Which Rocket Sim is easiest.

[PDawg]

What is the easiest site to use for a Rocket Simulator? I just want to see what my potential altitudes would be and have a printout if I show up to an official club launch. Thank you.

 

[rharshberger]

What is the easiest site to use for a Rocket Simulator? I just want to see what my potential altitudes would be and have a printout if I show up to an official club launch. Thank you.

Thrustcurve.org for an online quick simulation, but for a better simulation try OpenRocket v22 which is free or RocSim 10 (definitely not free), OR and RS are full simulation programs...design, build, shows stability and Center of Pressure, Center of Gravity, stability over time, velocity, altitude, descent rates...lots and lots of things.

 

[bjphoenix]

I used to use WRasp, fairly easy to use but somewhat unsophisticated.
I've been using Open Rocket which is harder to model in but if you can find a commercial kit close to what you are flying you can get some pretty comparable numbers from it.
I have some ideas to compare some typical production kits in WRasp and Open Rocket to see how close they are.

 

[jqavins]

One thing about ThrustCurve.org (apart from that it's a terrific resource and we should all bow down in gratitude to @John Coker who runs it) is that you need to enter the rocket's C_D. RS and OR calculate an estimate for you. It's not a great estimate, since drag is really hard to predict, but it's better than pulling a number from your posterior orifice.

 

[lakeroadster]

What is the easiest site to use for a Rocket Simulator? I just want to see what my potential altitudes would be and have a printout if I show up to an official club launch. Thank you.

Open Rocket will get you what you're after, and a lot more. And it's hard to beat free.

 

[K'Tesh]

Here's a little primer on OR...

https://www.rocketryforum.com/threa...e-users-guide-to-creating-or-ork-sims.168514/

 

[Cape Byron]

+1 on Open Rocket. It will deliver what you want.

 

[TomBroad]

OR is great -- the beta versions even better -- but it still is not, in my opinion very flexible or accurate at predicting altitude. Especially in that it does NOT allow for a Cd override.
Case in point is my launch today:
PML Phobos on an AeroTech I284. OR predicted a bit less than a mile, and based on previous flight data I knew that was bunk. Lacking any way to adjust Cd directly, I needed to "lie" about the finish of the rocket, saying that my beat-up old Phobos had a pristine smooth finish, and then it predicted 5697 with conditions adjusted to anticipated field conditions. I stuck a few simple parameters into ThrustCurve and got a prediction of 5959. Actual was 5956 -- @JohnCoker missed it by only THREE FEET. OR missed by nearly THREE HUNDRED feet.
OR might be good for a "guesstimate" when designing, but once a rocket is dialed-in from a few flights with varying engines, and a Cd back-calculated, ThrustCurve is my go-to. THANKS @JohnCoker for a fabulous feature -- simple for not, it works great.

 

[rharshberger]

OR is great -- the beta versions even better -- but it still is not, in my opinion very flexible or accurate at predicting altitude. Especially in that it does NOT allow for a Cd override.
Case in point is my launch today:
PML Phobos on an AeroTech I284. OR predicted a bit less than a mile, and based on previous flight data I knew that was bunk. Lacking any way to adjust Cd directly, I needed to "lie" about the finish of the rocket, saying that my beat-up old Phobos had a pristine smooth finish, and then it predicted 5697 with conditions adjusted to anticipated field conditions. I stuck a few simple parameters into ThrustCurve and got a prediction of 5959. Actual was 5956 -- @JohnCoker missed it by only THREE FEET. OR missed by nearly THREE HUNDRED feet.
OR might be good for a "guesstimate" when designing, but once a rocket is dialed-in from a few flights with varying engines, and a Cd back-calculated, ThrustCurve is my go-to. THANKS @JohnCoker for a fabulous feature -- simple for not, it works great.

And your motor happened to perform almost exactly on spec, and the atmospheric model just happened to work out, pure luck you were within three feet, sorry but being within 3' was pure luck, within 3-5% is considered to be a good sim.

 

[neil_w]

What is the easiest site to use for a Rocket Simulator? I just want to see what my potential altitudes would be and have a printout if I show up to an official club launch. Thank you.

