Thrustcurve Open Thread

[dhbarr]

OK, on the desktop browser you should be able to search for a range of diameters as well as either single or a range of average and maximum thrust.
Maximum thrust also shows up in the search results if there's space.

Really great stuff, love this resource.

 

[smstachwick]

Hey!

I’m loving the new features on the site. I did notice a few things that might merit some investigation or updating though.

1.). The Contrail G300 has its total impulse listed at 161 N-s, peeking out of the G range and into the low end of H territory. The thrust curve in OpenRocket shows it closer to 100 N-sec. Could this have been a result of confusion with the Contrail H hybrids?

2.). It appears that the Aerotech I40 has gone out of production, according to the Master Motor Matrix dated 8/24/2021. R.A.T.T. also no longer appears to be producing hardware or reloads, according to their website. Some portions of the HyperTek website have not been updated in 20 years, with MSRPs replaced by an instruction to call the dealer. Not sure if they’re OOP but I’ve got a hunch they’d be hard to find.

 

[JohnCoker]

1.). The Contrail G300 has its total impulse listed at 161 N-s, peeking out of the G range and into the low end of H territory. The thrust curve in OpenRocket shows it closer to 100 N-sec. Could this have been a result of confusion with the Contrail H hybrids?

Yeah, those could be bad data files. If you have a good one, please submit it and I will delete the other ones.

2.). It appears that the Aerotech I40 has gone out of production, according to the Master Motor Matrix dated 8/24/2021. R.A.T.T. also no longer appears to be producing hardware or reloads, according to their website. Some portions of the HyperTek website have not been updated in 20 years, with MSRPs replaced by an instruction to call the dealer. Not sure if they’re OOP but I’ve got a hunch they’d be hard to find.

I marked the AT 140 as OOP.

I'm not sure about HyperTek either; my feeling is that they are defunct, but at least for a while CTI was supporting them to some extent.

 

[mikec]

1.). The Contrail G300 has its total impulse listed at 161 N-s, peeking out of the G range and into the low end of H territory. The thrust curve in OpenRocket shows it closer to 100 N-sec.

The TMT cert document https://contrailrockets.com/TMTPapers/G300.pdf says 100 N-s but gives a thrust curve that looks nothing much like the one on thrustcurve, so certainly something is confused.

 

[JohnCoker]

The TMT cert document https://contrailrockets.com/TMTPapers/G300.pdf says 100 N-s but gives a thrust curve that looks nothing much like the one on thrustcurve, so certainly something is confused.

Thanks. I updated the info on the site to match that document and also uploaded it. (Where I have them, you can also download the certification letters on the motor pages.)

I agree that those simulator files don't look right.

 

[Neutronium95]

If you just want the thrust curves, the "combine motors" function at https://www.rocketreviews.com/combine-motors.html does this.

This is a great tool, but I really wish that Thrustcurve could implement something similar, since the EMRR database is a bit out of date, and it's also a bit of a pain to find motors in the list.

2.). It appears that the Aerotech I40 has gone out of production, according to the Master Motor Matrix dated 8/24/2021. R.A.T.T. also no longer appears to be producing hardware or reloads, according to their website. Some portions of the HyperTek website have not been updated in 20 years, with MSRPs replaced by an instruction to call the dealer. Not sure if they’re OOP but I’ve got a hunch they’d be hard to find.

The I40 was relatively recently certified, and should go on sale sometime early this year.

 

[smstachwick]

The I40 was relatively recently certified, and should go on sale sometime early this year.

Oh darn, I should have checked the certification date before posting.

 

[JohnCoker]

This is a great tool, but I really wish that Thrustcurve could implement something similar, since the EMRR database is a bit out of date, and it's also a bit of a pain to find motors in the list.

That's an interesting idea. Does it produce a RASP file as a result or just a thrust curve graph?

The I40 was relatively recently certified, and should go on sale sometime early this year.

Updated the motor back.

 

[jqavins]

I didn't know about this EMRR feature until I read of it here, so I went and tried it out.

That's an interesting idea. Does it produce a RASP file as a result or just a thrust curve graph?

The problem for me is that it produces a RASP file and not a graph. I don't need a RASP file, since I can just load the cluster configuration in RS or OR; it's the graph I want.

 

[mikec]

I didn't know about this EMRR feature until I read of it here, so I went and tried it out.The problem for me is that it produces a RASP file and not a graph.

It produces a RASP file and a thrust curve graph. Presumably you want an altitude simulation?

I guess thrustcurve could do this, but it would have to have a specific interface to do it.

