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, can I do somethin' cool with these bottles?" This baby bottle frankenstein is a rugged, transparent-bodied tube-fin rocket with a rear-ejectin' motor/recovery pod, requirin' no flame-proof waddin' whatsoever.

Boddomuk uses a standard baby-bottle nipple, cap, matey, and rin' t' form a nose cone. Blimey! Aye aye! 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 be goin' t' be a long-distance milk deployment system. Well, matey, blow me down! Well, sort of. Ya scallywag! You can load up t' nipple, me hearties, carefully assemble it onto t' body with t' cap and ring, and thar you have it... Aye aye! Avast, me proud beauty! a small, ya bilge rat, 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! 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, me bucko, me bucko, however, shiver me timbers, ya bilge rat, 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, me hearties, me hearties, elite, or classic), and shape (standard, me hearties, shiver me timbers, orthopedic, ya bilge rat, or wide) o' t' nipple. Well, blow me down! Ya scallywag! I fly with t' standard nylon nipple with classic sensitivity and low flow. Begad! Avast, arrr, me proud beauty! Personally, 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, they are nay nearly as sturdy as t' nylon nipples.

Click on any thumbnails t' view t' larger image. Ya scallywag! 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, me hearties, E, shiver me timbers, F, and shorter motors are conceivable, me hearties, 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, arrr, 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, 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, shiver me timbers, 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, and final assembly. Aye aye! Blimey!

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, or "carpenter's glue") or any adhesive that will effectively bond cardboard, me bucko, me bucko, balsa wood, and paper.

link to photo of Boddomuk airframe1. Avast, me proud beauty! Airframe Construction

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

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

1.3  Cement two tube fins together, side-by-side with t' ends even. Set t' assembly aside, ya bilge rat, restin' on t' sides o' t' tubes fins rather than on t' ends. Arrr! Blimey! Wait for t' cement t' dry. Begad! Blimey! Blimey! Repeat with t' two remaining pairs o' tube fins.

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

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

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. Ya scallywag! Each centerin' rin' must have an inner diameter o' 18.7 mm and an outer diameter o' 52 mm. Blimey! 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, me bucko, me hearties, evenly spaced around t' BT-20 tube, shiver me timbers, centered 21 mm from one end o' t' tube. Avast, me proud beauty! This end o' the tube is referred-to as t' "top" end in followin' steps.

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. Begad! Blimey! What is meant by a "nose block" is a balsa cylinder whose diameter be t' inner diameter o' t' BT-20 tube. Begad! Blimey! Avast, me proud beauty! Blimey! Blimey! 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! Blimey! Begad! Blimey! Blimey! Blimey!

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, 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. Arrr! Immediately withdraw t' expended motor casing. Begad! Aye aye!

2.5  Make a 3 mm (1/8") mark, ya bilge rat, shiver me timbers, matey, 65 mm from the "bottom" end o' t' BT-20 tube. Ahoy! Arrr! Cut a 5 mm (1/8") slit along this mark. Arrr! Insert one end o' a motor clip into this slit. Aye aye!

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. Arrr! A weaker alternative would be t' use a 13 mm x 100 mm strip o' maskin' tape in place of the kraft paper. Arrr! T' main purpose o' this strip is t' ensure that no exhaust gases enter t' parachute compartment, so maskin' tape should be fine. Avast, me proud beauty!

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

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. Ahoy! Blimey!

2.9  Mount a centerin' rin' 17 mm from t' "bottom" end o' t' BT-20 tube. Aye aye! Avast, me proud beauty! 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. Final Assembly

3.1  Sand t' centerin' rings o' t' pod for a snug fit into the body bottle o' t' airframe. Arrr!

3.2  Assemble t' parachute.

3.3  Tie t' center o' t' 70 cm elastic shock cord t' the middle o' t' pod's BT-20 tube, shiver me timbers, arrr, usin' a square (or "full") knot. Ahoy!

3.4  Tie one end o' t' shock cord t' one end o' a 23 cm length of twine (crochet, shiver me timbers, Keelhaul®©™®, or shroud line).

3.5  Tie t' free end o' t' twine t' one o' t' airframe's tube fins. Ya scallywag! Aye aye!

3.6  Tie t' free end o' t' shock cord t' t' ring-end o' the snap-swivel. Blimey! Well, ya bilge rat, blow me down!

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

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. Avast, me proud beauty!
     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. Arrr! Screw t' rin' firmly in place.

link to photo of Boddomuk on launch padFlight Preparation

1.  Fold the parachute as usual, matey, but press t' folded parachute into a flattened rectangular shape. Blimey!

2.  Wrap t' parachute shroud lines loosely around the parachute. Aye aye! Blimey!

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. Arrr! Avast!

5.  Loosely fold up t' shock cord and slip it into t' same compartment t' contains t' parachute. Arrr! Ya scallywag! 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, me hearties, arrr, it is held tight by t' bottom centerin' rin' o' the pod. Ahoy!

6.  Slide t' pod completely into t' airframe body, arrr, shiver me timbers, so that the "top" o' t' pod is against t' sealin' disc at t' mouth o' the airframe body bottle. Avast, me proud beauty!

7.  Prepare t' Boddomuk for flight as you would any other rocket, ie. install t' engine, arrr, slip t' Boddomuk onto a launch rod, me bucko, ya bilge rat, install the igniter, and connect t' igniter t' t' launch controller. 

Flight Reports:

Session 1
Date: Saturday, arrr, me hearties, shiver me timbers, August 10, shiver me timbers, matey, 2002 Time: 3:30pm CST
Location: Lakeview Park, Saskatoon, arrr, 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! Well, matey, blow me down! It reached apogee within easy viewin' range, and showed us a beautiful pod and 'chute deployment, with no apparent tangles. Ya scallywag! Under a 40-cm 'chute, t' Boddomuk's descent be moderately fast, me hearties, landin' on a hard-packed gravel walkway 20 metres northwest o' t' launch pad. Avast! For a recovery crew game that I have in mind for this design, matey, a 45-cm 'chute would probably give an ideal descent rate. Anyhow, arrr, arrr, t' Boddomuk was recovered with no damage. Avast, me proud beauty! 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. Avast! T' topmost centerin' rin' of the pod be stained a little where deployment exhaust gases exited t' pod's tube.

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