Model Rocketry and Siege Engine Glossary Letter C


Model Rocketry and Siege Engine Glossary Letter C

Glossary
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CA
Cyanoacrylate: a thin, very strong adhesive also known as Super Glue
Cabosil
A super fine silica. Unlike micro balloons, which are tiny glass spheres, Cabosil is "cut' glass fibers and very light. Used as a filler in epoxy fin fillets to reduce weight, and control sagging and dripping in thin epoxies
CAD
Canadian Dollar, currency
CAD
Computer Aided Design - The use of software and computers to assist and develop phases of design
Caliber
Ratio of a rocket’s diameter to its length. Example; if a rocket is 1" in diameter, then each 1" increment of distance along its length is a one-caliber measurement. See One-Caliber Stability
CAM
Computer Aided Manufacture - The use of software and computers to assist in manufacturing. The software combines the output of CAD with other data such as stock and tool geometry and produces the tool path as output
Camber
The increase in curvature of an airfoil along its chord
Cambered Airfoil
An airfoil (wing) on which only the top surface is tapered, the bottom surface remaining flat
Camouflage
A paint scheme used to conceal an object in its background
Canard
A fin or wing located at the middle or front of a rocket. Canard fins are often used on guided missiles since they make the missile less stable and easier to steer. Because canard fins move the center of pressure forward and tend to destabilize model or high power rockets, they are only used for style or to be true to a scale representation
Canopy
The fabric of the top of a parachute
Canted Nozzle
A nozzle positioned so that its line of thrust is not parallel to the direction of flight. See Vectored Thrust
Cantilever Beam
a projecting member, fixed at one end rigidly and free at the other. Wings and fins are both cantilever beams
CAR
Canadian Association of Rocketry: The organization governing model and high power rocketry in Canada.
Case, Casing
The outside framework of a rocket motor
Case Rupture
The splitting of the motor due to excessive pressure in the combustion chamber
Cast Propellant
A solid propellant formed by the pouring of a soft propellant into a mold to solidify into a hard grain. See Grain
CATO
Catastrophic Take Off (or Catastrophe At Take Off) A violent failure of the rocket motor casing, closures, or nozzle. This usually occurs at take off, and often results in the destruction of the airframe. The exact meaning of CATO is in dispute
Celestial Mechanics
That branch of mechanics concerned with mathematical development of postulates treating of the motions of celestial bodies
Center of Gravity
The point at which all the mass of a body may be regarded as being concentrated, so far as motion of translation is concerned. Center of Gravity - The point at which a rocket balances when completely prepped for flight
Center of Pressure
The point at which the aerodynamic lift on a rocket is centered
Centering Ring
A ring of paper, cardboard, plywood, or other material which connects the motor tube to the airframe, ensuring that the motor remains parallel to the rocket’s main axis. A motor tube requires at least two centering rings. More powerful motors sometimes require more
CG
See Center of Gravity
CHAD
Slang term meaning Cheap and Dirty. Most common usage is CHAD-staging, in which a booster motor is attached to the rear of a rocket motor in a single-stage rocket. Since the booster returns to Earth without a recovery device, this practice is a violation of NAR safety rules. This practice is also called Drop Staging
Channel
In radio communications. the band of frequencies within which a radio transmitter or receiver must maintain its modulated carrier signal
Chord
The short dimension (front-to-rear) of a glider’s wing. See Span
Chuff
Slang for a condition in which a motor fails to produce maximum thrust. The rocket’s speed and altitude suffer as a result. In a serious case, the rocket does not achieve adequate air speed and crashes
Chuffing
Intermittent burning of a rocket motor, accompanied by the sound of a steam engine starting
Class B Motors
Rocket motors containing more than 62.5 grams of propellant or motors that impart more than 120 newton-seconds of thrust
Class C Motors
Rocket motors contain less than 62.5 grams of propellant or impart 120 newton-seconds of thrust or less
Clean
A rocket design that is streamlined and free of projections
Clip Whip
Also called cluster cables. Short extensions at the end of a launch system with microclips
Closed Breech
Piston launcher where the piston is mounted on the launcher, the motor is mounted in the model and the piston movement is upwards with the model
Closure
The front and rear sections of a reusable motor assembly, which connect to the motor casing by threads, snap rings, or other method
Cluster
Two or more sol id rocket motors bound together so as to function as one propulsive unit
Cluster Cables
Also called clip whips. Short extensions at the end of a launch system with microclips
Clustering
A boost technique which uses 2 or more motors side by side in the same rocket
Clutter, RADAR
The visual evidence on the radar indicator screen of the sea-return or ground-return which tends to obscure the target indication
Coasting Phase
