Estes C5-3 motors available

[Senior Space Cadet]

Got this e-mail from Estes, as many of you are probably receiving now:

Not yet available from AC Supply. I think I still have a few "Super C" motors when they were produced by Centuri.

It's been back for a while now. I get mine from Estes. Estes is located in Colorado, so I can get their motors in a few days.
The Super Cs have limited use. They are best for heavy rockets. A C6-5 or C6-7 is a better choice for light rockets. Super Cs on a light rocket can cause issues and you won't get the altitude of the C6s.

 

[beeblebrox]

https://www.rocketreviews.com/compare-estes-c6-to-estes-c5.html
Something I don’t get on the data here, maybe @jadebox or another of many forum members smarter than me can explain.

How come the C6 is rated as 76%C and C5 only 56%C?

How can the C5 have equal propellant (actually slightly more) and lower total impulse?
To me, the area under the curve for the C5 appears to be AT LEAST as much as the C6, and it eyeballs slightly more.

Why is the C5 lighter (larger nozzle bore means less clay,bigger hole?)

Most of the C5's burn is at lower pressure, therefore ISP is lower. nothing to do with mass of the motor.

 

[Nytrunner]

I wonder how long ago the C6 was recertified. The BP blend has changed properties since then if I'm not mistaken

 

[Joekeyo]

The B14 looks more like a flash bang

Thats about right. Great motor for lofting heavy rockets or cluster for egg loft.

 

[Ronz Rocketz]

It's been back for a while now. I get mine from Estes. Estes is located in Colorado, so I can get their motors in a few days.
The Super Cs have limited use. They are best for heavy rockets. A C6-5 or C6-7 is a better choice for light rockets. Super Cs on a light rocket can cause issues and you won't get the altitude of the C6s.

It usually takes two weeks for Estes packages to reach me. Last week, it only took about 4 days which was amazing. Perhaps it caught a fast current.

Agree about the C motors. From my experience, the C5 is great for large fin rockets to overcome the initial weathercocking off the launch rod. This includes the Nike-x with its wide fins.

 

[jadebox]

If I understand you correctly, you are saying that the C5 nozzle is less efficient (not knocking you or arguing, I think that makes sense but I was a biology major not an engineering major, so I don’t have the savvy to figure it out myself.). I also understand (I think) that in some cases “less efficient” doesn’t mean “not as good”, in this case it may be less efficient in total impulse but still better for certain applications (like getting big draggy rockets off the pad.). Still, when I look at the the thrust curves, the C5 spike is significantly higher AND slightly longer lasting, and whatever you call the flat part of the curve (“plateau”?) is minimally lower in thrust and the C5 burn is slightly longer. So I am still at a loss, I thought the total impulse was basically the area under the curve. Eyeballing it the C5 looks higher. Also, C5 at 7.79 Ns and C6 at 8.82 gives a ratio of 0.88, while for “Motor Class” C5 at 56% C vs C6 at 76% C gives a ratio of 0.73. So my ignorance is showing again......

The total impulse is the area under the curve which is the same as the average thrust multiplied by the thrust duration.

A "56% C" versus "76% C" is based on where the total impulse of the motor falls within the total impulse range for C motors, not the range for all motors. A 1% C motor is just barely in the range for C motors while a 99% C motor is at the top of the range.

 

[Ronz Rocketz]

The total impulse is the area under the curve which is the same as the average thrust multiplied by the thrust duration.

A "56% C" versus "76% C" is based on where the total impulse of the motor falls within the total impulse range for C motors, not the range for all motors. A 1% C motor is just barely in the range for C motors while a 99% C motor is at the top of the range.

How many Estes C motors are there or are they including the delays as separate?

 

[jadebox]

How many Estes C motors are there or are they including the delays as separate?

Estes makes a C5 (with one delay) and C6 and C11 motors (with multiple delays).

 

[BABAR]

The total impulse is the area under the curve which is the same as the average thrust multiplied by the thrust duration.

A "56% C" versus "76% C" is based on where the total impulse of the motor falls within the total impulse range for C motors, not the range for all motors. A 1% C motor is just barely in the range for C motors while a 99% C motor is at the top of the range.

You still lost me. Are you saying the number is NOT proportional to the total thrust in Ns? Cuz the C5 and the C6 come in pretty close to even based on the graph, and are not nearly that far apart in thrust on the chart.

 

[Ronz Rocketz]

Estes makes a C5 (with one delay) and C6 and C11 motors (with multiple delays).

Estes is comparing the C5 with a C11 (in addition to the C6)? They're different sizes.

 

[mbeels]

So I am still at a loss, I thought the total impulse was basically the area under the curve. Eyeballing it the C5 looks higher.

