
(by Carl Tulanko - 11/25/00)
Brief:
This Launch Pad kit is an accurate 1/5.2 scale version of the U.S. Navy's
Standard AGM-78 air or ship launched missile. Additionally, it can be used as
the upper stage for the RIM-67A, which is sold separately by The Launch Pad as
a Plan Pak kit.
Construction:
The kit arrived in a plastic bag, similar to some Estes or Quest kits and
consisted of two BT80 2.6" body tubes with the coupler stored inside one
of the tubes, three sheets of balsa for the fins, a plastic nose cone, paper
templates for the fins and nose cone, an 18" mylar parachute and more!
What really impressed me were the laser cut motor mounts, which appear to be
much stiffer and stronger than Estes mounts. Another nice touch was the
link system for the parachute. About the only items lacking in the kit were a
set of decals and fin guides, but I had already been prepared for this from
reading comments on other Launch Pad kits. As this is an advanced kit, some
prior rocket building and finishing skills are a plus, but it can be assembled
by anyone that has a few smaller kits under their belt. Component Rating: 4 of
5
There are four pages of instructions
supplied with the model which take your through the building and finishing
process. The first step was building the scale nose cone, which requires you to
form a conical shaped "hat" from the supplied card stock. Light
steaming along with curling the edge of the paper helped shape it prior to
gluing, but every review I had read seems to have a some difficulty with this
process. I believe the reason for this is that, as you reach the tip of the
built up paper cone, there is no longer any paper overlap left to glue
together, not to mention it's impossible to get your fingers up there to hold
it together. So, I tried a different approach. I used aliphatic resin to glue
the paper cone seam and took my time, starting at the bottom and gluing in one
inch increments, working my way to the tip. While squeezing the freshly glued
section between two fingers, I placed the opposite bottom edge of the cone on
the lip of a table and pulled down. This drew the "gap" at the top
seam of the cone closed while I let the section between my fingers dry. In no
time I had worked my way to the tip. To finish off the tip of the cone, I took
a ¼" wood dowel and sharpened it with a pencil sharpener. Then I put
some glue on the tip of the paper cone, ran the dowel point inside the cone to
the point and pressed the assembly down against wax paper on a table until it
dried. This resulted in a perfectly shaped "hat".
In the next step, I deviated a bit from the
instructions and used 5 minute epoxy to glue my "hat" on rather than
the recommended CyA glue. I lightly coated the inside of the paper hat with the
epoxy, then placed it on the plastic BT80 nose cone and aligned it until
straight. The epoxy flowed down the inside of the paper to the plastic nose
cone seam, gluing it on, reinforcing the joint and hardening the paper like a
rock. I then coated the seam with Evercoat Formula 27 general purpose filler;
This stuff, if you have never used it is great; it easily sands off into a
powder. Finally, I decided to coat the entire nose cone with epoxy finishing
resin.
Much of the build process was spent on the nose cone, but, primed and
painted, the results were very rewarding. The rest of the assembly was straight
forward, with a few minor glitches. I notice the instructions did not tell you
to fill and sand the joint where the two body tubes are glued, so make sure you
do this prior to mounting the long fins. I used Aliphatic resin for gluing the
rest of the model.
Motor mount assembly was straight forward, as was fin assembly but you will
have to make your own fin guide. The balsa for the stabilizer (long) fins was
of good quality, but one piece was not quite wide enough to cut out two fins. I
wound up having two of the four fins about a 1/16" narrower than the
template. A fresh piece of balsa from my personal supply fixed the problem, but
I would like to see them ship sheets that are wide enough to do the job. I
decided to the leading edge of each lower fin and the leading and
trailing edges of each upper fin for scale appearance.

Afterwards, I opted to fiberglass the lower fins on for stiffening
and additional strength using ¾ ounce fiberglass cloth and 30 minute
epoxy. I had read of instances where people saw the surface mounting technique
lacking in strength and I didn't want this to become an issue. If you don't
fiberglass, make sure you use thin CyA to stiffen the soft balsa fins prior to
gluing them on. Location of the launch lug was not specified, which is normal
for these kits. I cut mine in half, gluing one piece on right at the top of the
lower fin and the other just above balanced CG. Construction Rating: 4 of 5
Finishing:
White primer was applied prior to the first sanding and I used 150 grit to cut
away any excess epoxy resin left from the fiber-. A second round of
primer was added and I used 220 grit to start and finished with 400 grit. In
the instructions they have you glue paper "panels" over the inside
length of each fin prior to assembly, but you risk tearing up the panels with
sandpaper during the priming stage. For this reason, I added my scale paper
overlays after all sanding was complete and prior to the last coat of primer.