 

[jqavins]

OK, I'll have to try again. When I picked a motor configuration (1×D12 + 2×A10) it gave me total impulse, average thrust, and a RASP file; no picture.

When I want a detailed simuation, I'd have a rocket design (RS or OR) to simulate, with the propper cluster or mounts. So I'd load the engines and go. I see no need of a combined RASP file. What I'd like, and I may be asking for something that's more trouble than it's worth, is a graph for combinations that I'm contemplating even before the rocket is designed.

Also, since ThrustCurve is handier than RS and OR at the launch site, it'd be nice to do the that level of simulation using the combined thrust data. But still I don't see any situation in which the combimed RASP file would be useful.

 

[Neutronium95]

OK, I'll have to try again. When I picked a motor configuration (1×D12 + 2×A10) it gave me total impulse, average thrust, and a RASP file; no picture.

When I want a detailed simuation, I'd have a rocket design (RS or OR) to simulate, with the propper cluster or mounts. So I'd load the engines and go. I see no need of a combined RASP file. What I'd like, and I may be asking for something that's more trouble than it's worth, is a graph for combinations that I'm contemplating even before the rocket is designed.

Also, since ThrustCurve is handier than RS and OR at the launch site, it'd be nice to do the that level of simulation using the combined thrust data. But still I don't see any situation in which the combimed RASP file would be useful.

I mostly use the combiner in late night Discord voice chats when the conversation turns to rather silly topics.

The Rasp file output is nice for when I want to simulate a rough design quickly. Like when my friends and I wondered how many I1299s could fit into a 20" tube, and how the resulting rocket would perform.

 

[DigBaddy]

Been using TC and the mobile app more and more, so I need to say it's absolutely fantastic and I have some ideas that might make it more so. Do with them as you wish; and maybe others can chime in on if they also feel they are useful ideas or not.

Much of what I've thought would be nice hinges on delays; especially for SU motors. If the recommended motors based on the inputs for a rocket result in less than ideal delay values; then maybe a caveat/warning is placed on that motor as too long/short of delay and risk of zipper or lawn dart Maybe the web page and app are doing that somewhat...but it just seems to be going on safe "up" values. An example may be a rocket that would be perfect with an AT F42 with a 6-second delay, but 4/8 are the only options. Not exactly massive comfort launching with either despite the thrust being what's needed.

The other idea I have is based on things I've built in a spreadsheet; to find ideal motors (thrust and delays) that work for multiple rockets. It'd be cool to select several from your saved rockets and have a "find common motors" option. When dealing with SU motors in 2-more packs or 24mm reloads in 3-packs, I may not want to buy motors that can only be used in one rocket over something that I can use in >1. Finding those overlaps easily for a fleet would be a heck of a feature.

Also, on the mobile app, I'm not finding where to plug in a custom stable velocity. Is that possible or a feature on the way?

Thanks again for the great software and website and considering the above opinions.

 

[mtnmanak]

If you try to use the Cesaroni files currently on Thrustcurve and open them in OpenRocket, it will throw an error and the program will not load the CTI motors. The error is in the M1060 motor entry - it includes two values for the 0.378 second time input. As noted, this will cause OpenRocket to throw out the whole CTI file.

You can edit the entry if you open the file in a text editor (personally, I just changed the second value to 0.491 seconds):

M1060 98 548 0 3.622 6.673 CTI
0.07 131
0.1 594
0.2 1453
0.238 1494
0.378 1450
0.378 1425
0.5 1423
1 1462
1.5 1456
2 1430
2.5 1376
3 1280
3.5 1190
4 1051
4.5 976
5 883
5.5 835
6 793
6.5 321
7 13
7.229 7
7.23 0

I checked, and the same error is in the RSE file, but it doesn't seem to make any difference in Rocksim:

