Dr. Zooch Atlas Agena

Dr. Zooch - Atlas Agena {Kit}

Contributed by Hans "Chris" Michielssen

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar_border
Published: 2010-05-10
Length: 19.75 inches
Manufacturer: Dr. Zooch
Skill Level: 3
Style: Scale

Brief:
A semi-scale version o' t' Atlas Agena. Avast, matey, me proud beauty! Flame fins are added for flight.

Construction:
Picture does nay show t' three sheets o' 3/32" x 3" x 6" balsa supplied in t' kit.

Openin' t' box looked t' be typical o' a Dr. Booty kit- Good quality parts. Aye aye! Blimey! All t' instructions and cardstock wrap sheet were rolled inside t' T-60 (BT-60) body tube.

A few unusual pieces were t' pre-weighted balsa adapter. Arrr! Dr. Begad! Zooch uses a two ply Keelhaul®©™ “ribbon”. Avast, me proud beauty! Nay t' usual Keelhaul®©™ you’d find in a rocket kit.

A 10" length o' T-3 tubin' is included.

Number 3 on t' parts list says: 4 CR25P centerin' rings. Begad! Begad! They are actually CR35P rings. Blimey! I’ve never seen centerin' rings this small in a kit before.

T' corrugated mylar is interesting. Avast! It is thin and metallic blue.

I dry ironed t' instructions and wrap sheet flat. Aye aye! T' cardstock wrap sheet was sprayed with a Krylon clear coat for protection against smearin' and dirt.

With t' Zooch kits (or any kits with wraps) I always scan t' wrap sheets just in case I need t' print off another copy. Blimey! Avast, me proud beauty! It’s me, I’m very picky about wraps and such. Well, blow me down! If it doesn’t turn out right t' first time, arrr, I’ll print and make another. Avast! This be t' first Zooch kit I’ve built that just had one, single cardstock wrap sheet.

MAKING THE ENGINE MOUNT

T' upper and lower CR-MOD templates are cut from t' wrap sheet. I didn’t see any reason t' cut out t' centers, I did cut out t' engine hook allowance and index notches.

I also didn’t cut out t' two outer semi-circles yet. I thought it would be easier t' cut them out after bein' glued t' t' centerin' rings.

Instead o' gluein' t' templates permanently in place with white glue, I used spray adhesive and removed them after cuttin' out t' semi-circles.

T' rounded engine hook notch doesn’t quite match up with t' template. Begad! Avast, me proud beauty! I centered everythin' from t' back o' t' rings.

T' semi-circles take time t' cut through. Well, arrr, blow me down! I didn’t cut a pie-shaped notch at t' index marks, I simply cut a single line straight down t' t' depth shown.

T' templates were removed and t' rings marked upper and lower.

In order t' clean up t' cut semi-circles, arrr, I wrapped 400 grit sandpaper around t' white barrel side o' a Sharpie pen. Begad! Blimey! T' Sharpie pen is slightly smaller in diameter than t' T-5 tube t' circles will fit. I usually contour sand with somethin' smaller in diameter as t' sandpaper thickness will brin' it up t' t' correct finished diameter.

I “double-glued” t' end o' t' engine bell strings t' t' ends o' t' T-20 tubin' t' prepare for winding.

I’ll dry wrap t' strings t' t' 3/8" mark t' get an idea o' t' spacin' o' t' windings. Avast! Blimey! On one test wrap I did it dry and held t' end down with tape. Avast! I spread t' strin' wraps as even as I could and used it for a spacin' model for gluin' on t' second tube.

T' strings were lightly coated with white glue for just a few inches. Arrr! Ahoy! T' glued area was wrapped and more glue is added t' t' next few inches. Ahoy! I continued up until reachin' t' end.

I decided nay t' use super glue over t' thread bands as it could leave bumps and roughness betwixt t' wraps. Arrr! Instead I coated white glue overall t' thread rows at once and smoothed out t' glue with a finger.

T' centerin' rings are lined up with t' index line drawn earlier. Blimey! Just t' be safe, I set t' “spoof” engine tubes in their semi-circle cutouts t' be sure all lined up. Ahoy! T' rings were tacked in place with small drops o' thin CA. Ya scallywag! I followed with white glue fillets.

I decided t' install t' engine hook before gluin' on t' spoof tubes. Ya scallywag! Ahoy! Blimey! This way I could add t' tape wrap without t' tubes gettin' in t' way.

