Cracked RMS liner

It is definitely a problem. Replace it (pardon tech post).

You would think that it would cause problems, maybe weakening the case from the impinging heat, but I've flown many a cracked AT liner with no problems, many of them the longer 38mm loads that require the seal disc. Still, replace it if possible.

Mike Fisher Binder Design

The purpose of the liner is to keep hot gasses from coming in contact with the casing. In the process it gets charred which is OK. If the liner is cracked or

the O-rings do not seal, combustion gasses can come in contact with the case and the results are not pretty. Something very much like that happened on a Titan booster some years back and the case (what was left of it) looked like someone had taken a can opener and run right up the side. The missile blew and took out most of SLC6 (Space Launch Complex 6) at Vandenburg. Your hairline crack might not cause a problem, but do you want to take the chance recognizing that the engine will CATO if it opens up under pressure.

Larry Hard> As I was assembling an AT J460 I noticed a hairline crack in the liner about

A liner crack forms a "nozzle" while flow around ends of liners and o-rings are more of an equalization flow. When you have a nozzle pointed precisely at your case wall on ignition, that is the worst possible failure mode.

Jerry

Every J-570 I've flown (20 plus) the liner has come out of the case with a full crack the entire length. The result is a line of hard residue, in the case, where the crack was. A little elbow greese removed the crud, but a slight line was left where the anodizing was removed. There was no other damage. Also, I've never had one CATO. I've also flown several other motors that had cracked liners, before hand. I CA'd the crack and the motors worked fine. This is NOT a procedure that I recommend, however. It's just that it wasn't that easy to get a replacment liner and I thought I'd try it. So far........no problems:-) As I understand it, the real "seal" for the motors needs to be to keep the hot gases from setting off the ejection charge too early. I've had many liners burn thru (one way or another:-) but as long as the hot gasses didn't leak by to the ejection charge.......the motor worked fine. I might also suggest that you greese the liner/inside of the case as to minimize the amount of contact the gases have with the case. Messy but the clean up is easier. To be as safe as possible though, use a liner that isn't cracked:-).

Lloyd Wood BRS Secretary Level lll

Sounds to me like a design flaw that is promotiong case crack. Our 38mm systems do not seem to suffer this fate. I find the liners almost always reuseable. We use the same liner supplier and specification as errortech too. Or they us.

Jerry

Yep. Same here. I've flown many with the cracked liners from rough dealer handling. Same experience as you, a line of hard residue, removed with cleaning.

Mike Fisher