I49/I59 failures

One of our club members had an I59 dump it's guts today. I have flown this motor myself, and feel that the only acceptable way to "build" it is with epoxy inhibiting the front end of the W9 grain. Said member used grease, OK per instructions, but you know, KA-BOOM.

I think the good people at AeroTech should ship these things with the front end already inhibited, or specify EPOXY in the instructions.

What do you nerds think?

I used one with no issues to set a TRA record. But Gary Rosenfield assembled it for me.
I have more reloads, I guess I will have to read the instructions.

M

I have flown the I59 many times over the years, and the instructions have changed during that time. I experienced one failure, during boost, that split the side of a much loved Dr. Rockets case. This was caused by a misunderstanding about the forward closure. A plugged forward closure is not the same as an endburn closure...:blush:
Since purchasing the correct closure, and following the directions, several successful flights have occurred.
The instructions say to inhibit the forward (flush) end of the sustaining (solid) grain, and installing a 1/16" grain O-ring between the bottom of the sustaining grain and the boost (W-9) grain. Inhibiting a Warp 9 grain sounds like an exercise in futility to me, and is not in the instructions. Bonding the sustaining grain is a relatively new procedure, and a good idea, IMHO.
Using the wrong closure will get you this:

So I'm planning on using my first I59 this fall. I have the correct forward closure. Read through the directions and I understand the sustainer grain/liner bonding, and the flush forward inhibiting . but is the OP suggesting applying epoxy on the forward face of the cored booster grain, as well as the grain o-ring?

No. I am suggesting that you use epoxy on the forward end of the sustainer grain only.

I did the certification firings for the I49 and I59 reloads and only used grease on the forward grain surface.
That said, something more robust as an inhibitor would be a step in right direction.

John

Built an I49 last Saturday at MUDROC per instructions using epoxy (15 min BSI) for forward end inhibition and grain to liner bonding. Smeared a bit of grease on it as I put forward closure on for good measure. Motor worked perfectly, great flight! Motor case was a bit dirty but otherwise ready to fly again. YMMV
William

I had two failures in a row on I49s, kept getting warranty replacement reloads and cases (but not rockets ). My problem was burning through the side of the case. My "fix" was to give the liner a GOOD coat of grease on the outside for a bit of extra protection. My final two flight were flawless. I'm not in a hurry to buy any more of them, though.