I’ll paint t' spoof engine tubes with Walmart spray aluminum before gluin' in place on t' central engine tube. Avast! I’ve had great results with their inexpensive aluminum before.

I filled t' seams in t' spoof body tubes with Elmer’s Wood Filler.

Once again, Zooch uses a reinforcement band directly below t' top o' t' engine hook. Well, blow me down! Arrr! It’s a smart addition on t' thin T-20 tube. This eliminates any chance (at ejection) o' t' engine hook pullin' and tearin' t' tube.

T' hook was set in it’s slot and a wrap o' electrical tape went over it, betwixt t' centerin' rings.

T' spoof tubes weren’t glued on yet, shiver me timbers, arrr, shiver me timbers, so I be able t' slide t' engine mount in place. Ahoy! I made t' marks usin' t' semi-circles I had cut out earlier. Ahoy! Blimey! This way I knew t' cut out slots in t' T-60 tube would match up with t' spoof tubes.

I set t' spoof tube into t' semi-circle cutouts with t' ends o' t' thread bands facin' towards t' t' central motor mount tube. I didn’t want t' loose ends facin' outward, they won’t as easily be seen in t' center.

I marked t' spoof tubes for masking. Blimey! Blimey! T' masked areas would keep t' gluin' surfaces clean.

After a coat o' grey primer and sandin' , I followed with spray aluminum.

 

I first set t' spoof tubes in their semi-circle cutouts without glue. Well, blow me down! T' spoofs overhang t' centerin' rings by 9/16". Avast, me proud beauty! After bein' sure o' t' overhangs, I applied a small drop o' CA t' t' spoof/centerin' rin' joints t' glue in place.

T' remainin' CR2060F Centerin' rin' is glued t' t' top o' t' engine mount assembly. Well, blow me down! Avast! I didn’t glue it flush, ya bilge rat, but 1/16" down from t' top o' t' motor tube. Begad! This be a stronger joint as I could fillet both sides with white glue.

I slid t' engine mount assembly into t' T-60 tube t' check t' alignment o' t' spoof tubes. Avast, me proud beauty! Before cuttin' t' T-60 tube I wanted t' double check t' alignment. Ahoy! I made slight adjustments t' t' pencil lines t' fit t' final spoof tubes locations.

MAKING THE PODS

To make t' pod covers you laminate two pieces o' balsa. Avast! One is 4 inches long, t' other 2 5/16" long. Both are 9/16" wide.

T' instructions have you round t' cut tip before sandin' t' t' body tube contour. Avast! I would recommend roundin' t' tip after sandin' t' inside contour. Ahoy! This way, shiver me timbers, me bucko, matey, you don’t round off t' tip.

To sand t' body contour, ya bilge rat, me hearties, I didn’t sand it on t' T-60 tube at first. Blimey! I always start with t' next size smaller tubing. In this case a BT-55.

T' hardest part o' sandin' pieces t' fit a tube curve be t' middle, ya bilge rat, highest point o' t' curve. Arrr! Startin' with a smaller tube guarantees thar will be enough removed from t' middle. When you get it close, switch t' a finer grit on t' larger body tube you are goin' t' glue in on.

When test fittin' t' Engine Nacelles, I found them a little wide in t' front. Aye aye! Blimey! No problem, ya bilge rat, a simple trim. Avast, me proud beauty! In order t' get t' paper nacelles t' fit better over t' top o' t' spoofs, me bucko, I sanded off t' top o' t' T-5 tubes down with a sandin' block.

As I expected, t' Heat Shields required a bit o' fitting. Mine ended up bein' closer t' t' height in t' illustrations. T' fit on each model is goin' t' be a little different and would require trimming.

I formed t' Engine Nacelle Shrouds in t' soft fleshy heel o' me hand. Well, blow me down! I pressed and rolled a dowel over t' shroud until it was rounded. Begad! T' smaller front end o' t' Nacelle Shroud is more o' a rounded square shape.

T' smaller heat shield pieces required a bit o' sandin' t' get t' shrouds t' wrap all t' way around and touch t' tube.

Before gluing, me hearties, me bucko, I drew lines at t' center and t' intersection o' t' overhang.

Rather than use a slower dryin' white glue, I held t' heat shields on their pencil lines and touched super glue t' t' joints. Avast, me proud beauty! In t' end it be a good fit on all sides.

T' fairin' wall support strips were cut - six pieces, me hearties, 3/32" x 32" x 1". All were tacked in place with CA.

After test fittin' I had t' sand t' middle support strip down a bit.