It is, and I see what you're saying about the eyeball area. My guess it comes down to something related to sampling, averaging, and possibly the method that the total impulse was determined. When they certify a motor, I think that several samples are tested and some methodology of averaging and statistics are used to determine the official measurements. Each motor burn will be a tiny bit different due to variations. Maybe the thrust curves posted are just two random motors, and not perfectly representative of the average. You could download the thrust curve data and numerically compute the total impulse.

Also, the rocket reviews site plotting does some strange kind of smoothing on the data, so you're not seeing the actual data, but some strangely smoothed results. For example, see the G79 data for a particularly bad example.

https://www.rocketreviews.com/compare-aerotech-g79w-to-aerotech-g77r.html
I think you'd have to download the thrustcurve data and look at the actual measurements and samples.

 

[mbeels]

FWIW, @BABAR I plotted the thrustcurve data, which makes it look quite different, I'd believe the total impulse of the C6 is higher looking at this data.

 

[jadebox]

You still lost me. Are you saying the number is NOT proportional to the total thrust in Ns? Cuz the C5 and the C6 come in pretty close to even based on the graph, and are not nearly that far apart in thrust on the chart.

Which number? The percentage? If so, yes, it is relative to the total impulse within the C motor range. A C motor at the low end of the C range (5.0 N-sec) would have a low percentage, near zero. A C motor at the top of the range (10 N-sec) would have a high percentage, near 100%.

If you divide each percentage by two then add 50, so that they represent the percentage from 0 N-sec to 10 N-sec rather than 5 N-sec to 10 N-sec, the ratio of the percentages will be about the same as the ratio of the total impulses.

 

[BEC]

FWIW, @BABAR I plotted the thrustcurve data, which makes it look quite different, I'd believe the total impulse of the C6 is higher looking at this data.

View attachment 431210

This is correct. Look at the certification data: https://www.nar.org/SandT/pdf/Estes/C6.pdf and https://www.nar.org/SandT/pdf/Estes/Estes_C5_2019.pdf

Certified total impulse for Estes C6s is 8.82 Ns. For the just-reissued C5-3 it is 7.79 Ns. This would be the area under the time-thrust curves shown here. For further comparison, the Estes 24mm C11s are at 8.80 Ns and the Q-Jet C12 is certified (by Tripoli) at 9.8 Ns.

I have always found that percentage of impulse category nomenclature really, really confusing.

 

[Initiator001]

Interestingly, Quest D16 maximum recommended liftoff weight is 128 grams, which seems low to me.

The Quest D16 is barely a 'D' motor. It is reminiscent of the old Cox D8 motor.
The D16 is also a progressive burn motor like Enerjet motors of 50 years ago. They reach their peak thrust after liftoff.
This accounts for their 'low' maximum lifoff mass rating.

 

[BEC]

I don't know where BABAR got 128 grams (4.5 ounces). Here is the info from a pack of C12-8s (date code on the motors 100818-01). Those max liftoff masses don't look very low to me. Six ounces for 8s delay up to 12 ounces for a 4s delay.

That said, having flown a bunch of these, 8s will be too long for a model more than about half that liftoff weight. But it will not have any problem getting up to speed off a three-foot rod on the way up.

It is true that the Q-Jet D16s are "baby Ds" at 12.4 Ns. But then 10.01 Ns would be a D. This sort of thing seems more prevalent in higher impulse classes.

 

[BABAR]

I don't know where BABAR got 128 grams (4.5 ounces).
View attachment 431230

Thanks for the correction. I KNEW I had seen a higher recommended max lift off weight on the packet insert, but I had discarded all the inserts when I organized my motors (much better organized than my workbench, unfortunately for my workbench..... )

So I went to the Quest website, which IS where I got the number I quoted.

https://www.questaerospace.com/2-Pack_D16-4_Q-Jet_Model_Rocket_Motor/p4193205_18980165.aspx
I figgered it was wrong, but I couldn’t find the documentation on the web to prove differently.

I have an unbuilt Estes Outlander (stock 18 mm mount) which I was thinking of modding for a 24 mm motor mount planning on flying it on Estes D12-3, as it looked underpowered for a C6-3. Then came the Q-Jet 18 mm D. But I am thinking the C5-3 might be perfect, I really don’t want it to go very high, I don’t want to add nose weight, I just want to get it off the rod with enough velocity to be stable and enough oomph to get it up 100-200 feet with ejection near apogee.

