Armadillo Aerospace News: Flameholder engines

We did a lot more development with various flameholders and ignition systems.
Slitting the tubing lengthwise and making crosses out of it was labor intensive, so we started working with 316 stainless angles. I had to go someplace other than McMaster-Carr for these — http://www.supremestainless.com/ had everything I needed in stock, but would only ship mill lengths (20’) by truck. I got some of each size from ¾” to 2” legs.
A single 1.25” angle across the chamber gave a visibly stronger flame than the tubing cross. The book “Gas Turbine Combustion” by Arthur H. Lefebvre (a good, informative book) has some data on flameholders that follow a few general trends: larger flameholders are more stable than multiple smaller ones, and for angular gutters, increasing the angle (from 60 to 90, for example) increases the stability, but at an increased pressure drop. Read More