Labeling Your Motors -> Less Destroyed Rockets

Just a suggestion...

After running into a bad batch of motors back in the 90's (I lost 3 rockets (two valuable kits, and one cheap scratchbuilt) out of the six motors I had), I learned that if I wanted to keep my rockets from being destroyed, I better know which group of motors came from which batch. I didn't know how to read the serial number info on the motors back then (still don't know, now that I think of it). So, when I buy motors, I always label them. I use the date that I purchased them, and if there are multiple packs of motors of the same type, I label them for that too.

So, say I buy multiple packs of D12-7's on July 5, 2013. Pack one would be labeled 13/7/05A (most of the world does YY/MO/DD) and then 13/7/05B for the second pack and so on.

This eliminates any fears that I have if one motor in a pack explodes on ignition, which other potentially defective motors are lingering in my stash. So, if what happened to me in the 90's should happen again, I'd immediately remove the remaining motors from that pack from being used. If a 2nd motor explodes I'd stop using any D12-7 purchased on that day. Now I know to get in touch with Estes (didn't have a computer w/the internet back in the 90's) to file a request for replacement.

Oh, and back in the 90's I had two taped together 2 stage rockets fail to ignite the upper stage. After recovering the wreckage, I was able to still use the upper stage motors for single stage launches, I now wonder if there was a problem with the nozzles of those upper stage motors that caused the ballistic returns. I will never know.

Pointy Side (Safely) Up!
Jim

There can certainly be no harm in this type of batch coding.

I don't know much about the manufacturing process of rocket motors, but I have spent many years in a beverage manufacturing environment.

The problem with your 'batch' analysis, Is that you have no way of knowing if to motors from the same pack came off the line sequentially, or even had the same batch of raw materiels. Or even if they came off the same filler/packer etc.

So.. In the beverage business.... closures (caps) all come from a suppler and get dumped into a large hopper. So, box#2 will get intermingled with some caps from box#1 (and #3). Who knows if their QC even requires them to track Raw Material Batch info?? So a problem with motor casings that may have happened way upstream by a RM supplier, could impact several runs of motors and maybe even on more than one line.

The latest pack of D12-3 motors I have appears to have an "A 01 04 13" code on them. So this appears to be a production date. Who knows what the "A" code is for. May be a production line or plant code. Point is... You really need to know how many plants and lines these motors come from. Marking your motors by the pack is ok, but I don't think it really guaranties anything.

It's not just production. Handling and storage after packaging can affect cato likelihood as well.

I'm not aware of any statistics on the subject but there's anecdotal reports aplenty of multiple catos from the same package.

Another good policy probably would be if you have a rocket you have a strong emotional attachment to, don't fly it on the first motor out of a package. Maybe pick up a couple E2X kits to serve as "tasters".

Of course catos will still happen to good rockets but maybe you can improve the odds.

I try not to worry so much about this issue. Luckily I haven't had very many CATO or motor issues over my 30 some odd years of off and on rocketry. Most of my mishaps have been repairable. Now I know some of us get very attached to our birds... some have a lot of time and effort poured into them, but keep in mind that we are igniting rocket motors! There is some risk involved. Personally I think it adds to some of the excitement!


Jerome