I found this comical review by Chan Stevens on RocketReviews

Wrapping up construction, I picked up the very heavy (over 4 ounce) rocket, and couldn't believe it was using an 18mm motor. (Ignoring Aerotech's hard-to-find 18mm D motors, this meant using a C6-3.) I think this is seriously underpowered on a C6-3 and the only reason I can think that Estes would also recommend B4-2 or B6-2's would be for flying in a school gymnasium. Heck, you could even go with an A8-3 and fly it in your living room, assuming you have vaulted ceilings! (Note to kids: don't try this at home! I was only kidding.)

https://www.rocketreviews.com/estes-industries-outlander-by-chan-stevens.html

 

[jadebox]

My Outlander didn't so much fly on a C6 as make a swan dive off the launch pad into the ground.

Edit: Oh ... And then I rebuilt it with a 24mm motor mount. I decided that since it probably needed a little nose weight for the larger motor anyway, it wouldn't matter if I stuck a little flashlight in the nose for the night launch our club was having. That was a bad idea.

 

[BABAR]

My Outlander didn't so much fly on a C6 as make a swan dive off the launch pad into the ground.

Surprisingly 2 of 3 of the reviewers on RocketReviews.com got decent flights.

https://www.rocketreviews.com/estes-industries-outlander-by-greg-brown.html
https://www.rocketreviews.com/estes-industries-outlander--by-greg-brown.html(Btw, this html tag is mislabelled, the review was by Eric Maher)





Vs
https://www.rocketreviews.com/estes-industries-outlander-by-chan-stevens.html
I built both my ExoSkell and Venus Probe with 24 mm mounts, which worked great. Wouldn’t have need them now with the 18 mm C5-3 and D16-4 motors now available.

 

[Nytrunner]

I have always found that percentage of impulse category nomenclature really, really confusing.

It is percentage of the difference between the motor's impulse and the previous motor class max impulse vs the range between both class's max impulse.

A G has max impulse of 160 N-s I'll call it I_p (Previous impulse)
An H has max impulse of 320 N-s I'll call it I_m (Max impulse)

The difference between the two Max's is 160 N-s I'll call it D_I

Take an H120 (My L1 motor), it has ~260 N-s placing it around the middle of H territory. We'll call it I

So the percentage (P_I) looks like this:
$$ \mathcal{P_I}=\frac{\mathcal{I}-\mathcal{I_p}}{\mathcal{D_I}}$$

Which becomes for the H120:
$$\mathcal{P_I}=\frac{260-160}{160}100=\frac{100}{160}100=62.5%$$

 

[Antares JS]

I have an unbuilt Estes Outlander (stock 18 mm mount) which I was thinking of modding for a 24 mm motor mount planning on flying it on Estes D12-3, as it looked underpowered for a C6-3. Then came the Q-Jet 18 mm D. But I am thinking the C5-3 might be perfect, I really don’t want it to go very high, I don’t want to add nose weight, I just want to get it off the rod with enough velocity to be stable and enough oomph to get it up 100-200 feet with ejection near apogee.

DO NOT try to fly the Outlander on a C5! I tried it and while it wasn't as bad as the C6, it was still bad, with the parachute only opening a few feet above the ground (instead of on the ground like it does on a C6). Use a composite D or mod for 24mm!

 

[BEC]

It is percentage of the difference between the motor's impulse and the previous motor class max impulse vs the range between both class's max impulse.

A G has max impulse of 160 N-s I'll call it I_p (Previous impulse)
An H has max impulse of 320 N-s I'll call it I_m (Max impulse)

The difference between the two Max's is 160 N-s I'll call it D_I

Take an H120 (My L1 motor), it has ~260 N-s placing it around the middle of H territory. We'll call it I

So the percentage (P_I) looks like this:
$$ \mathcal{P_I}=\frac{\mathcal{I}-\mathcal{I_p}}{\mathcal{D_I}}$$

Which becomes for the H120:
$$\mathcal{P_I}=\frac{260-160}{160}100=\frac{100}{160}100=62.5%$$

Thanks for the explanation as to how to figure it. That does help....and where the range of possibilities is so large (say, G on up) it makes sense to me to think of motors this way to some degree.

Applying this to the Q-Jet D16 at 12.4 Ns makes it a 24% D. Applying it to the current C5s at 7.79 Ns gives 55.8% C, the 8.82 Ns C6 is a 76%C and the 9.8 Ns Q-Jet C12 is a 96% C. Hmmmmm.....still not sure whether that helps or hurts. In this context it seems to magnify the actual differences in performance. If I think of their total impulses as a percentage of the maximum in the class (10 Ns) seeing the C5 at 78%, the C6 at 88% and the C12 at 98% seems to better fit how they perform relative to one another in a light model (I fly an altimeter in almost everything, every time, so I have data for this).

Of course in a heavier model, where the C5-3 (and the C12-4 and D16-4) are more suited, results tend to be some different.

