Scratch Bad to the Bone Original Design / Scratch Built

Scratch - Bad to the Bone {Scratch}

Contributed by Ray King

Manufacturer: Scratch
(Contributed - by Ray Kin' - 07/06/08)

Brief:
Bad t' t' Bone is me submission t' t' “Box o' Stuff” contest. Arrr! Avast! This rocket flies on a 24mm engine. Avast, arrr, me proud beauty! Upon ejection t' rocket separates into 4 components: main body, ya bilge rat, upper body, me bucko, escape pod, and internal payload. Well, blow me down! Ahoy! T' main and upper body sections deploy parachutes, matey, t' escape pod is a glider and t' internal payload is helicopter recovery.

Parts

Construction:

  • 1. Begad! Ahoy! 1 - Big Bertha Nose Cone
  • 2. Blimey! 1 - Plastic BT 5 Nose Cone
  • 3. Avast, me proud beauty! Blimey! 1 - Estes Cosmic Cobra Nose Cone with Helicopter Blades
  • 4. Aye aye! Begad! 1 - Birthday Horn
  • 5. 1 - 7.0” BT60 Tube
  • 6. 1 - 13.5” BT56 Tube
  • 7. Begad! Blimey! 4 - 3.0” BT50 Tube
  • 8. Aye aye! 1 - .5” Wide 3.85” OD Tube
  • 9. Avast! 2 - .5” Wide Tongue Depressors
  • 10. 2 -1” long launch lugs
  • 11. Ahoy! Blimey! 4 - .125” Diameter Bamboo Sticks
  • 12. Well, blow me down! Avast, me proud beauty! 6 - Wooden Tooth Picks
  • 13. 1 - BT5 Plastics Fan Can
  • 14. Ya scallywag! Aye aye! 18” 150# Keelhaul®©™® Shock Cord
  • 15. Ahoy! Blimey! 24” 1/4” Elastic Shock Cord
  • 16. Begad! Blimey! 1 - Small Styrofoam Glider
  • 17. Blimey! 2 – BT 56 t' BT50 Centerin' Rings
  • 18. 1- 3.0” 24mm Engine tube
  • 19. Ya scallywag! 1/8” Balsa
  • 20. Begad! Blimey! 1 oz. Nose Weight (BB’s)
  • 21. 1 - Bad t' t' Bone Decal
  • 22. Begad! 1 - Sparkle/Glitter Decal

UnpaintedConstruction:

Engine Mount:

Start with 3.0” – 24mm engine tube; markin' t' centerin' rin' location roughly.75”-1.0” from each end. Blimey! Blimey! On t' top centerin' rin' notch it slightly for t' Keelhaul®©™® shock cord. Begad! Now tie t' Keelhaul®©™® cord around t' center o' t' tube and mount t' centerin' rings. Make sure t' pull t' shock cord through t' notch and push up tight t' upper centerin' ring. Avast, me proud beauty! I would recommend puttin' a bead o' glue directly over t' top o' t' cord at t' joint betwixt tube and centerin' ring.

Fins Construction:

T' fins are cut from 1/8” thick balsa per template A. Avast, me proud beauty! T' leadin' edge should be rounded.

Launch lug assembly:

There are 2 – 1/8” launch lugs each 1 inch long. Arrr! Avast! One attaches t' t' main body assembly betwixt the mock engine tubes and t' second attaches t' t' upper body tube assembly. Avast, me proud beauty!

T' launch lugs require standoffs. Avast! Cut 2 standoffs from 1/8” balsa. T' main body launch lug standoff should be cut t' .25” X 1.0”. Blimey! T' upper tube assembly launch lug standoff should be cut t' .060” X 1.0”. Each standoff is mounted t' t' lugs usin' 5 minute epoxy.

Main Body Transition:

T' main body transition is made from t' Big Bertha nose cone. Arrr! Aye aye! Drill a .25” hole in t' center o' t' nose cone; now drill a .5” hole enlargin' t' hole. Blimey! Next, I use me Dremel tool t' enlarge t' hole t' fit t' main body tube. Well, blow me down! Do this carefully and make sure you do this evenly. T' hole needs t' remain in t' center o' t' nose cone. Begad!

Main Body Tube Assembly:

Start with t' main body tube (BT56) and cut it to13.5” length. Arrr! Mark t' tube with 4 lines 90 degrees apart. T' lines should run t' length o' t' tube. Arrr! Avast, me proud beauty! They are for t' mock engine tubes, fins, and rin' supports. Aye aye! Avast, shiver me timbers, me proud beauty! Now add a 5th line exactly betwixt 2 o' t' other lines. Mark this line as t' launch lug line. Well, blow me down! At this point t' main body tube should now have 5 lines. Blimey! Now draw a line around t' tube perpendicular t' t' 5 lines. Blimey! Begad! This line should be 2.5” from one end o' t' tube (mark this as t' top o' t' tube).

