2ND CATO !!

[rsbhunter]

Estes E12-4. Had launched a different rocket 10 mins prior with no problem. Then, BOOM.!!! I won't disparage Estes, but this is the second cato in the last 10 launches. Different power engines,but still a 20% failure rate. Ordered some AT E20 SU's. The cost is greater, but not if I figure in the cost of a rocket! Do the "other" rocket engines have the same problem? Thanks, rsbhunter

 

[OzHybrid]

The larger the Black Powder motor is, the more likely it is to have a crack in it. A crack in the propellant is an additional flame front which increases the pressure which increases the burn rate which increases the pressure.......etc, boom. Larger motors are composite propellant that have a rubbery composition that is less susceptible to issues. The D and E BP motors have a high failure rate relative to the B,C motors

 

[rsbhunter]

Great, maybe my cato rate will go away by going to composites....rsbhunter

 

[Zeus-cat]

Black powder E motors may be the most likely to CATO. The bigger the black powder motor, the more likely it is to CATO for a variety of reasons. I don't think anyone makes a black powder F motor anymore. And certain date codes are more likely to CATO. There is a list on the forum somewhere.

 

[Antares JS]

I don't think anyone makes a black powder F motor anymore.

Estes makes the 29mm BP E16 and F15.

Early batches of those had problems, but ever since they retooled their 29mm equipment a few years ago, I have not had a single issue with newer batches of them.

 

[ksaves2]

Great, maybe my cato rate will go away by going to composites....rsbhunter

It will go down but not go away. Still can have case failures with APCP with certed snap ring casings and the such.

 

[astronwolf]

I don't think anyone makes a black powder F motor anymore.

 

[rsbhunter]

It will go down but not go away. Still can have case failures with APCP with certed snap ring casings and the such.

I'll take the odds improvement. I know nothing is 100% certain. I plan on using the Aerotech 24mm RMS if I hear good things about them....rsbhunter

 

[loopy]

I'll take the odds improvement. I know nothing is 100% certain. I plan on using the Aerotech 24mm RMS if I hear good things about them....rsbhunter

I love my 24/40 case and use it often. The E18 is such a great motor.

 

[SolarYellow]

I'll take the odds improvement. I know nothing is 100% certain. I plan on using the Aerotech 24mm RMS if I hear good things about them....rsbhunter

There was a rash of CATOs around here this spring with the TARC teams using 24/40 cases. They were blowing out the tops. I saw a photo of a forward closure that had stripped with only two threads machined on it. Apparently, other FCs have three threads and did not CATO. I'm sure they're in contact with AT CS.

 

[rsbhunter]

I will make sure if I go that route (24/40) that it has the correct # of threads... is the 24/40 the only, or most versatile case? Thanks, you guys are a great source of knowledge! rsbhunter

 

[SolarYellow]

Most versatile case in the Hobbyline series overall is the 29/40-120. However, for LPR/MPR, I see the 24/40 as the workhorse. F24 and F39 are great value motors. In the full-E/baby-F range, the Quest E35 and F41 win on cost and ease of use, but they do require a 95mm MMT. The 24/60 is cool. I was running some sims last night where the D24 in the 18/20 case was the answer I was looking for and nothing else could match it.

 

[user 38430]

I've never seen a 29mm F motor CATO. The failure rate is so low I don't worry about it anymore. 400+ launches last year and 6 Catos seemed okay to me considering how cheap Estes is compared to everything else.

 

[loopy]

I will make sure if I go that route (24/40) that it has the correct # of threads... is the 24/40 the only, or most versatile case? Thanks, you guys are a great source of knowledge! rsbhunter

24/40 is the most versatile case for 24mm. The most versatile case below high power is the 29/40-120 case. If you're planning on doing mid power flying even remotely regularly, you need these two cases.

 

[sr205347d]

Black powder E motors may be the most likely to CATO. The bigger the black powder motor, the more likely it is to CATO for a variety of reasons. I don't think anyone makes a black powder F motor anymore. And certain date codes are more likely to CATO. There is a list on the forum somewhere.

I have been flying D12s a lot over the last couple of years. (My Bellyflopper, mostly. More recently in my Starship Glider.) They have been perfectly reliable, up until recently. I have had three D12-3 CATOs, two at the last launch. Makes me think the machine used to make the D12-3s needed maintenance. Has the Mabel mechanic retired?

I have flown several E12s over the last year, with only one CATO last summer.

 

[rsbhunter]

My other cato was with a D12-3 !!! And now the E12-4. I have the 29/40-120 hardware, and a couple reloads. Waiting on some stuff to mount the 1010 rail and finish the 12v launch controller, figured the low power reloadables would be fun...rsb

 

[cwbullet]

They happen. I would not dwell on it.

 

[Daddyisabar]

I had another new pack D12 3 cato last launch. It was in a rocket I had repaired from a previous cato. I had flown two D12 3s before in other rockets. I made disparaging remarks about Estes in front of Top Men.

It is so bad a Top Man I talked to will not fly D or E motors manufactured in all of '22-23. I will join that club. I might have just lost my Estes shill status but that is no big deal. To many BAD DATES with Estes.

