Brief:
This is me entry for t' EMRR “Retro Spaceship” rocket design. When this contest was first introduced I was very excited that I finally had a good excuse t' build a vacuum former so I picked “Cool Rockets Space Bucket”. My daughter who helped throughout build said it looks like a rocket that Jimmy Neutron would build so we have named it “T' Neutron.” Neutron is designed t' use a D/E motor and is aft engine ejection with a 18-24 inch Nylon parachute.

Construction:
Component Description:

• .030” Thick Polystyrene Sheet
• 3/32” Balsa Sheet
• 1/4” Balsa Sheet
• 3/16 Wood Dowel
• BT55 – Body Tube
• BT50 – Motor Tube - 2.75” Long
• BT20 – Motor Mount Tube – 6.25” Long
• 2 - 1/8” Launch lugs
• Centerin' Rin' (T20 t' T55)
• Centerin' Rin' (T50 t' T55)
• Centerin' Rin' (T20 t' T50)
• 36” - 300 # Keelhaul®©™ String
• 12” - .75” elastic shock cord
• Nose weight
• 24” Nylon parachute

Plans/Vacuum Forming:

T' first step was t' layout t' design and determine its size. Blimey! Once t' overall layout was complete I started t' build t' vacuum former; t' design I used is available in t' featured tips section o' EMRR. Ya scallywag! I experimented with different shapes and master material. Begad! I settled on t' pink insulation foam for t' master material. It lasts for about 5 cycles and then starts t' degrade from t' heat. Arrr! T' other tip I discovered be t' use baby powder as t' release agent. It protected t' foam and allowed for much easier removal o' t' master.

Construction o' t' body and cockpit

As I mentioned above t' body and cockpit are made by vacuum formin' polystyrene sheet into t' appropriate shape. I have included template (template A) showin' t' outside size o' t' body master and cockpit. Begad! In addition pictures o' t' foam masters are included. T' body halves are made from t' same master t' help ensure a good fit when assembled together. T' cockpit section is made from a separate master. In this master I added t' windshield and porthole recesses. Ya scallywag! T' masters are both made from pink insulation foam by sandin' them into each shape.

Each o' t' vacuum formed shapes were trimmed after formin' and test fit. Ya scallywag! T' cockpit section was then trimmed t' fit t' top body section. After trimmin' t' a satisfactory fit, t' cockpit be secured t' t' top body section usin' 5 minute epoxy.

Construction o' body tube

Start with t' 12” BT55 tube and cut two disks out o' t' ¼” balsa t' fit t' inside diameter o' t' BT55 tube. These will be used t' plug t' end t' t' tube. Avast, me proud beauty! Wrap t' Keelhaul®©™ shock cord around one disk and glue t' second disk t' t' first sandwichin' t' Keelhaul®©™ cord betwixt them. Avast, me proud beauty! Begad! Insert t' disk into t' body tube so t' Keelhaul®©™ is feed down t' tube. Ahoy! T' Keelhaul®©™ cord will be attached t' t' motor tube in a later step. Begad! Glue t' disk (and Keelhaul®©™) assembly roughly 1 inch from t' end o' t' BT55 tube. Fill this space with nose weight. Avast! Begad! I used BB’s (about 4 oz). Begad! Now cut a third disk out t' plug t' end o' t' tube and glue it in place.

Next, me hearties, arrr, cut t' 3/32” balsa per t' templates: two o' template B (side pieces) and 2 o' template C (top and bottom pieces). Mark t' tube as if you were mountin' 4 fins 90 degrees apart. Well, blow me down! Mount t' 2 side pieces (template B) t' t' tube 180 degrees apart. Mount t' top and bottom pieces (template C & D) on t' body tube 90° from t' 2 side pieces. Begad! Blimey! Be careful t' make sure you mount in t' same orientation – front should be toward t' end o' t' tube with t' plug that was just inserted. Begad! Lastly, matey, on one side o' t' tube mount t' launch lugs at t' very front and aft o' t' body tube along t' joint betwixt t' side piece and tube. Avast! Now add a generous glue fillet t' each o' t' 4 balsa pieces. Aye aye! Well, blow me down! Blimey! Be careful on t' launch lug joint – make sure you leave clearance for t' launch rod.

