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9.4.a Competition and Records: Getting Jump Started




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This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.

9.4.a Competition and Records: Getting Jump Started

From Jeff Vincent:

>I need a set of competition rocket plans Altitude, Streamer, Parachute can
>anyone suggest a site or a rocket for these events

Generally speaking, these events are fairly simple, and thus you don't
see as many plans published. Many simple kits ("3FNC" - 3 fins and a
nose cone) can be adapted to these events.

In general, you want a minimum diameter model (same tube diameter as
engine), at least 10:1 length:diameter (more if necessary to hold your
recovery device). Rounded nose cone. Three trapezoidal fins with
approximate dimensions: root - 1.5 dia, tip - 0.75 dia, span - 2 dia
(dia equals tube diameter). Checking stability before flying (finding
the CP with VCP for instance) is a good idea.

The duration models will have a thin shock cord (squid line or kevlar)
attached to one fin root (aka external shock cord). Launch guidance
can be provided by a tower or launch rod, piston launching
optional. Finishing should be minimal to give a smooth surface with
minimal added weight. Streamer will be a mylar streamer, ranging from
3x30" to 8x80" (or more). Thicker, stiffer mylar is usually better,
pleats ironed into the unattached end of the streamer help. Parachute
will be thin dry-cleaners bag or painter's drop cloth (0.25 mil or
so), with 8-16 light shroud lines, colored with magic marker, and
dusted with talcum powder. 'Chute sizes range from 12" to maybe 30"
(chosen as much for maximum duration as for feasability of recovery).

The altitude models will have a very slick finish (I use an automotive
primer polished with fine steel wool on a drill-lathe). Definitely an
internal shock cord as conventional models. Launch guidance should be
a tower, and a piston launcher is recommended for black powder
motors. Recovery by a small (for fast descent) but visible mylar
streamer (go more for length than width). Use powdered chalk or dry
tempera paint as tracking powder (provides a "mark" for the trackers
at ejection). In small diameter models, placing the TP in a paper
pouch aids deployment.

If you want to specify engine class, I can be more specific on model
and recovery device sizes. Also, some companies (QCR comes to mind)
offer good kits (provides plans and saves you the trouble of chasing
down parts from diverse sources).

 

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