Help needed: OpenRocket: "Forward end of airframe is open" when it clearly isn't

[le_zoink]

Hello all,

Sorry if i'm being a bit stupid, but I'm designing a two-stage rocket in OpenRocket and am encountering a problem: whenever I try to run a simulation, the software thinks my first stage is open-ended and thus doesn't give me any useful values concerning its flight. I haven't encountered anyone else having this problem other than a thread on this site from last year.

Is this problem due to an oversight on my part, or is the Openrocket on the fritz?

Here attached are a screenshot of the rocket and the .ork file. (Don't mind the lack of fins on the upper stage, that's intentional)

 

[Art Upton]

Hello all,

Sorry if i'm being a bit stupid, but I'm designing a two-stage rocket in OpenRocket and am encountering a problem: whenever I try to run a simulation, the software thinks my first stage is open-ended and thus doesn't give me any useful values concerning its flight. I haven't encountered anyone else having this problem other than a thread on this site from last year.

Is this problem due to an oversight on my part, or is the Openrocket on the fritz?

Here attached are a screenshot of the rocket and the .ork file. (Don't mind the lack of fins on the upper stage, that's intentional)

Simulation ran on my computer. Weird results likely because no fins?

 

[Art Upton]

 

[Art Upton]

 

[le_zoink]

Simulation ran on my computer. Weird results likely because no fins?

View attachment 672634

Even if I add fins to the upper stage, I still get this error.

 

[Art Upton]

Hello all,

Sorry if i'm being a bit stupid, but I'm designing a two-stage rocket in OpenRocket and am encountering a problem: whenever I try to run a simulation, the software thinks my first stage is open-ended and thus doesn't give me any useful values concerning its flight. I haven't encountered anyone else having this problem other than a thread on this site from last year.

Is this problem due to an oversight on my part, or is the Openrocket on the fritz?

Here attached are a screenshot of the rocket and the .ork file. (Don't mind the lack of fins on the upper stage, that's intentional)

If you add fins to the second stage and fly it alone, it does not give the warning and flies to 455 feet.

Fly both it flies to 972 feet, but gives you a warning about the "kick stage" being open




So adding fins the plot looks more normal, not sure why that error

 

[neil_w]

I think that open-tube warning will go away in the next release. In the meantime it can be ignored.

 

[JoePfeiffer]

Something we're working on for the next release is trying to do a better job letting users know exactly when and why simulation warnings occur, and only have actually useful warnings.
Anyway, from the current development version (so this is a sneak preview of the next release), here's a couple of screenshots.

First, the kickstage stage: hopefully it's clearer here that your warning is occurring at stage separation, when the kickstage, by itself, does indeed have an open forward tube. Since it's unlikely someone who doesn't have a recovery system in their booster cares about its flight, it is likely (as @neil_w says above) that this warning will go away. On the other hand, we should probably add a warning that your booster stage is coming in ballistic.

Second, the Upper stage: This stage, by itself, is unstable and tumbles while the motor is still burning. At this point there is nothing useful the simulation can tell you (we can't simulate skywriting in any useful sense), so the simulation aborts.