 

[Nytrunner]

Thanks for the explanation as to how to figure it. That does help....and where the range of possibilities is so large (say, G on up) it makes sense to me to think of motors this way to some degree.

Applying this to the Q-Jet D16 at 12.4 Ns makes it a 24% D. Applying it to the current C5s at 7.79 Ns gives 55.8% C, the 8.82 Ns C6 is a 76%C and the 9.8 Ns Q-Jet C12 is a 96% C. Hmmmmm.....still not sure whether that helps or hurts. In this context it seems to magnify the actual differences in performance. If I think of their total impulses as a percentage of the maximum in the class (10 Ns) seeing the C5 at 78%, the C6 at 88% and the C12 at 98% seems to better fit how they perform relative to one another in a light model (I fly an altimeter in almost everything, every time, so I have data for this).

Of course in a heavier model, where the C5-3 (and the C12-4 and D16-4) are more suited, results tend to be some different.

You're welcome!

Your curve fit makes sense to me because a rocket can fly on more than one class of motor. A full B is 50% the impulse of a full C and performance should be proportional (all else equal, accounting for weight differences)
Very true, a high % but low thrust motor will not be great for a model if it can't get it stable.

The other side of that example is the 1%N N10,000 and the 97%N N5800
One of them "looks" nastier by the name alone, but the other does significantly more sustained damage to a rocket

 

[BABAR]

DO NOT try to fly the Outlander on a C5! I tried it and while it wasn't as bad as the C6, it was still bad, with the parachute only opening a few feet above the ground (instead of on the ground like it does on a C6). Use a composite D or mod for 24mm!

Wow, okay, thanks. I was thinking that would have been the perfect motor. There is a RockSim file on RocketReviews I haven’t played with yet

https://www.rocketreviews.com/unknown-estes-outlander.html
But nothing beats personal experience.
@jadebox implied it didn’t go so well with a 24mm mount either, although I don’t know if that was due to the motor or the flashlight in the nose

Surprisingly to me, the mass of the D16 is not that much more than the C5


https://www.rocketreviews.com/compare-motors---estes-c5-to-quest-d16-q-jet.html
So I don’t think it would need to add any nose weight for the Q-Jet D16-4

a 24 mm mod would add a good bit of mass, twice that of the C5 and almost twice that of the D16

https://www.rocketreviews.com/compare-motors-508946.html
Just for the motor alone, the mount itself should on add a couple of grams,


Too bad this design doesn’t look like it will fly on a rail, I just got a 6 foot 10x10 rail button that I figured would help out on a lot of my more borderline designs.

This is one of those rockets when I get around to building it from a flying standpoint it will probably be one and done, just to prove it’s a “real” rocket. The I hang it from the ceiling over the TV. You just hope the single flight doesn’t suffer fecal turbine interaction.

 

[Antares JS]

Too bad this design doesn’t look like it will fly on a rail, I just got a 6 foot 10x10 rail button that I figured would help out on a lot of my more borderline designs.

I don't think a rail or longer rod would help. The C5 certainly got it off the pad with authority and flying straight. It was straight up and straight down without issue - the problem was that straight up and straight down took so little time because it's so heavy and draggy. If there was a such thing as a C5-1, that would probably be an ideal motor for the Outlander.

 

[BABAR]

I don't think a rail or longer rod would help. The C5 certainly got it off the pad with authority and flying straight. It was straight up and straight down without issue - the problem was that straight up and straight down took so little time because it's so heavy and draggy. If there was a such thing as a C5-1, that would probably be an ideal motor for the Outlander.

Might as well be a C5-0! Lol. @BEC ‘s post showing the “real” max recommended lift off weight for the D16 is encouraging, looks like it should get off the pad with authority fine, and with that amount of drag even with more total impulse probably won’t go out of sight. I have a medium size field, so won’t lose it (famous last words....)

 

[BEC]

I don't think a rail or longer rod would help. The C5 certainly got it off the pad with authority and flying straight. It was straight up and straight down without issue - the problem was that straight up and straight down took so little time because it's so heavy and draggy. If there was a such thing as a C5-1, that would probably be an ideal motor for the Outlander.

....and one of the odd quirks about the new C5-3 is that the delay is three Aerotech seconds rather than three Estes seconds....

 

[Nytrunner]

....and one of the odd quirks about the new C5-3 is that the delay is three Aerotech seconds rather than three Estes seconds....

Aight, I've missed out on the joke. Which one's fast/slow?

 

[BEC]

Estes delays generally tend to run short, Aerotech's tend to run long. The Estes C5-3 runs ~3.3s or a bit more.

 

[BABAR]

Aight, I've missed out on the joke. Which one's fast/slow?

Thanks, I was floundering on this too