Engine Dev Update

I picked up a new video camera. Thus, even better pictures and video of the engine tests. As you can see above, the shock diamonds are not as washed out as in previous pictures and movies. One of the mixed blessings about the new camera is the image stabilizer. It helps in getting crisper pictures, but the vibrations from the engine firing show up as a slower wiggle in the videos. The camera is on a tripod, not hand held while taping engine firings!

Even more engine testing going on. Our latest test chamber is performing flawlessly, and much better than we expected. We changed our injectors since our last engine update. In the previous movie you can hear a ‘hum’. That hum is instability at about 170 Hz. The new injectors have taken care of that as you can see in the these frequency analyses.

FFT of audio from previous postFFT of latest full thrust firing

We have now tested the engine down to 35% throttle with reasonable performance and still very stable. The major problem with 35% throttle is the amount of time it takes to get up to thrust. The startup transient is nearly 3 seconds long, and there is a lot of noise before the plume becomes visible.

Download the video here.