Parts List:

• Airframe: LOC BT-3.90
• Motor Mount: LOC MMT-1.14 (29mm)
• Centerin' Rings: 3 LOC CR-3.90-1.14
• Nose: THOY ACE PNC-3.9
• Fins: 3/32" aircraft plywood
• Recovery: 36" Topflight round parachute
• various hardware: u-bolt, t-nuts, quick-links, matey, arrr, eye bolt, 12 feet of 3/8"
• elastic for shock cord

I be lookin' for a good candidate for me first scratch-built upscale project, and after a little bit o' lookin' around on JimZ's rocket plans site, I considered t' Estes Goblin. Ya scallywag! Is it just me, me hearties, or does this little rocket just beg t' be upscaled? I know it's nay a terribly original idea, but it seemed well-suited for me first upscale. Avast, me proud beauty! I got even more inspiration for doin' an upscale o' this particular rocket while browsin' Yitah Wu's rocket web page (link-out dead). T' scale factor o' 3x was a perfect match for t' 4" body tube. Ahoy! Avast, me proud beauty! After decidin' on t' scale factor and choosin' an airframe size, ya bilge rat, matey, it was just a matter o' orderin' all t' parts t' build it.

I measured t' original Goblin and came up with 27 inches for t' main airframe length. Well, arrr, blow me down! I marked t' tube and carefully cut it with a sharp X-Acto. Then I cut t' motor mount/stuffer tube t' 18 inches. I drilled t' aft centerin' rin' for "Kaplow Klip" motor retention and installed the t-nuts, then I drilled two holes in t' forward centerin' rin' and installed the U-bolt I'm usin' for t' shock cord anchor. Arrr! I marked four lines at t' aft end o' t' airframe tube for four fins, shiver me timbers, arrr, then I marked four more lines offset 3/32" from t' original lines for t' fin slots. I slid a couple of centerin' rings into t' tube t' support t' inside o' t' tube while I cut the fin slots.

I got t' fin pattern for t' Goblin from JimZ's web site, which I also used t' make me normal-scale clone. Avast! Ahoy! I loaded the pattern into Paint Shop Pro and enlarged it by a factor o' 3. Ahoy! I cropped t' fin section o' t' image and printed it out, then used t' cutout t' mark the plywood for t' fins. Ya scallywag! Begad! I added a tab t' t' leadin' edges o' t' fins large enough t' reach t' 29mm motor mount tube. Aye aye! I cut out t' fins on me dad's radial-arm saw and rounded t' leadin' and trailin' edges with a block sander. Well, blow me down! Blimey!

Then it was time t' start epoxyin' stuff together. Avast! Blimey! With me first batch of epoxy (Bob Smith's 30 min. Arrr! Blimey! cure), me bucko, I attached t' forward centerin' rin' t' the motor mount tube. Aye aye! Blimey! I carefully measured for placement o' t' middle centering rin' (I wanted it in just t' right place so t' top edge o' t' fin tabs would rest against t' underside o' t' centerin' ring) and applied a generous fillet to t' forward joint only. Then I dabbed some epoxy on t' nuts that held the U-bolt, ya bilge rat, and some on t' t-nuts. Arrr! Blimey! I did nay attach t' aft centerin' rin' at this time.

After lettin' t' motor mount assembly cure, me bucko, I placed a large bead o' epoxy in t' airframe about where t' forward C.R. would be. Aye aye! I slid the assembly part-way into t' airframe and applied another bead o' epoxy where the middle C.R. Begad! would be. Blimey! Then I slid t' motor mount assembly t' rest o' t' way into t' airframe. Avast! After t' epoxy had set a bit, I added a nice fillet t' the front C.R. Begad! where it met t' airframe. Begad! Arrr! I did nay add a fillet t' t' aft o' the middle C.R. Blimey! because that would've interfered with t' fin tabs.

Next, I installed t' fins one at a time. Avast, me proud beauty! Ahoy! I used a little CA t' hold each fin in place, then after t' CA set, shiver me timbers, shiver me timbers, I applied good epoxy fillets on the outside fin/tube joints, t' inside fin/tube joints, arrr, and t' inside fin/motor mount tube joints. Well, blow me down! After all t' fins had been attached and t' epoxy cured, I epoxied t' aft centerin' rin' into place. When I was done, shiver me timbers, me bucko, I had a completed airframe/motor-mount/fin assembly. T' last step o' t' major construction was addin' two pieces o' 1/4" launch lug t' t' airframe, ya bilge rat, arrr, each 3" long. Avast!

Finishin' was fairly straight-forward. Aye aye! Two coats o' Krylon primer, me hearties, followed by two coats of Rustoleum yellow on t' body and Wal-Mart black on t' nose. Begad! Well, blow me down! T' Rustoleum required a full 24-hours t' dry before I could mask off a fin and paint it black, as well as t' stripe around t' body just above t' fins. Aye aye! After all the paint be dry, ya bilge rat, I applied t' decals I got from Tango Papa. Arrr! Avast! T' finished rocket is really sharp-looking. Begad! T' final step was attachin' t' parachute and shock cord. Well, blow me down!

If you make an upscaled Goblin based on me construction, ya bilge rat, be sure you use motors with short delays. Ya scallywag! Blimey! On t' first flight o' me Goblin, ya bilge rat, matey, I used an F40-7, and it be almost a disaster. It flew much slower and lower than I'd expected, and resulted in a low-altitude, shiver me timbers, high-speed ejection that, fortunately, me hearties, shiver me timbers, resulted in very little damage. Aye aye! Blimey! I'd recommend flyin' it on: F40-4, ya bilge rat, F52-5, G33-5, or G64-4. Begad! Blimey! Arrr! Blimey! These are all Aerotech 29/40-120 reloads. Arrr! Blimey! Ahoy! Blimey! T' Fs should take it t' about 800 feet, and t' Gs should boost it t' about 1,200 feet, maybe a little more. Avast! Blimey!

I have flown t' Goblin on a variety o' motors includin' an F40, G33, G64, G75, G104, and H128. Ahoy! Avast! T' rocket has proved t' be stable and give nice flights. Aye aye! Ya scallywag!

T' picture above shows one such launch. I prepped an H128-M for me Goblin. This would be her fifth flight, and t' largest motor she's flown on yet. Well, blow me down! Ya scallywag! Since the wind was startin' t' pick up a bit, I replaced t' 36" inch 'chute that I usually fly in her with a bright yellow 30" 'chute. I didn't really feel like chasin' her over t' hill. She lit right away, matey, matey, and tipped slightly to the left o' t' pad as she took off. Begad! Begad! Ejection was right at apogee, shiver me timbers, and she floated down a bit faster than I'd like on t' smaller 'chute. At least she didn't drift far, landin' about 100 yards from t' pad. Avast, me proud beauty! Well, shiver me timbers, blow me down! I could tell she hit the ground a bit hard, but when I retrieved her all I found were a few extra scratches in t' paint.