Although I don't have any inside info nor have I asked them, I tend to doubt that Hobby Lobby will carry the E12 motors any time soon - they just finished a major reset of the rocketry sections in their stores to include the Pro II series stuff. If they do ever carry them, I expect that they will only carry the E12-4 and E12-6 (like the E9 and D12 motors - no 24mm boosters or upper stage motors).
On the other hand, I couldn't believe that they are actually starting to put out Christmas merchandise already! They had a whole wall of wreaths and even a half isle of glass ornaments! And it ain't even July 4th yet!
Member of Launch Crue - http://launchcrue.org/
Hint #1: Do not use magician's flash paper for recovery wadding!
Hint #2: Clean your shoes after flyin' in that cow pasture - that ain't no dirt clod on the sole!
Well, I just had my first engine CATO in 40 years of on-and-off flying... the first E12-6 I tried. It was in a Vagabond modified to carry electronics, about 250g, that had flown at least 10 times. Lifted a little slow off the pad, and blew up at about 20', blowing out both ends of the engine and leaving the casing intact. Fortunately the payload was fine. Reported it to Estes and NAR...
I can see this engine getting a bad rep real fast based on some reports that I have heard about them blowing up at some of the large SoCal gatherings. As for me, I'm sticking to Aerotech RMS...
Has anyone seen these at hobby lobby? I cant wait to bet my hands on these. I think my QCC explorer is getting bored of D12s and C11s.
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NAR Jr. L1
TRA Jr. Flier
2013 motors: I:2, J:1
I went to a launch today with several packs of E12s and never got around to using one. The walk was long enough with the D motors.
I can't even imagine putting up a Magician on an E, it cruises out of sight on a D.
I'm sorry to hear problems are cropping up with the E12. So far, I have flown about a dozen of them and really like them. I have several unopened packs and for now will take my chances.
FAIW, in 40 years of flying, I've only has 2 BP CATOs...an E9 and a MicroMaxx II.
Last edited by rstaff3; 24th June 2012 at 04:18 PM.
I should have listened to Fred, he warned me that there had been a few CATOs with E12's at their last Lucerne Valley meet. "In Estes We Trust" I figured. I was wrong.
I think the issue is that BP is really only suitable for a certain amount of total impulse, D seems to be the limit. Once you start getting over 20 Ns the manufacturing techniques don't scale up well. That's probably why they went with an E9 in the first place, instead of trying to scale up the D12, they figured that it was safer. Unfortunately, unless you have a light rocket, the long burn engines don't help much; you need a big push to get velocity off the rod/rail or you're going to go overstable. I guess I'll try to find the Aerotech RMS E18 load, it seems to be about the right size for a self-imposed 1000' ceiling with a 200-250 g rocket. A 3-pack of these loads is the same price as a 3-pack of the Estes BP E's.
Flew an E12-6 two weeks ago in a Mega Mosquito, and flew the remaining two motors today in my Maxi Alpha 3. All flights went perfectly. I really like this motor; it's got the D12 'kick' off the pad with a nice extended burn. I don't get anywhere near the weathercocking that the E9 would give if conditions weren't absolutely perfect.
Stan Senesy - L3
TRA #12302, NAR #88713
Ns burned in 2013: 7450 (46% M)
Ns burned in 2012: 11083 (8% N)
Jersey Devil Rocketry
Well, they did not scale up the D12, because the nozzle is smaller on the E12 than on the D12, so there is a good chance it is operating at a higher pressure than a D12, but a lot has to do with the size of the peak thrust "dome" which is a function of the diameter of the propellant grain, the diameer of the centerbore/nozzle throat and the depth of the centerbore.
They had an E15 BP motor many years ago and it had serious problems and was recalled. I think the E12 problems can be analyzed and corrected. it could be anything from a better rounded tip on the centerbore tooling (if and only if the problem is a crack in the propellant formed by a sharp edge and drying of the moise propellant over time) or it could be a problem caused by incorrect moisture content during motor loading in the machine or incorrect loading pressure. Or it could even be a tiny dimensional problem in the cardboard casing that affects motor behavior during and post loading (loose casing could swell too much during loading or tight casing might not swell enough to form mechanical bond of propellant and nozzle to casing.).