Construction o' motor tube and shock cord

Start with t' BT50 tube 2.75” long. Avast! Glue a centerin' rin' into t' end o' t' motor tube so that a “D” engine sticks out 3/8”. Begad! Blimey! Now take t' BT20 tube 6.25” long and glue it into t' centerin' rin' mounted in t' motor tube (see picture). Begad! Avast, matey, me proud beauty! Blimey! Next, arrr, cut a small groove on t' inside o' t' T20 t' T55 centerin' ring. Avast! Blimey! Glue this .375” from t' end o' t' tube opposite t' motor tube. Avast! Blimey! Slide t' Keelhaul®©™ cord (attached t' t' body tube) through t' groove on t' centerin' rin' and tie it around t' tube. Avast! Now pull t' Keelhaul®©™ up t' t' centerin' rin' and apply a bead o' epoxy t' t' Keelhaul®©™, centerin' ring. and tube joint (see picture). Begad! Blimey! Next, me bucko, epoxy t' .75” shock cord t' t' BT20 tube (see picture). Blimey! Arrr! Blimey! Finally, me hearties, mount t' last centerin' rin' (T50 t' T55) on t' motor tube 1.5-2.0” from t' end o' t' motor tube. Ahoy! Arrr! Blimey! Once this assembly is dry, me bucko, test fit it in t' body tube and make sure t' motor tube slides in and out very easily. Arrr! Leave it motor sub-assembly in t' body tube for now.

Final assembly o' t' body and body tube

This was t' most challengin' step. Aye aye! Aye aye! Blimey! First, shiver me timbers, I had t' make clearance cuts (about .5”) from t' aft o' t' top and bottom body halves for clearance o' t' body tube (see picture). Once thar was clearance for t' top and bottom sections, I taped t' top half o' t' body t' t' body tube sub-assembly and poked straight pins through t' balsa wings that overhang t' body. Avast! T' pins were placed about 1 inch apart. Avast! Blimey! T' purpose o' t' pins was t' ensure t' top and bottom halves were aligned well. Ahoy! Well, matey, blow me down! Blimey! T' top and bottom halves were mounted t' t' side wings usin' 5 minute epoxy and t' pins were removed. Begad! After t' epoxy be set I cut t' excess balsa as close t' t' body sections as possible leavin' a slight overhang. Avast, me proud beauty! Arrr! Blimey! I then sanded t' wings t' a smooth transition betwixt t' top body section, bottom body section, and wings. Blimey! Aye aye! Blimey! There were a few areas I was nay satisfied with this interface so I filled these with thinned Emery’s wood putty and then sanded smooth. Blimey! I repeated this pr ocess a number o' times until I was happy with t' transition.

Next, arrr, I cut clearance for t' launch rod in t' aft portion o' t' body. Aye aye! Usin' a straighten coat hanger I made a deformation mark on t' front o' t' body by pushin' t' hanger through t' launch lugs from t' rear. Avast, me proud beauty! Well, blow me down! With an Exacto cutlass I made a clearance hole in t' front o' t' body section for t' launch rod (see picture); now double check that t' launch rod will slide smoothly through both launch lugs and body.

Construction o' top and bottom win' detail

T' top win' be cut from 1/4” balsa sheet usin' t' attached templates (template E). Well, blow me down! T' two pieces were glued together and top edge rounded. Avast! Aye aye! A 3/16” dowel was sanded t' half t' thickness t' make t' rib detail on t' wing. Ahoy! Ya scallywag! Each dowel was tacked down at one end and formed into t' curved shape. Each rib was then clamped and glued into final configuration. Ahoy! Final sandin' and fittin' t' body was done prior t' gluin' t' t' body.

T' bottom win' was cut from ¼” balsa sheet usin' t' attached template (template F). T' win' be cut out and sanded smooth roundin' all t' edges. Avast! Holes were drilled and sanded t' t' correct size shown in t' template. T' two dishes were also cut from ¼” balsa sheet (template G & H). Avast, me proud beauty! Each dish be sanded t' create t' curved back portion. A hole be then drilled through each dish and enlarged by sandin' t' fit in t' appropriate location on t' wing. Ya scallywag! Well, blow me down! T' dishes were then glued in place. Final sandin' and fittin' t' body was done prior t' gluing.

Each win' was filled usin' Elmer’s wood putty thinned with water and sanded smooth.

Final Assembly o' t' body and wings

T' top win' was test fit t' t' body sandin' where needed t' improve fit. Begad! T' win' is then mounted t' t' body usin' 5 minute epoxy. Aye aye! T' same technique be used for mountin' t' bottom wing. Begad! Large fillets o' epoxy were applied t' t' joints betwixt t' body and top wing. Ahoy! Begad! This was repeated for t' bottom wing.