Now, me bucko, matey, mark t' 4 - 3.0” BT50 tubes with lines 180 degrees apart. Next, mount these 4 tubes (mock engine tubes), one on each o' t' lines on t' main body tube. Ahoy! T' engine tubes should mount flush with t' bottom o' t' main tube. Well, blow me down! Ya scallywag! Make sure they are straight and align with t' main body tube. Arrr! Avast! Once dry add generous fillets betwixt t' body tube and mock engine tubes – I like t' use 5 minute epoxy for this.

Next, ya bilge rat, arrr, t' fins can be mounted on each o' t' engine tubes. Arrr! Align t' fin t' be flush with t' bottom o' the tubes. See pictures t' ensure they are installed in t' correct orientation. Once dry add generous fillets betwixt the fin and t' tube.

Next, ya bilge rat, mount t' main body tube transition. Begad! Blimey! Slide t' transition on t' t' tube in t' correct orientation. Well, blow me down! Blimey! Avast! Blimey! Slide it down t' t' mock engine tubes. Avast! Blimey! Now apply a liberal amount o' glue above t' line (I used 5 minute epoxy) and slide the transition up until it is even with t' tube. Aye aye! Blimey! Begad! Blimey! Make sure t' transition is straight, matey, otherwise t' upper tube assembly will nay be straight.

Now take t' tongue depressor; cut t' radius ends off and cut it into 4 -1 inch lengths. Well, blow me down! These can now be mounted on t' 4 lines in line with t' fins. Aye aye! T' mount t' tongue depressor directly under t' transition and once again when dry add generous fillets usin' 5 minute epoxy.

Last but nay least – mount t' engine tube assembly in t' main body leavin' about .5” o' t' engine tube stickin' out t' end o' t' rocket. Avast, me proud beauty! Make sure t' Keelhaul®©™® shock cord extend out t' top end o' t' tube. Begad! Blimey! Attach an additional elastic shock cord and 18” plastic parachute to t' Keelhaul®©™® shock cord.

Party Horn Upper Body Tube Assembly:

T' upper body assembly is made up of: party horn, me bucko, plastic fin can, me hearties, shiver me timbers, nose cone, 5 tooth picks, arrr, arrr, shiver me timbers, launch lug assembly and BT60 tube.

Start by mountin' t' plastic fin can t' party hornpipe with 5 minute epoxy. Avast! Ahoy! Also, me hearties, arrr, use 5 minute epoxy t' fill in the top gap betwixt t' fin can and t' party horn. Now, take t' nose cone and cut off t' area that would typically go into a body tube. Blimey! Next, matey, arrr, drill a .125” hole thru t' very tip o' t' nose cone. Avast! Aye aye! I have found this is typically easiest t' drill from t' inside out. Now, shiver me timbers, mount 1 o' t' tooth picks in this hole with 5 minute epoxy. Begad! I also, matey, spread a thin coat o' epoxy on t' t' tooth pick t' strengthen it as much as possible. Avast, me proud beauty! Well, blow me down! Note: it is very likely this tooth pick could break on recovery so you may choose nay t' add this feature – I believe t' aesthetics are worth some maintenance. Now, t' nose cone can be mounted t' party horn.

After t' fin can and nose cone have dried mount one tooth pick on t' end o' each fin – see pictures.

T' final step is t' attach t' shock cord. Ahoy! Aye aye! I used t' traditional Estes approach for this on this section o' the rocket. A 12” plastic parachute is attached t' t' shock cord.

Center Rin' Assembly:

Mark t' 3.85” OD rin' as if you were mountin' 4 fins 90 degrees a part on it. Now, cut 4 pieces of 1/8” balsa per Temple B. These can be glued on each line in t' same orientation. Begad! Avast! T' fin support rods will mount to each o' these.

NOTE: Read t' paintin' and finishin' section before doin' this step. Begad! Now mount t' large rin' t' t' ring supports on t' main body assembly. Begad! Once this is dry t' bamboo support rods can be mounted t' t' edge o' t' fins and rin' adapters.

Escape Pod Assembly:

T' escape pod glider is a Styrofoam glider similar t' those used in on t' FlisKits Tri-Glide rocket. T' only thin' required is t' add a tooth pick t' secure t' glider durin' lift off. Avast! Cut a tooth pick in half and coat with Styrofoam safe CA. Begad! T' tooth pick should be placed in t' center o' t' front support o' t' glider. Avast! Durin' launch the toothpick will rest inside launch lug o' t' plastic fin can at t' top o' t' rocket.

