My two-stage "Einstein" rocket looks as it if will be ready for International Rocketry Week in the UK . It's my first attempt at HPR staging so I want to get it right.
The basic design is a 3 inch phenolic body, glassed from the base to the sustainer motor section. It weighs about 3.5 kg dry mass, and is about 2.5m (8ft 4in) tall.
On a 54mm J295 to 38mm I212 is simulates to around 7000 ft and burns out at around Mach 0.8, which allows the use of a barometric altimeter without having to faff around with Mach delays.
I'm using the motor delay grain to deploy the chute on the booster. I'm having difficulty calculating the correct delay for the booster deployment. As a first attempt I disabled the sustainer motor tube in Rocksim, and launched it on just the booster motor. I figured that would give me an idea of the altitude and delay at which the booster parachute needs to deploy. It's telling me 5000 ft and 17 seconds, which means the booster could drift for miles. This feels wrong, as staging takes place at seconds and 1500 ft. I find it difficult to believe that the booster will coast for 13 seconds and 3500 ft. I rather think it would tumble.
Can anyone offer any advice how to get a better estimate of the booster delay?