Less finely ground clay the cause of CATOs in Estes motors??

[techrat]

Recently, I purchased a load of D12s from someone getting out the hobby. His motors are older, but work fine. At a recent launch at our local group (CENJARS), we had a number of CATOs with E's and D's -- and while perusing the motor selection from a local vendor (Rocketship Games), I noticed that the clay that provides the end-cap and nozzle of newer Estes motors is of a much more coarse grain. It's no longer like sand, but more like fine gravel.

I'm wondering if anyone has had the chance to investigate this -- and determine if this is the reason that D and E motors have a 1 in 10 chance of being a CATO these days. I've taken to running a ring of epoxy around the clay of the nozzle when dealing with the newer motors -- but I've had no issue with the older motors.

Thanks!!

 

[smstachwick]

Recently, I purchased a load of D12s from someone getting out the hobby. His motors are older, but work fine. At a recent launch at our local group (CENJARS), we had a number of CATOs with E's and D's -- and while perusing the motor selection from a local vendor (Rocketship Games), I noticed that the clay that provides the end-cap and nozzle of newer Estes motors is of a much more coarse grain. It's no longer like sand, but more like fine gravel.

I'm wondering if anyone has had the chance to investigate this -- and determine if this is the reason that D and E motors have a 1 in 10 chance of being a CATO these days. I've taken to running a ring of epoxy around the clay of the nozzle when dealing with the newer motors -- but I've had no issue with the older motors.

Thanks!!

The epoxy fix is well-known but I haven’t heard any discussion of the clay or seen this.

This reply is mainly a bump.

 

[DJRNY]

The epoxy fix is well-known but I haven’t heard any discussion of the clay or seen this.

I'm fairly new here so I haven't previously heard about the epoxy fix. Is it described somewhere?

 

[kjhambrick]

+1 for a link ... I've googled it to no avail.

Thanks !

-- kjh

 

[lakeroadster]

.... the reason that D and E motors have a 1 in 10 chance of being a CATO these days.

I think you need to leave D motors out of the mix. I've never had a D motor fail.​

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As for epoxy, I've heard of folks "plugging" a motor with epoxy. But never heard of using epoxy on the nozzle? There's not enough of an extension of the motor tube to even glue too?​

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[sr205347d]

I recently had a D12-3 blow the plug of burning propellant out the front. The nozzle held firm.

 

[Capt. Eric]

This can be a frustrating experience, especially when it is ongoing for so long, and Estes has not stated the cause, if they know (so far as I am aware). I was doing the above mentioned epoxy add-on and it seemed to be working well. Then in January I had 2 CATO's with E12-4's that had the epoxy.

That was frustrating enough. Even more frustrating has been Estes. In the past their customer service was great. Apologized, replaced the engines, and even replaced the kit. (Although didn't state the cause) This time is very different. I've emailed Estes a bunch of times. Their auto reply acknowledges receipt, and they consolidated the emails into one ID number. But the assigned CS rep, Scott, has not actually responded at all. Been trying to get some kind of reply for more than a month. Dead silence. Even if the reply was "sorry, we don't deal with this anymore." I could accept that. But to have zero response is about the worst way they can handle this. Basically giving their customer the finger.

So last night I sent them a last statement expressing my disappointment, and vowing that I am switching to Quest/Aerotech for my E and D motors.

I used to be a fan of Estes. No longer. The "New Estes" sux! Overpriced old designs, no interesting new designs, mandatory pricing to mess with retailers, and a complete lack of customer service. How they think all this is a good way to run a business is beyond me.

 

[sr205347d]

vowing that I am switching to Quest

Um, see this thread:

Thread 'Q-Jet Follies'
https://www.rocketryforum.com/threads/q-jet-follies.182433/

 

[Capt. Eric]

I think you need to leave D motors out of the mix. I've never had a D motor fail.

I am in the same club techrat is. We have had a few D12 failures, including this past weekend. Not as many as with the E's, but it does happen. Even the graph you post shows they are having more failures.

