Model Rocketry and Siege Engine Glossary Letter F


Model Rocketry and Siege Engine Glossary Letter F

Glossary
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FAA
US Federal Aviation Administration. This is the organization that governs airspace in the U.S. HPR hobbyists must obtain a waiver from the FAA for permission to fly large or high (2000+’) altitude rockets. Equivalent to Transport Canada and the Air Ministry in the United Kingdom
FAR101
FAA regulations regarding airspace use for hobby rocketry
Fairing
Rigid or semi-rigid coating used to streamline the airflow around a rocket component sticking out in the airflow
Featherweight Recovery
A recovery method used by very light model rockets. Typically, the rocket ejects its motor and then floats to the earth like a feather, its extremely low weight never allowing it to become aerodynamically stable
Fiberglass®
A synthetic material consisting of glass fibers spun and woven into a mat-like cloth adhered to a rocket with epoxy resins. It is used to add strength to high power rockets, so that they can withstand higher-powered motors than they otherwise could. Although fiberglass is a commonly used word, it is actually a trade mark of Owen-Corning Inc
Filler
A substance applied to a surface to fill gouges in the surface or help shape the surface
Fillet
A smooth line of adhesive which is built up at the root of a fin to strengthen the joint formed by the fin and the body tube
Fin
A fixed or adjustable airfoil at the rear of a rocket for the purpose of flight control or to stabilize it in flight.
Fin Canister
A section of tubing with fins mounted on it, intended to slide over the airframe. Also called a fin can
Finishing
The art of giving a model a smooth, streamlined outside surface
Firewall
A bulkhead designed to prevent fire from passing that point
Flame Bucket
An opening at the base of a launch pad to allow the exhaust to vent. One side is angled to form a blast deflector
Flap
a movable control surface on an aircraft or rocket that deflects air. Ailerons, elevators and rudders are all flaps. Flaps are also used as airbrakes
Flashbulb
A magnesium-filled glass bulb, once commonly used in photography. In rocketry, flashbulbs are used to ignite thermalite fuses or BP charges for second stage ignition or recovery device deployment. They have the advantage of requiring very low electrical impulses to activate them. However, this attribute also makes them susceptible to accidental activation by static electricity
Flashpan
A type of ignition sometimes used for BP clusters. The rocket is placed in a pan covered with a thin layer of black powder. When the rocket is to be launched, the powder is ignited with an electrical igniter. The resulting flash sends burning particles into the motor nozzles and fires all the motors in the cluster simultaneously.
CAUTION: This technique presents dangers when used with black powder, and must NEVER be used with composite motors which ignite from the front
Flat Spin
A spin around the short axis of a rocket while the craft is descending in a horizontal attitude
Flex Wing
A wing that employs a thin flexible for the main lifting surface stretched over a semi-rigid frame
Flight Line
The area at a launch site where rockets are prepared by participants. The forward-most area where spectators are permitted
Flight Path
The line connecting successive positions of an aircraft while in flight, relative to the ground
Flight Profile
A graphic representation of a aircraft’s flight as seen from the side, showing its position and altitude
Flightworthy
An aircraft or rocket, having undergone inspection and possibly testing, that has been determined to be ready and sound to fly
Flutter
An oscillation of regular period but irregular amplitude caused by a momentary disturbance but maintained by the characteristics of the fluttering component
Flying Wing
An aircraft, whose wing is designed and balanced for stable flight, that does not rely on stabilizers or canards to maintain the flight stability
Foam Core
A built up wing using shaped Styrofoam rather than the classic sticks and ribs, then covered with a thin cover of wood such as balsa
Form Drag
Drag resulting from the shape of an object, causing turbulence of the airflow. An example is a square wing edge versus a rounded streamlined edge
Freefall
The fall of an object without guidance or retardation other than through drag
Free Flight
Unconstrained and unassisted flight of a rocket, relying on the rocket’s inherent stability
Friction
The resistance an object encounters while moving across the surface of another object
Friction Fit
The joining of two objects, relying not on adhesive but on the tight fit caused by one object being inserted into another, such as the nose cone inserted into a body tube
Frontal Area
the surface area of a rocket which faces directly into the airflow
Fuselage
The structure or airframe that houses payload, crew or passengers. Although not inaccurate, this term is used more commonly with regard to airplanes than to rockets


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