Solid Rocket Propulsion

Solid Rocket Propulsion

Introduction

The Solid Six are the team within DARE specialising in solid rocket propulsion and have existed as a team since 2009. A large portion of DARE’s rockets has been launched using DARE’s internally developed solid rocket engines.

Since its founding, the team has created a body of knowledge with regards to the development and testing of solid rocket motors. Over the years, the team has developed numerous engines, many of which have been launched in rockets. These include the reliable Small Rocket Project and  DX-1 engines, the latter of which are used in the CanSat and ACT rockets, as well as the two stage engine for Stratos I.

The teams perform a range of work, from the development of our own solid propellant, ALAN-7, (an Ammonium-nitrate and Aluminium based propellant), to the design, manufacturing and testing of engines of a range of sizes.

Current Work

Over the past year, the Solid Six have worked to develop our biggest and most powerful solid engine yet, the DXS Asimov (DARE experiment solid ‘Asimov’). The engine was designed for implementation in the Aether-launcher, one of DARE’s technology demonstrators intended to fly at supersonic speeds.  This engine was developed using Kalinidex (“Rocket Candy”),  which uses sorbitol as a fuel and potassium nitrate as an oxidizer.

As part of the development of the engine, the team has explored and tested a larger glass-fibre engine casing, a new nozzle design, manufactured from pertinax and aluminium, and a new igniter. This igniter consists of a commercial ammonium perchlorate grain housed in a 3D printed basket, a pyro-bolt and two squibs.

One of the main improvements from the previous engine, the Leonidas-5, was with respect to the start-up transient. This was done using the new igniter design and the optimised nozzle design, which saw the thrust curve made steeper and the specific impulse increased.

Several single grain motor (SGM) and igniter tests were performed successfully, which were used to improve the efficiency of the motor and its burn parameters. The tests were then scaled up to a full-scale motor (FSM). The FSM was the final design for the DXS-Asimov, containing 7 propellant grains, each weighing approximately 4.6 kg, and measuring roughly 2 m long. Unfortunately, these tests were not successful, and as such, the team is currently reanalyzing the design. This will be done by improving our knowledge of the propellant Kalinidex, or by exploring the possibilities of other propellants, as well a working to improve our simulation tool and validate our calculations.

This work will improve the reliability and performance of our engines and will aid the development of a full-scale motor which may be implemented in a future model of the Aether Rocket.

 

Full-scale Asimov test

The Solid Propulsion Team (Solids) testing single grain motors at the Artillerieschietkamp ‘t Harde

Solid six team with a full-scale Asimov engine

 

Engines

DXS Asimov FSM

  • Propellant: Kalinidex (Potassium Nitrate – Sorbitol)
  • Total impulse: 40,335 Ns
  • Specific impulse: 126 s
  • Max Thrust: 7714 N
  • Average Thrust: 6464 N
  • Burn Time: 6 s
  • Chamber Pressure: 500 psi
  • Number of static tests: 0
  • Number of flights: 0

DXS Asimov SGM

  • Propellant: Kalinidex (Potassium Nitrate – Sorbitol)
  • Total impulse: 4800 Ns
  • Specific impulse: 126 s
  • Max Thrust: 860 N
  • Average Thrust: 600 N
  • Burn Time: 8 s
  • Chamber Pressure: 500 psi
  • Number of static tests: 3

LEONIDAS 5

  • Propellant: Kalinidex (Potassium Nitrate – Sorbitol)
  • Total impulse: 30,000 Ns
  • Specific impulse: 120 s
  • Max Thrust: 6500 N
  • Average Thrust: 5500 N
  • Burn Time: 5.5 s
  • Chamber Pressure: 500 psi
  • Number of static tests: 1
  • Number of flights: 0

L5SGM

  • Propellant: Kalinidex (Potassium Nitrate – Sorbitol)
  • Total impulse: 5000 Ns
  • Specific impulse: 100 s
  • Max Thrust: 1000 N
  • Average Thrust: 850 N
  • Burn Time: 6 s
  • Chamber Pressure: 500 psi
  • Number of static tests: 2
  • Number of flights: 0

MAXIMUS-C

  • Propellant: Alan-7 (Ammonium Nitrate – Aluminium)
  • Total impulse: 20,000 Ns
  • Specific impulse: 200 s
  • Max Thrust: 10,000 N
  • Average Thrust: 10,000 N
  • Burn Time: 5 s
  • Chamber Pressure: 450 psi
  • Number of static tests: 0
  • Number of flights: 0

BEM

  • Propellant: Alan-7 (Ammonium Nitrate – Aluminium)
  • Total impulse: 5000 N
  • Specific impulse: 200 s
  • Max Thrust: 1500 N
  • Average Thrust: 1000 N
  • Burn Time: 5 s
  • Chamber Pressure: 550 psi
  • Number of static tests: 20+
  • Number of flights: 1

FLAMING TIGER

  • Propellant: Alan-7 (Ammonium Nitrate – Aluminium)
  • Total impulse: 900 Ns
  • Specific impulse: 200 s
  • Max Thrust: 400 N
  • Average Thrust: 300 N
  • Burn Time: 3 s
  • Chamber Pressure: 450 psi
  • Number of static tests: 2
  • Number of flights: 1