Well the first THOR suffered a fatal maiden flight, and we just can't have that so THOR 2 has been built.
Instead of going over build pics again I'll just document what has been done differently this time. Basically nothing with the rocket has been changed, I tried some different techniques with the fillets and they came out nice.
I also knew ahead of time what I would need for vent holes, port holes, shear pin holes, etc.. and where so these were drilled and placed ahead of time before paint. This ended up giving me much cleaner looking holes in the body tube.
The body tube around each hole was then soaked with CA to reinforce the areas.
The failure last time was with the LOC motor adapter, 54mm to 38mm that I used to fly the J350 in the rocket.
As you can see above to the left end of the motor adapter you can see the glue residue from where the thrust ring was.
Here's another picture of the adapter, you can see again the reside at the bottom of the 54mm tube on the left, the thrust ring in the middle, and then the 38mm motor tube on the right, it got enough of a head of steam before it struck the electronics bay that it ripped both the upper centering ring and cardboard off the 38mm tube. The lower centering ring it ripped off of the 54mm tube as well as some of the cardboard.
All the damage to both the rocket and the adapter is secondary to the thrust ring letting go, so here's the fix for THOR 2. Maybe a little gutsy but I've gone ahead and used the same motor adapter but with some modifications.
To the left is the 54mm tube, this time I marked where the adapter will sit, instead of flush with the end of the 54mm tube it's moved up 1/8" to allow a second epoxy fillet on it. Then I drilled 4 1/8" holes evenly spaced and centered where the thrust ring will go for epoxy rivets.
A generous amount of epoxy was then applied and the thrust ring inserted onto the 54mm tube.
The 38mm tube to the right is then inserted into the 54mm tube and heavily epoxied in, all is done with 30 min epoxy.
The adapter above is after completion. At the top of the tube in this picture it's hard to see but the epoxy is in one application coated from the end of the 38mm tube all the way down it to the centering ring inside the 54mm tube, over that centering ring and over the 54mm tube to the thrust ring, it's all one solid piece of epoxy and very heavily applied. The bottom of the thrust ring has another heavy fillet although it's very hard to see in this picture.
I left the picture fairly big so that you if you look close you can see the mound of epoxy at the top of the 54mm tube. This adapter is oriented upside down from how it will actually be used so that you can see the details better.
Both the centering rings inside of the 54mm tube are heavily coated with epoxy and I think that this time it should hold fine. I've seen online that these adapters are supposed to weigh in at 4 oz, with these modifications and a ton of epoxy mine still only weighs in at 3 oz, so I'm assuming what I've seen online must be a misprint.
The old THOR on the left and the new one on the right. THOR 2 on the right should get it's maiden flight April, 2004.
End weight everything but the motor and ejection charges is 105.5 ounces, or 6.5lbs.
Thor 2 lifting off on an AT J350 at the TRF launch in Whitakers, NC April 2004.
Video of flight here.
Thor 2 lifting off on an AT I285 Redline motor in Pickrell, NE. May 2004
Video of flight here.
Thor 2 lifting off on a CTI K445 3/19/05 with the THOR group in Nebraska. Flight to 7,428' at 657 mph.