No, that's LOX, illuminated by sunlight. That engine start does seem to
have had a longer fuel lag than normal, though. Perhaps the sequencer
was targeting a particular LOX dome temperature to ensure full density
and prevent a mixture ratio departure during the start. In videos of the
Xracer in flight, you can see the LOX Chill valve cycling to control the
dome temperature for that very reason; on some starts the of Ez-Rocket's
engines the mixture could momentarily go very rich and cause a brief
flameout and relight, begging for a hardstart. We added chill valves for
all our LOX-using engines after that and I had fewer heart palpitations.
On 2019-08-07 9:21 AM, John Dom wrote:
Just wondering. Looking at the stage 2 onboard camera footage: it showed a wet non-luminous exhaust as if it were water vapor. Does that imply unburnt RP-1 surplus (fuel rich) of the stage 1 exhaust would **not** be luminous in the vacuum of space like in part of the return trajectory? Not clear to me.
Unless stage 2 combustion was not as fuel rich as stage 1 is the reason.
Anybody?
John
