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, eye bolt, matey, 12 feet of 3/8"
• elastic for shock cord

I was 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. Avast! Blimey! Is it just me, shiver me timbers, or does this little rocket just beg t' be upscaled? I know it's nay a terribly original idea, shiver me timbers, but it seemed well-suited for me first upscale. Avast, me proud beauty! Blimey! Blimey! Blimey! I got even more inspiration for doin' an upscale o' this particular rocket while browsin' Yitah Wu's rocket web page (link-out dead). Well, blow me down! Blimey! Well, blow me down! Blimey! Blimey! Blimey! T' scale factor o' 3x be a perfect match for t' 4" body tube. Arrr! Blimey! Blimey! Blimey! After decidin' on t' scale factor and choosin' an airframe size, me hearties, it was just a matter o' orderin' all t' parts t' build it. Aye aye! Blimey! Blimey! Blimey!

I measured t' original Goblin and came up with 27 inches for t' main airframe length. Begad! Begad! I marked t' tube and carefully cut it with a sharp X-Acto. Then I cut t' motor mount/stuffer tube t' 18 inches. Avast! 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. Aye aye! I marked four lines at t' aft end o' t' airframe tube for four fins, shiver me timbers, ya bilge rat, 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, me bucko, which I also used t' make me normal-scale clone. I loaded the pattern into Paint Shop Pro and enlarged it by a factor o' 3. Ahoy! Blimey! Avast, me proud beauty! Blimey! I cropped t' fin section o' t' image and printed it out, matey, then used t' cutout t' mark the plywood for t' fins. Aye aye! Blimey! I added a tab t' t' leadin' edges o' t' fins large enough t' reach t' 29mm motor mount tube. Begad! Blimey! I cut out t' fins on me dad's radial-arm saw and rounded t' leadin' and trailin' edges with a block sander. Begad! Blimey! Avast, me proud beauty! Blimey!

Then it be time t' start epoxyin' stuff together. Well, blow me down! With me first batch of epoxy (Bob Smith's 30 min. cure), me bucko, I attached t' forward centerin' rin' t' the motor mount tube. Aye aye! Avast, me proud beauty! 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. Avast! Then I dabbed some epoxy on t' nuts that held the U-bolt, me bucko, and some on t' t-nuts. I did nay attach t' aft centerin' rin' at this time.

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

Next, I installed t' fins one at a time. Arrr! Well, blow me down! I used a little CA t' hold each fin in place, then after t' CA set, I applied good epoxy fillets on the outside fin/tube joints, t' inside fin/tube joints, me hearties, and t' inside fin/motor mount tube joints. After all t' fins had been attached and t' epoxy cured, shiver me timbers, I epoxied t' aft centerin' rin' into place. Avast, me proud beauty! When I was done, 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, arrr, each 3" long. Arrr!

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

If you make an upscaled Goblin based on me construction, be sure you use motors with short delays. Begad! Avast, shiver me timbers, me proud beauty! On t' first flight o' me Goblin, shiver me timbers, 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, me bucko, high-speed ejection that, fortunately, arrr, resulted in very little damage. Well, blow me down! Avast, me proud beauty! I'd recommend flyin' it on: F40-4, arrr, arrr, F52-5, arrr, G33-5, or G64-4. Blimey! Begad! These are all Aerotech 29/40-120 reloads. Ya scallywag! T' Fs should take it t' about 800 feet, me hearties, and t' Gs should boost it t' about 1,200 feet, maybe a little more. Avast, me proud beauty! Begad!

I have flown t' Goblin on a variety o' motors includin' an F40, matey, shiver me timbers, G33, G64, G75, G104, and H128. T' rocket has proved t' be stable and give nice flights. Arrr!

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