And cato is *NOT* an acronym. Never has been and never will be.
-Fred Shecter NAR 20117 L2
FSI used to build some pretty big BP motors, all the way up to the F100... but from what I've read, the F100 was about as likely to go boom as whoosh....
In a sense you're right... the bigger the BP motor, the more likely a failure is, and it's generally recognized that the F100 is about pretty much the top of the scale of what's possible for a BP motor with any commercial producibility and reliability...
Later! OL JR
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Just flew my first two of these E12s as a cluster in a viper IV. I would say the flight was rather underpowered, which is interesting considering the power is = to an F24. Not exactly chump change! The flight was barely safe and stable with recovery = 4 seconds delay, but too slow for a day with wind.
Didn't get the impression that these were much more powerful than D12s... probably need to use 4 next time.
Unstable by design
www.wooshrocketry.org NAR Sec. 558
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I flew three in my Thoy Snipe last weekend. It was clearly a faster boost then on three E9s. I can't say how the altitude varied between the 12's and 9's, but the altitude was not even close to three D12s.
-Fred Shecter NAR 20117 L2
As it was argued in the BATF hearings, BP burns by deflagration and AP simply burns fast, once you heat them up and get them pressurized. That's why they can be a pain to ignites sometimes, I have never gotten a First-Fire igniter to work with the Aerotech E20 single-use engines. An F100 would be an HP engine nowadays, since it's over 80 Ns.
As ususal, you are most likely technically correct, however whenever you say that you had a CATO anybody in the hobby knows what you're talking about. Correct or not, it's become part of the jargon.
Also, Take-off is synonymous with liftoff or blast-off so it fits perfectly into the acronym CATO as it has become known.
The main point though as I see it is that acronyms are fun and rocketeers love their acronyms. Why would you want to spoil the fun?
If someone types "cato," this pleases the people who say (maybe rightly so, I'm not well-informed enough to decide) that it is simply an abbreviation for catastrophe, but may tick off those who insist that it stands for "Catastrophe At Take Off". If someone types "CATO," it pleases those who say it is an acronym, and the people who say it isn't an acronym can read it as if the person is shouting, because exploding rocket motors make them angry.
Therefore, with "CATO," everyone is happy. Problem solved!
Everyone knows that CATO stands for Cato At Take Off.
I enjoy pointing out the stupidity of the bacronym defenders.
It makes no sense and defending the bacronym is saying "I know that I am wrong, but I do not care. I insist that my mistake be propagated to dumb-down the rest of the world."
Try to logically explain this: Motor failures occur at any time during burn, not just on or near the pad. Rockets do not "take off", aircraft "take off". See my PDF for the complete discussion of how insisting on using the "take-off" explanation makes the bacronym defender look and sound scientifically ignorant.
When there is a motor failure that blows the casing to bits at hundreds of feet in the air at high speed , such as the numerous Ellis E motor failures I saw, how can that have any connection to "take off"? When a delay is many seconds too short or an ejection charge is missing and the rocket crashes, how is that an event that happened during "take off"?
If something is incorrect, I will point it out AND I will explain why it is incorrect. I understand that many people picked up the incorrect meaning from others they met or from the websites that list it incorrectly. There are plenty of websites with bogus info, including many with quack science and urban legends. If I see an urban legend I will say so and point to the debunking site, such as snopes to explain why it is bogus.
So, on to the other false info recently posted. FSI F100 motors were black powder in a cardboard casing. Never were they composite motors. They were never 100 N average thrust (and someone used Ns which looks like Newton seconds which is total impulse, not average thrust. Perhaps they were trying to make N a plural, but we do not do that with metric units, like g for grams is never written as gs for plural. Yes, pounds is abbreviated lb or lbs for plural, but that is not metric.) Anyway, the F100 used "100" more as an advertising thing, and NAR S&T made them change it to F80 for the last few years of production since 100 was not allowed per NFPA. NAR knew they were never close to 100, or even 80 N in average thrust, but they had to at least label them in accordance with the Model Rocket Motor NFPA code.
-Fred Shecter NAR 20117 L2