That is 6-second delay. The burn time is about 1.6 seconds.

I am looking at a 2 second delay before the actual burn for an upper stage engine. The booster would ignite the upper stage, then drop off. The sustainer would produce just enough gas to drop the base pressure for 2 seconds or so to allow it to act as a boosted dart, then after the velocity burns off some, the actual burn would start. For B altitude, I have always wondered if this would help. I was working on that with 13mm engines in the early 70's when the rug got pulled.

I suppose I could fly the combination in Rocksim, but it is not the same without the sulfur smell.

__________________
Carl McLawhorn
NAR#4717 L2
semroc.com