(06/01/98) The Mirage was the
second medium-power rocket and the first
Aerotech kit that I built. In
addition, this kit is the largest rocket that I have ever built, towering
87" (that's 7'- 3"!).It is 2.6" in diameter and weighs 31
ounces.It flies with 29mm motors. In a nutshell, it's a whole lot of
rocket! The kit comes with three body tubes with
couplers, plastic nose cone, and launch lugs. Due to mid-separation, it comes
with the hardware necessary to attach two 8 foot shock cords and two nylon
parachutes (one 22" and one 30"). The motor mount hardware includes a
LABYRINTH cooling mesh and ejection baffle, which eliminates the need for
wadding, as well as a motor retention hook. There are three large plastic fins
with tabs for mounting in Aerotech's FIN-LOK system through a pre-slotted
body tube. Lastly, there is a large Mirage decal.
The Aerotech web site indicates that
this kit comes with a 24mm adapter. My kit did not and quite frankly due to
size and weight the only 24mm motors I would use would be F24 and F39 and then
flights would be less than 400 feet. I think its a misprint on the web site
because the catalog does not indicate a 24mm adapter.
There are six pages of clear, illustrated instructions.
There are a couple of breakouts which provide a location guide for the motor
mount and a detail of the fin. The remaining illustrations provide adequate
information for assembly. The instructions also provide clear warnings on use
of glue, such as, not putting it on the shock cord since it will weaken it and
to avoid getting glue into the FIN-LOK ring's. The instructions are
in logical order and can ensure a successful assembly if followed.
The instructions suggest using medium viscosity CA,
however, I used 5 and 30-minute epoxy. In doing so, I had to wait a few extra
minutes between steps, however, I still built the entire kit in about one and a
half hours.
The assembly of this large rocket was very easy and there
were no problems. All of the parts fit and went together as described. The most
difficult part of this rocket is dealing with it's height. If you're not extra
careful, you will certainly hit the ceiling a few times. Also dealing with it's
size adds a challenge to finishing.
During the finishing stage I decided to not fill the body
tube grooves with anything and just build it up using Plasti-Kote primer. This was not the
best decision. This was not the best decision. It took about 5 coats, sanding
inbetween each one, before the grooves were filled. The nose cone was one of
the biggest problems due to the molding grooves left on each side.
Once fully primed, I chose to paint the rocket with a
deep maroon metallic automotive lacquer. I painted the entire rocket this
color. Then I took a can of chrome paint and sprayed the nose cone and the
upper section of the rocket, not protecting anything from over spray. I think
this gave a nice "fade-in" look.
The kit comes with one decal with the
name Mirage
on it, however I did not choose to use it at
first. I have since gone back and used it. I followed the directions completely
and cut out the decal, peeled the back off, dipped it into some soapy water
then applied it to the body. I adhered nicely.
Overall, for CONSTRUCTION I would rate this kit
5
points. I didn't find a single problem.
The Mirage has a mid-separation design
which releases the upper five foot section to descend on it's own 22"
parachute. The second 30" parachute carries the bottom, fin and motor,
section down.
The kit uses two launch lugs. One is on the upper section
and the other is on the bottom section. These two need to be aligned to allow
for a smooth launch off of the guide rod. The last page in the instructions are
the "Operation Instructions" and they indicate that "a 1/4"
diameter metal launch rod at least 36" long (as measured from the top of
the blast deflector)" should be used. This can not be correct and must be
a blanket operation instruction for other
Aerotech kits since the top
launch lug is about 38" from the bottom of the rocket. I used a five foot
rod and even that seemed a tad bit short.
The maiden voyage was on an
Aerotech Single-Use F25-6.
Excellent slow and loud lift off. Excellent slow and loud lift off. The F25
powered the Mirage
to a fully observable apogee (wRASP says about
675 feet), then about 2 seconds after apogee the ejection charge pushed the
upper section away and both parachutes deployed. The upper section came down
faster than the lower section. The lower section drifted more than the upper
section, so it would be good to have a flying partner to help in retrieval.
The second flight was supposed to be on a G80-7, however,
after 4 puffs this motor was not going to ignite. So the second flight was on
an Aerotech
EconoJet G35-7. This flight was also great to watch with separation at
apogee.
The LABYRINTH ejection gas cooling system
did exactly what it claims to; "The ignition of the ejection charge
creates a burst of hot expanding gas which is cooled by the permanent metal
mesh . . . The cooled gas flows around the baffle, pressurizes the parachute
bay and ejects the nose cone (or payload bay) and parachute." I had no
damage to my shock cords or parachutes.
One other interesting fact about the
Mirage is how well suited it is for many different motors. According to
wRASP, the Mirage
will have excellent flights (with ejection
very near or at apogee) on Single-Use motors, F20-4, F25-4, F50-6, G80-7 and
RMS motors, F52-5, G33-5 and G64-7. I'm sure the North Coast Rocketry
Darkstar F62-6 would also give a nice flight. I look forward to using some
of these other motors!
For FLIGHT/RECOVERY, I would rate this kit
5
points.
Overall, for the price and ease of build, the
Mirage is a great kit for someone looking for a very large, mid-powered
rocket with little experience. I give the kit an OVERALL rating of
5
points.