Public Missiles - Callisto

Public Missiles Callisto

Public Missiles - Callisto

Contributed by Nick Esselman

Published:	2010-11-13
Diameter:	2.20 inches
Length:	46.00 inches
Manufacturer:	Public Missiles
Style:	Sport

(04/01/98) Wow! That was what I first thought as I surveyed the contents of my Public Missiles' Callisto. Why? Well, as I have said in my introduction page I am getting back into rocketry and am moving toward mid-power models. Of course, I have experience building many Estes' kits, most of which weigh less than 2 ounces and are less than 24" long, however, the Callisto is 25 ounces (1 1/2 pounds) and is about 46" tall. It was definitely a wow!
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The instructions were clear and there were enough illustrations to ensure understanding. You will need two types of epoxy (5 min and 15 min) and you'll want to scuff all parts being bonded to ensure strong bonds. Both items were brought out in the instructions. Also, the next time you stop by a Chinese restaurant be sure to keep a set of chop sticks. They work great for spreading epoxy up into the airframe and allow the inside edges of the fins. I tape two together for additional length and also wipe them clean after use.

The Callisto was straight forward and easy to build. If you are looking for a "quick-build" model then the Callisto is not your choice, that is, if you use epoxy as recommended. Take your time and you will find that this kit is very satisfying.

[Picture] All the parts were cut precisely and fit very well. The airframe is PML's phenolic tubing which is very rigid. The fins are PML's G-10 fiberglass. I found this material easy to work with, however, take care when rounding the leading and trailing edges and be sure to rough the entire surface at all bonding joints before painting. The slotted airframe made fin alignment a breeze and ensures a very strong structure. I was surprised not to find an "eye" screw for attaching the shock cord to the nose cone but that was remedied with a quick stop at a local hardware store. Another nice feature, I have not experienced before, is the piston ejection system. This eliminates the need for recovery wadding. This eliminates the need for recovery wadding. The kit uses a PML's Dura-Chute parachute, which is high quality rip-stop nylon with a spill hole.

[Picture] Finishing the model offered some challenges. First, the phenolic tubing has fairly deep grooves that need to be filled if you are going for a smooth finish. I used a ready mix, fast drying spackle which worked nicely. I then used Plasti-Kote primer from a local automotive store. This is a thicker sandable primer which works well in filling in the imperfections on the model. One of the most annoying imperfections was in the plastic nose cone. There were mold grooves along both sides that took a lot of primer to finally fill in. After priming and sanding, I chose automotive lacquer paint for my colors. The kit came with a single decal sporting the word "Callisto" in red with black outline. I wasn't interested in decal from the beginning since the color scheme I chose was blue and gold.

I was a bit disappointed that the model didn't come with a motor stop to prevent the motor from dislodging with the ejection charge. I have come to learn that this is fairly common. None the less, I added hardware to allow me to mount a clip to prevent the motor from kicking out. I used "T" Nuts on both sides, mounted and epoxied to the rear centering ring. Then I was able to screw in two small clips that slide over the edge of RMS or Single-Use Motors.

[Picture] Ready to fly. I chose the Aerotech RMS - 29/40-120 Reloadable Motor System. I was pleased to find that it allowed me to choose from several "F" and "G" power motor reloads. In addition, it does not require a thrust-ring since it has a small flange to prevent the motor from going through the motor mount tube. I found the best price for Aerotech motors at Hobby L'inc.

I flew it first on a Darkstar F62-6 since I was nervous using my RMS motor for the first time. Perfect flight with ejection just at the back portion of apogee. This built nerve for a F52-5. This time ejection occurred 1-2 seconds after apogee, but again a beautiful flight and recovery. Impressive! I'm hooked!

Who knew that this rocket would become my Level 1 certification kit? Well, when money ran low and time ran out, the Callisto became the rocket of choice for my Level 1 certification. I really wanted something heavier. But at NARAM-40, she was loaded up with a H128-Medium and successfully turned in a qualifying Level 1 certification flight. Again, proving the sturdiness and versatility of this kit.