The origin of my effort to epoxy the nozzles in is due to the nozzles being blown out, in every case that I have examined. In one instance I found the pristine nozzle on the ground next to the pad. So the theory WAS that the nozzle was being blown out and allowing the core to burn too fast/hot. I had started adding epoxy to all my D & E motors, which I fly a lot of. Had a perfect record... until January when I had 2 CATO's. So that wasn't "it."

Aerotech!

 

[mlytle0]

This can be a frustrating experience, especially when it is ongoing for so long, and Estes has not stated the cause, if they know (so far as I am aware). I was doing the above mentioned epoxy add-on and it seemed to be working well. Then in January I had 2 CATO's with E12-4's that had the epoxy.

That was frustrating enough. Even more frustrating has been Estes. In the past their customer service was great. Apologized, replaced the engines, and even replaced the kit. (Although didn't state the cause) This time is very different. I've emailed Estes a bunch of times. Their auto reply acknowledges receipt, and they consolidated the emails into one ID number. But the assigned CS rep, Scott, has not actually responded at all. Been trying to get some kind of reply for more than a month. Dead silence. Even if the reply was "sorry, we don't deal with this anymore." I could accept that. But to have zero response is about the worst way they can handle this. Basically giving their customer the finger.

So last night I sent them a last statement expressing my disappointment, and vowing that I am switching to Quest/Aerotech for my E and D motors.

I used to be a fan of Estes. No longer. The "New Estes" sux! Overpriced old designs, no interesting new designs, mandatory pricing to mess with retailers, and a complete lack of customer service. How they think all this is a good way to run a business is beyond me.

A lot of things at Estes has changed under new management. They now own GOEX so Black Powder production is in house, and they have become a more vertically integrated company, good for profitability, and are a BP supplier for the U.S. military. That said, one old Youtuber who is a muzzleloader fan has tried the new Goex powder and claims it's not as good as the old, less consistent.

Maybe they're making too many changes too fast, or just have too many things on their plate.
Maybe they have to go through trial and error to relearn how to make reliable BP engines.

 

[Capt. Eric]

Um, see this thread:

Thread 'Q-Jet Follies'
https://www.rocketryforum.com/threads/q-jet-follies.182433/

Aerotech isn't perfect, but...
A. they have had fewer CATO's than Estes, from my observation
B. I'd rather replace the igniter than the entire rocket
C. At least Aerotech is willing to engage in the discussion, even on a public forum like this. Estes has decided to ignore us and hope we just go away while still buying their crap.

I won't dismiss Estes products all together. Their smaller engines are fine, and cheaper than Qjets. Some of their rockets are fun and reasonably priced (others not). But again, their ignoring customers is just the worst.

 

[Capt. Eric]

A lot of things at Estes has changed under new management. They now own GOEX so Black Powder production is in house, and they have become a more vertically integrated company, good for profitability, and are a BP supplier for the U.S. military. That said, one old Youtuber who is a muzzleloader fan has tried the new Goex powder and claims it's not as good as the old, less consistent.

Maybe they're making too many changes too fast, or just have too many things on their plate.
Maybe they have to go through trial and error to relearn how to make reliable BP engines.

The production D&E issues I think were from before the new management. They used to handle it reasonably well (though not perfectly - never said a cause). The negative changes have been in the last year or so. I understand they need to be profitable. I don't mind slightly higher prices, especially if they are transparent about it. But they are not respecting their customers anymore like they used to.

 

[Capt. Eric]

But techrat's original post was about the clay cap and nozzle material. Didn't mean to go off topic. Anyone have any real info on that subject?

 

[lakeroadster]

Th origin of my effort to epoxy the nozzles in is due to the nozzles being blown out, in every case that I have examined. In one instance I found the pristine nozzle on the ground next to the pad. So the theory WA that the nozzle was being blown out and allowing the core to burn too fast/hot. I had started adding epoxy to all my D & E motors, which I fly a lot of. Had a perfect record... until January when I had 2 CATO's. So that wasn't "it."

