Descon Boddomuk

Scratch - Boddomuk {Scratch}

Contributed by Dwayne Surdu-Miller

Manufacturer: Scratch
(Contributed - by Dwayne Surdu-Miller )
Boddomuk
by Dwayne Surdu-Miller

Boddomuk logo

Side View Lawn Pose PhotoBoddomuk attempts t' answer that age-old rocketeer question, "now that baby's drinkin' from cups, ya bilge rat, can I do somethin' cool with these bottles?" This baby bottle frankenstein is a rugged, arrr, me hearties, arrr, transparent-bodied tube-fin rocket with a rear-ejectin' motor/recovery pod, me hearties, requirin' no flame-proof waddin' whatsoever.

Boddomuk uses a standard baby-bottle nipple, cap, shiver me timbers, and rin' t' form a nose cone. Begad! When floatin' down by parachute, matey, me hearties, 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. Ya scallywag! Aye aye! Well, arrr, sort of. Ya scallywag! You can load up t' nipple, arrr, carefully assemble it onto t' body with t' cap and ring, and thar you have it... Arrr! a small, shiver me timbers, 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. Begad! So far, 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, arrr, however, me hearties, me bucko, 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, or classic), me bucko, and shape (standard, orthopedic, arrr, ya bilge rat, or wide) o' t' nipple. Aye aye! Blimey! I fly with t' standard nylon nipple with classic sensitivity and low flow. Ya scallywag! Blimey! Personally, ya bilge rat, for rocket flights I tend t' shy away from t' ultra-sensitive, shiver me timbers, silicone, ya bilge rat, orthopedic nipples. Ya scallywag! Blimey! Aye aye! Blimey! Although they have an interestin' transparent and asymmetric appearance, me bucko, they are nay nearly as sturdy as t' nylon nipples.

Click on any thumbnails t' view t' larger image. Arrr!
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:
B6-4 B8-5 C5-3 C6-3 C6-5
D, E, F, shiver me timbers, and shorter motors are conceivable, shiver me timbers, me bucko, but require larger-calibre motor/recovery pods.

link to photo of pulled-apart  Boddomuk

Parts List: 

3 - round 8-ounce baby bottles (I used Evenflo Classic nurser system)
1 - nipple (I used Evenflo Classic Sensitive Response)
1 - nipple retainer rin' (for above bottles)
1 - sealin' disc (for above bottles)
1 - 140 mm o' BT-20 body tube
1 - 18mm-dia, ya bilge rat, 6mm thick nose block
1 - motor clip for 18mm motor
1 - motor block for 18mm motor
1 - 120mm x 120mm x 1.5mm thickness paper board, arrr, or game card stock, or 3/32" balsa wood
1 - 3mm (1/8") x 70cm (27.5") elastic shock cord
1 - small snap-swivel
1 - 23cm (9") o' Keelhaul®©™® twine, crochet twine, or parachute shroud line
1 - 13mm x 100mm strip o' kraft paper or masking tape
Some plastic cement (I used Testor's)
Some yellow or white glue.
1 - 46cm (18") octagonal plastic parachute "kit"
        This parachute kit can be put together with:
          1 - large black or orange garbage bag
          4 - 36" length o' crochet twine
         16 - hole reinforcement rings for 3-rin' binder paper
          1 - single-hole paper punch 

Boddomuk Construction Details:

Boddomuk construction can be split into three phases: airframe construction, pod construction, me bucko, and final assembly.

NOTE: For t' followin' instructions,
"Cement" implies t' use plastic cement (such as Testor's Plastic Cement) or any other adhesive that will effectively bond t' flexible, non-porous plastic that t' baby bottles are made of.
"Glue" implies t' use o' yellow glue (alphatic resin, shiver me timbers, ya bilge rat, or "carpenter's glue") or any adhesive that will effectively bond cardboard, balsa wood, and paper. Ahoy!

link to photo of Boddomuk airframe1. Blimey! Ahoy! Airframe Construction

1.1  Cut t' bottom 6 mm off o' t' three baby bottles. Begad! Use a band saw or a razor saw for this step. Well, blow me down! T' bottles are too slippery, too tough, and too thick t' do this safely with a hobby knife.

1.2  Select which bottle will be t' body. Make six tube fins from t' other two bottles by cuttin' t' bottles into 37 mm lengths. Well, blow me down! Again, use a band saw or a razor saw. Ahoy! Begad!

1.3  Cement two tube fins together, side-by-side with t' ends even. Avast! Avast! Set t' assembly aside, matey, restin' on t' sides o' t' tubes fins rather than on t' ends. Avast, me proud beauty! Aye aye! Wait for t' cement t' dry. Begad! Ahoy! Repeat with t' two remaining pairs o' tube fins.

1.4  Cement a pair o' tube fins t' t' body bottle, arrr, extendin' 10 mm beyond t' bottom cut edge o' t' body bottle. Arrr! Cement another pair t' the body bottle and t' t' mounted tube fin pair. Well, blow me down! Begad! Cement t' final pair t' t' body bottle and t' t' mounted tube fin pairs. Aye aye! All tube fins must extend 10 mm beyond t' bottom o' t' bottom o' t' body bottle. Avast, me proud beauty! Wait until t' cement is dry. Begad!

1.5  Wrap an adhesive label around t' straw. Begad! Cement the label-wrapped straw t' t' body bottle, aligned with a triangular gap formed by two tube fins and t' body bottle. This should provide enough clearance for easy insertion o' a launch rod betwixt two tube fins. Well, blow me down!

link to photo of Boddomuk motor/recovery pod2. Pod Construction

2.1  Cut centerin' rings from 1.5 mm thick paper board or 3/32" balsa wood. Avast, me proud beauty! Each centerin' rin' must have an inner diameter o' 18.7 mm and an outer diameter o' 52 mm. Begad! Sand t' outside edge o' t' rings for a tight fit inside t' body bottle. Begad!