Flights

Comments:

S.O. (June 1, 2000)

The Callisto is a class act all the way. It is perfect for people wanting to step up from Aerotech or some LOC rockets. Construction was easy (if you are good at using epoxy) although time consuming. Most of the time I spent on it was filling the deep grove. (but now you can get the new tubes!!!) Lastly the versatility, I can use F's to I's (maybe J's on the new QT) and 500' to HIGH (sorry don't know the exact numbers). I rate it 6 out of 5 (everyone HPR or not should buy this kit, this one will be your old reliable.)

T.B. (July 1, 2001)

I really love my Callisto. Mine came with the Quantum tube and 38mm motor mount. Fins are G-10 fiberglass and tube came pre-slotted for through the wall fin mounting. Made a 29mm adapter so I can fly it on F's and G's (for now). It was my first experience with the piston ejection system and I found it easy to install. I used both 5min and 15min epoxy for construction which I found straight forward with easy to follow instructions from PML. I painted the rocket with Krylon white sandable primer with red fins and nose cone then gave it several coats of Krylon high-gloss crystal clear coat. I attached the supplied 24in nylon chute to the "D" ring at the top of the piston with a "quick link". My first flight was with and Aerotech G38. The Callisto shot off the launch rod and straight up for an excellent flight and recovery. I plan on using this rocket for my level-1 cert on either a H45 (38mm) or an H128. All in all I would give this rocket a 5/5 in all aspects. Although it does not come with any type of motor retention, I found it easy to fabricate one by just drilling two appropriate size holes in the thick plywood bottom centering ring, using long screws and fabricating wire retaining straps that loop across the two screws and over the motor (on each side of the nozzle for a very positive retention. Great rocket kit and with Quantum tube finishing was a breeze.

J.B. (May 5, 2003)

I build my Callisto as per the instructions. The only thing I changed was I epoxied a 10-28 NF nut to the inside of the bottom centering ring (above a drilled hole) that allowed me to use a machine screw and a metal retainer for the motor. The kit went together very easily and according to the instructions. I was very happy with it. I was very glad I added the screw for motor retention because there was not enough motor tube extend below the bottom centering ring to tape a motor to it as the motor instructions said. I launched it four times at the Tripoli "Battle Park 2003" launch in VA. The first 2 launches were on F25W-4 SU Aerotech motors. The flights were great! The delay was almost perfect. The only issue I have is that with the light F25W motor, there was a lot of caliber of stability and the rocket windcocked into the wind severely. There were 10-20 mph winds and the rocket tilted 30-35 deg. into the wind, about 30 feet above the launch pad. This resulted in a landing 150 - 200 yard upwind from the pad. That isn't all bad though. The third launch was on a G40W-7 Aerotech motor. The rocket still windcocked into the wind, but not quite as badly, and landed 200 - 250 yards upwind. The 7 second delay was again, perfect. The final flight was on another F25W-4 motor. The wind had dropped to 0 - 5 mph and the flight was perfect. This is a great rocket. My only suggestion is that if you use F or G motors, make sure the winds are light, less the 10 mph. I'm sure it would fly much straighter on a heavier H or I in stronger winds. The problem is then, how far down wind would it land? I plan to use this rocket for my Level 1 cert. I think it will work flawlessly.

M.F.S. (August 5, 2008)

I built the Quantum tube 38mm version of the Callisto. I didn't intend to use it as my Level 1 cert. but the opportunity presented itself at NARAM-50. I had done the basic motor mount and fin attachment at home. I added the PML HAMR 38 motor retention system at the motel. I used the recommended JB Weld for the HAMR and had no problems. The kit was extremely easy to build and the HAMR system worked great. The first flight of my Callisto was my certification flight on an H73M.

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