<engine mfg="Cesaroni Technology Inc." code="M1060-Classic" Type="reloadable" dia="98."
len="548." initWt="6673." propWt="3622." delays="1000" auto-calc-mass="1"
auto-calc-cg="1" avgThrust="1029.14" peakThrust="1494." throatDia="0."
exitDia="0." Itot="7440.7" burn-time="7.23" massFrac="54.28" Isp="209.48"
tDiv="10" tStep="-1." tFix="1" FDiv="10" FStep="-1." FFix="1" mDiv="10"
mStep="-1." mFix="1" cgDiv="10" cgStep="-1." cgFix="1">
<data>
<eng-data t="0." f="0." m="3622." cg="274."/>
<eng-data t="0.07" f="131." m="3619.77" cg="274."/>
<eng-data t="0.1" f="594." m="3614.47" cg="274."/>
<eng-data t="0.2" f="1453." m="3564.65" cg="274."/>
<eng-data t="0.24" f="1494." m="3535.96" cg="274."/>
<eng-data t="0.38" f="1450." m="3435.65" cg="274."/>
<eng-data t="0.38" f="1425." m="3435.65" cg="274."/>
<eng-data t="0.5" f="1423." m="3352.46" cg="274."/>
<eng-data t="1." f="1462." m="3001.37" cg="274."/>
<eng-data t="1.5" f="1456." m="2646.27" cg="274."/>
<eng-data t="2." f="1430." m="2295.05" cg="274."/>
<eng-data t="2.5" f="1376." m="1953.57" cg="274."/>
<eng-data t="3." f="1280." m="1630.35" cg="274."/>
<eng-data t="3.5" f="1190." m="1329.76" cg="274."/>
<eng-data t="4." f="1051." m="1057.04" cg="274."/>
<eng-data t="4.5" f="976." m="810.368" cg="274."/>
<eng-data t="5." f="883." m="584.136" cg="274."/>
<eng-data t="5.5" f="835." m="375.063" cg="274."/>
<eng-data t="6." f="793." m="176.943" cg="274."/>
<eng-data t="6.5" f="321." m="41.374" cg="274."/>
<eng-data t="7." f="13." m="0.727739" cg="274."/>
<eng-data t="7.23" f="0." m="0." cg="274."/>

 

[DarthMuffin]

If you try to use the Cesaroni files currently on Thrustcurve and open them in OpenRocket, it will throw an error and the program will not load the CTI motors. The error is in the M1060 motor entry - it includes two values for the 0.378 second time input. As noted, this will cause OpenRocket to throw out the whole CTI file.

Same issue with the CTI K1200 motor. I had to manually edit out at time entry to get it to work.

 

[heada]

For those motors, go to the page for each on thrustcurve and report an error. It can be fixed so they don't have to be edited anymore.

 

[jqavins]

Better yet, look at the thrust curve from the cert documents and submit not just an error report but also the correction.

 

[JohnCoker]

If you see errors, please report them. I fixed both motor files directly by deleting the duplicate points so these two are taken care of.

 

[JohnCoker]

Much of what I've thought would be nice hinges on delays; especially for SU motors. If the recommended motors based on the inputs for a rocket result in less than ideal delay values; then maybe a caveat/warning is placed on that motor as too long/short of delay and risk of zipper or lawn dart Maybe the web page and app are doing that somewhat...but it just seems to be going on safe "up" values. An example may be a rocket that would be perfect with an AT F42 with a 6-second delay, but 4/8 are the only options. Not exactly massive comfort launching with either despite the thrust being what's needed.

I'm not sure how to determine how close the delay must be, but that's an interesting idea.

The other idea I have is based on things I've built in a spreadsheet; to find ideal motors (thrust and delays) that work for multiple rockets. It'd be cool to select several from your saved rockets and have a "find common motors" option. When dealing with SU motors in 2-more packs or 24mm reloads in 3-packs, I may not want to buy motors that can only be used in one rocket over something that I can use in >1. Finding those overlaps easily for a fleet would be a heck of a feature.

That's an interesting idea and very doable.

Also, on the mobile app, I'm not finding where to plug in a custom stable velocity. Is that possible or a feature on the way?

I don't think that's currently an option. I need to resurrect the mobile app at some point. Note that the web site is responsive so should work nicely on any size device.

 

[dhbarr]

I'm not sure how to determine how close the delay must be, but that's an interesting idea.


That's an interesting idea and very doable.


I don't think that's currently an option. I need to resurrect the mobile app at some point. Note that the web site is responsive so should work nicely on any size device.

+1, I stopped using the mobile app w/ the site revamp.

 

[dhbarr]

tl;dr: page naming, column naming, column ordering, units, and rounding should be uniform across

• summary.html
• complete.html
• spreadsheet.xlsx
• spreadsheet.csv

In Motor Guide,
Complete Results
has the columns ordered differently than
Results

Please consider
adding Velocity and Accel to Complete Results; and
moving Diam. and Weight either all the way right or all the way left
so that all of the columns from summary.html keep their same order in complete.html

Further, please consider
normalizing page naming
so that one is displayed as "Motor Guide Summary Results" and the other "Motor Guide Complete Results" or similar.

In addition, please consider
having the motors tab first in
https://www.thrustcurve.org/motors/guide/622c97bd1bc201000433c255/spreadsheet.xlsx and
normalizing units and rounding vs.

https://www.thrustcurve.org/motors/guide/622c97bd1bc201000433c255/spreadsheet.csv

e.g.

