OpenRocket "Forward end of airframe is open"

[Macrophage42]

I have a 3-stage rocket using BT-60 body tubes and a PNC-60A nose cone. When I run a sim, I get this warning, "Forward end of airframe is open". How do I fix this?

OpenRocket file attached.

 

[BEC]

I've been meaning to ask this question as I did a sim of the TK-45 Beta (two stage 13mm motor-powered model) and get the same error, though the simulation results are quite plausible based on some instrumented flights of a Beta. I'd also post the .ork, but it's not on this machine, and the one it's on is packed for our trip to the WSMC very early in the morning.

The file was done with the Windows version of 22.02. (and yes, I know that technically there is no "Windows version" per se)

 

[neil_w]

Generally this means you have a body tube without a nose cone in front of it.

I cant run OR right now (on vacation without a computer) so if you need further assistance post a screenshot.

 

[techrat]

Delete the nosecone and then add it back. Maybe Open rocket is just having a bad day.

 

[Steve Shannon]

Delete the nosecone and then add it back. Maybe Open rocket is just having a bad day.

Or at least make sure the nosecone is owned by the sustainer...

 

[lakeroadster]

Hmm... I opened your file and no warnings

Neat rocket.. that'll be a fun launch, staging occurs where it can be easily viewed.

 

[kjhambrick]

I have a 3-stage rocket using BT-60 body tubes and a PNC-60A nose cone. When I run a sim, I get this warning, "Forward end of airframe is open". How do I fix this?

OpenRocket file attached.

Microphage42 --

I opened your Triad.ork without any warnings on my Linux Laptop.

Maybe [Save]->[Exit] then restart OR and [Open Recent] ?

-- kjh

A Picture:

 

[Reinhard]

Renaming the body tubes, to give them individual names, shows that the warning originates from the lower stages (I was sloppy and named them top down, not in order of operation).



I also checked with the included three stage example file, and this is where it gets odd. The warning appears there too, but varies on the different flight configurations.

Simulation 1:


Simulation 2:

And no warning on Simulation 3:


All simulations were rerun after changing the name of the tube. All the motors have the same external dimensions.
It doesn't seem to be a problem yet, but it might be an indication that something under the hood works differently than intended.

Reinhard

 

[lakeroadster]

@Macrophage42 @kjhambrick and @Reinhard

What version of Open Rocket are you using? Version 22.02 Opens the file with no errors

 

[Reinhard]

I can open it with OR 22.02 (Windows setup) without problems, but after simulating it the warning appears on mouse hover in the list of simulations. It's only a warning though without any apparent ill effects.

I also tried OpenRocket-15.03.jar, but that doesn't work with the posted file that was created with a newer version.

Reinhard

 

[lakeroadster]

I can open it with OR 22.02 (Windows setup) without problems, but after simulating it the warning appears on mouse hover in the list of simulations. It's only a warning though without any apparent ill effects.

I also tried OpenRocket-15.03.jar, but that doesn't work with the posted file that was created with a newer version.

Reinhard

Yeah, that's weird. I run the simulations in 22.02 windows and still get no warnings whatsoever.

 

[kjhambrick]

@Macrophage42 @kjhambrick and @Reinhard

What version of Open Rocket are you using? Version 22.02 Opens the file with no errors

lakeroadster --

I am running OR version 22.02 on Slackware Linux 15.0 with openjdk11-11.0.19_7

No errors here when I opened Microphage42's Triad.ork nor when I added a new Motor Selection: C6-0 ; C6-0 ; D12-3 and Plotted that Stack.

-- kjh

 

[Reinhard]

@lakeroadster and @kjhambrick

Just to be explicit: When you run a simulation from Triad.ork, your simulation results shows the "Green Orb" and "Green Check Mark" icons? On mouse hover the tool tip "Simulation x, Up to date, No warnings" is shown? (Like in the last screenshot in my post #8)

Reinhard

 

[JoePfeiffer]

After stage separation, the forward end of the bottom and second stages are open, so you're getting a warning that any simulation results from those stages are not to be trusted. I'm sort of torn on whether that warning does more harm than good, since you probably already knew that...
On the example rocket, hmmmm..... I don't know why the third simulation isn't showing it. That will take some thought.

 

[Reinhard]

On the example rocket, hmmmm..... I don't know why the third simulation isn't showing it. That will take some thought.

I just noted a detail. Simply opening the file and running the simulations over and over will most of his time result in no warning for Simulation 3, but in about 10% of runs, the warnings will also appear on Simulation 3. So far, it's always either both warnings (forward end open and large angle of attack) or none of it. I wasn't able to trigger a different outcome on Simulation 1 or 2.

By the way, do you want bug reports on Github for those "looks odd, but doesn't seem to cause any further harm" things or do you prefer them for only more clear cut bugs?

Reinhard

 

[neil_w]

By the way, do you want bug reports on Github for those "looks odd, but doesn't seem to cause any further harm" things or do you prefer them for only more clear cut bugs?

File them all.

 

[JoePfeiffer]

File them all.

We try to watch all the various sources we have for bug reports (email from the error dialog, the old OR bugs mailing list, here, our discord server, reddit, facebook...) but the github issues page at https://github.com/openrocket/openrocket/issues is where we track, triage, and discuss the actual reports. That's the best place to tell us about them, no matter how minor or ephemeral they are.

 

[BEC]

Here is my Beta:



Yes, the nose cone belongs to the sustainer.

 

[kjhambrick]

@lakeroadster and @kjhambrick

Just to be explicit: When you run a simulation from Triad.ork, your simulation results shows the "Green Orb" and "Green Check Mark" icons? On mouse hover the tool tip "Simulation x, Up to date, No warnings" is shown? (Like in the last screenshot in my post #8)

Reinhard

Reinhard --

I don't see the red exclamation point on my Linux Laptop.

That may be because I have not properly configured Java for my High-Rez ( 4K ) Native Laptop Monitior.

I've got green dots on each Sim Row though:



Sorry about the ugly text ... I've gotten used to it

Thanks for working on making OR better All'Y'All !

-- kjh

IMPORTANT P.S. I do see 'Forward End of Airframe is Open ; Large Angle of Attack Encountered ( 20.1 deg ) when I hover over any of the Sims which I never noticed before !

 

[bad_idea]

Sorry about the ugly text ... I've gotten used to it

Slackware is fun, but so many paper cuts! It's been a few years since I ran it in anything but a test VM. I recall there was a way to get better fonts, but I've long since forgotten what it was. (Just checked my notes, which are usually copious when it comes to OS configuration, and I didn't find it.)

 

[kjhambrick]

bad_idea --

I've been a Slacker since way back when and it's come a long way but it still is fun

It's odd ... my fonts work fine in all my other Apps except in Open Rocket 'text dialogs'.

Not sure why and I would need to spend some time finding out which Java GUI is running behind Open Rocket on Linux ( Swing or JavaFX or AWT or ??? )

I imagine it is a simple config that has nothing to do with Open Rocket ...

No matter, all I am really after is for now is a safe VRod and sane Altitudes for the Waiver and the Launch Site so the nasty text dialog fonts have never been a roadblock.

-- kjh

 

[thzero]

It's Swing

 

[Art Upton]

Linux Mint

 

[Macrophage42]

I am the original poster of this thread. Thanks for all the responses. From the responses, I gather that the warnings can be ignored, and that the simulation results are not affected by them.