posted here so it would be more visible. Maybe I’m an outlier.

https://github.com/openrocket/openrocket/issues/1555
The auto-open behavior is most useful when creating new configurations, I think. When duplicating configurations, especially when multi-stage (probably the most common use for duplicating) it's benefit is less clear, and most likely we should just disable it. We'll think about it.

 

[bad_idea]

I posted here so it would be more visible. Maybe I’m an outlier.

If you are, I'm the same kind of outlier. I can live with it, but it's not ideal.

The auto-open behavior is most useful when creating new configurations, I think. When duplicating configurations, especially when multi-stage (probably the most common use for duplicating) it's benefit is less clear, and most likely we should just disable it.

I think you hit the nail on the head right here.

 

[BDB]

I finally got around to downloading the new OR (version 22.02.beta.04 for Mac). It looks great and works well when I build a rocket from scratch or load the examples. But when I try to open a .ork file that I have previously built and simulated, I keep getting an error. Does anyone know what is causing this? (Sorry if it has already been answered somewhere in the previous 20 pages of this thread.)

 

[neil_w]

Please post the file.

 

[BDB]

So I think I figured it out. I keep most of my rocketry files in a Dropbox folder. I can access the folder through the Mac finder, but they are apparently stored only in the cloud. That used not to be the case, but it sounds like this is caused by an issue with Mac OS 12.3 or higher (I'm running 12.5). Once I told Dropbox to store the files locally, I could open them.

If anyone else has this same issue, here's how to solve it

 

[H. Craig Miller]

Questions for those using canted fins in OpenRocket.

1. Does anyone use fins with a cant of greater than 15 degrees during verticle flight; the answer is no if the fins cant for glide recovery, but not for verticle flight.
2. If the answer to 1 is yes, what is the greatest number of degrees that you need the fin cant to be, and can you post an .ork file showing how the fins are being used?

 

[Endymion42]

Just started using OpenRocket. Was trying to reconcile actual weight of my rocket with weight predicted by OpenSim as I am having stability issues I am not expecting. One thing I noticed was that the weight of the Estes C6-7 motor in OpenRocket is 23.1 grams, whereas the Estes specifications show 24.3 grams and my actual measurement of an instance of a C6-7 motor was 24.8 grams. Is there a way to adjust the motor weight (I don't want to override the whole model to adjust the weight).

Thanks in advance,
John

 

[DeltaVee]

Just started using OpenRocket. Was trying to reconcile actual weight of my rocket with weight predicted by OpenSim as I am having stability issues I am not expecting. One thing I noticed was that the weight of the Estes C6-7 motor in OpenRocket is 23.1 grams, whereas the Estes specifications show 24.3 grams and my actual measurement of an instance of a C6-7 motor was 24.8 grams. Is there a way to adjust the motor weight (I don't want to override the whole model to adjust the weight).

Thanks in advance,
John

The weight in open rocket's database presumably comes from the measurements taken during certification testing. I don't think one or two grams will make much of an impact though. What you could do I suppose is place a mass element at the center of where the motor is as a crude approximation. That said, if you're stability relies on dropping one or two grams somewhere, you may want to consider adjusting your fin size/ placement. That's assuming of course you are not modeling something like a micro-max size rocket! But then you likely wouldn't be talking about a c6-7.

 

[Endymion42]

Thanks, the total discrepancy is much more than a gram or two, more like 9 grams. I am systematically measuring each piece and comparing to OpenRocket numbers and adjusting as needed to balance the books. Thanks for the thought on adding the mass element; I'll use that for the motor discrepancy.

John

 

[H. Craig Miller]

The weight of the Estes C6-7 motor in OpenRocket is 23.1 grams, whereas the Estes specifications show 24.3 grams and my actual measurement of an instance of a C6-7 motor was 24.8 grams.

In reality, the mass of the Estes C6 motor depends upon the delay time, 0=20.2g, 3=24.1g, 5=24.0g, and 7=24.2g [see Estes Certification]; there is also a manufacturing tolerance of a few percentage points, plus or minus. OpenRocket uses ThrustCurve data (as does Rocksim) which data currently has a propellant mass of 10.8g and total mass of 23.1g for all delays as shown on the attached RASP file; candidly, the 23.1g total mass could be a typo and probably should be 24.1g, the total mass of the C6-3, rather than 23.1g which does not correlate to the total mass of any delay value.

 

[Tobor]

Isn't it possible to just edit the Estes eng/rse file then place it in OR's ThrustCurves folder for assimilation?