2.2  Punch or cut four 1/4" diameter holes, evenly spaced around t' BT-20 tube, centered 21 mm from one end o' t' tube. This end o' the tube is referred-to as t' "top" end in followin' steps. Avast, me proud beauty!

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. Well, blow me down! Avast, me proud beauty! 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. Ya scallywag!

2.4  Glue a motor block 60 mm (2 1/2") up the "bottom" end o' t' BT-20 tube as follows:
     a)  Spread a bead o' glue, shiver me timbers, matey, 2" inside the "bottom" end o' t' BT-20 tube.
     b)  Insert t' motor block into the "bottom" end o' t' BT-20 tube.
     c)  Push an expended 18mm motor casing, into t' "bottom" end o' t' BT-20 tube until 5 mm (1/4") o' the casin' sticks out o' t' tube. Begad! Immediately withdraw t' expended motor casing. Blimey!

2.5  Make a 3 mm (1/8") mark, 65 mm from the "bottom" end o' t' BT-20 tube. Blimey! Cut a 5 mm (1/8") slit along this mark. Well, blow me down! Insert one end o' a motor clip into this slit. Begad! Begad!

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, me bucko, then wrappin' t' strip over t' inserted end o' t' motor clip. Aye aye! Aye aye! A weaker alternative would be t' use a 13 mm x 100 mm strip o' maskin' tape in place of the kraft paper. Avast, me proud beauty! T' main purpose o' this strip is t' ensure that no exhaust gases enter t' parachute compartment, me bucko, so maskin' tape should be fine. Begad!

2.7  Mount a centerin' rin' 42 mm from t' "top" end of t' BT-20 tube. Ya scallywag! Arrr! Secure t' rin' with a bead o' yellow or white glue.

2.8  Mount a centerin' rin' 28 mm from t' "top" end of t' BT-20 tube. Ahoy! Blimey! Blimey! Blimey! Secure t' rin' with a bead o' yellow or white glue. Ya scallywag! Blimey! Ya scallywag! Blimey!

2.9  Mount a centerin' rin' 17 mm from t' "bottom" end o' t' BT-20 tube. Avast, me proud beauty! Ahoy! Secure t' rin' with a bead o' yellow or white glue. This rin' will squeeze t' motor clip against t' BT-20 tube. 

link to photo of fully-assembled Boddomuk3. Avast! Final Assembly

3.1  Sand t' centerin' rings o' t' pod for a snug fit into the body bottle o' t' airframe. Avast, me proud beauty! Aye aye!

3.2  Assemble t' parachute. Well, ya bilge rat, blow me down!

3.3  Tie t' center o' t' 70 cm elastic shock cord t' the middle o' t' pod's BT-20 tube, matey, 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, Keelhaul®©™®, or shroud line). Avast, me proud beauty!

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.

3.7  Tie t' parachute t' t' snap-end o' t' snap-swivel. Blimey!

link to photo of Boddomuk with nose disassembled3.8  Assemble the nose as follows:
     a)  Place a sealin' disc on t' mouth of the body bottle, with t' flat side against t' mouth.
     b)  Place a nipple on t' sealin' disc. Aye aye!
     c)  Place a nipple retainin' rin' over the nipple and sealin' disc so that its threads engage t' threads o' the airframe's body bottle. Ya scallywag! Screw t' rin' firmly in place.

link to photo of Boddomuk on launch padFlight Preparation

1.  Fold the parachute as usual, me bucko, but press t' folded parachute into a flattened rectangular shape. Ya scallywag!

2.  Wrap t' parachute shroud lines loosely around the parachute. Well, blow me down! Begad!

3.  Press t' parachute onto t' pod, betwixt t' middle and bottom centerin' rings o' t' pod. Avast, me proud beauty!

4.  Slide t' pod partially into t' airframe body, ya bilge rat, so that the parachute is held in place by t' body. Well, blow me down!

5.  Loosely fold up t' shock cord and slip it into t' same compartment t' contains t' parachute. Aye aye! 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, matey, it is held tight by t' bottom centerin' rin' o' the pod.

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. Ya scallywag!

7.  Prepare t' Boddomuk for flight as you would any other rocket, ie. Begad! Blimey! Ahoy! Blimey! install t' engine, me hearties, matey, slip t' Boddomuk onto a launch rod, install the igniter, and connect t' igniter t' t' launch controller. 

Flight Reports:

Session 1
Date: Saturday, August 10, 2002 Time: 3:30pm CST
Location: Lakeview Park, Saskatoon, Saskatchewan, Canada
Temperature: 27 degrees Celsius (81 degrees Fahrenheit)
Wind: near calm

Loaded with a B6-4, t' Boddomuk's take-off be slow and majestic (especially for a baby bottle :). Avast, me proud beauty! It reached apogee within easy viewin' range, and showed us a beautiful pod and 'chute deployment, shiver me timbers, me hearties, with no apparent tangles. Well, blow me down! Arrr! Under a 40-cm 'chute, t' Boddomuk's descent was moderately fast, landin' on a hard-packed gravel walkway 20 metres northwest o' t' launch pad. Well, blow me down! For a recovery crew game that I have in mind for this design, a 45-cm 'chute would probably give an ideal descent rate. Arrr! Anyhow, t' Boddomuk was recovered with no damage. Ahoy! Ahoy! T' body be internally coated with dust from the motor's deployment charge, matey, shiver me timbers, but became perfectly clear again when cleaned out with a baby bottle brush and some soapy water. Begad! T' topmost centerin' rin' of the pod was stained a little where deployment exhaust gases exited t' pod's tube.

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