(12/01/01) When I saw the new release of the Tiny
Pterodactyl I had to get one...so I did. It arrived 1 week before a planned
trip to Michigan where I was going to be flying at 3 Oaks. So I had a short
period of time to build it. But that was all I needed with the ease of this
I also did a comparison on Mid to High Power Starter Rockets -
This was my third PML kit, but only my first using
Quantum Tube. I have been very pleased with my
(Level 1 Cert Rocket) and
so I was expecting nothing less. In addition all three rockets are based on the
2.1" airframe and all have the exact same nose cone.
Pterodactyl is the hatchling compared to the large 7.5" Pterodactyl and
the 3.9" Pterodactyl Jr. As stated it has a 2.1" airframe and stands
25.5" tall. It comes configured with a 29mm motor mount.
The kit includes a pre-slotted 2.1" diameter Quantum
(QT) body tube. It uses three (3) 0.062" thick G10 fins with
through-the-wall-to-the-motor-mount tabs. It has a standard (sturdy) PML
2.1" Nose Cone. A standard PML Piston Recovery system with a Piston, a 3'
Piston Strap, a 9' Tubular Nylon Shock Cord, and an 18" PML parachute. A
29mm motor tube and two 3/16" plywood centering rings. Two (2) 3"
Brass Launch Lugs for a 1/4" rod. And lastly a single peel-n-stick
There are seven (7) 5.5" x 8.5" pages of
instructions with the kit, plus an insert for the Dura-Chute (preparation and
folding), an insert for Do's and Don'ts of Quantum Tubing, an insert for the
Piston Recovery system, and an insert for tying Tubular Nylon. The instructions
are thorough and include illustrations to assist in every aspect of building
the rocket. The CP is identified in the instructions along with instruction for
dealing with CG.
First, PML recommends the use of epoxy
for the assembly of this rocket. I wanted to try something different. I had
purchased some ProBond Polyurethane Glue. It is called "The Ultimate
Adhesive", "Bonds Virtually Everything", "Super
Strong", "Sand Easily", "Water Proof", and
"Stainable/Paintable". The outside cover said that it is the strength
of epoxy without the mixing. So I went for it.
general, I found the glue easy to work with exception for one primary issue. It
expands in volume after being applied. (notice in the picture the difference
from the wet on left to fully cured on right) This was not a problem for
attaching the centering rings to the motor tube and to the inside of the body.
It was fine for attaching the strap to the motor tube and to the piston. It was
fine for mounting the fins through-the-wall to the motor mount. It did not
appear that it would work well for the fin fillets so I didn't use it. I did
fillet the rear centering ring and piston (see below) and it did okay there.
The main problem is that you just don't know how much it is going to expand on
you. Once dry it appears porous, but it does sand easier than epoxy and I had
no primer interactions.
Construction is very straight-forward on the Tiny
Pterodactyl. I did alter the construction process in a couple of ways and will
touch on those below.
The instructions initially have you install the rear
(notched) centering ring onto the motor tube and then to slide the piston strap
through the notch to glue to the motor tube in the next step. I reversed this
process only because I saw myself having trouble sliding it through the notch
afterward. I had to sand the inside diameter of both centering rings slightly
to get a good fit. The ProBond Polyurethane glue performed very well here and
may be a good alternative (and cheaper) than epoxy.
The fins fit perfectly both into the QT and all the way
to the motor mount. For internal fillets, I used the Polyurethane glue by
squeezing it onto the joint between the motor tube and fin and then holding the
rocket at a downward angle until the glue had run to the end of the fin tab, I
then set it horizontal to stop the running. This worked well, too, with one
exception. I got a run that found its way out of the fin slit and ran across
the fin. I was able to clean this off of the G10 fin using a razor
I used epoxy for make the fin fillets since the
Polyurethane glue expands.
building the piston, the Polyurethane did fine but since it takes much longer
to set than 5-minute epoxy I had to tape the little tab on the strap back to
the bulkhead. The piston also required a lot of sanding to get it to fit and
move smoothly in the Quantum Tube. This is different than my previous
experience with PML kits. The Callisto didn't require any sanding and the
Phantom only required a little.
Two other changes I made were the adding of blind T-Nuts
to the rear centering ring before gluing in place and the use of Rail Buttons
instead of Launch Lugs. The latter is a bit concerning because of the piston
that slides inside of the airframe. The Rail Buttons had to be mounted so as
not to interfere with this piston. I mounted mine at 1/2" and 7 1/4"
from the rear. The one at 7 1/4" leaves plenty of room for the piston,
parachute, shock cord, and nose cone without hitting the screw that protrudes
into the airframe.
