The Lazy RSO's motor guide

During my first RSO experience at Southern Thunder this year, I really wished I had a motor curve reference at hand to end arguments quickly with data. Especially when technology isn't cooperating, and fliers threw out the motor datasheet 5 months ago.

That being said, I began whipped up these motor guides for whenever I find myself under the tent again, and figured I'd share it for anyone else that was interested.


The major sections are broken out motor diameter, and, for lookup convenience, the listing is by Designation (A3,A8,B4,B6, etc.....)
~Nyt

**Note** The online view makes the page numbers in the doc footers screwy. Once downloaded, it should be back to normal, and the dynamic index functional again.
$$Update$$ Volume 2 (L1 High Power) is now live. Links added for Volumes 3 (L2) and 4 (L3). Check recent posts to for updates.

Lazy RSO's motor guide Vol. 1

Lazy RSO's motor guide Vol. 2

Lazy RSO's motor guide Vol. 3

Lazy RSO's motor guide Vol. 4

Thank you Sir! This is not only handy for RSO's but for digging thru the bins to see what you have left to fly what's survived. Not that I have a high attrition rate, but the weather changes, too! Good snap shot for knowing at a glance how a motor comes off the rails.

Have you thought about adding an MRLOW table also?

I've seen a few disappointed young'ens when they've realised their over the max weight for their motor...

Neat compilation. One small comment: the curves for the Quest B6 and C6 motors appear to be for the German-made motors, not the more recent Chinese ones. There is a significant difference, especially with the C6s which burn for nearly 2.5 seconds. Here's a screen shot of the NAR cert page for the Chinese Quest C6s.

fyrwrxz said:

Thank you Sir! This is not only handy for RSO's but for digging thru the bins to see what you have left to fly what's survived. Not that I have a high attrition rate, but the weather changes, too! Good snap shot for knowing at a glance how a motor comes off the rails.

Click to expand...

You're welcome! If you Really know how your model behaves, I think you could make some rail exit guesses, although I'd prefer sim results for that realm.
But you can bet I'll have it with me the next time I'm shopping in the motor trailer!

snrkl said:

Have you thought about adding an MRLOW table also?

I've seen a few disappointed young'ens when they've realised their over the max weight for their motor...

Click to expand...

Key word being "Recommended". The thrustcurve and flier's model are everything an RSO needs to make a valid decision (plus wind at the field of course). It can also serve experienced rocketeers that know how to read a thrustcurve as well as serve as a teaching tool. Although I think including a 7:1, 5:1, 3:1 Thrust/weight plot in the front matter for reference as well (maybe one in oz/grams and a larger scale in lbs/kg).

I also don't actually like that variable very much for reasons that are stated pretty well in the PoF 214 excerpt below.

"Before getting into the procedure, I hope you can grasp that the maximum lift-off weight for the motor is going to depend on the size and configuration of the rocket, and the weather conditions on the day of the launch. The reason is that these variables also affect the trajectory of the rocket. Anything that affects the trajectory of the rocket will affect the maximum lift-off weight of the motor. This is important, because there is not a single “maximum recommended lift-off weight” that can be used for all sizes of rockets.

This may be contrary to what you’ve been used to for all your rocketry career. That MRLOW number you see published on the manufacture’s web site is only good for a very narrow set of conditions. You really have to generate the number yourself based on the design of the rocket you’ve created."


Plus, I'd have to go and lookup/calculate that for dozens of motors across multiple manufacturers, and this is the LAZY RSO's motor guide after all.

BEC said:

Neat compilation. One small comment: the curves for the Quest B6 and C6 motors appear to be for the German-made motors, not the more recent Chinese ones. There is a significant difference, especially with the C6s which burn for nearly 2.5 seconds. Here's a screen shot of the NAR cert page for the Chinese Quest C6s.

Click to expand...

Thank you! That's the kind of motor history that I'm still new to. I'll investigate and update accordingly.
Since this was a general export from ThrustCurve, there's a good chance some OoP motors snuck into my list.

Very cool, THANK YOU for the time and work you put into this guide.

Nytrunner said:

Thank you! That's the kind of motor history that I'm still new to. I'll investigate and update accordingly.
Since this was a general export from ThrustCurve, there's a good chance some OoP motors snuck into my list.

Click to expand...

I was amused to see the long OOP Estes C5 in there....

BEC said:

I was amused to see the long OOP Estes C5 in there....

Click to expand...

Also noted.

I'll make a point to pull that one when I refresh the doc.
I already updated the Quest curves and was working on the thr/wgt graphs while the laundry was drying.

Someone want to let John Coker or Mark Kolesch know that the Quest curves need updating?

Nytrunner said:

Also noted.

