(Contributed - by Bob Harrington - 01/02/05)
Brief:
This rocket is a scale model V2 that was converted from a cardstock display
model. The model was a free download from
Currell Graphics and
is available in a black and white test pattern or the operational camouflage
scheme. I built the black and white version featuring a parachute recovery.
Construction:
The components used:
- printed cardstock parts
- 3.25" BT-20 engine tube
- engine hook
- CR520P engine block
- 24" x 1/8" elastic shockcord
- 10" plastic parachute
- clay nose weight
Parts were printed on 110# cardstock. All of the centering rings used the
optional stiffeners to make them double weight. Rings G4 and G5 were the rings
that held the motor tube and were reinforced with an additional layer of
cardstock and the center hole was cut to fit over a BT-20. The main body tube's
forward stiffening ring was recessed 2.5" from the forward end to allow
for the nose cone shoulder, wadding and parachute.
The fin unit was assembled following the instructions and the exhaust cone
was trimmed to fit the motor tube and the motor tube was glued in place.
The fins have a 4 piece internal structure that is probably the most
difficult part of the assembly. The vane assemblies were left off because they
would be in the way of the motor. A 1" strip of cardstock was formed into
a ring that just fit into the main body and was glued to the nose code to form
a shoulder. The shock cord was attached with the standard paper tri-fold mount.
Clay was added to the nose to bring the balance point to 10" from the nose
with a C6-5 installed.


Finishing:
Finishing was easy. Everything was preprinted so no painting or decals was
needed. I didn't clearcoat it before test flying it and there was one slight
watermark on it that is barely visible. I plan to clearcoat it before the next
flying session.
Flight:
I flew this model a total of 4 flights. I used B6-4s for all flights. The
forward compartment above the forward stiffening ring is just large enough for
wadding and parachute. The flights were straight with the launch slow enough to
be able to follow the flight easily. I anticipate that a B4-2 or B4-4 would
give it an even more scale-like launch.
Recovery:
The model was recovered using a 10" parachute made from a plastic
tablecloth available at any party store. It comes in at least a dozen colors
and has a slight texture that prevents the parachute from sticking together
like most kit chutes. Recovery was fairly quick on this size parachute but no
damage occurred on any flight. On one flight, the parachute got caught in the
nose cone stiffener, failing to deploy, and the rocket came down with just the
shockcord between the two pieces yet it still suffered no damage.
Summary:
This is a fun project for anyone with a little cardstock modeling experience.
The fins have a built up internal structure that makes it a little more
difficult than most cardstock conversions.