Payload Assembly & Painting:

T' payload be t' Estes Cosmic Cobra nose cone with helicopter recovery so no real assembly was required – only addin' t' rubber bands – see flight prep.

Finishin' this required sandin' t' moldin' partin' line and until t' entire nose cone be smooth. I applied 2 or 3 coats o' automotive gray primer sandin' in betwixt each coat with 400 grit sandpaper. Aye aye! Aye aye! Next, I applied a Hot Pink Pearl (Model Master #4643) after this dried. Begad! I masked t' stripes and applied gloss black (Model Master #4695).

Finished Paintin' & Decals:

T' Estes t' Estes Cosmic Cobra nose cone really inspired t' color scheme o' this rocket – I liked on the pink blades really contrasted with t' black nose cone. Ahoy! I painted t' entire rocket prior t' addin' t' center rin' and rin' supports. I would highly recommend this approach. Well, matey, blow me down!

First, me bucko, I filled all t' balsa components, me bucko, sanded and filled until they were completely smooth. Begad! Blimey! Arrr! Blimey! Next, I applied a couple o' coats o' primer sandin' after each. I painted t' entire rocket Hot Pink Pearl (Model Master #4643). Blimey! Blimey! Arrr! Blimey! After maskin' t' mock engines I applied t' Cadmium Yellow (Model Master #4611) t' t' mock engines and t' tooth picks on the upper fin can. Avast! Blimey! Next, me hearties, I masked and applied gloss black (Model Master – 4695). After t' black had dried for about 48 hours I added t' Bad t' t' Bone decal and t' sparkle decals t' t' upper fin assembly and center ring. Ya scallywag! Blimey! The final step was t' apply 3 coats o' Krylon Acrylic Crystal Clear #1303.

Flight Prep:

Prior t' t' first flight I decided t' do t' spin test and had t' add an ounce o' nose weight. Ya scallywag! Aye aye!

Payload flight prep is pretty simple; add rubber bands t' activate t' bands when free from a body tube.

T' big question was how t' get t' payload (Estes Cosmic Cobra nose cone) out o' t' upper tube o' t' rocket. Ya scallywag! I decided t' add a loop t' t' upper shock cord roughly 5-6” from t' end o' t' tube (see picture). Avast, me proud beauty! T' loop wrapped around t' very tip o' t' nose cone; t' thought be that t' shock cord would pull t' payload out when the parachute opened up.

Here is me recommended approach: Prep a D12-3 engine, shiver me timbers, add t' igniter and tape in place (no launch lug). Ahoy! Aye aye! Add a handful o' “dog barf” and stuff t' t' bottom o' t' main tube assembly. Well, blow me down! Begad! Now roll each parachute and load the lower assembly parachute and then t' upper parachute both in t' main body tube assembly. Ya scallywag! Begad! Next, me bucko, load t' payload into upper tube assembly (hookin' t' tip o' t' nose cone into t' loop o' t' shock cord). Avast, me proud beauty! Avast, me bucko, me proud beauty! Now carefully and neatly stuff the remainin' shock cord into t' main body tube and slip t' upper and main tube assembly together. Finally, arrr, shiver me timbers, the escape pod (glider) hangs from t' launch lug on t' plastic fin can at t' very top o' t' rocket.

Flights:

I be very pleased with all 3 flights; t' launches were straight even with t' extra mass o' t' glider. Ahoy! Blimey! The rocket hit apogee and then ejection. Aye aye! Blimey! Blimey! Blimey! T' glider separated and flew like a champ. Blimey! Blimey! T' payload started t' spin and although nay as fast as a competition helicopter it be spinning. Next, I saw both parachutes open and drift t' the ground. Blimey! Blimey! T' flight o' t' glider was incredible about 70-80 seconds. T' second flight be also very good; however, ya bilge rat, the glider was lost on t' local school – Bummer!! Blimey! Blimey! Blimey! T' third and final flight be also good even without t' glider. I need t' find out where t' buy more gliders!

Deployment Launch Rod

Summary:

Pros:

T' four recovery pieces keeps you busy watchin' their descent. Begad! Blimey! T' escape pod (glider) performed much better then I expected. Avast! Blimey! Avast, shiver me timbers, me proud beauty! Blimey!

Cons:

T' tooth pick at t' tip looks great, but broke after t' first flight – I think I will make this a press-in component that can be removed prior t' a flight or is at least very easy t' replace.

Other:
Overall this was a great project – t' “Box o' Stuff” was a bit intimidatin' when all t' parts were laid out on t' floor. Blimey! Begad! After, comin' up with t' concept, things just seemed t' flow together. Begad! I be very please with flights and can’t wait t' buy more gliders. Begad! Thanks t' EMRR and Todd Mullins for puttin' this contest together. GREAT WORK!!!

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