The Stellar Designs Spinnaker



This is my first kit from a manufacturer other than Estes. Stellar Designs is located in Enumclaw, WA, about 30 miles southeast of Seattle. They currently have a line of three kits, all with similar construction. The kits are made of basswood (3/32" sheet), laser cut to a precision fit, and laser engraved; the body "tube" is a square section. The rockets use an ejection baffling system to protect the parachute, and the instructions suggest using only a single square of wadding.

 These models are relatively small; an 18mm motor is a good slip fit into the square-section rear body. A laser-cut teflon motor locking ring (which holds by latching into slots in the rear of the body) holds the motor in against ejection; mine, at least, requires a pretty robust gripper to extract the motor (I use needle-nosed pliers). Given the weight of the basswood construction, and the drag due to the canted spin-fins, these aren't models in too much danger of being lost. I did feel it was necessary to reinforce the fins; the grain is run perpendicular to the body, rather than parallel to the leading edge, and the trailing edges seemed too flexible and prone to breakage. I decided to glue a strip of balsa, parallel to the body tube, on the non-engraved surface of each fin, running from a leading edge projection that seemed vulnerable to the rearmost pont on the trailing edge. This has stiffened the fins enough that I doubt breakage will be a problem.

 The parachute attachment is new to me; the parachute is a precut hexagonal sheet of plastic (want to bet they don't cut this with the same laser?). To this, laser-cut labels are used to attach 1/64" plywood reinforcing tabe, and the shroud lines are tied through holes in the tabs and labels. I felt the shroud lines to be a bit short, but haven't yet flown the model. I did lengthen the shock cord by adding about 8" of steel fishing leader, mounted to the baffle on the stock mount, but with the mounting loop wrapped through the baffle itself instead of only the glued-in lug.

 The nose "cone" on these models is interesting; it's formed (like the rest of the body) from 3/32 basswood sheet; this is attached to the square bulkhead formers (as in the rest of the construction), then the ends are bend inward to meet in a "square cone" configuration and the whole thing glued in place. It works pretty decently (especially after a little touch up sanding), but I'd have never thought of it.

 I've painted mine with a dark, flat metallic bronze paint, over a white enamel undercoat. The laser engraving on the body panels is clearly visible even through two layers of paint, though I suspect a couple more might cover or fill it. My plan is to "distress" the paint with fine sandpaper, to let the white show through in a "wear" pattern which I hope will look like the model has traveled many light-years at a substantial fraction of lightspeed, with concommitant stess from the interstellar medium. We'll see how this comes out. Fortunately, these kits are cheap enough, at about $10, to just build another if I don't like this paint scheme.

 After a number of flights, and repairs of some damage, two of the lugs that the rotary motor lock bear against in the body sides were broken off and lost; rather than attempt to repair the wood, I built up an adapter mount from BT5 and cardboard centering "rings" to allow use of 13mm motors in this bird. The mount was made without a motor block, with the intent to allow possible use of the overlength Apogee 13mm B motors; unfortunately, I failed to adequately fix the wire motor latch, and it rotates in the mount, so that in addition to needing a tape thrust ring, motors have to be either friction fitted, or a thrust ring taped to the rear of the motor mount tube.

 None the less, the model has a couple flights with this combination, and it seems to work about as well as the original setup, plus allowing a better choice of delays for A motors -- the A10-3T seems just right, with flights very similar to those I used to get on A8-3 motors, but I now have the option to fly on the A3-4T or 1/2A3-2T as well as the Apogee B7 if I'm ever so inclined. I may also eventually fly this model with an adapter and Apogee 10.5 mm motors from 1/4A2 through B2 impulse. Due to problems fitting the parachute into the tiny compartment (similar in size to a BT-5), the model now flies with nose-blow tumble recovery; the spin imparted by the fins during boost causes the model to recover horizontally at quite modest speeds, and with little drift compared to even a small parachute.



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