2004
Direct
Non-electronic Staging from Reloadable Composite Motors to Black Powder
Motors
Jay Calvert
NAR
# 71767
C Division
The objective of this study was to determine whether direct
pyrotechnic staging, without the use of onboard electronic ignition
systems,
could be used to reliably ignite a black powder (BP) sustainer motor
from a
reloadable ammonium perchlorate composite propellant (APCP) booster
motor.
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Placed "just outside" the top four trophy places
2005
The
Relationship between Super-Roc
Length and Drag Coefficient:
NAR # 71767
C Division
The effect of super-roc length on drag coefficient, peak
altitude, and super-roc altitude event scoring was determined
empirically
(Phase I) in a series of test flights and compared to Rocksim
simulations of
the same models (Phase II). In Phase I,
a D impulse super-roc equipped with a very small altimeter was flown in
five
different length configurations ranging from 48” to 120” (three flights
in each
configuration). The data shows a clear
decrease in altitude with increased length, due to weight of the added
airframe
tube and increased drag. After adjusting
for increased weight, the coefficient of drag (CD) was backtracked from
the
altitude data using Rocksim. CDs ranged
from 1.31 for the shorter model up to 3.22 for the longest super-roc. The SRA scores (length times altitude) were
remarkably constant over the entire range of allowed lengths,
suggesting that
there is no “best length” in this event.
When the same rockets were carefully modeled in Rocksim, the
predicted altitudes
varied considerably from the observations.
Rocksim underestimated the performance of the shorter rockets
and
overestimated the performance of the longer ones. As
a result, Rocksim mistakenly indicates
that a maximum length super-roc will have significant advantage over a
medium
or short super-roc in the same impulse category.
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Placed 3rd in C Division
Optimizing Rocket Shape to Maximize
Altitude
Alexander “Beandip” Calvert
NAR # 77390
A
Division
For my NARAM R&D project, I built four model rockets
with the same weight and internal volume.
I put an altimeter in the rockets and flew each of them three
times. I recorded how high they
went. My hypothesis was that the skinny
rockets would go higher than the fat rockets because the skinny rockets
have
less drag. Fat rockets have more frontal area so they have to move more
air out
of the way. However, extremely skinny
rockets tend to collapse or fold or bend while flying.
A skinny rocket might also have too much
surface drag. You have to try to make a
rocket not too fat and not too skinny.
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Placed 3rd in A Division