That part of the rocket’s flight between burnout and the airstart of the next stage or between burnout and activation of the recovery system
Coefficient of Drag (Cd)
The aerodynamic drag of a rocket as a function of its speed and cross-section. An indication of a rocket’s aerodynamic efficiency. See Drag Force
Cold Power
A type of rocket motor powered by CFC refrigerant under pressure. All support for this line was discontinued in the mid-seventies because of concern over the effect of CFC’s on stratospheric ozone
Combustion Chamber
The part of the motor where the actual combustion occurs. Composite fuels require a set pressure in the combustion chamber to continue burning at the proper rate. Failure to maintain the pressure results in chuffing
Competition Model
Model whose design is optimized expressly for a particular competitive event
Component
A manufactured part required to assemble a model, such as fins
Composite
A solid rocket motor type which uses two or more substances for combustion, neither component being black powder. A typical composite motor in hobby rocketry uses rubber as a fuel and ammonium perchlorate as an oxidizer
Composite (material)
Two or more separate and distinct materials, the combination of which produces a new material with more desirable properties such as increased strength, lower density or better workability
Compound Dihedral Angle
A "bent wing", in which a glider’s wing describes two straight planes at different vertical angles, with the tip pitched at a steeper angle than the root. See Dihedral
Computer
A mechanism which performs mathematical operations
Concentric
Having a common center
Cone
See Nose Cone
Cone Stability
The inherent stability of conic shapes to fly without fins provided the CG is ahead of the CG
Conic
Of or pertaining to a cone
Coning
An unstable flight condition in which a rocket’s spin causes the rear portion of the rocket to describe a circle. Coning greatly increases aerodynamic drag and reduces peak altitude
Configuration
The arrangement of fins, wings and other parts of a rocket or aircraft
Contact Cement
An adhesive that is applied to both parts to be joined and allowed to set up. They are bonded on contact, usually permanently
Continuity
The condition of a continuous circuit in a launch system once safety has been closed. A continuous electrical circuit will allow electricity to flow, so in the context of a launch controller "Continuity" means the igniter circuit is correctly connected and the rocket motor is ready to be ignited
Control, BANG-BANG
A control system used in guidance wherein the corrective control applied to the missile is always applied to the full extent of the servo motion
Control, Proportional
Control in which the action to correct an error is made proportional to that error
Control Surfaces
Surfaces such as flaps and ailerons used to control the attitude of a rocket or glider aerodynamically
Copperhead®
A style of igniter which uses two flat copper wafers separated by a paper insulator. Heat generated by current passing through the copper ignites a thin layer of pyrogen at the igniter’s head. See Crapperhead
Core
The hole or slot in the grain of propellant in a motor. Alteration of the core’s shape determines the thrust characteristics of the motor
Core Ejection
Ejection of a central pod holding the motor from the rear of the model
Core Sample
What happens when an airframe devoid of nosecone punches into the ground without benefit of recovery system. Named for the tubular sample of sod and dirt stuffed into the body tube on impact. Also known as "drilling for oil." See Lawn Dart.
Count-Down
In the final process for the launching of a rocket missile or vehicle, the action of checking each system or subsystem one after the other, using a count, e.g., T minus 60 minutes, in inverse numerical order so that the count narrows down at the end to 4-3-2-1-zero, minus 1, minus 2, etc., during which time the button is pressed, i.e., the propellant is ignited
Coupler
A section of tube or a precision cut piece of wood used to connect 2 sections of larger body tubing
Covering
Material covering the framework of a structure
CP
See Center of Pressure
CPR
Close Proximity Recovery: an electronically-controlled system that permits high-altitude rockets to have most of their descent controlled with a drogue. The main parachute deploys at lower altitude
CPSC
Consumer Product Safety Commission. Rules restrict use of HPR motors (H and up) to adults 18 years of age and up
Crapperhead
A slang reference to the Aerotech Copperhead®, an igniter which is not renowned for its reliability
Craze, Crazing
Cracking of paint or fogging of acrylic resin due to incompatibility of paint, primer, adhesive, and/or material
Cross Section
The area exposed if a part is cut through
CRSO
Chief Range Safety Officer. The CAR Officer in charge of all RSO's. RSO's are charged with maintaining safety standards for safe launch operations at CAR-sanctioned rocket launches. See CAR. See RSO
Cut-Off Velocity
The velocity at the point of thrust termination
Cyanoacrylate
Adhesive developed through the space program. Adhesive hardens very quickly and forms a high strength bond without the mixing of components. Also known as Superglue, Crazyglue, and CA


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