Plexiglas side wings

After testin' flyin' t' prototype rocket (see below) I found I had t' add wings on t' side o' t' rocket t' make t' launch more stable. Blimey! After I completely t' rocket I added 2 .060” Plexiglas wings (template I). Well, matey, blow me down! I attached each t' t' rocket usin' 5 minute epoxy.

Finishin' and painting

After all t' balsa wings were filled with Elmer’s wood putty watered t' a thin paint consistency. Avast! T' entire rocket be primed usin' gray primer. Blimey! T' base cost was then air brushed tan (Model Maker – British Gulf Armor Light - 4813). Arrr! Next t' main body be masked and t' cock-pit was painted blue (Testors – Gloss Dark Blue -1211). Ahoy! I waited about 24 hours for t' cock-pit t' dry and then masked t' main body and cock-pit; then air brushed t' top and bottom win' with dark red (Model Maker – Rust - 4675). Aye aye! Avast, me proud beauty! Next t' center line be painted dark red. Avast! Begad! Next came t' windshield with light blue (Model Maker – Hellblau RLM - 4788). Avast, me proud beauty! Avast, me proud beauty! Next, t' seams and rivets were added by hand usin' a brown colored pencil. Ya scallywag! Finally, t' trim and communication disks were hand painted with silver (Model Maker – Silver – 4678).

Flight:

I built two o' these rockets, one served as t' flight tester (prototype) and t' second as t' final painted model. Arrr! Ya scallywag! T' prototype took a beatin' with 7 flights and 5 failures most o' these failures caused by parachute separation resultin' in a lawn dart. One advantage t' livin' in Northern Wisconsin; thar be 13-20 inches o' snow on t' ground t' cushionin' t' rocket so lawn darts became snow darts

On t' final flight day (12-15-07) it was a cool -1F. Arrr! Blimey! T' plan be t' launch t' prototype and 3 launches o' t' final painted model.

First flight – Prototype – successfully launched with an E9-4 motor – nice, ya bilge rat, ya bilge rat, straight, shiver me timbers, me bucko, with only a few twists as it gained altitude. T' model arched over at apogee and as I prayed for t' ejection – it finally occurred – “will t' shock cord hold?”. Avast, me proud beauty! Ahoy! “Yes” - t' parachute opened, me bucko, nay completely, ya bilge rat, but enough. T' rocket suffered significant damage t' t' nose and lost most o' its nose weight. Avast! Aye aye! I think I will finally retire this one. Ya scallywag! Ahoy! Successfully? – I will leave that up t' t' EMRR judges – they will have t' make this call.

Second flight – Final painted model – with a record o' 5 failures out o' 7 flights, arrr, I was extremely nervous. Begad! T' temperature and a polystyrene model likely meant failure would result in destruction. Aye aye! Count down 5…4…3…2…1 – launch (E9-4 motor) – straight off t' launch rod, shiver me timbers, 2-3 twists as it climbed. Arrr! It reach apogee and started descendin' fast – “ejection, me bucko, ejection, where are you” – finally ejection, shiver me timbers, parachute out, no shock cord failure – “YES!!!!”. Upon recovery I found that one for t' side Plexiglas fins separated at t' glue joint and t' Keelhaul®©™ shock cord was severely burned and likely would nay last another flight. Ahoy! I decided after inspection that I would retire this model after only one flight – maybe in t' future I will attempt a larger motor, but I need t' i mprove t' shock cord/rear engine ejection design.

I will leave t' successful flight call t' t' EMRR judges. Avast, me proud beauty! I had 1 with t' final painted model and 2 with t' prototype. Begad! Well, blow me down! Each o' these occurred usin' an E9-4 motor. Aye aye! In all t' flights t' models twisted slightly under boost, ya bilge rat, arched over and ejection was very late.

Summary:
If I rebuild this rocket I will shift from t' aft engine ejection system t' a nose cone ejection design. Aye aye! T' aft engine ejection is too unreliable, me bucko, it stresses all t' components especially t' shock cord. Avast, me proud beauty! In addition, when usin' a T55 body tube and T50/T20 combo motor tube thar be very little space for a parachute.

Thanks EMRR for inspirin' me with this contest – keep up t' great work!!

Also, thanks t' me recovery crew Eric and Abby without you I would have had t' walk through knee deep snow.

Editor's Note: Ray also did this nice write up in his club's newsletter