Open Rocket Deployment System Simulation Error

kemal eliacik · Feb 13, 2019

Hi, We are getting an error during the simulation. Despite we had adjusted an ejection altitude that has lower velocity it says that recovery device deployment at high speed, as we denoted at the picture. how to fix this issue?

dhbarr · Feb 13, 2019

Attach your sim ( .ork )

kemal eliacik · Feb 13, 2019

dhbarr said:
Attach your sim ( .ork )

Would you instruct me to how to fix?

tim cubbedge · Feb 13, 2019

Looking at your ork file will make it easier to analyze without a bunch of people guessing but my first thought is your drogue is too small.

dhbarr · Feb 13, 2019

OpenRocket's file format is .ork .

Attach a copy of your simulation to this thread.

kemal eliacik · Feb 13, 2019

Firstly, thanks for your response. However, since there is a competition, I will not be able to share the file.

Steve Shannon · Feb 13, 2019

Try a larger drogue chute at apogee.

kemal eliacik · Feb 15, 2019

I tried but it didn't.

dhbarr · Feb 15, 2019

If you won't attach your super-secret sim, at least tell us how big the thing is, how much it weighs, and what motor you've chosen.

Otherwise stop just posting that it didn't work.

BDB · Feb 15, 2019

That warning means that either the deployment is too early (while the rocket is still going up) or too late (while the rocket is going down). The output of the simulation will tell you how fast the rocket is moving at deployment. The ideal would be 0, meaning that deployment happens at apogee. The sim will also tell you the optimal delay time. Adjust your delay time to that number and the warning should go away.

Are you planning to use electronic deployment? If so this is a moot point. If you are using motor deployment, you will have to adjust the delay to match the sim for the actual flight.

Rex R · Feb 15, 2019

from the limited info posted, this is a dual deploy bird. open rocket from what I have seen always complains about deployment speed for the main chute, I will admit that deploying the main chute at 130mph is likely to be problematic. my guess is that you are going for a drogueless system, OR doesn't do drogueless, you'll have to use a dummy chute to bring your descent speed down to a more likely speed(30 - 40 m/s)(OR thinks that the rocket is coming in ballistic, and it will still complain about deployment speed).

BDB · Feb 15, 2019

Good point, Rex. I didn't check out his flight profile graph in the original post. The OP needs a bigger drogue or to ignore the warning and hope for the best.

Steve Shannon · Feb 15, 2019

kemal eliacik said:
I tried but it didn't.

You have to participate more in solving your own problem. Otherwise I don’t know how we can help. It’s obvious from the warning and the graph you included that the warning is that software thinks the rocket is falling too fast when the main opens. When you tried a larger chute did the velocity in the warning decrease? If so, keep trying larger drogue chutes. Or try a very large one to see if that stops the warning.
Also, look to see if the velocity at which such a warning appears is configurable.

Bat-mite · Feb 15, 2019

Every single one of my sims for all my rockets always gives that warning. And I summarily ignore it. I don't think OR understands DD. It expects a nice, soft apogee deployment speed for the main, but with DD you are falling at a good 75 fps under drogue, more if you are drogueless or using a streamer.

Personally, I would ignore it.

afadeev · Feb 15, 2019

kemal eliacik said:
Firstly, thanks for your response. However, since there is a competition, I will not be able to share the file.

Then launch, and see what happens...
OR sim results may be wrong, or they may be wright. Only one way to find out!

a

kemal eliacik · Feb 15, 2019

[QUOTE = "BDB, posta: 1860146, üye: 24157"] Bu uyarı, dağıtımın çok erken (roket hala yükselirken) veya çok geç (roket aşağı inerken) anlamına gelir. Simülasyonun çıktısı, roketin açılma sırasında ne kadar hızlı hareket ettiğini size söyleyecektir. İdeal olan 0 olacaktır, yani dağıtım apogee'de gerçekleşir. Sim ayrıca size en uygun gecikme zamanını söyleyecektir. Gecikme sürenizi bu numaraya ayarlayın ve uyarı kaybolmalıdır.

Elektronik dağıtım kullanmayı mı düşünüyorsunuz? Eğer öyleyse bu bir tartışma noktasıdır. Motor dağıtımını kullanıyorsanız, gerçek uçuşun sim ile eşleşmesi için gecikmeyi ayarlamanız gerekir. [/ QUOTE]

Evet, elektronik dağıtım kullanmayı düşünüyorum.

Steve Shannon · Feb 15, 2019

kemal eliacik said:
[QUOTE = "BDB, posta: 1860146, üye: 24157"] Bu uyarı, dağıtımın çok erken (roket hala yükselirken) veya çok geç (roket aşağı inerken) anlamına gelir. Simülasyonun çıktısı, roketin açılma sırasında ne kadar hızlı hareket ettiğini size söyleyecektir. İdeal olan 0 olacaktır, yani dağıtım apogee'de gerçekleşir. Sim ayrıca size en uygun gecikme zamanını söyleyecektir. Gecikme sürenizi bu numaraya ayarlayın ve uyarı kaybolmalıdır.

Elektronik dağıtım kullanmayı mı düşünüyorsunuz? Eğer öyleyse bu bir tartışma noktasıdır. Motor dağıtımını kullanıyorsanız, gerçek uçuşun sim ile eşleşmesi için gecikmeyi ayarlamanız gerekir. [/ QUOTE]

Evet, elektronik dağıtım kullanmayı düşünüyorum.

Here’s the translation:

This warning means that the deployment is too early (when the rocket still rises) or too late (the rocket goes down). The output of the simulation will tell you how fast the rocket moves during opening. The ideal would be 0, ie the distribution takes place in apogee. Sim will also tell you the most appropriate delay time. Set the delay time to this number and the warning should disappear.

Are you considering using electronic distribution? If so, this is a point of discussion. If you are using engine deployment, you must set the delay for the actual flight to match the sim.

Yeah, I'm thinking of using electronic distribution. [/ QUOTE]

mikec · Feb 15, 2019

A quick skim of the source code at https://github.com/openrocket/openr...et/simulation/BasicEventSimulationEngine.java shows

Code:

if (status.getRocketVelocity().length() > 20) {
status.getWarnings().add(new Warning.HighSpeedDeployment(status.getRocketVelocity().length()));
}

So this seems to be hardwired for any speed above 20 whatever the internal units of OR are -- meters/sec?

Buckeye · Feb 15, 2019

Bat-mite said:
Every single one of my sims for all my rockets always gives that warning. And I summarily ignore it. I don't think OR understands DD. It expects a nice, soft apogee deployment speed for the main, but with DD you are falling at a good 75 fps under drogue, more if you are drogueless or using a streamer.

Personally, I would ignore it.

Not only that, the warning says the high speed is 58 m/s, but the maximum descent speed on the graph is only 30 m/s. Even if is it raising the error on the max total velocity being 58 m/s, and not just the vertical velocity (as shown in the graph), then the side speed from the wind needs to be ~50 m/s (112 mph). Not happening.

This is a bogus error all the way around. Ignore it. Maybe it will get fixed in the next release, if there ever is one.

Open Rocket Deployment System Simulation Error

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