Finishing was fabulous with QT. I used 320 grit all over
the entire surface of the rocket and fins. I used 220 on the nose cone. I then
primered with Plasti-Kote Sandable Primer. I used a thick coat on the nose
cone. I sanded everything again with 320. Primed a 2nd time. I sanded and did
the nose cone 2 more times to fill in a slight mold line. I ended up using some
left over Rustoleum Hammer-look Gold paint. (just like this stuff, but really
took away from the smooth finish the QT would allow). I then applied the decal.
I should have then used a clearcoat to seal the peel-n-stick decal, but I was
already in Michigan a day before the launch.
Overall, for CONSTRUCTION I would rate
½ points. The parts were of great quality and the fit of the fins
was perfect. Motor retention would be nice and there is definitely room for it.
The biggest disappointment was the amount of sanding I had to do on the
PML recommends motors ranging from the F37 (810 feet) to
an H55 (4432 feet) and everything else in the 29mm range.
The altitudes above are based on a finished weight of 18
ounces. Surprisingly my finished weight was 17 ¼ ounces. This is
surprising because my finished kits are usually so much off of the
manufacture's finished weight. Some heavy, some light, just never this
My first flight was on an F40-7 (left), which PML says
should get 1639 feet. The F40 I was using had failed to light 7 times with
various ignitors, so I also used a
Slim Gem which I had to build into the motor because it was slightly too
large to pass through the nozzle. It lit. It launched. I barely got the picture
and it was a great flight despite the high winds. It landed about 50 feet from
the pad. F40's and Econojets will be good launch companions with this one
(although I have G25-10 that might find its way into the Tiny
I felt that the descent was very fast (although it was
appreciated with the wind on that day). Parachute size calculators suggest that
the parachute should be 30" in diameter. PML provides an 18" with a
3.5" spill-hole. It comes down fast. PML does offer a 24" parachute
option (for regions with hard landing surfaces...can you say desert?).
flying opportunity required a 24mm adaptor so I could fly it using my 24mm RMS
system. I flew it three more times on E28-4's. RockSim says 606 feet with my
rocket's weight. This is great for the small field.
The first flight (right) was straight and true. Ejection
was with a "pop" as the piston "popped" out of the tube.
Descent was fast and it was recovered without damage.
The next flight (same day), I couldn't get the piston
back in to where it was nor did it slide easy. I pushed it in and twisted it
back and forth and up and down. When it came out it had black stuff on it. I
didn't have sand paper with me, so I scrapped the piston lightly with a hobby
knife until all the black was removed. Repeated that process again before it
slide nicely in the tube. Then I launched it.
This time is seemed to come off the pad at a slight
angle. It looks like (from a picture) that my ignitor leads went up with it and
pulled off just as it was leaving the rail. Let this be a reminder to self and
all reading to secure those ignitor leads at the base of your launch pad. The
flight was successful, just at an unplanned angle.
flight (3rd on E28-4) was the next day in absolutely perfect calmness. I had
the same trouble with the piston (right) so I sanded it to remove all the black
stuff before going out to the launch field. The flight was as the first E28.
Straight and true with ejection at apogee. This is a good small field motor and
rocket combination. PML should advertise it with 24mm motors E30 SU, E28 RMS,
F24 RMS and F39 RMS. I'll be flying it on the 24mm F's too. I don't expect too
much more altitude (200 feet) since the 24mm RMS F's are only 10 newtons more
than the E's...baby F's so to speak.
For FLIGHT/RECOVERY, I would rate this kit
½ points. I'm really not sure why I'm having so much trouble with
this piston system. I have never had trouble after getting the initial fit. I'm
wondering if the Quantum Tube attracts more soot than the PML Phenolic tubing.
Don't get me wrong, I LOVE the piston systems! This one is just taking a little
more work than the rest. Descent rate is flier's choice, but the 18" with
3.5" spill hole is fast. RockSim says 19 feet/sec but another calculator
says 25 feet/sec. It's fast. The rocket is tough and can take the landings
though so maybe it's a blessing in disguise. The remainder of the flying
experience is great. This is a stable rocket and possibly the only one by PML
that can fly on 24mm E motors. Why would PML want that? To reach some
additional fliers. Get a couple of designs under 16 ounces and they will, no
doubt, have new customers.
the Tiny Pterodactyl is a nice addition to the PML and my flight. I'm glad I
built it because it had been a long time since I built a PML kit and to
experience Quantum Tubing. I would recommend this kit to anyone wanting to try
a mid-power kit. I would suggest getting the 24" parachute option and also
building up a 24mm adaptor. Remember, it doesn't have to be out-of-sight
(literal) to be an out-of-sight (slang for cool) flier. Quality components and
unique looks makes this a nice rocket to add to the fleet. Then start thinking
about the Pterodactyl Jr. or even that ultimate 7.5" Pterodactyl. I give
the kit an OVERALL rating of