Purpose:

The goal of the project is to construct an experimental hybrid rocket engine from scratch using readily available materials.


The Design:

The rocket design will use aspects of the German V2, the SS67B-1 from systeme solaire, and the few hybrid designs located around the Internet. We were going to build the SS67B-1 to spec, but the blueprint package was incomplete and systeme solaire failed to respond to our emails concerning the engine. Since this is our first rocket we decided that the final design will be old school, similar to the SS67B-1 and will be built such that we can upgrade the system in the future.

System Schematic.

Why a Hybrid:

A hybrid engine, also known as composite engine, is a combination of solid and liquid propellant engines. The fuel is usually in a solid form and is located within the combustion chamber. The oxidizer is the liquid component and is injected into the combustion chamber to promote the combustion of the solid propellant.

Advantages:

• The hybrid fuel is usually in granules and burns only on contact with the oxidizer, this greatly reduces the possibility of catastrophic failures occurring.
• The flow rate of the oxidizer can be controlled, thus making the rocket throttleable and restartable.
  
• Higher degree of safety because of the previous advantages, and the rocket can be shutdown if needed.
• Can use more environmentally friendly fuels.
• Require support for only one fluid systems, they compare in performance to liquid systems while requiring only half of the “plumbing”.
• The solid fuel grain of the hybrid gives it volumetric sizing advantages over the tankage required for liquid systems.
• Safer fabrication, storage, transportation and operation due to both the inert fuel and separated propellants.
• Higher specific impulse than solids and higher density impulse than liquid systems.
  

Disadvantages:

• Hybrids cannot match the density impulse of solid rockets.
• Increased level of complexity
• Combustion efficiencies are slightly lower than liquid or solid systems.
• Lower thrust-to-weight ratio, due to the extra hardware for the tank & longer combustion chambers.