If just getting started with OpenRocket, open up the Simple Rocket design example to see how a sim is constructed.

Be aware, though, that if you're trying to simulate an already-built rocket, then you don't need most of the interior stuff. You just need the exterior components (nose, tubes, transitions, fins) and a motor mount. Then weigh the whole thing and measure CG (balance it on your finger and measure the balance point from the nose of the rocket) and use it to override CG and mass of the sustainer. Then you're good to go. It is very quick to put together such a model for a simple rocket.

Simulation software is normally discussed in the Electronics and Software forum (https://www.rocketryforum.com/forums/rocketry-electronics-software.36/); you can get all the help you want there (or here, but it's better to keep the discussions in the right place if possible).

OR is great -- the beta versions even better -- but it still is not, in my opinion very flexible or accurate at predicting altitude. Especially in that it does NOT allow for a Cd override.
Case in point is my launch today:
PML Phobos on an AeroTech I284. OR predicted a bit less than a mile, and based on previous flight data I knew that was bunk. Lacking any way to adjust Cd directly, I needed to "lie" about the finish of the rocket, saying that my beat-up old Phobos had a pristine smooth finish, and then it predicted 5697 with conditions adjusted to anticipated field conditions. I stuck a few simple parameters into ThrustCurve and got a prediction of 5959. Actual was 5956 -- @JohnCoker missed it by only THREE FEET. OR missed by nearly THREE HUNDRED feet.
OR might be good for a "guesstimate" when designing, but once a rocket is dialed-in from a few flights with varying engines, and a Cd back-calculated, ThrustCurve is my go-to. THANKS @JohnCoker for a fabulous feature -- simple for not, it works great.

You *can* override Cd in OR using the latest beta... or rather, I should say that the feature is there but it is not working correctly right now. I'd expect it to be fixed in the next beta (or if not, then at least in the final release.)

 

[DaHabes]

I've been using Rocksim for 15 years. I've also tried Open Rocket (but not the beta). I think Rocksim is better for complex models. If you can swing the dough for it and plan to use it for 20 years, it's a no-brainer. If money is tight, then Open Rocket.

 

[cwbullet]

I alike and use both.

 

[Back_at_it]

This is almost like asking which glue is best

I've used ThrustCurve, Open Rocket and RocSim. My preference is Open Rocket. Very simple to use, does 98% of what I need it to do (the latest release might do 100%) and the best part is that there are some real super users on this site to help out when you have questions.

I can show you how to use it at the next launch as I have it on the laptop that I bring with me.

 

[Alan15578]

Centuri TIR-100. You can't get easier than that.

 

[tsmith1315]

OR might be good for a "guesstimate" when designing, but once a rocket is dialed-in from a few flights with varying engines, and a Cd back-calculated, ThrustCurve is my go-to.

I never intend on teasing a waiver, so I don't need or even want super accuracy. A ballpark estimate is fine for my flying.

But, for posterity, here it is from the horse's mouth:

The simulator in ThrustCurve.org is very basic; it's just to get an idea of which motors will work for a rocket. I would trust a real simulator such as RockSim or OpenRocket if accuracy really matters.

Note that I do not intend to compete with the real simulators. The goal for the ThrustCurve.org motor guide is minimal inputs and quick simulations across many motors.

 

[Banzai88]

OR is great -- the beta versions even better -- but it still is not, in my opinion very flexible or accurate at predicting altitude. Especially in that it does NOT allow for a Cd override.
Case in point is my launch today:
PML Phobos on an AeroTech I284. OR predicted a bit less than a mile, and based on previous flight data I knew that was bunk. Lacking any way to adjust Cd directly, I needed to "lie" about the finish of the rocket, saying that my beat-up old Phobos had a pristine smooth finish, and then it predicted 5697 with conditions adjusted to anticipated field conditions. I stuck a few simple parameters into ThrustCurve and got a prediction of 5959. Actual was 5956 -- @JohnCoker missed it by only THREE FEET. OR missed by nearly THREE HUNDRED feet.
OR might be good for a "guesstimate" when designing, but once a rocket is dialed-in from a few flights with varying engines, and a Cd back-calculated, ThrustCurve is my go-to. THANKS @JohnCoker for a fabulous feature -- simple for not, it works great.

