
(Contributed - by Lance Alligood
- 09/10/03)
Brief:
The Liberator is a complex jet
fighter-like design single-stage low power rocket that's built (and weighs)
like a tank. The manufacturer rates it as skill level 3.
Construction:
The kit contains:
- 18in BT-56 body tube (slightly larger than BT-55)
- Plastic nose cone with canopy bubble
- Laser cut balsa wood fins
- "Jet engine intake" wrap-around and fin reinforcement sheet
- Decal sheet
- Parachute plastic sheet (for 18" chute)
- Self-closing plastic bag with launch lugs, motor tube, thrust ring,
centering rings, shroud line, parachute reinforcement rings, and elastic shock
cord.
- Instruction manual
The good news: My first impression when opening the bag was that the parts
appeared to be of great quality. I'd never built an LPR kit with laser cut fins
and it's clear to see why they're all the rage. (In fact, this was my first
non-Estes LPR.) The high quality of the balsa is worth noting as well. The nose
cone was made (and had the weight of a scaled down version) from the same
plastic used on mid and high power rockets. The canopy for the cockpit was part
of the nose cone. When dry fitting the parts, the nose cone also fit snuggly--I
can see why tubing slight larger than BT-55 is used. It simply would not fit in
anything smaller. The instruction manual appeared to be very thorough. 7 pages
(on 8.5"x11" paper) front and back showing 26 steps (not including
giving the rocket a , preparation, warrantee, and Canada's model
rocket safety code). To be Canadian friendly, all steps were in English and
French. This also was the first rocket I'd ever built where I had to assemble
the parachute. The plastic for the chute is considerably thicker than any Estes
chute I've ever seen.
The bad news: Dry fitting the motor mount found all parts to be rather
loose fitting. Sliding the beefy (for an LPR) centering rings into the BT-56
was loose as well. All of this is noted in the instructions too. I didn't care
for the way outer edges were defined on the cardstock template. Instead of
thin, sharply defined lines to cut out, there are areas of gray shaded areas
that define the parts not to be used. As carefully as I cut the pieces out,
there was a slight inconsistency in part sizes (like for the "top"
fin). Perhaps the most disappointing item was the shock cord. It was merely a
piece of elastic. 30 inches of quarter-inch 100% stretchy rubber. No polyester.
As determined as I was to build this kit entirely stock, the image of the nose
cone and chute drifting off as the rest of the sustainer tube plummets to the
earth when the shock cord burns through was something I just couldn't get out
of my head. I chose to use 3ft of 1/4" elastic from my supply box.
Construction was guided well by the manual. First was the motor mount.
Another item of note is that the MMT uses a small threaded L-shaped piece of
metal in place of the bent metal clip for motor retention. Once assembled, you
twist the end over or away from the MMT tube to hold or remove the motor,
respectively. A different mousetrap, if you will.
Next was the body wrap. Cut from the cardstock, folded along marked lines,
and initially tacked on to the body tube lengthwise. The instructions do a good
job to recommend that enough time be given to let the glue dry after each step
here. The wrap eventually goes around the entire tube with parts flared out to
create the air intakes. Despite my careful marking of the tubes I managed to
get the cardstock attached slightly crooked...but again, that was completely my
own fault and wouldn't be enough to detract from the overall design and flight
of The Liberator. Also I found that using a paperback book helped hold the
cardstock in place while drying so that I could briefly attend to other
matters. And I was hoping that the cardstock would "heal" somewhat
when the glue dried. The paper used is a little sensitive to the moisture in
white glue to the point of being visible and slightly raised to the touch.
Hopefully primer and sanding will reduce or eliminate the glue lines.
The cardstock already has the markings on it as to where all the fins
should be placed. There are 6 pieces of balsa that cover the bottom of the
rocket and one fin on the top. The top fin has 2 other pieces of cardstock
glued onto each side to aid in adhesion to the body tube. These extra flaps do
add weight and in my opinion detract from the overall sleekness of the design
but definitely gives extra rigidity to the fin and should prevent it from ever
popping off on a hard impact. Also, running a bead of glue along where the fins
come in contact with one another greatly increases rigidity and should
eliminate any potential fin flutter.
The rest of the construction is routine...glue on the decorative pieces and
launch lugs, glue in MMT, 3-fold shock cord mount, assemble parachute.
Something that will surprise those concerned with the wing aerodynamics is that
it's not till step 24 that you are recommended to round the wing edges. I
didn't bother with doing that and left the wings as is but I can see where you
might accidentally round an edge (or part of one) that shouldn't be... Still, I
would think it much easier to sand the wings before they are glued onto the
body tube.
Once assembled, I liked the plane-like look to it. The wings provide enough
sustainable lift I, in fact, was able to get it to glide quite a ways when
throwing it horizontally (across the room onto a nearby bed or sofa). This bird
is heavy though. Even with the thick paint job on my stock Big Bertha, the
naked Liberator feels noticeably heavier.
On construction alone, I think skill level 3 is pretty accurate considering
the complexity of the cardstock body wrap. It's definitely a technique that you
won't see in many kits.
