A couple of weeks ago, I had both motors in a pack of Qjet E26-4 blow out the nozzle. Both nozzles had been significantly enlarged by the propellant in a nice symmetrical manner that basically looked like they had been purposely drilled out. About 1/4" diamenter. Did some repairable damage to rocket. Date code: 080321. Checking Motorcato.org, half of the reported cato's for this motor carry that same date. Yes, yes, I know this is a quite small sample size. But half? Unfortunately, that is a probably unavoidable problem with Motorcato.org - we don't know how many were flown successfully. Some? Many? Most? Or possibly none? But I feel that the date code info there is useful in trying to avoid possible troublesome batches of motors.
Digging around this forum, I see mention of Qjet nozzle issues on motors made mid 2021, so that fits with this experience. Both of the nozzles seemed OK when I was installing the igniters (starters, whatever), although the rubber tubey thingy that is supposed to hold the igniter in place was very loose and didn't work. Had to use a piece of masking tape. The nozzles didn't seem to be soft.
Anyway, I purchased 2 packages of new motors from a different vendor hoping that I might receive newer stock. But, yup, you guessed it. Both packs carry the 080321 date.
I really don't want to subject the rocket unnecessarily to more damage. Not sure what to do. I could try to return them, but shipping would be roughly half what they are worth. Combine that with packaging, time spent, etc. and I'm not inclined to do that for the marginal benefit.
I contacted Aerotech warranty, and they are sending replacements for the 2 that blew. I haven't tried reaching out to them regarding my concerns about the new ones received. I probably should, but most manufacturers of just about any product don't do warranty replacements of stuff that you are afraid might break.
Not sure if there is any inspection that I can do beside the obvious quick look that could detect a problem.
Suggestions?
Digging around this forum, I see mention of Qjet nozzle issues on motors made mid 2021, so that fits with this experience. Both of the nozzles seemed OK when I was installing the igniters (starters, whatever), although the rubber tubey thingy that is supposed to hold the igniter in place was very loose and didn't work. Had to use a piece of masking tape. The nozzles didn't seem to be soft.
Anyway, I purchased 2 packages of new motors from a different vendor hoping that I might receive newer stock. But, yup, you guessed it. Both packs carry the 080321 date.
I really don't want to subject the rocket unnecessarily to more damage. Not sure what to do. I could try to return them, but shipping would be roughly half what they are worth. Combine that with packaging, time spent, etc. and I'm not inclined to do that for the marginal benefit.
I contacted Aerotech warranty, and they are sending replacements for the 2 that blew. I haven't tried reaching out to them regarding my concerns about the new ones received. I probably should, but most manufacturers of just about any product don't do warranty replacements of stuff that you are afraid might break.
Not sure if there is any inspection that I can do beside the obvious quick look that could detect a problem.
Suggestions?
