Kismet

🌱 Component basics

Title	Kismet Hybrid Engine
Description	The Kismet hybrid engine uses N₂O as the oxidizer and HTPB as the fuel. The original iteration of this engine was designed between 2017 and 2018, and first flew on the team’s UXO rocket at the 2018 SAC. The current iteration of Kismet is the third in the series. Changes in this iteration include new SRAD pneumatically-actuated oxidizer vent and injector valves, a nitrous oxide fill-sensing system, and a 3D-printed nozzle. These changes were motivated by a desire to increase the apogee of the rocket, as well as the reliability of pre-launch operations. The key design parameters for the current engine design are given below:
Anatomy diagram
Key to anatomy diagram	Vent Section Oxidizer Tank Injector Section Combustion Chamber

Specifications

Propellants

Fuel: 90% HTPB / 10% powdered aluminum metal – 5.58 kg (12.3 lb) total

Oxidizer: N₂O – 20.41 kg (45 lb)

Injector

36-element showerhead: 25 mm length x 2 mm diameter holes. AISI 304 stainless.

Nozzle

Nozzle: Shape – 80% Bell. Throat diameter – 38 mm. Exit diameter - 83.53 mm. Chamber/Inlet diameter - 95.08 mm. A_e/A^t - 4.83. Convergent Angle - 35°. Divergent Angle - 18.89°.

Chamber

6-slot pseudo-finocyl grain geometry (19.05 mm slot width, 38.1 mm core diameter, 18.4 mm slot depth).

OD – 127 mm. ID – 120.65 mm. Fuel grain length – 665 mm. Fuel grain Diameter - 114.3 mm (120.65 mm with G11 liner).

Cooling: The HTPB fuel grain is cast into a 3.175 mm (⅛”) thick G11 fiberglass tube which acts as insulation to protect the aluminum combustion chamber from heat