Finishing:
I didn't break out the Elmer's Fill 'n' Finish because I wanted to see how this
high quality/density balsa directly reacted to Krylon primer. The body tube
spirals are so light (especially when compared to the edge of the cardstock
wrapped around the body tube), I didn't bother filling them in either. Once
primed, there's a lot of area to sand for an LPR but it didn't take very long
due to the quality materials. Care needs to be taken on the body wrap so as to
not cause any unwanted dents or creases. Also, the nose cone is made of
high-density polyethylene, which is an unusual material for an LPR. Take it
from someone who has built MPRs & LPRs: rinse the nose cone and then sand
it with 250 or 320 grit sandpaper before you even think about putting on any
paint. Otherwise the paint will peel right off the waxy surface. A couple of
coats of primer and she was ready for final gloss coats.
I liked the paint scheme on the packaging insert over the camouflage scheme
shown on the website, but used gloss black instead of red to accent against the
silver underside. I'm pretty pleased with the results. There are self-adhesive
decals--lots of them--and the kind that you also have to cut out individually
too. Sunward Aerospace is a Canadian company but they're nice enough to
recognize the customer base in the US and UK. Included is a nice choice of
flags, logos, and symbols to represent all 3 countries equally. The decals
provide an excellent finishing touch to the rocket. Lastly, I put an accent
stripe around the canopy bubble (since the canopy and nosecone had both been
painted black) with a new Sharpie metallic silver marker. I hope these pens
become available in more colors...they offer a paint-like quality but with the
fine detail and application of a marker. Excellent for detail work.
And like I mentioned above, The Liberator is HEAVY. Finished weight (sans
motor) is 4.5oz! I knew early on that this rocket was going to be
underpowered--even on a C6--based on weight alone. I don't have access to one
but my gut tells me that the only way this bird is going to achieve decent
altitudes is for those brave souls with an AT D21. Let see how she flies...
Construction Rating:
4
½ out of 5
Flight:
First flight recommendation is a B6-2. Uh, I don't think so. Seeing how my Big
Bertha flies best on a C6-3 and weighs a full ounce LESS, I'm not putting The
Liberator up on anything else the first time out. I felt the shorter delay
would be a good idea, again, due to the weight.
I prepped it with a few pieces of wadding, readied the motor and put it up
on the pad. It was breezy day but I still aimed the rod straight up. The
Liberator had a slow but straight liftoff to maybe 300ft before the wind pushed
it over into an upside down position (the belly of the plane facing the sun)
where it ejected at apogee. I apparently didn't put in enough wadding as all
but 2 of the shroud lines burned through. The body tube stayed horizontal the
whole way down so the broad wings and the little drag provided by the chute
allowed it to still land safely without damage.
The wind
had calmed slightly right before the second flight (on the same day). I
borrowed an 18in Estes chute (with a 2in spill hole) from my Fat Boy and put in
a couple more pieces of wadding--I think I used 5 squares--than last time. I
also tried to put The Liberator on the pad so that any wind would blow across
the fins instead of pushing the bottom of the rocket like a sail, as was the
case on its maiden voyage. This proved to work quite well as I'd say the second
flight peaked closer to 450ft (but still well short of the manufacturer's
claimed 600ft). Ejection was right at apogee, only the chute came out but
didn't open. The body tube again remained parallel to the ground during the
entire descent until it landed on the soft, grassy field. Post-flight analysis
revealed a couple of scratches, a slightly dented decorative fin tube, an
Estes-style dent in the body tube from the nose cone, and a poorly packed
chute. User error was the cause of poor recovery this time.
I waited to have the third flight on a calmer day. Well, at least on the
ground anyway. I discovered there were some gentle high winds that The
Liberator got caught up in but not till it boosted nicely to ~400ft. The nose
just started to rotate downward as the chute deployed perfectly this time. I
was using an Estes 18in chute with a 2in spill hole cut in it so it descended
quickly, touching down 200ft from the pad. Finally a completely successful
flight! My advice: only fly this rocket on calm days.
I didn't try The Liberator with a longer delay than the C6-3. I bet with the
couple extra seconds in a C6-5, you might be able to get a brief glide (as my
pre-finishing tests showed) before ejection. (I even wonder if it's possible to
get this design to have a complete glide recovery...?)
Recovery:
I obviously had a couple of serious recovery problems with The Liberator, both
of which can be traced back to operator error. However, given a calm day and
when nothing goes wrong, it recovers reasonably well if not a little fast. For
an LPR it does descend quickly, even on an 18in chute, so it shouldn't drift
much for those folks flying this rocket on a small field.
I plan to repair the kit chute with Kevlar®
shroud lines as the plastic is a significantly higher grade than what comes
with an Estes kit.
Flight Rating:
4
out of 5
Summary:
This is a very attractive and durable kit but I'd have to say that I'm not sure
if I'd fly it as regularly as other kits in my fleet, mostly because of the
risky recovery. Anyone who is big into military/scale kits and/or someone
looking for a new challenge in LPR building might find The Liberator a welcome
addition to their fleet. It's a real shame that this kit is limited to only
18mm motors. With the rugged construction and high quality parts, this rocket
should be able to handle the motor mount and thrust of at least a 24mm Estes
D12... I mean it looks like a jet, so why not have it take to the skies like a
jet!
Overall Rating:
4
out of 5