What's Special About Model Rocket Engines?
Model rocket engines are one-time use controlled explosives that power hobby model rockets and boost them over 1,000 feet off the ground in a couple of seconds! These powerful miniature jet engines rely on a number of special technological advancements to achieve this efficiency and reliability. For one thing, model rocket engines are encased in a hardened, multi-ply and adhesively bonded paper casing that feels hard to the touch and cannot be sufficiently crushed to impair or endanger the engine. This special protective casing is very important to the overall safety and durability of these model rocket engines. Without them, we could have many more instances of these special engines leaking hazardous propellants and combustibles all over the place and harming hobbyists and bystanders. Model rocket engines also need to have some way to ignite reliably and safely. This is the next special feature that makes model rocket engines the mini marvels they are.
Ignition Systems for Model Rocket Engines
When a model rocket is attached to the guide rod and resting on the launch pad, ready for flight, its model rocket engine is slightly protruding down into the center of the space between its guiding fins. The engine is faced down, exposing its next technical marvel: there is a small concrete plug at the bottom of every model rocket engine that terminates in a small central hole.
This hole is where the model rocketeer will insert the business-end of a launch fuse. The launch fuse is then connected to the alligator clips of the launch commander which generates the electric ignition impulse which causes the fuse to spark the engine. This small concrete hole at the bottom of model rocket engines is another remarkable feature because it allows the hobby to maintain a relatively high level of safety - it's hard to accidentally ignite a rocket engine alone.
Meanwhile, the small concrete hole in the base of most model rocket engines allows for reliable and hassle-free ignition. Because the concrete plug also protects the internal highly combustible propellants, it serves a protective and anti-combustive purpose.
Partly because model rocket engines are so safe and reliable, the hobby itself has been catapulted to new rungs of popularity in the past couple decades. It's now very easy to walk into your local toy or hobby store and pick up a model rocket kit for about 20 bucks. This basic model rocket kit will allow you to quickly and easily assemble a functional model rocket. You'll also need to buy the launchpad equipment, some fuses and a packet of recovery wadding. Finally and most importantly, you'll need to pick up as many model rocket engines as you want to make flights that day.
Model rocket engines are classified based on their different sizes and total outputs of thrust. The smaller the engines (in the A classes) the smaller and lighter the rocket. An engine in the C class is much larger and more powerful than engines in the B class, for instance. D and E class model rocket engines are comparatively gigantic and are capable of generating sufficient thrust for long enough to power an oversized heavy model rocket carrying an altitude camera to heights of over 1,000 feet!