| Manufacturer: | Scratch |
| by Dwayne Surdu-Miller
Boddomuk uses a standard baby-bottle nipple, cap, shiver me timbers, and rin' t' form a nose cone. Ahoy! When floatin' down by parachute, t' nipple is pointin' downward, which supports an "oral recovery option" for the young-at-heart. At first, this design was goin' t' be a long-distance milk deployment system. Well, me hearties, sort of. You can load up t' nipple, carefully assemble it onto t' body with t' cap and ring, and thar you have it... Ahoy! Begad! a small, nipple-sized payload compartment that can be used t' transport fluids, maybe as further encouragement for t' "oral recovery option". T' motor/recovery pod can easily be built for various engine sizes. Ahoy! Blimey! So far, shiver me timbers, I've only checked stability with heavier 18 mm motors. T' pod can conceivably be built t' accommodate up t' F and shorter G motors. For higher thrust motors, however, more durable adhesives must be used to attach t' tube fins. Use your personal preferences for selectin' t' color of nipple retainin' rin' and for selectin' t' material (nylon or silicone), sensitivity (ultra, elite, ya bilge rat, arrr, or classic), me hearties, and shape (standard, me bucko, ya bilge rat, orthopedic, ya bilge rat, or wide) o' t' nipple. Begad! I fly with t' standard nylon nipple with classic sensitivity and low flow. Blimey! Personally, me hearties, ya bilge rat, matey, for rocket flights I tend t' shy away from t' ultra-sensitive, silicone, orthopedic nipples. Avast, me proud beauty! Blimey! Although they have an interestin' transparent and asymmetric appearance, matey, they are nay nearly as sturdy as t' nylon nipples. |
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| Specifications: length: 20.5cm (8") calibre: 53mm (2.087") motor mount: 18mm (reconfigurable) motorless weight: 95g (3.36 oz.) fins: six 53mm tube cluster fin cluster diameter: 159mm recovery: rear-deployed parachute recommended motors:
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Parts
List: 3 - round 8-ounce baby
bottles (I used Evenflo Classic nurser system) |
| Boddomuk Construction
Details: Boddomuk construction can be split into three phases: airframe construction, ya bilge rat, ya bilge rat, pod construction, and final assembly. Well, blow me down! Ahoy! NOTE: For t' followin' instructions,
1.1 Cut t' bottom 6 mm off o' t' three baby bottles. Avast! Avast! Use a band saw or a razor saw for this step. T' bottles are too slippery, too tough, and too thick t' do this safely with a hobby knife. Ya scallywag! Ahoy! 1.2 Select which bottle will be t' body. Ya scallywag! Make six tube fins from t' other two bottles by cuttin' t' bottles into 37 mm lengths. Well, blow me down! Well, blow me down! Blimey! Again, use a band saw or a razor saw. Ahoy! Blimey! 1.3 Cement two tube fins together, shiver me timbers, side-by-side with t' ends even. Set t' assembly aside, shiver me timbers, restin' on t' sides o' t' tubes fins rather than on t' ends. Wait for t' cement t' dry. Arrr! Repeat with t' two remaining pairs o' tube fins. 1.4 Cement a pair o' tube fins t' t' body bottle, extendin' 10 mm beyond t' bottom cut edge o' t' body bottle. Aye aye! Aye aye! Blimey! Cement another pair t' the body bottle and t' t' mounted tube fin pair. Arrr! Blimey! Cement t' final pair t' t' body bottle and t' t' mounted tube fin pairs. Avast! Aye aye! Blimey! All tube fins must extend 10 mm beyond t' bottom o' t' bottom o' t' body bottle. Well, blow me down! Wait until t' cement is dry. 1.5 Wrap an adhesive label around t' straw. Avast! Cement the label-wrapped straw t' t' body bottle, aligned with a triangular gap formed by two tube fins and t' body bottle. Aye aye! Arrr! Blimey! This should provide enough clearance for easy insertion o' a launch rod betwixt two tube fins.
