(by Simon Crafts - 06/04/06)
The Binder Design Stealth Jr is a single stage, 29mm mid-powered rocket kit
with recovery. The kit features four 1/8" aircraft plywood main
fins, four small 1/8" aircraft plywood fins, a generous payload
, 12 feet of 3/16" tubular nylon shock cord, and a 24" Binder
Design premium chute. The kit includes pre-slotted airframes for an easier
build and comes with a fin alignment guide.
The kit comes extremely well packaged and includes all of the components
necessary to complete the rocket for flight. The packaging is very well laid
out with all of the smaller parts in sub-packages within the main bag. The kit
included the following parts:
- 1 Binder Design 5:1 plastic ogive
- 4 plastic rivets for securing the nose cone to the bay
- 1 payload tube, 12" long x 2.6" heavy kraft paper tube,
pre-slotted for the forward fin attachment
- 1 tube, 22" long x 2.6" OD heavy kraft paper tube,
pre-slotted for attachment of the main fins, and pre-marked
- 1 5" long heavy paper (kraft) tube
- 1 29mm tube, heavy kraft paper, 11" long
- 1 thick paper 1/4" launch lug, 4" long
- 4 pre-cut and sanded forward fins, 1/8" aircraft plywood
- 4 pre-cut and sanded main fins, 1/8" aircraft plywood
- 2 centering rings for the motor mount to the 2.6" airframe, made from
1/4" lite ply
- 1 plate, pre-drilled for the eyebolt, 1/4" lite ply, for
attachment inside the tube coupler
- 2 #6 eyebolts for attachment, complete with 4 washers and 4 nuts
- 12' of low-stretch tubular nylon for the shock cord
- 24" premium heavy-duty rip stop nylon parachute
- 10 pages of very well illustrated instructions
- A fin alignment
- 1 vinyl "STEALTH" decal. My decal was a metallic silver color.
rocket was my second Binder Design kit to cross my build table and like the
first, it was a pleasure to build.
First, the instructions are outstanding! Lots of illustrations and
information to walk you through a straightforward build. I kind of jumped
around a bit so the actual sequencing of my build is a bit different from the
instructions but that is not because the provided build sequence is illogical
or anything. I just went about building how I wanted to.
The first step is to drill a hole in one of the motor mount centering rings
to attach one of the two eye-bolts for shock cord attachment. The eyebolt is
then secured to the through the hole with a washer and nut on
both sides for a snug, secure fit. Then the motor mount is assembled by gluing
only the forward centering ring (the one with the eyebolt) at this time. I
opted to sand the glassine layer off of the motor mount tube first for better
glue adhesion for both the ring and the fins which are attached during a later
step. Secondly, because the components involved are kraft paper and plywood, I
opted to use Elmer's ProBond wood glue in the construction process. Although
the instructions call for 15 or 30 minute , I elected for this building
technique after much discussion on The Rocketry Forum with other builders as
well as it was my preference. The aft centering ring is not glued to the motor
tube at this time so that it can be removed after the initial tack of the fins
for internal fillets. This is well spelled out in the instructions.
The next step is to tie the shock cord to the eyebolt. A nice diagram is
provided to describe perfectly the suggested knot to be used (a three-wrap
"blood knot"). The instructions called to slather epoxy over the knot
to prevent it from loosening later. I found this to be a good suggestion.
After the glue on the forward ring and the epoxy on the knot has set, the
next thing to do is pull the shock cord down through the motor tube so that it
isn't in the way, apply to the inside of the airframe at the forward
edge of the main fin slots, and slide the motor mount in to glue the forward
ring in place. Again, the aft ring is only dry fit on the motor mount tube and
should only be dry fit within the airframe to make sure the tube is centered
properly as the glue sets. The instructions suggest a nifty
"tape-tab" method for removing the snug-fitting aft ring later.
Furthermore, the instructions point out you must take care to not get glue
inside the airframe in the vicinity of the aft ring so that it can be removed
Next, the main fins are applied. I dry fit the fins first to make sure that
the slots were cut well and they were a great fit. They were just a shade
longer (1/16" of an inch or so) than the fin tabs, so I elected to make
them snug against the rear of the fin slots for uniformity. Before applying the
fins, I sanded the glassine layer off the airframes exterior about 1/8"
around each fin slot for better glue adhesion. Glue is applied to the fin root
and they are slid through the slot for attachment to the motor mount tube.
Again, care is taken to not get glue on the aft ring area at this time. I
simply did not put glue on the 1/2" or so of the fin tab at the rear to
prevent a "squish out" that could become a problem there. The
provided fin-alignment template made getting them nice and perpendicular a
While the main fins are drying, the canard fins can be attached to the
pre-slotted payload. The builder is instructed to insert the tabs on the
canards 1/8" through the slots and then apply good fillets inside and out.
