Brief:
This is me entry for t' EMRR “Retro Spaceship” rocket design. Ya scallywag! When this contest be 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”. Ya scallywag! 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 be t' layout t' design and determine its size. 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. I experimented with different shapes and master material. Begad! I settled on t' pink insulation foam for t' master material. Begad! Arrr! It lasts for about 5 cycles and then starts t' degrade from t' heat. T' other tip I discovered was t' use baby powder as t' release agent. Avast, me proud beauty! Begad! 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. Avast, me proud beauty! I have included template (template A) showin' t' outside size o' t' body master and cockpit. Ya scallywag! In addition pictures o' t' foam masters are included. Begad! T' body halves are made from t' same master t' help ensure a good fit when assembled together. Blimey! T' cockpit section is made from a separate master. Ya scallywag! Begad! In this master I added t' windshield and porthole recesses. Avast, me proud beauty! 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. T' cockpit section was then trimmed t' fit t' top body section. After trimmin' t' a satisfactory fit, t' cockpit was 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. Blimey! Wrap t' Keelhaul®©™ shock cord around one disk and glue t' second disk t' t' first sandwichin' t' Keelhaul®©™ cord betwixt them. Insert t' disk into t' body tube so t' Keelhaul®©™ is feed down t' tube. Aye aye! Begad! T' Keelhaul®©™ cord will be attached t' t' motor tube in a later step. Well, blow me down! Glue t' disk (and Keelhaul®©™) assembly roughly 1 inch from t' end o' t' BT55 tube. Fill this space with nose weight. Begad! Begad! I used BB’s (about 4 oz). Begad! Avast, me proud beauty! Now cut a third disk out t' plug t' end o' t' tube and glue it in place.

Next, me hearties, cut t' 3/32” balsa per t' templates: two o' template B (side pieces) and 2 o' template C (top and bottom pieces). Well, ya bilge rat, blow me down! Mark t' tube as if you were mountin' 4 fins 90 degrees apart. Begad! 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. Ya scallywag! Be careful t' make sure you mount in t' same orientation – front should be toward t' end o' t' tube with t' plug that be just inserted. Lastly, me bucko, 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. Blimey! Begad! Now add a generous glue fillet t' each o' t' 4 balsa pieces. Well, blow me down! 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. Ahoy! Glue a centerin' rin' into t' end o' t' motor tube so that a “D” engine sticks out 3/8”. Arrr! Now take t' BT20 tube 6.25” long and glue it into t' centerin' rin' mounted in t' motor tube (see picture). Well, matey, blow me down! Next, cut a small groove on t' inside o' t' T20 t' T55 centerin' ring. Avast! Glue this .375” from t' end o' t' tube opposite t' motor tube. Arrr! Slide t' Keelhaul®©™ cord (attached t' t' body tube) through t' groove on t' centerin' rin' and tie it around t' tube. Now pull t' Keelhaul®©™ up t' t' centerin' rin' and apply a bead o' epoxy t' t' Keelhaul®©™, me bucko, centerin' ring. Ya scallywag! and tube joint (see picture). Next, epoxy t' .75” shock cord t' t' BT20 tube (see picture). Finally, mount t' last centerin' rin' (T50 t' T55) on t' motor tube 1.5-2.0” from t' end o' t' motor tube. Well, blow me down! Once this assembly is dry, shiver me timbers, test fit it in t' body tube and make sure t' motor tube slides in and out very easily. Aye aye! Well, me bucko, blow me down! 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. First, 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). Begad! Ya scallywag! 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. Ya scallywag! Ahoy! T' pins were placed about 1 inch apart. Aye aye! T' purpose o' t' pins was t' ensure t' top and bottom halves were aligned well. Aye aye! Well, blow me down! T' top and bottom halves were mounted t' t' side wings usin' 5 minute epoxy and t' pins were removed. Arrr! After t' epoxy was set I cut t' excess balsa as close t' t' body sections as possible leavin' a slight overhang. Begad! I then sanded t' wings t' a smooth transition betwixt t' top body section, matey, bottom body section, ya bilge rat, and wings. Begad! There were a few areas I be nay satisfied with this interface so I filled these with thinned Emery’s wood putty and then sanded smooth. Begad! Arrr! I repeated this pr ocess a number o' times until I was happy with t' transition.

Next, I cut clearance for t' launch rod in t' aft portion o' t' body. Arrr! Blimey! 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. Begad! Blimey! 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). T' two pieces were glued together and top edge rounded. Arrr! A 3/16” dowel was sanded t' half t' thickness t' make t' rib detail on t' wing. Ahoy! Ahoy! Each dowel was tacked down at one end and formed into t' curved shape. Blimey! 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' be cut from ¼” balsa sheet usin' t' attached template (template F). Ahoy! Avast! T' win' be cut out and sanded smooth roundin' all t' edges. Avast! Begad! 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. Avast! A hole was then drilled through each dish and enlarged by sandin' t' fit in t' appropriate location on t' wing. T' dishes were then glued in place. Blimey! Ya scallywag! Final sandin' and fittin' t' body be 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' be test fit t' t' body sandin' where needed t' improve fit. Aye aye! T' win' is then mounted t' t' body usin' 5 minute epoxy. Avast! T' same technique be used for mountin' t' bottom wing. Ahoy! Large fillets o' epoxy were applied t' t' joints betwixt t' body and top wing. Begad! Ahoy! This be 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. Well, blow me down! 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. T' entire rocket be primed usin' gray primer. Avast! T' base cost be then air brushed tan (Model Maker – British Gulf Armor Light - 4813). Arrr! Begad! Next t' main body be masked and t' cock-pit was painted blue (Testors – Gloss Dark Blue -1211). Avast, me proud beauty! Begad! 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). Ahoy! Blimey! Next t' center line was painted dark red. Begad! Begad! Next came t' windshield with light blue (Model Maker – Hellblau RLM - 4788). Next, t' seams and rivets were added by hand usin' a brown colored pencil. Finally, ya bilge rat, 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. Blimey! Well, blow me down! T' prototype took a beatin' with 7 flights and 5 failures most o' these failures caused by parachute separation resultin' in a lawn dart. Ahoy! Aye aye! One advantage t' livin' in Northern Wisconsin; thar was 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 be a cool -1F. Ahoy! 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, straight, me hearties, 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?”. Blimey! “Yes” - t' parachute opened, me hearties, arrr, nay completely, matey, but enough. Aye aye! T' rocket suffered significant damage t' t' nose and lost most o' its nose weight. Well, blow me down! Avast, me proud beauty! I think I will finally retire this one. Begad! 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, I be extremely nervous. Aye aye! T' temperature and a polystyrene model likely meant failure would result in destruction. Count down 5…4…3…2…1 – launch (E9-4 motor) – straight off t' launch rod, shiver me timbers, ya bilge rat, 2-3 twists as it climbed. Blimey! Avast! It reach apogee and started descendin' fast – “ejection, shiver me timbers, ejection, where are you” – finally ejection, matey, parachute out, me hearties, arrr, 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. Well, blow me down! 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! Avast, me proud beauty! I had 1 with t' final painted model and 2 with t' prototype. Begad! Each o' these occurred usin' an E9-4 motor. Avast! In all t' flights t' models twisted slightly under boost, matey, me hearties, 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. Arrr! T' aft engine ejection is too unreliable, it stresses all t' components especially t' shock cord. Begad! 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, matey, me hearties, 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