I think you have some settings amiss.
All of my OR Sims have been within 5% without adjustment. After first flight adjustment, they've all been within 3%.

 

[TomBroad]

And your motor happened to perform almost exactly on spec, and the atmospheric model just happened to work out, pure luck you were within three feet, sorry but being within 3' was pure luck, within 3-5% is considered to be a good sim.

My point was that the simple and easy to use sim in ThrustCurve (for whatever reason you may want to attribute) is generally very close to reality and OR is seldom within hundreds of feet of reality -- as this one example showed. If OR was within 3-5% I'd be pleased with that too. Perhaps when OR finally allows the override of Cd that situation may change.

 

[Back_at_it]

My point was that the simple and easy to use sim in ThrustCurve (for whatever reason you may want to attribute) is generally very close to reality and OR is seldom within hundreds of feet of reality -- as this one example showed. If OR was within 3-5% I'd be pleased with that too. Perhaps when OR finally allows the override of Cd that situation may change.

While I don't fly high power yet and cannot comment on how accurate any of the programs would be in predicting altitude for those rockets, I can confirm that Open Rocket is pretty darn close in the low to mid-power range. I have about 190 flights with altimeters on board and most are easily within the 3-5% range for accuracy. Generally when I see one that is outside the 3-5% range it's due to something that I forgot in my simulation or I'm trying to SIM a rocket design that was outside the capabilities of the program. BTW, I still prefer 15.03 to the newer 22.02.04.

Example of some recent flights would be Nasa Pegasus 2.5" upscale build. Flown on a E30-4, the projected apogee was 508ft. Recorded apogee was 489ft. Considering that this is a 16.5oz plane design rocket with external tubes and wings and was flown in 7-10 mph winds, that's close enough for me.

Second example would be the Falcon Commander Upscale. Flown on an E30, the projected apogee was 769ft. Recorded apogee was 746ft. I feel both of these are pretty darn close.

In all honesty, The apogee is fun to play around with but I use the SIM programs more for stability and to ensure that the motor I selected has sufficient thrust to get the rocket safely off the pad. I'm not into big air and prefer to keep my rockets at or below the 1000' mark.

 

[neil_w]

BTW, I still prefer 15.03 to the newer 22.02.04.

Can you expand on this please?

 

[Back_at_it]

Can you expand on this please?

I've had a number of freezes while designing, updating and saving in the latest version. There also seems to be a memory leak as the program eventually gives an out of memory error if you have opened more than a couple of sim files.

Also seemed to have lost the ability to click on the components of the rockets to bring up the details screen when in 3D unfinished mode. With the newer release I need to go back and find the component in the list view to click and see details.

I do like the new features but I don't really use them right now. I'm sure they will get put to good use as my designs become more complex.

 

[Titan II]

Rocksim works very well, is accurate, easy to use, and does not crash.

 

[neil_w]

I've had a number of freezes while designing, updating and saving in the latest version. There also seems to be a memory leak as the program eventually gives an out of memory error if you have opened more than a couple of sim files.

Please report these freezes if you can, so we can look into them. We've found the latest beta to be quite stable. What OS are you on? Are you using the packaged installer or JAR file?

Also seemed to have lost the ability to click on the components of the rockets to bring up the details screen when in 3D unfinished mode. With the newer release I need to go back and find the component in the list view to click and see details.

Are you trying to double-click to open up the component editor or just single-click to select?

 

[G_T]

For simple sims, I prefer RasAero. My standard is 1% error, with EX solid propellant motors, for altitude. I usually hit that standard, worst error in last 5 such flights was 3%, accountable due to wind that I didn't put in the sim.

RasAero is concerned about the exterior shape of the rocket. You don't have to add motor tubes etc. So it is quicker to set up and use. You also don't have to guesstimate a Cd.

All the tools have a learning curve.