Chamfering the edges of each overlay made them lay down smooth. This was also a
good time to add scale rivets. The recommended method of using pinheads just
didn't cut it for me, especially when there are 144 rivets on the finished
rocket! You can buy stick-on rivets from a R/C helicopter dealer on the net,
but they only sell them in large quantities and are a bit pricey. I opted to
use a very simple and cheap method derived from experiences in R/C aircraft. I
filled a syringe that had the needle ground flat on the tip with a white canopy
glue found at many hobby shops called RC-56 and "dropped" a small
ball of glue at each location for a rivet. The glue ball flattened somewhat
when it hit the surface and made a perfect rivet. If a mistake was made, I just
wiped it off with my finger and tried again. With this method, scale rivets
were finished in less than an hour, including drying time, and the cost was
minimal. Note that Elmers White glue could also be used, but I like RC-56
because it is waterproof when dry and it's consistency doesn't require any
dilution.
The paint scheme in the instructions shows a very basic color scheme for a
single standard model, but if you want it to look like the missile on the LP
website, you're pretty much on your own. Mine was painted in the same colors as
the website model, which is actually the paint scheme for the upper stage of
the RIM-67 rocket. I used Rustoleum flat white for the body and Testors
military federal standard paints for the light gray nose cone and dark gray
fins. I just wish there were more pictures available that showed labels and
letters.
All in all, the instructions are pretty good for painting a single stage
rocket. One of the last steps performed is the installation of the shock cord
and parachute. The recommended method of attaching the shock cord is to use a
supplied Estes type tri-folded paper glued to the side of the body tube. This
is not satisfactory for a model of this size. One of my best friends and long
time rocket modeler, Ken, recommended I take 2 sets of 70 lb test Kevlar line
and loop, tie and CyA them around the motor mount. I followed his advice, then
drilled a small hole through the mount plate right up against the motor tube.
The Kevlar line was threaded through the hole and extended six inches out the
top of the body tube, where I tied it to the shock cord. This is a much
stronger and safer way of mounting the cord and will help prevent those nasty
"zippers" that can occur when too much stress is put on wall mounted
lines during ejection. Finish: 3 ½ of 5
Construction Rating:
4
out of 5
Flight:
Flight: The motor recommended for first flight was a D12-3, which is what I
used to make this bird airborne. I wound up using a large sized Pratt
Heatshield instead of wadding! The rocket lifted off the pad each time easily,
which surprised me for a model of such size. Flight was straight and true; it
took to the skies like it was on rails! Listed and supported motors include the
D12-3, E15-4 and RMS F24-4. For the next group of flights I want to try the RMS
E18-4W, the RMS F24-4W will be a definite must, but only on a calm day. I'll
repost a quick update after the holidays on the success of the larger engines.
Recovery:
Recovery: The parachute deployed right at apogee. The gold mylar chute supplied
in the kit was very easy to spot and the rocket landed safely with all parts
intact. I had wondered about the 18" parachute being enough, since the
instructions tell you to build two of them. I believe this may have been a
misprint from a previous generation, but on lower level flights, a larger
parachute is something I may use. I was please that I decided to beef up the
fins during the build process and do recommend it to those wanting to build a
sturdier model. For reference, my rocket weighed in at 8.3 ounces without
motor, which seems about right for a mid powered model of this size.
Flight Rating:
4
out of 5
Summary:
The AGM-78 is nothing less than AWESOME! The rocket just plain looks good, and
is a very close scale representation of the real deal. Construction is easier
than it looks and the end result was worth any extra effort. A few things could
be improved, such as the supplied balsa stock (or lack of enough), parachute
mount and specifications for CG. I would also like to see additional
documentation showing more scale lettering information and placement. These
minor flaws aside, this is one fine model. Just keep in mind that this is
definitely a builder's kit, which worked out well as I really enjoy the
building process. I now have a fleet addition that would make any modeler
proud. If you like the Launch Pad kits, then you have to get one of these; it's
a great buy for the buck! Now, about the only thing I'm still missing is the
two stage RIM-67 version, which I intend to remedy real soon, but that's
another story.
Overall Rating:
4
out of 5
(by Greg Burke)
This kit is relatively straight forward.
The instructions are pretty easy to understand, and are also correct. The
manufacturer gives some hints on detailing and that's the hardest part. They
suggest using the heads of pins for the rivets in the fins. This took up the
bulk of my building time as it took over 150 pin heads to accomplish this. The
only problems that I had with the kit is the balsa stock provided with the kit.
It's really soft and needs to be reinforced. Unfortunately I didn't do this and
I broke a fin and one of the runners on the first flight. Speaking of flights,
I flew the model on a D-12-3 for the first flight. Boost was real good and
ejection happened right on time. The landing hurt though as that's when it
broke it's fins. In conclusion this kit is cool. You need some modeling
experience to do the job right though, (not for beginners). When I fix mine,
I'm going to reinforce the fins to make them more durable. This is a must
buy, the thing looks great just sitting out being displayed. At about $20 it's
a good bargain too.
* SPECIAL NOTE off of RMR from Chuck Barndt,
President of The Launch Pad