 

[rsbhunter]

Yeah, mine shows 23 (I think) I'm going to composite,,,,the money I save on rockets will pay for the cost difference...I know they can have problems, but I'm done with Estes D and E engines...rsbhunter

 

[ksaves2]

Great, maybe my cato rate will go away by going to composites....rsbhunter

Maybe but then you'll have to deal with case burn throughs with commercial reloadables. I have two 29mm Al cases with the same failure holes at the base
from a commercial load. I have several with burn throughs with my research loads in a commercial case but that's my risk and don't beech about it to the maker. My propellant I guess can get hot. Some of the case failures occur with ground tests with research loads which is fine as at least I don't lose a rocket with it's electronics. I think I had a couple of 2 grain 38mm case burn throughs with commercial only loads.

I had single use APCP perform anomalously but indeed it's rarer than BP. I have a big bag of old Estes BP motors out in the garage leftover from grade school days from BEFORE Estes converted to the metric system. All English system rated motors that have been temperature cycled so much they'd probably CATO. Well maybe the booster motors might work but then again not. Maybe only of value to an motor collector.

 

[rsbhunter]

Until I hit a 20% rate of failure with Composite engines, I'll go with those....nothings infallible, but the rate I'm getting for me, isn't acceptable....time will tell. rsbhunter

 

[sr205347d]

Having lost all faith and confidence in my D12-3s with date code E22 0323, I built a rocket just for them. I call it CATO Bait. The motor is friction fit, so it can blow out the back with minimal damage. The rocket is light and draggy, so shouldn't hurt itself in a hard landing.





Very entertaining. The only damage to the rocket is to the parachute and shock cord.

 

[rsbhunter]

Yeah....again...I have gone to using Aerotech RMS motor system. The reloads are alittle more expensive, until you add in the cost of rockets. I had a Hi Flier XL that cato'ed...Estes sent me anew one, and two engines...two flights later, Deju vu all over again...blew out the side wall on the new one. I might continue to use the B & C class motors from Estes, but for D, E F and now G, it's Aerotech for me...rsbhunter

 

[John Taylor]

Estes E12-4. Had launched a different rocket 10 mins prior with no problem. Then, BOOM.!!! I won't disparage Estes, but this is the second cato in the last 10 launches. Different power engines,but still a 20% failure rate. Ordered some AT E20 SU's. The cost is greater, but not if I figure in the cost of a rocket! Do the "other" rocket engines have the same problem? Thanks, rsbhunter

ESTES has known about the E12 engines for years blowing up. They worked on the engine manufacturing machine and they got better but they still are #1 on the M.E.S.S. reports for catos and ejection failures.
Composites are the only way to go.
Much more reliable and fun. More noise, smoke, fire, and performance at compariable pricing per Newton Seconds.
I fly only Composites above D impulse.

 

[cwbullet]

ESTES has known about the E12 engines for years blowing up. They worked on the engine manufacturing machine and they got better but they still are #1 on the M.E.S.S. reports for catos and ejection failures.
Composites are the only way to go.
Much more reliable and fun. More noise, smoke, fire, and performance at compariable pricing per Newton Seconds.
I fly only Composites above D impulse.

E12a initially worked well when they first replaced the E9. The E9s were the CATO queens. The E12s replaced them as the top cato from Estes in recent years and now the D12s are doing the same. SAD!

 

[neil_w]

E12a initially worked well when they first replaced the E9. The E9s were the CATO queens. The E12s replaced them as the top cato from Estes in recent years and now the D12s are doing the same. SAD!

Well... there is a recent batch of D12 date codes that have a problem, but it sounds like it's been identified, and otherwise they have a very good record. E12s have been suspect for a long time.

 

[mlytle0]

I've always wondered if D12's have a slightly lower 'fill' in the casing then a C6 with the same length casing because as far back as the end of the sixties when the D was created they were fighting cato problems, which were made worse as the propellant grain gets longer, especially in casings larger than 18 mm.
In Harry Stine's handbook, he makes mention of Estes originally adding Dextrin adhesive to the Black Powder to try to prevent grain/casing debonding.
I think they dropped that later, as it didn't seem to make any real difference.

Of course, going to longer casings and grains moving to the 'E' class, exacerbates the problems.

 

[SolarYellow]

I bought a Hi-Flier XL for $3.19 from Hobby Lobby yesterday. Some minimal modification to the fins improves the stability enough that it's about 12% of airframe length with an E12 hanging out fully aft of the airframe. I think that's my new CATO-resistant concept. Just use a chunk of coupler/motor block inside a short MMT to "plug in" to the normally-positioned MMT. If the motor CATOs by rupturing the case, hopefully all that needs to be replaced is the "adaptor/extension" piece. When flying non-suspect motors, the normal MMT could be used.

I'm torn between design concepts. One is, as in post #22 above, just make sure any forward-directed CATO can easily eject the laundry. The problem with that is that I'm going to have a metric carp-ton of D12-3s, which are too short a delay for this rocket.

The other concept is to vent the ejection charge and do electronic ejection with an Apogee. I would use "ribs/spokes" ( kinda like TTW fins, but not actually TTW fins because I'd be using the stock fins kinda normally) to connect the MMT to the airframe so any forward pressure is vented aft. The area of the "donut" is about 75% greater than the area of the inside of a 24mm Estes case. The chamber ahead of the MMT will be sealed with a bulkhead, making the volume as large as it can be. I'd use electronic ejection to handle the laundry. This would have the advantage that on a nominal flight, the rocket just wouldn't care about the ejection delay, so I could fly any 24mm motors in it.

I've previously been thinking about a full scratch built downscale of the Big Daddy to BT-80. It provides significantly more bypass area for a forward-directed CATO to vent out the back, but it also would probably be better suited to a D12-3 if I wanted to risk motor eject.