 

[H. Craig Miller]

Isn't it possible to just edit the Estes eng/rse file then place it in OR's ThrustCurves folder for assimilation?

Motor files may be easily added to OpenRocket. Modifying an existing ThrustCurve file packaged with OpenRocket, not so much. And, if modified, the modifiied motor definition may be overwritten when the next version of OR is installed. The better solution would be for ThrustCurve to correct the RASP motor file being used by OpenRocket.

 

[smstachwick]

Motor files may be easily added to OpenRocket. Modifying an existing ThrustCurve file packaged with OpenRocket, not so much. And, if modified, the modifiied motor definition may be overwritten when the next version of OR is installed. The better solution would be for ThrustCurve to correct the RASP motor file being used by OpenRocket.

Is the method described here no longer an option?

https://www.rocketryforum.com/threads/openrocket-12-03-motor-data-editing.38002/

 

[H. Craig Miller]

Is the method described here no longer an option?

https://www.rocketryforum.com/threads/openrocket-12-03-motor-data-editing.38002/

OpenRocket has evolved a great deal in the 10 years since OR 12.03 was first available.

As to your question, this evolution includes the incorporation of Dave Cook's parts library and all of the ThrustCurve motor files, both of which are regularly updated. Those who use certified motors should see a significant decrease in need, most will have no reason to add motor files to OpenRocket, save those few on the cutting edge who may need files for just released motors during the period of time between certification and inclusion in the ThrustCurve database. And, being able to "uncheck" manufacturers and the use of other filters takes away most user concerns regarding seeing undesired motors. For those using experimental motors, motor files for those may placed in a single common directory and referenced (added) as before on the Preferences -> General tab.

Insofar as editing OpenRocket's internal motor database is concerned, this is not recommended unless you are experienced in Java and OpenRocket's data file structures. Quite frankly, if you are running the current Beta version of OpenRocket, I'd be interested to hear why you are trying to modify the internal motor database, what is it that you are trying to achieve?

 

[smstachwick]

OpenRocket has evolved a great deal in the 10 years since OR 12.03 was first available.

As to your question, this evolution includes the incorporation of Dave Cook's parts library and all of the ThrustCurve motor files, both of which are regularly updated. Those who use certified motors should see a significant decrease in need, most will have no reason to add motor files to OpenRocket, save those few on the cutting edge who may need files for just released motors during the period of time between certification and inclusion in the ThrustCurve database. And, being able to "uncheck" manufacturers and the use of other filters takes away most user concerns regarding seeing undesired motors. For those using experimental motors, motor files for those may placed in a single common directory and referenced (added) as before on the Preferences -> General tab.

Insofar as editing OpenRocket's internal motor database is concerned, this is not recommended unless you are experienced in Java and OpenRocket's data file structures. Quite frankly, if you are running the current Beta version of OpenRocket, I'd be interested to hear why you are trying to modify the internal motor database, what is it that you are trying to achieve?

I’m actually operating a legacy version I believe, I’d have to double-check. I haven’t run an update in some time if ever.

 

[waltr]

A very nice thing with OR is you can have multiple versions installed and run any of them.
It is not an 'update' that wipes out previous versions.
This makes trying a newer version risk free.

 

[H. Craig Miller]

A very nice thing with OR is you can have multiple versions installed and run any of them.
It is not an 'update' that wipes out previous versions.
This makes trying a newer version risk free.

Yes, and no. Although it is true that multiple versions of OpenRocket can be installed and simultaneously run, certain files and file locations are shared, especially as between the beta releases. Care should taken when changing OpenRocket files and file locations.

 

[JoePfeiffer]

Isn't it possible to just edit the Estes eng/rse file then place it in OR's ThrustCurves folder for assimilation?

Yes. But that difference in mass isn't going to be the cause of his unexpected results.

 

[4regt4]

Not sure if this has been reported. I do an overall RocForum search for "Scale Fin" and not much shows up.

Trying to downsize an existing file from 4" size to 3". Resized everything just fine, until I got to the fins.

Select the fins in the component list, then click "Shape" tab. The fin has some curves that are simulated with many separate points. Click on "Scale Fin" and.....

Get a pop up that starts with "OpenRocket encountered an uncaught exception." It asks that I report the bug. Last line in the window says "This can be done automatically if you have an internet connection." But I don't see how to do this. I click on "View Bug Report", get a window with a lot of text. It gives a pair of links to either report online - which only goes to a login window for which I don't have username or password, or I can send an email. But there is no way obvious to me has to how to send all that text by email. There isn't a "Select all" option anywhere, however I can manually select the text by clicking and scrolling the mouse. But then I can't do anything with it. Right click does not bring up a menu to copy-and-paste.

