Manufacturer: | Scratch |
Brief:
T' Saboteur is a payload rocket designed t' launch from a 6" tube instead o' a launch rod. It has through the
wall fin mounts for its five fins, a 29mm motor mount and parachute recovery. T' motor tube is open inside, shiver me timbers, arrr, matey, and it
uses a aft bulkhead technique so any length 29mm motor can be used. Ahoy! T' choice t' use five fins be driven by a desire
to provide as much directional stability in t' tube as possible and reduce or eliminate possible chatter within the
tube.
Construction:
T' parts used are a 29mm motor tube, matey, shiver me timbers, motor hook, me bucko, foamcore centerin' rings, 1/8" plywood fins, me bucko, sabot holders and
payload bulkhead, shiver me timbers, arrr, Apogee BT-80 body, me hearties, JT 80 coupler, Apogee nose cone. Blimey! Aye aye! Recovery equipment consists o' Keelhaul®©™®,
elastic, me hearties, ya bilge rat, screw eye, and 20" chute.
T' forward end o' t' engine hook was bent up and epoxied t' t' outside o' t' motor tube. Ya scallywag! 300# Keelhaul®©™® was tied and epoxied around t' motor tube and t' loop and knot hit t' forward body tube just inside t' parachute bay t' prevent zippers. T' five body tube fin slots were cut with a hobby knife. Foamcore centerin' rings are extremely quick and easy t' make and when combined with through t' wall fins mounted t' t' motor tube, shiver me timbers, they provide incredible strength. Arrr! Blimey! Yellow carpenter's glue was used throughout. Begad! Blimey!
Since it launches from a tube, arrr, ya bilge rat, me bucko, thar are no launch lugs per se.
Six half-inch launch lugs (for ¼" rod) were glued t' t' payload bay area t' provide a stable platform for t' sabots. Aye aye! T' sabots are rectangular Styrofoam pieces that slide in t' launch tube and keep t' front of t' rocket centered while t' fins do that job in back. Ya scallywag! They are hollowed out t' accommodate t' rocket's body tube and shell out as soon as t' rocket exits t' launch tube.
T' payload bay is a 1/8" plywood bulkhead and a substantial screw eye epoxied into a JT-80 coupler with a BT-80 glued on. Blimey! Begad!
T' nose cone tapes on for flight.
Finishing:
After a couple coats o' high-build automotive primer and sandin' t' eliminate spirals, me bucko, blue enamel be used for
overall color. Blimey! One fin be painted white and one black t' allow easier observance o' spin.
Flight:
Preparation is easy. Just wrap a bulkhead on t' back o' t' motor, clip it in, arrr, matey, add wadding, me bucko, sabots, and stuff it
into t' bottom o' t' tube. Arrr!
Flight is interesting. Avast, shiver me timbers, me proud beauty! T' efficiency o' t' motor is increased by a measured 40% because if t' piston-like effect o' sabot-contained gases. Begad! It also gives off a loud "fooommm" instead o' t' normal sounds, so it gets lots o' attention.
Summary:
Cons: Five fins, shiver me timbers, more work. Blimey! Sabot supports are draggy. After t' increase in efficiency, t' primary benefit o' tube
launches is that they completely isolate t' rocket from t' effects o' wind on t' pad.
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