I was apprehensive with this at first, since there was no interior tube for
these fins to attach to. In the end however, these fins are relatively small so
this was a non-issue. I applied a thick bead of glue to each side of the fin
tab on these forward fins before sliding them in so that there would be
something for them to "grab" with and not fall all the way through
the slot. If any of this glue beaded up on the outside of the airframe during
insertion, I just leveled it out with my finger and chalked it up as part of
the filleting process, which worked great! I used a small (1/16") wooden
dowel to get the glue in there for the internal fillets. A dowel that small was
not necessary, it's just what I had on hand at the time.
Back to the main fins. After they have dried to the motor mount tube, the
aft ring is removed and six fillets are applied to each fin. Two on each side
at the motor mount tube, two on each side at the inside of the airframe, and
two on each side on the outside of the airframe. With four fins, that's 24
fillets. Again, I used wood glue for this and just slathered it in there with
my little wooden dowel. It took some patience, but I got it done without much
trouble. I did discover that I could fully apply half of the fillets on the
first pass, let them set a bit with the rocket held horizontally, then roll the
rocket over 180 degrees and apply the other half.
While the fillets were drying, the bulkhead/payload coupler is built and
attached. First, the remaining provided eyebolt is secured to the pre-drilled
bulkhead plate in the same fashion as the other eyebolt was to the forward
centering ring. Two washers and two nuts make for a nice fit. Then the bulkhead
plate is glued into the inside of the tube coupler about 1/8" in from one
end. Fillets are added to both sides of the bulkplate to complete the assembly.
After the glue has dried enough where the fillets won't run, the coupler is
glued into the bottom of the payload tube with the bulkhead/eyebolt at the
bottom. The coupler is installed about 2.5" into the payload tube, leaving
2.5" for a into the main airframe when the rocket is assembled.
At this point, I set the whole thing aside for the evening to let all the
fillets cure completely and picked up the build the next day.
I started construction the following morning knowing that the finish line
was near and I'd have a finished bird! I started by removing the dry fit rear
centering ring. I opted to drill it and install a pair of T-nuts in it for
positive motor retention clips before gluing it in. I then slathered the glue
on the inside of the airframe and over the motor tube and slid it in. It wanted
to bind and grab because of the wood glue and it took some "coaxing"
with a small hammer but I got it in without mishap.
Then the launch lug is installed. As is mentioned in other Binder Design
reviews, the launch lug is a very tight fit on a 1/4" . I
tested the lug on my rod before gluing it on and opted to ditch it in favor of
a pair of shorter 1/4" lugs that I had in the parts box from
Components. I sanded the glassine off of the pre-marked launch lug line as well
as the lugs and put one near the top of the lower airframe and the other near
Then the nose cone is slid into place and drilled for the rivets that hold
it in, which I feel is a slick method of making sure you don't lose your cone
without gluing it in. This enables the builder to remove it and actually
utilize that big payload bay! First, the nose cone required about 10 wraps of
masking tape to get a secure fit in the payload tube. This is common with
Binder Design kits, and although the shoulder is loose within the airframe, the
OD of the base of the cone matches the OD of the airframe very well. Once the
nose cone is in, four holes are drilled at 3/4" below the top of the
payload tube for the plastic rivets. With the payload tube marked for the
provided cuts for the canard fins, getting these holes evenly spaced around the
tube was a snap. After the four holes are drilled, the plastic rivets are
simply pushed through the holes, effectively locking the cone in place until
the rivets are removed.
All that's left now is to tie the shock cord to the eyebolt on the payload
and attach the chute. The shock cord is tied to the forward eyebolt in the
exact manner as it is to the forward centering ring. As for the parachute, the
instructions call to use the "pull through the loops" method and
attach it directly to the shock cord a few inches below the knot at the
bulkplate attachment point. I opted to attach the to a heavy sampo
/clip instead so I could remove it for storage and possible use in other
birds. For flight, I'd just clip the parachute to the eyebolt.
PROs: Great packaging, wonderfully clear instructions, good fitting high
quality parts that can be assembled without special building techniques, and no
"gotchas" in the build that I can think of
CONs: The launch lug is too tight and needs replaced, and there is no
positive motor retention provided (minor detail).
I hardly bother with filling tube , especially with mid powered rockets.