Aerotech!

That epoxy you're putting around the nozzle on the motor tube.... is doing nothing. There's simply not enough motor tube extension.​

 

[Capt. Eric]

That epoxy you're putting around the nozzle on the motor tube.... is doing nothing. There's simply not enough motor tube extension.​

Disagree. There isn't much, but the theory is that we need to add "a little more" resistance to the nozzle being blown out. The process Estes uses takes most of the load, just needs a little more help. Getting a fillet into the corner around the perimeter (avoiding the hole) will certainly add a little strength. But the point is moot since it did not prevent the issue from happening. Seemed to work for a while. I probably launched about 20 with no problems. But then it did.

 

[lakeroadster]

Disagree. There isn't much, but the theory is that we need to add "a little more" resistance to the nozzle being blown out. The process Estes uses takes most of the load, just needs a little more help. Getting a fillet into the corner around the perimeter (avoiding the hole) will certainly add a little strength. But the point is moot since it did not prevent the issue from happening. Seemed to work for a while. I probably launched about 20 with no problems. But then it did.

The epoxy won't see any loading, until the nozzle fails..... all those you launched that worked... didn't need the epoxy.​

​

But if it makes you have a warm fuzzy feeling.... modifying motors.... which isn't allowed.​

 

[cvanc]

Yeah, the rules kinda stand against this.

BUT...

But if it were me I'd try something that soaked in a bit, like CA.

Signed,
Rebel without a clue

Also signed,
Don't come to me if it doesn't work

 

[Capt. Eric]

Yeah, the rules kinda stand against this.

BUT...

But if it were me I'd try something that soaked in a bit, like CA.

Signed,
Rebel without a clue

Also signed,
Don't come to me if it doesn't work

It's no more of an engine modification than putting tape around the casing for a friction fit. But once again, the point is moot. I didn't say that was the ultimate solution. Not sure why you guys are still arguing against it. I guess it makes you feel "warm and fuzzy".

 

[Paul Howard]

I have also wondered about adding Cyanoacrylate into the clay nozzle for adding strength of the ceramic and getting a better bond to the paper casing. I have not yet had an Estes D12 blow the nozzle out on me, but I don't have any of the more recently made D12's since all the corporate changes have happened. I have had that problem about 50% with Q-Jet B and C motors with ceramic nozzles eroding asymmetrically sending the rocket into pronounced arcing flight.

One problem I have had repeatedly is D12 Non-Ejection from too little ejection charge with too thick of a ceramic cap - I have verified this by taking X-Rays of D12's at work. Every time there is a thin layer of Ejection Charge, there is thicker ceramic over it as if a "fill sensor" makes up for less Ejection charge by filling with more ceramic. So I carefully use an X-Acto knife to carve an "X" into the ceramic until I see a hint of BP, then put masking tape over it and since then I've had 100% success, even with motors that barely blew through the cap even with the "X" (which really backs up my practice of doing the "X" - otherwise I'd have more lawn darts). Yes, I have contacted Estes about this and they recently responded that they would forward my info to the Motor-Making People. I've also put the info on www.motorcato.org.

As far as the arguments against "mods to motors", plenty of experienced people check the amount of BP Ejection Charge in their composite motors by removing the cap, dumping out the BP and measuring the BP by volume or weight and usually adding more if needed (I have not heard of anyone removing Ejection BP because there was too much) and re-capping. So the "No Motor Mod" rule makes sense because a LOT of average rocket flyers aren't super knowledgeable or experienced - and I've gotten on a few people's case at hobby shops when they've bragged about loading more BP in the body tube above the motor with metal shavings added to "firework" their rocket and blow it up for the "idiot boom-factor". I've made it known to them how that gives all the rest of us a bad image and just creates local ordinances against rocketry in general and it is very unsafe- so I agree such rules should be in place but the "idiot boom-factor" crowd are not NAR members and are generally unaware of NAR and on the idiot-side of everything they do. That said, a lot of us experienced flyers have made things safer for everyone by doing safety and function goal-minded Motor Mods.