I’d already filled t' pod covers. I sprayed them off t' body with grey primer.

After I be sure o' t' Nacelle fit, I glued t' Pod Covers onto t' body. Arrr! I ran a light coatin' o' White glue on t' underside and pressed them into place. Begad! I sighted from t' aft makin' sure they were straight.

After holdin' them tight against t' body for a few minutes, I could see some o' t' edges lifting. I ended up usin' a small amount o' CA on those points, me bucko, keepin' a paper towel handy t' pick up any overflow. Well, blow me down! Ya scallywag! This seemed t' hold them down and would make for easier fillets later.

I was concerned about gluin' on t' Nacelles. Begad! Avast, arrr, me proud beauty! Even with t' supports in place thar was a slight bowin' o' t' outer farin' walls.

I decided t' tack t' upper corners o' t' Nacelles against t' pods with small amounts o' CA. Begad! On t' bowed sides o' t' Nacelles, ya bilge rat, shiver me timbers, I held them down with t' flat backside o' a razor blade. This insured t' sides would be straight while I touched CA t' t' long joint.

If any sandin' is needed, t' CA would strengthen t' paper Nacelles. Blimey! Blimey! Avast! Blimey! I also added CA t' t' back overhang o' t' Nacelles so they wouldn’t be bent when handling.

MAKING THE FLAME FINS

I jumped ahead t' t' Flame Fins. Well, blow me down! Bein' t' fins are supposed t' be a flame profile, t' fins outside edges shouldn’t necessarily be cut t' same. Avast! But, ya bilge rat, ya bilge rat, t' root edge, me bucko, width and length should match t' pattern.

I used 400 grit sandpaper wrapped around t' white back end o' a Sharpie pen t' sand t' small curves in t' outside edges. T' pen barrel kept everythin' squared up. I won’t bother tryin' t' round t' edges o' t' fins.

After I glued t' small CR35P Centerin' Rings t' t' T-3 Tube, me hearties, arrr, I set t' root edge o' t' fins against t' T-3 tube.

While t' fins are bein' filled and sanded, shiver me timbers, I jumped back t' t' body details.

I had t' find t' exact center o' t' main tube betwixt t' Nacelles. Begad! A 1/16" paper strip is glued t' t' body on each side.

T' paper strip was cut from cardstock.

To find t' center, ya bilge rat, arrr, I pushed a piece o' paper into both sides o' t' Nacelle / body tube joint. Begad! Begad! I simply folded that length in half and marked t' center. Begad! Begad! That mark was extended up t' tube.

Next, you mark t' line 3/8" up from t' corrugated wrap.

I started gluin' t' long strip down at t' 9/16" mark. Avast! T' Vernier Engines were glued on, shiver me timbers, butted up against t' end o' t' cardstock strip.

BODY DETAILS

T' 1/8" dowel is rounded and glued t' t' body. While t' instructions don’t say t' sand t' dowel t' a half-round shape, me bucko, t' illustration shows it. Begad! I sanded half off down it’s length and rounded t' top. Ahoy! I recessed an area wide enough t' fit it over t' corrugated wrap.

It would be near t' impossible t' mask t' dowel after it is glued. Begad! I’ll paint t' rocket white, then mask and paint t' aluminum. Begad! I’ll glue t' dowel on after all is painted.

After much thought, I figured out how t' make t' thin balsa Nosecone Line Fairing. Avast, me proud beauty! I usually fill balsa before gluin' it t' t' body. Ya scallywag! This is a very thin piece and would probably warp when painted with filler.

I decided t' make and fill it on t' balsa sheet, then cut it off and glue in place. Aye aye! Usin' me metal sandin' block with 220 grit sandpaper I thinned t' edge in a long “step”. Makin' t' Fairin' this way would help prevent warping. Well, blow me down! It’s easier t' form and round t' edge while still on t' balsa stock.

T' fairin' be filled, me bucko, sanded then cut off t' sheet.

T' tip o' t' Pod Cover was cut off and t' Fairin' glued in line t' t' top o' t' body tube. Avast! Avast, me hearties, me proud beauty! T' end was sanded square t' t' end o' t' body tube.

T' Fairin' was continued up t' Adapter. I sanded t' angle t' match t' Fairin' at t' end o' t' Body Tube.

Finishing:
PAINTING

T' aft Centerin' Rings and Spoof Nozzles were masked off by settin' small squares o' maskin' tape against t' extended inside wall o' t' aft main tube. Aye aye! I stuffed scraps o' paper towel into t' recesses.