Designation​

Manufacturer​

Diameter (mm)​

Length (mm)​

Type​

Propellant​

Case​

T:W​

Weight (g)​

Liftoff (s)​

Stable (mm)​

Guide (m/s)​

Burnout (m)​

Burnout (s)​

Apogee (m)​

Apogee (s)​

Velocity (m/s)​

Accel (m/s²)​

Delay (s)​

Recover (g)​

Result​

G300-PVC​

Contrail​

38​

406​

hybrid​

​

38 16 F PVC (90CC)​

20.4​

1442​

0.00​

290​

44.5​

11​

0.3​

163​

5.6​

63.4​

537.9​

5.3​

1227​

good​

vs.

Designation​

Manufacturer​

Diameter (mm)​

Length (mm)​

Type​

Propellant​

Case​

T:W​

Weight (g)​

Liftoff (s)​

Stable (mm)​

Guide (m/s)​

Burnout (m)​

Burnout (s)​

Apogee (m)​

Apogee (s)​

Velocity (m/s)​

Accel (m/s²)​

Delay (s)​

Recover (g)​

Result​

G300-PVC​

Contrail​

38 mm MMT​

0.406​

hybrid​

​

38 16 F PVC (90CC)​

20.4​

1442​

0​

290​

44.5​

11​

0.3​

163​

5.5​

63.4​

537.9​

5.3​

1227​

good​

 

[JohnCoker]

tl;dr: page naming, column naming, column ordering, units, and rounding should be uniform across...

You're right, I'll look at those discrepancies. I may not have complete control of what's displayed, but I'll make sure that at least the same numeric values are written.

 

[JohnCoker]

@dhbarr OK, I made a pass through the code that generates numeric values for the spreadsheets and made sure the rounding was more consistent. (There were strange bugs with JavaScripts Number.toFixed so I am using another method now.) Also, the diameter and length in the CSV files have been fixed.

We can discuss adding more columns and rearranging later, but I wanted to fix the clear bugs as a first step. Thanks for taking the time to take a close look!

 

[dhbarr]

In https://www.thrustcurve.org/motors/compare.html , when

You haven't selected any motors for comparison. As you view details of different motors, the ones you've seen most recently will be visible in Recently Viewed and you can compare them. You can also compare motors from the Attribute Search results.

" Attribute Search " points to " http://localhost:3000/motors/search.html " instead of " https://www.thrustcurve.org/motors/search.html ".

 

[JohnCoker]

" Attribute Search " points to " http://localhost:3000/motors/search.html " instead of " https://www.thrustcurve.org/motors/search.html ".

Good catch. That'll be an easy fix.

 

[dhbarr]

I love this tool. Nitpicky feature requests are how I show my affection

In Attribute Search https://www.thrustcurve.org/motors/search.html under HazMat Shipping, please consider flipping the order of the first two entries from

0 HazMat 0 exempt 0 both​

to

0 exempt 0 HazMat 0 both​

In this way, the left option will always be "safe bets" and the right option will always be "everything".

On a related note, please consider whether ingesting NAR Contest Certified status might make sense.

 

[JohnCoker]

I love this tool. Nitpicky feature requests are how I show my affection

In Attribute Search https://www.thrustcurve.org/motors/search.html under HazMat Shipping, please consider flipping the order of the first two entries from

0 HazMat 0 exempt 0 both​

to

0 exempt 0 HazMat 0 both​

In this way, the left option will always be "safe bets" and the right option will always be "everything".

On a related note, please consider whether ingesting NAR Contest Certified status might make sense.

Good ideas. I just need a list of which motors are contest-certified.

John

 

[Neutronium95]

Good ideas. I just need a list of which motors are contest-certified.

John

If you do that, it might also make sense to consider the TARC motor list. Although that is pretty broad, and I think that it includes pretty much all of the F motors and below from Estes, Aerotech, and Cesaroni, so it might not be too useful.

 

[dhbarr]

Good ideas. I just need a list of which motors are contest-certified.

John

NAR Certified Motor List - National Association of Rocketry

NAR Certified Motor List Note: "Contest approved" means approved for use in contests flown under the NAR US Model Rocket Sporting Code. This is not the same as approved for use in HPR or FAI contests. Note: click on the motor type (below) to download the Engine Data Sheet in PDF Format. Last...

www.nar.org

has a Contest Approved bit.

 

[JohnCoker]

OK, I'll add both. I just have to figure out how to update the site now. Heroku/Salesforce had some security problems and they got rid of the convenient GitHub auto-deploy. There's always something...