Model Forum / General / Rockets / November 2007

AeroTech has engineered a new, greatly improved G80T Blue Thunder
single-use model rocket motor, which is being shown for the first time
to attendees of the iHobby Expo trade show in Chicago, IL from October
18-21.

The motor, which has been under development since July of 2006, features
an all-new molded phenolic casing with a built-in thrust ring, and ships
with a FirstFire Jr. 2-lead igniter. More importantly, it generates a
total impulse over 40% greater than that produced by the
current-generation G80T, along with a gorgeous translucent blue exhaust
plume studded with prominent "mach diamonds".

"We used every trick in the book on this motor, and then invented some
new ones" stated AeroTech/RCS president Gary Rosenfield. "As AeroTech's
flagship single-use model rocket motor, we wanted the new G80T to embody
the various casing and propellant technologies that we've been
developing over the past few years, and to meet or exceed the
performance and features of competitive offerings in as many areas as
possible."

Ever since the November 2004 release of the first redesigned G80T in the
current-generation molded casing, some AeroTech customers have expressed
disappointment in the loss of total impulse from the previously
certified 116 newton-seconds using a built-up paper-phenolic case
design, to under 100 newton-seconds in the molded version. The loss was
a consequence of translating the earlier motor design to the molded
casing, which required a heavier case wall and substantial insulation
thickness to protect it from excessive heating caused by the original
G80T's "C-slot" propellant grain geometry.

The new G80T uses a dual "BATES" center core-burning grain
configuration. This eliminates the need for extra case insulation and
allows the largest diameter grain possible with a full 62.5 grams of
propellant, the maximum permitted for a "legal" model rocket motor. The
propellant composition was optimized to increase density and specific
impulse (Isp) as much as practical within the parameters of AeroTech's
DOT shipping classification and the inherent limitations of small rocket
motor design. The nozzle exit cone was molded with a higher expansion
ratio to increase motor efficiency. Other, proprietary design techniques
were used as well.

Combined, these improvements have resulted in a delivered total impulse
in excess of 130 newton-seconds, the highest ever achieved for a
production single-use model rocket motor. The actual total impulse will
be revealed once National Association of Rocketry (NAR) certification is
granted for the new design. All this was accomplished without the use of
exotic propellant chemicals or excessively high chamber pressures that
could compromise motor reliability and safety.

The new G80T will be available in time delays of 7, 10 and 13 seconds.
The 4-second delay has been discontinued, and customers are advised to
use the next longer delay time increment for their rockets, due to the
greatly increased total impulse. Other specifications of the new G80T
include a burn time of 1.7 seconds, loaded weight of 128 grams, fired
weight of 59 grams, diameter of 1.125" and a casing length of 4.88". The
molded aft thrust ring has dimensions of 1.25" diameter X .25" long.
Though the new G80Ts have a different exterior appearance due to the
molded aft thrust ring, they will be clearly marked to differentiate
them from the older G80Ts.

No user certification is necessary to purchase the G80T, though
customers must be at least 18 years of age. AeroTech is now accepting
orders for the new G80T motor and anticipates NAR certification to be
received in late October to early November. Deliveries to dealers and
distributors are expected to begin in late November.

A representative thrust curve of the new G80T, the NAR certification
document, and motor instructions will be posted to the AeroTech Resource
Library at http://www.aerotech-rocketry.com as soon as they become
available.

AeroTech Consumer Aerospace is a division of RCS Rocket Motor
Components, Inc., Cedar City, UT.

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