- May 9, 2019
- Reaction score
I've got my first two stage rocket nearly finished and I'm re-running a number of simulations to get a feel for what I can anticipate out of flight performance. My local field options are pretty tight so I am trying to keep altitudes under 3000 feet otherwise my recovery goes from occasional trees to full on forest. This presents some challenges to the event timing since there's very little coasting between boost and sustainer phases. Picking a relatively weak sustainer motor is a given unless I want to GPS tag a rocket eating tree. Where I'm more concerned is the choice of booster motor. Sustainer ignition is going to base off time delay with altitude and velocity gates (Raven 4) parameters so there will be a "no go" built in if things go sideways. My question is if there is a minimum recommended thrust to weight ratio. Obviously, higher is better for attaining greater acceleration and giving me more time in the programmed launch parameters. The 5:1 minimum T:W for single stage flight seems to be a bit weak in what motors I've simmed for my booster although they are great at keeping the altitude down. Is there a better safe minimum for two stagers? If it helps, basic specs on mine are 70" combined length, 1800 grams and stability margin of 3.5-4.75 depending on the motor choices. 38mm in the booster and 29mm in the sustainer. Thanks for the feedback.