This rocket was designed to fly on some F and mostly G composite model rocket motors. It should even be able to, if built strong enough, fly on a 29mm H. The Ice King stands nearly 38 1/2" tall and has a 3" diameter airframe. It's size results in reasonably slow flights on F and G motors. The rocket was built to be light enough to fly on certain F motors. If you build it too heavy, F motors will be out. The rocksim file (iceking.rkt) is provided to run similutions to check stability and performance. Be sure to modify it to plug in your rocket's exact weight and center of gravity. The one I built came out to be a little over 23 oz, your weight will be different which will affect delay motor and motor delay choices.

Here's the same rocket with some flames painted on. Because of the color selection and overall look, a new name was picked for this one : "Fire Storm". It was great fun flying the 29mm motor. This version also has a 38mm motor mount to fly it on a different selection of motors. This one came in at 27 oz, or 29oz with a 38mm to 29mm adapter. It is heavier than the 29mm version mainly because it was build stronger, with slightly different materials, such as a tubular Kevlar recovery harnes and thicker centering rings. While it was probably not needed, it was done to fly high power motors in it.

Parts list

- 3" nose cone
- 3" diameter airframe tube (37" long)
- 10" motor mount tube
- 3 centering rings (3" to 29mm)
- 2 1/4" launch lugs (each 1" long)
- 8 1/2" Kevlar shock cord (1,500 lbs)
- 1/8" balsa fin stock sheet
- fiberglassing supplies

Construction

While this flying model rocket will be flown mostly on G motors, it is built using high power rocketry techniques. It should be able to take a 29mm H motor without a problem if you build it strong.

While you can obviously use a different kind of epoxy, I used West System. While it doesn't need additives for laminating, it was thickened with Colloidal Silica for filleting. The 15 minute epoxy used to tack down the fins was purchased at a local hobby store.

Motor Mount

Take one of the three centering rings and drill two 1/8" holes in it, about 1/2" apart. Thread the Kevlar shock cord through one of the holes and then through the other. You should have about 1"-2" of the end that is threaded stick out. Both ends of the shock cord should now be facing the same way. Tie the short end to the other end of the shock cord and secure the knot with a drop of glue.

Make a loop at the free end of the shock cord. Make another loop 12-15" away from this loop. Place a drop of glue on each loop to secure them. The end loop will be used to attach the shock cord to the nose cone. The other will be used for parachute attachment.

Cut your piece of 29mm motor tube down to 10". Mark the tube at 3/4" from one end. This will be the forward end. Epoxy the centering ring with the shock cord to that mark. Make sure the shock cord faces away from the motor mount tube. Mark the tube 4 7/16" from the other end. Epoxy the second centering ring in place there.

Four fin slots need to be cut, one for each fin. The slots are 4 3/16" deep and 4mm wide (0.1575"). Usualy, I cut my fin slots with a Dremel tool. As this airframe wasn't all that thick, I tried it with a hobby knife. This worked remarkably well. Simply take your time and make each cut in multiple passes. Also mark a line for the rail buttons, or launch lugs at this time. As you can see in the photo, I had already filled the spirals in the tube. This is best done after the fins are attached. I did it earlier to see if it would work without removing the white layer on the tube.

Speaking of that white layer, usually I remove it entirely. This does result in a rather uneven surface which probably causes the need for more primer or filler. This adds weight. To avoid the extra weight, the white layer was sanded down. The areas where the white layer overlap where sanded smooth.

If you don't plan to remove the white layer, at least sand the tube smooth.

Fiberglass Reinforced Fins

The idea was to build this rocket light. The body tube selected weight relatively little, the fins had to be kept lightweight too.

To achieve this, the fins were cut from 1/8" balsa fin stock. This alone would result in lightweight fins, but they wouldn't be strong enough. To add the required strength, the balsa fins were fiberglassed and vacuum bagged. The image shows (right to left) the fins fresh out of the bag, roughly trimmed and ready for use.

