Model rockets facts

Cameras and video cameras can be launched onHigh powered model rockets can carry large payloads,
model rockets to take photographs in-flight. Modelincluding cameras and instrumentation such as GPS
rockets equipped with the Astrocam or Snapshot filmunits, and are not much different from their military
camera or the Oracle digital camera, or with homebuiltcounterparts. However, unlike military rockets,
equivalents, can be used to take aerial photographs.high-powered model rockets generally do not contain
These aerial photographs can be taken in many waysany type of guidance system.
and with many different types of cameras.Since the September 11, 2001 attacks, high powered
Mechanised timers can be used to take photographs.model rocketry in the United States has been even
Passive methods are also employed, such as stringsmore carefully monitored by the government. Engine
that are pulled by flaps that respond to windvendors and participants must be licensed, and all
resistance. Microprocessor controllers can also behigh-power flights require FAA notification.[citations
used. However, the rocket's speed and motion canneeded]
lead to blurry photographs, and quickly changing lightingRecovery
conditions as the rocket points from ground to sky canModel and high-power rockets are designed to be
have an impact on video quality. Video frames cansafely recovered and flown repeatedly. The most
also be stitched together to create panoramas. Ascommon recovery methods are parachute and
parachute systems tend to fail, model rocket camerasstreamer.
need to be protected from impact with the ground.Tumble recovery
Instrumentation and experimentationThe simplest approach, and one only appropriate for
Model rockets with electronic altimeters can report andsmall rockets or rockets with a large cross-sectional
or record electronic data such as maximum speed,area, is to have the rocket tumble back to earth. Any
acceleration, and altitude.rocket which will enter a stable, ballistic trajectory as it
Model rocketeers often experiment with rocket sizes,falls is not safe to use with tumble recovery.
shapes, payloads, multistage rockets, and recoveryParachute/Streamer
methods. Some rocketeers build scale models ofThe approach used most often in small model rockets.
larger rockets, space launchers, or missiles.It uses the ejection charge of the motor (see below)
High Power Rocketry (HPR)to deploy, or push out, the parachute or streamer. Air
As with low power model rockets, high power rocketsresistance slows the rocket's fall, ending (hopefully) in a
are also constructed from lightweight materials, butsmooth, controlled, gentle landing.
instead of paper, plastic, and wood, usually fiberglass,Glide recovery
composites, and aluminum are needed to withstand theIn glide recovery, the ejection charge either deploys an
higher stresses during flight which often exceeds Machairfoil (wing) or separates a glider from the motor. If
1 (~700 mph) and over 10,000 ft altitude.properly trimmed, the rocket/glider will enter a spiral
High power model rockets are propelled by largerglide and return safely. In some cases, radio-controlled
motors ranging from class H to O and can be up torocket gliders are flown back to the earth by a pilot in
40 feet tall. Their motors are almost always reloadablemuch the way as R/C model airplanes are flown.
rather than single-use in order to reduce cost.Helicopter recovery
Recovery and/or multi-stage ignition may be initiatedThe ejection charge, through one of several methods,
by small on-board computers, which use an altimeterdeploys helicopter-style blades and the rocket
or accelerometer for detecting when to ignite enginesauto-rotates back to earth.
or deploy parachutes.