For now, it looks like I have to manually recalculate a couple of dozen curve points.

Hans.

 

[SiboVG]

Not sure if this has been reported. I do an overall RocForum search for "Scale Fin" and not much shows up.

Trying to downsize an existing file from 4" size to 3". Resized everything just fine, until I got to the fins.

Select the fins in the component list, then click "Shape" tab. The fin has some curves that are simulated with many separate points. Click on "Scale Fin" and.....

Get a pop up that starts with "OpenRocket encountered an uncaught exception."

That issue has been reported on GitHub (link 1, link 2) and has already been fixed here. The patch will be included in 22.02.beta.05 (will be released soon).

It asks that I report the bug. Last line in the window says "This can be done automatically if you have an internet connection." But I don't see how to do this. I click on "View Bug Report", get a window with a lot of text. It gives a pair of links to either report online - which only goes to a login window for which I don't have username or password, or I can send an email. But there is no way obvious to me has to how to send all that text by email. There isn't a "Select all" option anywhere, however I can manually select the text by clicking and scrolling the mouse. But then I can't do anything with it. Right click does not bring up a menu to copy-and-paste.

The normal bug reporting procedure is done on the GitHub repository of OpenRocket. I understand it can be tedious to work with if you're not used to it. I've created an issue request to make bug-reporting more user-friendly here.

 

[Endymion42]

Had the same issue with scaling. Glad to know it’s reported and addressed.

 

[smstachwick]

Does OR assume a specific airfoil cross-section when the option is selected to airfoil the fins? I’m guessing a bi-convex would cut through the air much better than a simplified one at transonic speeds

 

[waltr]

Does OR assume a specific airfoil cross-section when the option is selected to airfoil the fins? I’m guessing a bi-convex would cut through the air much better than a simplified one at transonic speeds

Good question and I would also like to know the answer.

As a wish list-- I would like other fin profiles available. I typically bevel the fin leading and trailing edge but then unsure of which to pick to sim.

 

[prfesser]

Does OR assume a specific airfoil cross-section when the option is selected to airfoil the fins? I’m guessing a bi-convex would cut through the air much better than a simplified one at transonic speeds

My understanding is that "Rounded" means bi-convex or semi-cylindrical on leading and trailing edges. "Airfoil" means rounded leading and tapered trailing edges.

 

[neil_w]

Good question and I would also like to know the answer.

As a wish list-- I would like other fin profiles available. I typically bevel the fin leading and trailing edge but then unsure of which to pick to sim.

That's a good question. I think bevels are a common enough profile that it should be offered in the program. I will submit a feature request.

I don't have an immediate answer as to which existing profile would model most closely to bevels. Will ask around.

 

[JoePfeiffer]

Does OR assume a specific airfoil cross-section when the option is selected to airfoil the fins? I’m guessing a bi-convex would cut through the air much better than a simplified one at transonic speeds

It's not that detailed. It just estimates pressure drag based on whether the leading edge is square or rounded ("airfoiled" is same as rounded), then estimates base drag based on square, rounded, or airfoiled (airfoiled has 0 base drag).

 

[Charles_McG]

That's a good question. I think bevels are a common enough profile that it should be offered in the program. I will submit a feature request.

I don't have an immediate answer as to which existing profile would model most closely to bevels. Will ask around.

Seems like an opportunity for a plug-in. Select a file with a table of drag and Cp by AoA and Mach Number and feed it into the formulas during the sim. 3D rendering different profiles is a different beast if I understand how the plug-in work at all.

 

[JoePfeiffer]

Good question and I would also like to know the answer.

As a wish list-- I would like other fin profiles available. I typically bevel the fin leading and trailing edge but then unsure of which to pick to sim.

Heck, I'd like to see someone look up airfoil characteristics and put a more serious fin profile model in it! Your use case is probably best modeled by "rounded" depending on the angle of the bevel. If it's a real knife-edge (think Nike) probably airfoiled would be better.

 

[thzero]

Heck, I'd like to see someone look up airfoil characteristics and put a more serious fin profile model in it! Your use case is probably best modeled by "rounded" depending on the angle of the bevel. If it's a real knife-edge (think Nike) probably airfoiled would be better.

Yeah that'd be nice Joe.... mmms, isn't it kinda funny that OpenRocket is "open", as in "open source" and in GitHub where anyone with the abilities can contribute!