Scratch Goblin-MMX Original Design / Scratch Built

Scratch - Goblin-MMX {Scratch}

Contributed by Gene Wolski

Manufacturer: Scratch
Style: Downscale

(Scratch) MMX GoblinBrief:
This rocket is me tribute t' t' Goblin which is one o' me all time favorite rockets. Avast, arrr, me proud beauty! I be inspired t' build this rocket after stumblin' over plans for a diminutive paper Goblin on t' internet and realizin' that I had a Quark nose cone and BT-5 tube in me supplies box. How convenient!

Construction:
From me supplies box:

  • PNC-5A nose cone (from Estes Quark)
  • BT-5 body tube, me bucko, 3.75"
  • 1/16" balsa fin stock
  • Mylar streamer, 1/2" x 6"

From FlisKits:

  • 0.010" launch lugs, 1/4" long
  • EB-2.5 MicroMaxx engine block
  • CRF-2.5-5 centerin' rings, arrr, matey, qty 2
  • BT-2.5-0112 motor tube
  • 16 lb Keelhaul®©™ thread, 10"

Construction be straightforward. Begad! Ahoy! I printed out t' paper Goblin plans and measured t' body tube length (3.75" inches). Well, blow me down! Begad! I then cut t' BT-5 t' length and startin' fittin' t' Quark nose cone. Ya scallywag! It took some minor sandin' o' t' nose cone shoulder t' get t' proper fit. Blimey! I had ordered parts from FlisKits which arrived promptly as always. Ahoy! I started assemblin' t' motor mount by installin' t' engine block in t' motor tube usin' an expended MicroMaxx motor. Avast! Ya scallywag! I placed a small drop o' glue in t' motor tube, swirled it with a toothpick, then inserted t' expended motor until about 1/8" was stickin' out o' t' tube. Begad! I removed t' motor casin' and set t' tube aside t' dry.

Once t' engine block had dried, shiver me timbers, me bucko, matey, I glued t' forward centerin' rin' flush with t' forward end o' t' motor tube. Blimey! Blimey! I then glued t' aft centerin' rin' 1/8" from t' end o' t' motor tube. Blimey! I tied a slip knot on one end o' t' Keelhaul®©™ thread and placed it over t' motor tube, pulled t' knot tight, then ran t' loose end through t' notch in t' forward centerin' ring. Avast! Avast! Blimey! I secured t' Keelhaul®©™ with a couple drops o' glue.

In preparation for installin' t' motor mount in t' body tube, arrr, I ran t' loose end o' t' Keelhaul®©™ back through t' motor tube. Ahoy! Ya scallywag! I placed a couple drops o' glue in t' body tube, swirled it with me trusty toothpick, then installed t' motor mount with t' aft centerin' rin' flush with t' end o' t' body tube.

I printed out a fin markin' guide usin' VCP and marked t' fin locations and launch lug line on t' body tube. I then used a sharp hobby knife and metal straight edge t' cut t' fin pattern out from t' paper plans. Begad! I cut out four fins from t' 1/16" balsa and rounded t' leadin' and trailin' edges with sandpaper. Aye aye! I glued t' fins on t' body tube and applied several thin coats o' glue for fillets, me hearties, sandin' smooth after each. Well, blow me down! Begad! I then glued t' launch lugs flush with t' top and bottom o' t' body tube.

 

Finishing:
I didn't spend a lot o' time sealin' t' balsa fins, shiver me timbers, matey, so finishin' be pretty straightforward. Avast, me proud beauty! I applied one coat o' gray primer, ya bilge rat, me bucko, sanded smooth, then painted t' final color coats. Begad! I painted t' body yellow and t' nose cone red t' match t' non-standard paint scheme on me full size Goblin. Well, blow me down! After painting, ya bilge rat, I used CA t' attach a small block o' plastic inside t' nose cone t' anchor t' top end o' t' Keelhaul®©™ shock cord. Aye aye! Begad! I attached t' mylar streamer t' t' shock cord usin' a small piece o' mylar tape. My micro Goblin be ready t' fly!

 

Flight and Recovery:
To prepare t' micro Goblin for its maiden flight, I put a small ball (1/4" deep) o' waddin' in t' body tube, folded t' streamer, and packed everythin' loosely in t' body tube before puttin' on t' nose cone. Blimey! Avast! I installed an MMX motor in t' motor tube and secured it with a short piece o' 1/4" maskin' tape. Blimey! After walkin' out t' front door t' me local micro test range (front yard), I put a fresh igniter in t' silo launch and put t' Goblin on t' launch rod. Avast! After a quick (I mean quick) countdown by me 3 year old son, t' Goblin ripped into t' air for a near perfect flight. Avast, me proud beauty! Avast! It landed in t' street with no damage.

Success! Blimey! T' micro Goblin be now ready for its debut at our next club launch on 2/15/09. Launch at t' club was picture perfect! Blimey! Third and fourth launches from t' front yard were excellent as well. T' Goblin is a great flyin' rocket!

Summary:
Buildin' t' micro Goblin be a great experience. Begad! I found t' buildin' and launchin' as rewardin' as any o' me other low/mid/high power rockets. You really can't beat rockets that fit in a shoebox which can be launched in t' front yard!

comment Post a Comment