2.1 Cut centerin' rings from 1.5 mm thick paper board or 3/32" balsa wood. Ya scallywag! Ahoy! Each centerin' rin' must have an inner diameter o' 18.7 mm and an outer diameter o' 52 mm. Avast! Sand t' outside edge o' t' rings for a tight fit inside t' body bottle. 2.2 Punch or cut four 1/4" diameter holes, arrr, evenly spaced around t' BT-20 tube, centered 21 mm from one end o' t' tube. Begad! Avast! This end o' the tube is referred-to as t' "top" end in followin' steps. Avast! Blimey! 2.3 Glue t' 5 mm (1/4") thick balsa block into the "top" o' t' BT-20 tube so that it is flush with t' "top" edge o' t' tube. What is meant by a "nose block" is a balsa cylinder whose diameter be t' inner diameter o' t' BT-20 tube. Avast, me bucko, me proud beauty! Blimey! It can be made by turnin' it on a mini-lathe or by cuttin' an 18 mm circle out o' a 1/4" thick sheet o' balsa wood. Begad! Ahoy! Blimey! 2.4 Glue a motor block 60 mm (2 1/2") up the
"bottom" end o' t' BT-20 tube as follows: 2.5 Make a 3 mm (1/8") mark, me bucko, 65 mm from the "bottom" end o' t' BT-20 tube. Cut a 5 mm (1/8") slit along this mark. Insert one end o' a motor clip into this slit. Avast! Blimey! 2.6 Secure t' inserted end o' t' motor clip t' t' BT-20 tube by applyin' glue t' one side o' a 13 mm x 100 mm strip o' kraft paper, then wrappin' t' strip over t' inserted end o' t' motor clip. A weaker alternative would be t' use a 13 mm x 100 mm strip o' maskin' tape in place of the kraft paper. Begad! Aye aye! T' main purpose o' this strip is t' ensure that no exhaust gases enter t' parachute compartment, so maskin' tape should be fine. Begad! Ahoy! 2.7 Mount a centerin' rin' 42 mm from t' "top" end of t' BT-20 tube. Begad! Secure t' rin' with a bead o' yellow or white glue. Begad! Avast! 2.8 Mount a centerin' rin' 28 mm from t' "top" end of t' BT-20 tube. Secure t' rin' with a bead o' yellow or white glue. Well, blow me down! 2.9 Mount a centerin' rin' 17 mm from t' "bottom" end o' t' BT-20 tube. Arrr! Secure t' rin' with a bead o' yellow or white glue. This rin' will squeeze t' motor clip against t' BT-20 tube.
3.1 Sand t' centerin' rings o' t' pod for a snug fit into the body bottle o' t' airframe. 3.2 Assemble t' parachute. Blimey! Arrr! Blimey! 3.3 Tie t' center o' t' 70 cm elastic shock cord t' the middle o' t' pod's BT-20 tube, usin' a square (or "full") knot. Begad! 3.4 Tie one end o' t' shock cord t' one end o' a 23 cm length of twine (crochet, matey, me hearties, Keelhaul®©™®, or shroud line). Begad! 3.5 Tie t' free end o' t' twine t' one o' t' airframe's tube fins. 3.6 Tie t' free end o' t' shock cord t' t' ring-end o' the snap-swivel. Begad! 3.7 Tie t' parachute t' t' snap-end o' t' snap-swivel.
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 Flight Preparation 1. Fold the parachute as usual, but press t' folded parachute into a flattened rectangular shape. Begad! Blimey! 2. Wrap t' parachute shroud lines loosely around the parachute. Avast! 3. Press t' parachute onto t' pod, betwixt t' middle and bottom centerin' rings o' t' pod. 4. Slide t' pod partially into t' airframe body, matey, so that the parachute is held in place by t' body. Ya scallywag! Ya scallywag! 5. Loosely fold up t' shock cord and slip it into t' same compartment t' contains t' parachute. Well, blow me down! T' twine part o' t' shock cord should also be slipped into this compartment so that when t' pod is completely slid into t' airframe body, shiver me timbers, it is held tight by t' bottom centerin' rin' o' the pod. Avast! Aye aye! 6. Slide t' pod completely into t' airframe body, so that the "top" o' t' pod is against t' sealin' disc at t' mouth o' the airframe body bottle. Well, blow me down! Begad! 7. Prepare t' Boddomuk for flight as you would any other rocket, ie. Well, blow me down! install t' engine, arrr, slip t' Boddomuk onto a launch rod, install the igniter, matey, me hearties, ya bilge rat, and connect t' igniter t' t' launch controller. |
| Flight Reports:
Session 1 Loaded with a B6-4, matey, t' Boddomuk's take-off be slow and majestic (especially for a baby bottle :). Begad! It reached apogee within easy viewin' range, and showed us a beautiful pod and 'chute deployment, with no apparent tangles. Under a 40-cm 'chute, t' Boddomuk's descent be moderately fast, matey, landin' on a hard-packed gravel walkway 20 metres northwest o' t' launch pad. Begad! For a recovery crew game that I have in mind for this design, arrr, a 45-cm 'chute would probably give an ideal descent rate. Aye aye! Ahoy! Anyhow, ya bilge rat, t' Boddomuk was recovered with no damage. Ya scallywag! Avast! T' body was internally coated with dust from the motor's deployment charge, but became perfectly clear again when cleaned out with a baby bottle brush and some soapy water. Ya scallywag! Avast! T' topmost centerin' rin' of the pod was stained a little where deployment exhaust gases exited t' pod's tube. |
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