My experience with rockets of this class and higher is that people don't look
at them with magnifying glasses and inspect your fine modeling skills as when
showing off finely crafted "model" rockets. So, no comment on the
spirals from me. I don't find them noticeable, particularly with these tubes
anyway. However, I did use Elmer's Fill 'n' Finish to patch the gaps in the
forward and rear ends of the fin slots where necessary. The instructions
suggest a spot-putty or Bondo type product for this, but being paper and wood,
I thought the wood would be fine. I dabbed it in there and sanded off
the excess which came out great!
For the fins, I masked the tube areas off and applied two heavy coats of
Folk Art sanding sealer and sanded with 400 grit between coats. This
filled all the grains in the fins to a plastic-like, smooth finish.
The nose cone required minor sanding to remove some mold flashing in
addition to standard sanding needed on a plastic cone prior to painting for
For paint, I was happy to work with a rocket with a single color paint
scheme for a change. and paint. Simple. I gave it two coats of Krylon
gray primer, sanding in between coats. For the main color, the kit art appears
to be gloss black with a white decal. Since my provided decal was metallic
silver, I opted for Rustoleum Midnight Black Metallic. This stuff looks
splendid, dries quickly, and goes on smooth.
After the paint dried overnight, the decal was applied. For me, I laid the
decal on the airframe before removing the backing paper to make sure it would
look good in the designated spot. At first, I laid it entirely on the lower
airframe, just below the seam of the airframe and the payload bay. This just
made the decal look to low or off-center somehow to me. So after thinking about
it a bit, I slid it forward with the "H" on the payload, the
"STEALT" on the lower airframe, and the seam splitting the
"T" and "H". This looked a lot better to me. So I took
great care to make sure I had the canard fins and main fins lined up, removed
the backing paper, sprayed the decal and that application spot with soapy
water, laid it down, pressed out the bubbles, let it dry, and presto! Being a
stickler for making sure everything lines up for flight, this decal placement
actually helps in the field. Just slide the two halves together and twist until
the decal is in alignment. Ready to go!
PROs: One color paint scheme and high quality cut-vinyl decal.
out of 5
My first flight with this rocket was going to be part of my first experience
actually building and using motors, so naturally I was nervous. With the
recommended motors being simply "F and G", that wouldn't settle for
me. I emailed Mike Fisher with Binder Design and he sent me the file
for this rocket. I used RockSim to run the "non-Level 1" reloads
through the sims to try and come up with some better suggestions. I had the
cases, so what the heck.
My first concern in picking motors wasn't so much the altitudes. I was
looking for the slowest projected velocity at deployment based on my simulation
inputs. I printed out my simulation data and was off to a Tripoli club launch
where Tim Lehr, the "Wildman" from Wildman Rocketry, was the onsite
vendor and was a great help. My first choice was a G64-7 reload but that wasn't
available. My second choice was a G54W in my 29/100 case with a RDK-3 short
. That was the ticket for the day.
The Stealth Jr was my 5th flight of the day. The reload was assembled and
installed, and I clamped down my home grown motor retention clips. Then, I
dropped a couple of handfuls of "" cellulose wadding in the
airframe, looped in that long shock cord, folded and packed the parachute, and
put the payload bay in place and headed for the pads.
was a perfect first flight. Straight as an arrow with a nice quick boost. The
delay change to the 6 second delay was even better. Just as the rocket
flattened out at apogee, the payload separated at ejection and you could see
the big chute unfurl and inflate before that 12' cord uncoiled completely. The
rocket gently swung into recovery position and drifted down for a soft landing
on the sod.
The second flight was a personal launch at a friend's farm. This time, I
had gotten a hold of a G64-7 for my 29/40-120 case. The results were the same,
only a much snappier boost and quite a bit higher. Again, a great flight
with a sweet looking, sweet flying bird.
What can you say? Stable, arrow straight and looks good on the pad and in the
CONs: A more definite motor selection matrix would be a plus.
The provided parachute is just beefy. Nice heavy shroud lines, and my flights
provided a nice, soft deployment and scratch free landings.
I might consider a tubular
protector for the shock cord for longevity, but I have had no problems with
scorching or melting to this point. Dog barf works great for me as a ,
and after two flights the Stealth Jr is still "good as new."
PROS: My flights recovered perfectly with acceptable drift and no damage.
CONS: Can't think of any!
out of 5
I really like this rocket! Great materials, great packaging, goes together
well, and looks really great when you're through. A super solid build that
feels light, yet extremely sturdy. My next flight is planned with an H165R
reload for a Level 1 certification flight. Based on my experience flying this
rocket and the simulated of about 2100' with that reload, I'm sure
that it will be very doable. I'd recommend this rocket to anyone in the market
for a 29mm powered kit.
out of 5