I'll make a point to pull that one when I refresh the doc.
I already updated the Quest curves and was working on the thr/wgt graphs while the laundry was drying.

Someone want to let John Coker or Mark Kolesch know that the Quest curves need updating?

Click to expand...

Hey - I've got a dozen C5-3 motors left... [emoji16]


Sent from my iPad using Rocketry Forum

I have some, too.....and some B8-5s.

Rev A is live and I just checked to make sure the link in Post #1 brings up the new version.

I decided to keep the C5 just because, but I couldn't even find the B8 lol.

Something I need to know for the Hi-power listings: Are Animal or Gorilla motors still in production?

My plan is to do AT, CTI, and Loki for those lists. Not going to bring hybrids into the mix because I'm hoping that anyone rolling up with one of those will Know Their Stuff and have the necessary documentation.

Nytrunner said:

Rev A is live and I just checked to make sure the link in Post #1 brings up the new version.

I decided to keep the C5 just because, but I couldn't even find the B8 lol.

Something I need to know for the Hi-power listings: Are Animal or Gorilla motors still in production?

My plan is to do AT, CTI, and Loki for those lists. Not going to bring hybrids into the mix because I'm hoping that anyone rolling up with one of those will Know Their Stuff and have the necessary documentation.

Click to expand...

... & GSE

In some situations I bet the flyer knows more the the standing RSO.

I'm sure each party has a largely overlapping knowledge set, each one also having experience the other may not.

Hence charts & questions

Nytrunner said:

I decided to keep the C5 just because, but I couldn't even find the B8 lol.

Click to expand...

Here's the B8.

They were decertified as of 7/1/2001. They give a small model one heck of a kick in the tail.

The C5-3s went decertified one year later.

Since we're talking about using no-longer-certified motors, here's how to fly 'em and still meet the NAR safety requirements (necessary at NAR launches and such): https://www.nar.org/wp-content/uploads/2014/07/NAR-Expired-Motor-Testing-Program.pdf

Updated Vol 1 to include the missing G75 (and a logo I threw together while waiting for the spin cycle to end)

Just started Working on Vol 2: Level 1 High Power

Nice work. Thank you sir!

captbk said:

Nice work. Thank you sir!

Click to expand...

Stick it! (as in sticky post, of course) Nytrunner, maybe you can get a mod to do this.

I appreciate the sentiment, but I think it'll need some more utility and a couple more volumes before becoming Stick-worthy.

Speaking of utility, what do people think of a unit conversion page? (ala, textbook style?)
My schooling was mechanical engineering, so I have basic conversion factors pretty much drilled in my brain, but I realize that's not true for everyone. Possible value-added?

I just added this document to my on-field reference book. Thanks!

LW Bercini said:

I just added this document to my on-field reference book. Thanks!

Click to expand...

Glad it can serve!


For unit conversion, I'm thinking basics like force (lb/N/(oz?) ), distance and it's derivatives (ft/m, ' , " ), Maybe even quick factors like "Oz times 1.4 = 5x Thrust/weight in Newton's" [Although as I type this I realize I already made thrust/weight graphs......]

Volume 2 (Rev New) is now uploaded. Contains L1 motor curves for Aerotech, Cesaroni, and Loki.

By the way, does anyone know why Hypertek shows up when filtering on CTI in Thrustcurve?

Nytrunner said:

By the way, does anyone know why Hypertek shows up when filtering on CTI in Thrustcurve?

Click to expand...

Hypertek is now owned by CTI..

Thanks! Fascinating.

Does this mean Cesaroni will now be producing Hypertek hybrid systems?

Thanks for the effort. Well done.

captbk said:

Thanks for the effort. Well done.

Click to expand...

Well, the first 2 weren't that bad.

But.....I just asked thrustcurve to spit out L2 motors by AT, CTI, and Loki, and now I have 210 motors to collate for Volume 3......Not sure If I have enough lunch breaks to throw it together before I'm no longer able to edit the title post, but I'll see what can happen!

Nytrunner said:

Well, the first 2 weren't that bad.

But.....I just asked thrustcurve to spit out L2 motors by AT, CTI, and Loki, and now I have 210 motors to collate for Volume 3......Not sure If I have enough lunch breaks to throw it together before I'm no longer able to edit the title post, but I'll see what can happen!

Click to expand...

If you do a Google spreadsheet, I'd be happy to help.

dhbarr said:

If you do a Google spreadsheet, I'd be happy to help.

Click to expand...

Now that's an idea!
Currently I'm just working in word (since I originally made the first one for me). I'll pm you.

**Update** I added links to placeholder docs in my Drive for Volumes 3 and 4. For now they'll just make you laugh, but they'll get real as they're finished.

Thanks for this! Potentially very useful.

One note: you should add the 38mm G motors somewhere.