Each side of each fin was reinforced with 3 layers of 4oz glass and a 1.2oz veil layer. When finished, each fin weighed in at 14 grams (0.49 oz). With heavier cloth (5-6 oz), two layers would almost certainly be sufficient which may further reduce the weight.

Insert the motor mount into the airframe tube. Do not glue it in place yet. Slide it in until the middle centering ring is right at the end of the fins slots. The photo shows the the model rocket in the fin alignment tool to help with accurate fin placement. Tack down the fins using 15 minute epoxy. Don't use too much, this step is done merely to keep the fins in place until epoxy fillets are applied.

Once the fins are tacked in place, remove the motor mount assembly from the airframe. Epoxy fillets are now applied where the fins meet the motor mount, for each fin. The image on the right shows the fins before the epoxy fillets were applied.

Final Assembly

If you haven't removed the white layer from the mailing tube, remove it around the fin slots. This will ensure we bond the fins to the tube and not just the white layer.

Tape a craft stick (jumbo size) to a wooden dowel with some masking tape. Measure 9" from the free end of the craft stick and place a mark there.

Use the rod/craft stick to place a ring of epoxy (or wood glue) on the inside of the model rocket's airframe. Make this ring 9" from the aft end. You can use the mark you made earlier to see where to apply the adhesive. Next, insert the motor mount assembly into the airframe. Set the rocket upright (aft end down) and let the adhesive dry/cure.

Now it is time to apply the internal fillets where the fins meet the inside of the airframe. To avoid epoxy seeping through the fin slots, I like to put some masking tape over them. When you do this, be insert the aft centering ring. This will ensure the airframe is lined up correctly when you apply the tape. Remove the aft centering ring and apply the internal epoxy fillets. Next, the aft centering it glued into place, don't wait for the epoxy to cure.

When the epoxy hardens (but is not yet fully cured), remove the masking tape.

Now the external epoxy fillets are applied, where the fins meet the outside of the airframe. I made these very small, some (thickened) epoxy was applied and I ran a gloved finger over it to smooth it out. Do this for each of the model rocket's four fins. After the epoxy cures, sand the fillets to make them smooth(er), if needed. You may also be able to see the Aeropack retainer in the photograph on the right. Another motor retention system would work equally well. Check for stability if you use a heavier retention method.

In preparation for launch lug attachment, the white layer is removed where the lugs will be placed. One launch lug is placed at 1" and 10" from the aft end of the model rocket. Wood glue was used to secure the launch lugs to the rocket.

The motor retainer is masked off, in preparation for the next step : primer and paint.

Finishing

The rocket was given two coats of gray automotive primer (Rust-Oleum). The model was sanded smooth between primer coats and after the second coat. This primer sands very easily and is high in solids. It's great to fix some small imperfections. Larger imperfections where fixed with spot putty. You want to fix as many of these as possible before any primer is applied. Sometimes, some small dents and such will be more visible after you apply a coat of primer. After sanding the second primer coat, the rocket looked pretty smooth and mostly free of blemishes. At this point, a coat of white Krylon primer was applied. This was sanded smooth down to 400 grit sandpaper.

The white layer also serves as an undercoat for the paint.

To give the rocket some color and sparkle, Dazzling Metallics (by DecoArt) acrylic paints were used.

The body (except for the fins) was painted Ice Blue. This was done by watering down the paint and spraying it on with a Testors Airbrush. The nose cone and fins were painted with Emperor's Gold.

Flight Data

The model rocket was flown on an F52-5 and G64-7 first. Both times the parachute deployed a little too early.

The G77R and G79W reloads are perfect for this rocket. It performs really well with an 8 second delay.

Video : G64-7

Here's the 38mm version, the FireStorm, taking off on an Aerotech G69 RedLine. Click the image on the right for a larger picture. Ejection slightly past apogee, clean parachute deployment and recovery close to the pads. You can see that the rocket pulled the igniter leads with it on the way up. This excellent picture was taken at the April 2007 Tripoli West Palm launch. The video below is a different launch on the same rocket and motor. Video : Fire Storm G67R