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1/10 Vanguard, NARAM
41, AZ (1999)
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The NARAM-41 Vanguard project actually
began as the testbed for my planned R&D project on guidance… and it sort
of mushroomed on me, much like the NARAM 40 Mercury Redstone had.
Though it didn't fly at NARAM-41 due to
wind conditions and small field (the required minimum engine combination
would have lofted the upper stage to over 1000 feet and likely would have led
to a loss of that stage to the surrounding woods…along with about $400 worth
of electronics) the model did prove the concept of a very large sport scale
entry of its type and the viability of such an entry at the national level.
The NARAM-41 competition model has now
been "reduced" to the third of my Vanguard boilerplate models and
is currently being extensively modified to ease prepping, improve
reliability, and reduce weight.
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The first boilerplate model, shown here,
was originally conceived to get an idea of the strength, rigidity, and weight
of the ultra light .4mm plywood construction technique that it utilized. It
was also originally intended as a single stage model to test aerodynamic
characteristics (without guidance). As the project advanced, this boilerplate
eventually acquired the guidance package of the NARAM-40 Redstone, a second
stage utilizing the engine gimbal from the NARAM-40 Redstone, a new gimbal
for the first stage motor, a pneumatic recovery system for the first stage,
and a new mechanical recovery system deployment mechanism for the upper
stage. In the configuration you see here, it weighed about 2.9 pounds.
The first test flight turned out to be an
accidental launching of the upper stage (just a couple of minutes after this
photo was taken) due to a glitch in the R/C-triggered upper stage ignition.
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Dan Steuttgen is holding the upper stage
before installing it on the booster. The upper stage actually weighed more
than the first stage as it contained all the electronics and the majority of
the batteries (there were four sets in this version of the model).
Upper stage ignition was via R/C and would
not be armed until it was plugged into the first stage. After an
unintentional flight of the upper stage shortly after this photo, upper stage
ignition was changed and would be accomplished via inertia switch with the
circuit armed via R/C after the model becomes airborne.
Though the stage was tremendously
underpowered, the guidance showed its functionality as the upper stage popped
from the booster stage and struggled to stay pointed skyward during thrust
before falling to the ground.
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This is the "business" end
of Vanguard BP1 (first boilerplate). What you see here are the 29mm gimbaling (two-axis) main motor, two 13mm mini motor mounts
(to act as simulated turbo-pump exhausts), the pneumatic fill valve, and the
scale gimbal support struts.
Even after close
examination, most people can't figure out how the "stick shift"
multi-axis gimbal mechanism works. The entire mechanics (servos, linkages,
etc) is sandwiched into the small gap you see between the end of the body and
the circular thrust ring.
Also on the thrust ring
are two coaxial pullout plugs (one just visible above-right of pneumatic
filler), external charging plug for first stage batteries, and the electrical
supply posts for the 13mm motor igniters.
Based on Martin Company
drawings, the gimbal is very nearly scale in size and configuration.
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For the first Vanguard
boilerplate model, the gimbal assembly from the NARAM-40 Redstone was used
without modification (except for the addition of the ignition power supply
posts visible to the left of the motor).
The hodge-podge
appearance of the ring surrounding the motor is a result of additional
reinforcing added at the last minute to the Redstone at NARAM-40 to eliminate
the risk of ring flex with a higher thrust motor.
The entire gimbal can be
unbolted and removed from the model as a unit and the cylindrical extended
shell of the gimbal cartridge slides into the staging coupler of the first
stage.
The two coaxial plugs
above and below the gimbal in this picture provide for first stage gimbal
signal and power. Passing a noise-free signal from the fore end of the second
stage to the aft end of the first stage while providing for secure fit and
perfect alignment without undue friction was a major issue during the first
three boilerplate phases.
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The autopilot (it really
isn't a "guidance" system...it just makes sure the model flies straight up) and
electronics package (left) and the upper stage gimbal removed from model.
The electronics are all
secured to the "platform" with foam mounting tape. Between the two
rings at the bottom of the platform are the four horizon sensors and recovery
servo. The entire platform design was dramatically changed for the
competition model.
The gimbal shown here is
the 2nd generation unit and can house up to a 32mm motor. A total
of 11 conductors interface here. The gimbal also has to be pressure-tight
since it must contain the pressure of staging which forces the stages apart.
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