The 3-d drawings for the sustainer and its cross-section view can be found below.
Figure 1: Sustainer.
Figure 2: Cross-section view of the sustainer.
Here, the thrust curve for the sustainer can be found.
Figure 3: Sustainer thrust curve.
This is an M1329 motor, with a total impulse of 5.8 kNs.
The average pressure is 660 psi with a peak pressure of 825 psi.
With a mass of 6.5 lbs, the propellant contributes to more than 49% of the mass of the whole motor, which is 13.22 lbs.
Lastly, the expansion ratio for our booster is 19.75.
The nozzle has a throat diameter of 0.675 in and an exit diameter of 3.0 in. The throat length is 0.1 in.
The divergence and convergence half angles are 15.0 and 60.0 degrees, respectively. A close-up 3-d drawing of the nozzle can be found below.
The propellant used in both motors of the rocket is the Cherry Limeade.
As far as the sustainer motor is concerned, there are a total of 3 grains. From the top end of the motor up to the nozzle, these grains are ordered as follows:
3. Finocyl: This grain has a cire diameter of 0.85 in, with 4 fins. Each fin has a width of 0.20 in and a length of 0.65 in. The outer diameter of the grain is 2.56 in with a total length of 8.0 in. It has a mass of 1.968 lbs.
For reference, the motor simulation file can be found here: 5.8KNs_M1300_24in.ric