 

[Paul Howard]

Recently, I purchased a load of D12s from someone getting out the hobby. His motors are older, but work fine. At a recent launch at our local group (CENJARS), we had a number of CATOs with E's and D's -- and while perusing the motor selection from a local vendor (Rocketship Games), I noticed that the clay that provides the end-cap and nozzle of newer Estes motors is of a much more coarse grain. It's no longer like sand, but more like fine gravel.

I'm wondering if anyone has had the chance to investigate this -- and determine if this is the reason that D and E motors have a 1 in 10 chance of being a CATO these days. I've taken to running a ring of epoxy around the clay of the nozzle when dealing with the newer motors -- but I've had no issue with the older motors.

Thanks!!

Good to know! Thanks!!!

 

[Paul Howard]

A lot of things at Estes has changed under new management. They now own GOEX so Black Powder production is in house, and they have become a more vertically integrated company, good for profitability, and are a BP supplier for the U.S. military. That said, one old Youtuber who is a muzzleloader fan has tried the new Goex powder and claims it's not as good as the old, less consistent.

Maybe they're making too many changes too fast, or just have too many things on their plate.
Maybe they have to go through trial and error to relearn how to make reliable BP engines.

Good to know! Thanks!!!

 

[SolarYellow]

There is an NAR competition rule that says nothing will be glued to a motor, but that is the competition rule book, not the safety code. So I would not regard the addition of epoxy or CA around the nozzle as discussed above to be in violation of the language from Estes, as it is expressly intended to enhance the reliability in operating exactly the way Estes intended the motors to operate, and does not in any way alter the intended combustion, thust-generating, or ejection processes. IMO, IANAL.

 

[shockie]

I think the larger Estes motors are prone to blowing out the nozzle and or clay cap may be due to over-pressuruzation. The nozzle and clay cap basically have a mechanical bond with the Kraft paper tube.and it the chamber pressure gets too high, the nozzle etc may just be blown out.

Or as Matt Steele's report from years past, thermal cycling can cause the grain/casing bond to separate.

I once had a D motor, that I put in the wrong igniter plug, and the engine. Ignited and did it's burn on the pad, but the nozzle with the igniter plug still in the nozzle was ejected.

 

[ed_w]

. . .

One problem I have had repeatedly is D12 Non-Ejection from too little ejection charge with too thick of a ceramic cap - I have verified this by taking X-Rays of D12's at work. Every time there is a thin layer of Ejection Charge, there is thicker ceramic over it as if a "fill sensor" makes up for less Ejection charge by filling with more ceramic. So I carefully use an X-Acto knife to carve an "X" into the ceramic until I see a hint of BP, then put masking tape over it and since then I've had 100% success, even with motors that barely blew through the cap even with the "X" (which really backs up my practice of doing the "X" - otherwise I'd have more lawn darts). Yes, I have contacted Estes about this and they recently responded that they would forward my info to the Motor-Making People. I've also put the info on www.motorcato.org.

. . .

I've also had this problem more than once with the D motors. I'll have to try the "carve an X" trick. Thanks for the idea. I use a lot of D motors and have also had one or two of them cato. Most have worked fine.

 

[Stefan2k4]

Just a thought, but could it be a separation between the bottom of the propellant grain and the top end of the nozzle, causing the failures? Think about it, if there was a crack to develop there it would expose a lot more surface area to the flame front. This would cause a pressure spike and also might make the nozzle easier to blow out. I don't know, but if this is the case, applying epoxy or anything else to the bottom end of he nozzle wouldn't seem to help much.

As for CA, I would caution that it can sometimes get very hot when applied to some materials. I'd be rather cautious about putting a drop of that into the business end of a BP motor. Not saying it would, but if it somehow got hot enough to ignite the motor in your hand, youd likely have a very bad day.

