R-9 Test Results

I have recently acquired new materials for use in casing construction

The idea is that instead of locating a nozzle manifold on the inside of the rocket casing, it is placed directly on top, and then held in place with a external tube placed over top

The first test did not perform as expected

Initial observation noted a strong start, followed by a significant amount of excess burn time (read, it burned 10 seconds longer than expected), and 2 columns of what I expect is un-reacted oxidizer (saltpetre)

There must have been some form of chamber breach resulting in either a loss of pressure or loss of pressure build up, since it started nominally and burned for longer than normal
It was either that or a failure to start caused by the nozzle exhaust releasing enough pressure to stop the fuel burning quick enough after the igniter was ejected, but i am unsure of how to prove either of these cases

As for the columns, I have taken extensive photographs to document them

It has however been evident that the fuel mixture needs some work, since a lot of un-reacted saltpeter is always found at or behind the exhaust

I think this can be attributed to less than optimal mix of the ingredients, which is why I’m temporarily shifting focus to R&D for a better ball mill
I have ran out of fuel either way, so i find it best if i invest time now to make sure the next batch will be better, this is also why I’m temporarily changing the ratio of fuel and oxidizer (Saltpeter / Sorbitol) from 65% / 35% to a ratio of 60% / 40%, this is in an effort to reduce un-reacted reagents, though this mixture is on paper less ideal power wise (Source: Nakka-Rocketry)
This could also influence the casting process, for better or worse, but this has yet to be tested

As always, the raw data (In a 7-Zip archive):

I also recommend Notepad++ for viewing and editing

On to R-10