Armadillo Aerospace News: Engine work

We built a couple more test engines this week. We reconfigured the data acquisition to read pressure between the cold pack and the hot pack, and final chamber pressure on all runs.
We built a welded engine with 600 grams of ring catalyst in the hot section in a single layer, and a slightly drilled out spreading plate.
This started out with great thrust – over 700 lbf, but it tailed off after a couple seconds. This turned out to be due to many of the rings on the bottom squashing flat under the heat and pressure.
Initial: 730 lbf from 293 psi feed, 187 psi mid, 154 psi chamber
Final: 575 lbf from 278 psi feed, 198 psi mid, 120 psi chamber Read More