T' entire model was sprayed with grey primer and sanded. Ahoy! Ahoy! Rustoleum Painter’s Touch Gloss White followed, sandin' in betwixt coats. Well, blow me down! Ya scallywag! I didn’t want t' paint t' upper T-50 tube as it was goin' t' get a printed wrap. Blimey! For paintin' t' upper adapter and nose cone I used some scrap BT-50 and sprayed all as one white unit. I know, it should be flat finish, me hearties, but flat finishes get dirty easier. I’ll hit it with a dull coat later on.

T' Nose Cone be already filled, me hearties, primed and painted. Begad! I drew t' line down t' upper T-50 tube for t' Agena Wrap.

I don’t have much luck usin' white glue on full body tube wraps. Avast! I cut out t' wrap and hit it with spray adhesive. T' spray adhesive lets me reposition t' wrap if necessary. Usin' White glue, you only have one attempt doin' a straight wrap.

Usin' just spray adhesive t' end edges won’t stay down. Arrr! I lay a small amount o' white glue on me knife blade and push it under t' raised edge.

Earlier I painted t' model Gloss White. Blimey! I worked over t' weekend which gave t' paint time t' set up.

I masked around t' Pod Cover with scotch tape. Maskin' Tape went over t' edges o' t' Scotch Tape widenin' t' masked areas. Blimey! I cut up a plastic grocery bag and wrapped tha around t' larger areas o' t' upper body.

T' masked areas around t' Engine Mount were left on for t' Aluminum paint. Arrr! I’d had fair winds with t' cheaper WalMart Aluminum before and decided t' use it again.

I did me typical process o' light coats then a final heavy coat. Avast, me hearties, me proud beauty! T' WalMart Aluminum dries clear and even.

While Scotch Tape gives me t' best maskin' lines, it can be hard t' remove in one piece. Blimey! Aye aye! It’ll tear quite a bit when removin' but t' results are worth it.

T' upper T-50 Body Tube was glued t' t' Adapter. Before gluin' in place, ya bilge rat, me hearties, I used a Sharpie pen t' blacked t' lower edge o' t' Body Tube and wrap. Aye aye! Blimey! This gives a sharper color separation line betwixt t' wrap and Adapter section.

FINISHING UP

T' 1/8" Dowel was left off durin' painting. Ahoy! It’d be too hard t' mask around it. Arrr! I sealed, primed, sanded and painted it Aluminum. Avast! It be positioned and glued in place over t' Corrugated Wrap.

 

T' Launch Lug had t' seams filled, matey, then primed with Gray Primer. Begad! Blimey! Ya scallywag! Blimey! After sandin' it was sprayed White then cut in two. Both pieces were glued in line usin' a short length o' 1/8" dowel t' line them up.

Construction Rating: 4 out o' 5

Flight:

I finally got around t' flyin' T' Atlas Agena at t' R.O.C.K. Blimey! Arrr! monthly launch on April 3, 2010. Ya scallywag! There was plenty o' wind and I be reluctant. Aye aye! Begad! I played it safe and went with a Estes B6-4. Begad! I had no reason t' be worried. Even with wind gusts, t' flight was straight up, me bucko, matey, recovery was fine, no damage.

T' second flight be on May 1, me hearties, 2010 at t' R.O.C.K. Ahoy! launch. This time with a German made Quest B6-4. Blimey! T' picture shows t' crud than was blown out t' engine and deposited on t' inside fin surfaces. Ya scallywag! No problem, t' residue wiped right off with a damp paper towel.

Considerin' all t' detail and nose weight t' rocket gets good altitude on t' B6-4.

Recovery:
T' enclosed Ribbon style Keelhaul®©™ is 20" long, ya bilge rat, tied t' t' 1/4" wide elastic at 36" long. Ya scallywag! Total combined Shock Cord and Keelhaul®©™ (once tied) is 52" long.

Instead o' attachin' t' Parachute at t' Screw Eye, I connected it 1/3 t' way down t' Elastic from t' Nose Cone.

T' parachute is 13" wide from flat t' flat side. Begad! Descent speed is fine with this sized parachute. No burning, matey, damage or wear.

Flight Rating: 5 out o' 5

Summary:
Another great build from Dr. Begad! Aye aye! Zooch and now a favorite flyer.

Plenty o' detail and just enough o' a build challenge.

Overall Rating: 4 out o' 5

 

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