 

[Paul Howard]

Just a thought, but could it be a separation between the bottom of the propellant grain and the top end of the nozzle, causing the failures? Think about it, if there was a crack to develop there it would expose a lot more surface area to the flame front. This would cause a pressure spike and also might make the nozzle easier to blow out. I don't know, but if this is the case, applying epoxy or anything else to the bottom end of he nozzle wouldn't seem to help much.

As for CA, I would caution that it can sometimes get very hot when applied to some materials. I'd be rather cautious about putting a drop of that into the business end of a BP motor. Not saying it would, but if it somehow got hot enough to ignite the motor in your hand, youd likely have a very bad day.

Great points you bring up about a gap/crack bringing up the burn area and a pressure spike.

Even BETTER Point you bring up is the possibility of CA generating heat during the soaking-in of CA into the ceramic. I agree, that is worth a GREAT deal of Caution! I have some "bad batch H 21 __ __" A10-0T boosters that I cut open just for the Black Powder (I pulverize it with a mortar and pestle for igniters I re-use). I think I'll open up one of them and leave just a very small dab of BP stuck to the nozzle ceramic and go outside and drip some CA on the aft end of the remaining nozzle and watch the soak-pattern and wait and see if it generates enough heat to set off the BP residue remaining before I try it on a D12 motor.

Thanks!!!! - PTH

 

[shockie]

I would contact Estes and ask them if they're using a different clay type/formulation?


TSP like Pyrodyne back in the day, used a ceramic type clay mixture.

 

[lr64]

Great points you bring up about a gap/crack bringing up the burn area and a pressure spike.

Even BETTER Point you bring up is the possibility of CA generating heat during the soaking-in of CA into the ceramic. I agree, that is worth a GREAT deal of Caution! I have some "bad batch H 21 __ __" A10-0T boosters that I cut open just for the Black Powder (I pulverize it with a mortar and pestle for igniters I re-use). I think I'll open up one of them and leave just a very small dab of BP stuck to the nozzle ceramic and go outside and drip some CA on the aft end of the remaining nozzle and watch the soak-pattern and wait and see if it generates enough heat to set off the BP residue remaining before I try it on a D12 motor.

Thanks!!!! - PTH

Might be a good idea to test the CA on the BP, in case, while working on the nozzle, a little dripped inside. You'd have to figure out how to drip the CA from a safe distance, obviously, though that doesn't have to be infinity if the motor is opened up. Or you could temporarily plug the nozzle with something weak while CA'ing the nozzle. Or both. Seems like epoxy, or thinned epoxy, might be safer. Or water based polyurethane, or any of a bunch of other things*. Plugging the nozzle may prevent stuff dripping into the motor that would interfere with ignition.

*But probably not nitrocellulose based lacquer or glue, which are pretty common.

 

[shockie]

Great points you bring up about a gap/crack bringing up the burn area and a pressure spike.

Even BETTER Point you bring up is the possibility of CA generating heat during the soaking-in of CA into the ceramic. I agree, that is worth a GREAT deal of Caution! I have some "bad batch H 21 __ __" A10-0T boosters that I cut open just for the Black Powder (I pulverize it with a mortar and pestle for igniters I re-use). I think I'll open up one of them and leave just a very small dab of BP stuck to the nozzle ceramic and go outside and drip some CA on the aft end of the remaining nozzle and watch the soak-pattern and wait and see if it generates enough heat to set off the BP residue remaining before I try it on a D12 motor.

Thanks!!!! - PTH

I opened up Estes ABC motors back in the day when I was 13. I've also removed the ejection charge and then used an eye dropper with a drop of water and dissolved the delay train to get booster motors.

If you look at the backside of the nozzle and pop it off from the propellant grain you'll see a slight bowl shape that has black powder grains press into the clay itself.

Maybe Estes should put a little bit of grog in their clay to bite I to the cardboard tube for a better mechanical bond.

I don't think the Estes BP motors go above 200-300 psi chamber pressure depending on the motor.