MadMat Posted December 23, 2017 Posted December 23, 2017 (edited) I've been making 2,3 and 4" cylinder shells for some time now and am thinking about starting 5". I was wondering at what diameter does one start using MCRH (or equivalent). I was guessing at 6" but not sure. BTW I stopped spiking the burst charge at 4". Edited December 23, 2017 by MadMat
NeighborJ Posted December 23, 2017 Posted December 23, 2017 (edited) For cylinder shells I use only granulated BP. As they get larger I use increasingly larger quantities of polverone but MCRH can compress and cause a flowerpot during lift. I do occasionally use MCRH for large rocket headers because they aren't subjected to the same forces and weight is a concern. Edited December 23, 2017 by NeighborJ
OldMarine Posted December 23, 2017 Posted December 23, 2017 Most people say they use MCRH in 5" and up ball shells. I tried some in a 4" dusted with whistle and wasn't impressed with the break.
NeighborJ Posted December 23, 2017 Posted December 23, 2017 I've been making 2,3 and 4" cylinder shells for some time now and am thinking about starting 5". I was under the assumption that the 5" shells he is starting are cylinder shells.If not, then yes, MCRH on 4" and bigger.
dynomike1 Posted December 23, 2017 Posted December 23, 2017 I use mcrh on everything except lift. I put it in and pack it tight even cylinders.
NeighborJ Posted December 23, 2017 Posted December 23, 2017 Ok, are you using thick end disks? 1/8", I've made my end disks in the past from ramboard and decided after a few flower pots to use only BP. I've recently switched to 1/8" disks but haven't revisited using MCRH in those shells.
OldMarine Posted December 23, 2017 Posted December 23, 2017 Oops, missed the reference to cylinders. I haven't used MCRH in any of those.
calebkessinger Posted December 24, 2017 Posted December 24, 2017 Most folks don't use mcrh for cylinders. They don't pack well enough to survive lift. But.. for a rocket heading I see no terrible downside as long as you can make them work. Most folks us a cannule. Filled with hot bp and then pack the space around the stars with polverone
dynomike1 Posted January 5, 2018 Posted January 5, 2018 I guess i cheated a little, i kinda pressed the end disk.
Merlin Posted July 6, 2018 Posted July 6, 2018 (edited) I used MRCH for the last two years in 3 and 4" cylinders and have never had a flower pot. I boost with nitrate flash and get very good breaks. I also lift with mcrh with no problems. I do use thick end discs. Based on this thread y'all are probably thinking I wouldn't know a problem if I saw it. It is just so efficient to coat rice hills in a cement mixer than granulating. Maybe I've been lucky but so far no failures. Edited July 6, 2018 by Merlin
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