
(Contributed - by Philip Levanda - 06/23/05)
Brief:
When I was standing in line at the RSO getting ready to put this baby up on a
J528, a bystander said to me "You ready to lose that hypodermic
needle?". This is a high altitude kit that was made for J motors. At 89in
long and 3in diameter, it is long and sleek with short fins. It can easily
reach mach on a big J.
Construction:
This lit includes:
- 2 very strong 3" phenolic body tubes
- 1 coupler
- 1 nose cone
- 1 54mm MMT
- 1 Slimline motor retainer.
- 1 nylon shock cord
- 1 Kevlar®
shock cord
- 1 Fireball anti-zipper ball
- 2 bulkheads
- 1 piece 1/4" threaded rod
- 1 54mm 3 fin fincan
- 2 centering rings
- 1 18" drogue
- 1 36" Tac 1 main parachute
- 2 Acme conformal rail guides
- 1 Decal
- Eyebolts, nuts, and washers
- Board and lug for the electronics were talked about in the instructions but
not included with my kit.
This is an almost ready to fly kit. It comes with just about everything you
need to build the rocket short of epoxy. The fin can is a big time saver as
there is no need to align the fins.
Most high power rocket kits I have seen either come with sparse
instructions, if any at all. This kit, on the other hand, came with very
detailed instructions including helpful pictures and tips on how to assemble.
It even had tips in the back for packing and getting the Vertical Assault ready
for launch.
I started first thing with the fincan and motor mount. They
recommend JB Weld because of its ability to handle high temperatures. I agree
with this recommendation, so I used it. The only problem with JB Weld is that
it takes hours to set, so I put the Slimline on and said goodnight. The next
day I mixed another batch of JB Weld and slid the fincan and centering mini
coupler on applying a decent amount to keep it in place. Then I said goodnight
to the rocket again as I waited for the JB Weld to dry. I usually like to
eyebolt my shock cord in but with a 54mm MMT in a 3 inch rocket there just
isn't room for it. Instead I measured off the Fireball to meet the end of the
tube and epoxied the cord to the MMT. Once the fincan and MMT was assembled, I
mixed up a big batch of 5 minute epoxy and slid it into the slotted tube. In my
opinion, the thin coupler put at the back to help keep the slotted tubing in
round and give you an extra bit of area to glue to may be too thin. It didn't
stay well and barely worked. If it was a bit more substantial, I think it would
have been easier to use. Filleting the fincan is a bit messy. The slots have
some play in them so the epoxy oozed through. The directions almost recommend
just pouring it in and to use a large amount. I did it about half way, applying
a generous amount and making some small fillets. A foam filler might be a good
idea to fill those gaps between the fins.
Next I installed the eyebolt in the nose cone. The instructions tell you to
cut a big hole in the side of the cone shoulder so you can put the nut on the
back of the eyebolt. I wasn't thrilled with that idea but after looking at it,
that seems the only way to get it on there. Doing this also leaves a nice hole
in case you need to add nose weight.
Last thing to assemble is the avionics bay. I was not thrilled
with the included setup at all. Giant Leap makes some great avionics bays so I
was a little disappointed by the one included with this kit. It consisted of
two bulk heads and a 1/4" threaded rod. The instructions talked about a
piece of wood and a tube to attach the electronics to but they were no where to
be found. One threaded rod in an avionics bay to me just isn't a good idea. For
one you are putting all your recovery stress on that one rod from the chutes
and you've also got an altimeter in there that can spin and jostle around. I
happened to have some 1/4" rod lying around so I simply just added a
second one. I used some old fin material for the mounting board and installed
my Missile Works RRC2X altimeter and switch. I used two 1/2" caps to
hold my black powder charges.
Finishing:
I used some nice metallic red paint which gives it a slight automotive finish
to it. I think it went on good and looks great. The provided decal went on
smooth and has survived a few flights without any clear coat. I did not fill
the grooves which are in my opinion some of the nastiest I've ever seen on a
tube. They are close together and deep, but the tubes are so strong, I can't
complain about that. These tubes feel stronger than some glassed tubes I've
seen.
Construction Rating:
3
½ out of 5
Flight:
Giant Leap recommends any motor from high thrust Hs through medium Ks which
makes this a very versatile rocket if you have the to go that high. I
went conservative on its first flight and used an I285 with a medium delay. I
mocked up the Vertical Assault in RockSim 8.0 and it said 1900 or so feet. When
I went to balance this rocket with the I285 in it I was a little disturbed to
see it almost 5 calibers overstable. This might be due to the fact that I used
a less epoxy than they recommend in the fincan. It could also be the fact that
it has tiny fins and is very long. Not having an easy solution to this I did
some research on long rockets that are overstable. I read a few things and it
looked as long as it wasn't launched in 15+ mph winds I should be fine with
some weathercocking.
I took this rocket out to NERRF 2005 for its maiden flight. I flew it twice
over those 3 days. Since this was the first flight and the fact that I did not
ground test the ejection charges, I used the motor delay and put in a 30"
drogue just in case my electronics failed or I didn't put in enough black
powder. I loaded it on an extreme rail which the conformal launch lugs glided
on nicely. Turned on the electronics and moved behind the LCO.
5...4...3...2...1...ignition. She went up pretty straight there was a slight
kick into the wind once off the rail but I attribute that to the light motor.
Other than that, it was a nice, straight flight. Both chutes deployed--one at
apogee and the other at 500 feet, right where I set the altimeter. With the
large drogue it almost made it into some trees. Thankfully it landed about 15
feet short of them. I recovered it easily with zero damage--not even a scratch
in the paint. The altimeter beeped out 1900 something feet which was right on
with RockSim. On the second launch, I took it up a notch and loaded a Loki J528
in there. This time I used the 18" drogue that came with the kit and I
left the 17 second full delay in the Loki motor. After a few false starts,
which we figured out was a blown fuse in the switch box on the setup, the LCO
made the count and that thing disappeared. Zero hesitation. No weathercocking.
Nothing. It left the rail quick, fast, and in a hurry. The altimeter beeped out
5964 feet. Again, the dual deploy went perfectly and I didn't need the Loki
delay redundancy.
I used the 54-38mm Slimline motor mount adapter for both motors. The Loki
motors are not compatible with Slimline motor retainers. The Loki rep at the
NERRF launch suggested I just tape the back of the motor to the retainer for
positive retention. That worked out great. Not sure what I can do if I want to
put a 54mm Loki in there, as it's hard to tape the back when I can't get my
hand in there.
One thing I can say about the main shock cord is that I badly burned two of
them. I will use less BP next time and I put a Kevlar®
cord protector on the base of the nylon shock cord.
Recovery:
PROs:
- Dual deploy went off without a hitch
- Zero damage after 2 flights not even a scratch in the paint.
CONs:
- Protect that forward shock cord
- TAC-1 chute is a tight squeeze in that 3" body tube
Flight Rating:
5
out of 5
Summary:
This is a great kit. They label it almost ready to fly but it took me about the
same amount of build time any other kit would. The fin can makes it easy but
waiting for the JB Weld to dry negates any time saved. Next to the fiberglass
rockets I have built, this is the strongest kit out there. You're not gonna
zipper it and you not gonna hurt it. This would make an excellent L2 kit. The
main CON I think is the altimeter bay. Toss in an extra 1/4" threaded rod
and include all the parts next time.
Overall Rating:
4
½ out of 5