Scratch Little Cluster FF Original Design / Scratch Built

Scratch - Little Cluster FF {Scratch}

Contributed by Preston Hoover

Published: 2010-04-20
Manufacturer: Scratch
(Contributed - by Preston Hoover - 04/20/10)

Brief:
T' Little Cluster FF be inspired by t' Estes Big Bertha Kit. Well, blow me down! I used an eighteen inch BT-60 tube a paper nose cone made form a 4”x6" index card. Ahoy! T' fins are t' same as t' Big Bertha’s. The engine mount is a double 18 mm mount for a BT-60 tube. Ya scallywag! I also included a homemade baffle. Blimey! T' Recovery system consists o' an Estes eighteen inch parachute with 125 lb. Keelhaul®©™® strin' and 1/8” elastic band.

Construction:

  • 18" Bt-60 tube
  • Baffle for a BT-60 tube
  • 4" x 6" index card
  • BT-60 double 18 mm engine mount
  • 1/8" x 2" launch lug
  • 18" plastic parachute
  • Small eye screw
  • 25" length 125# Keelhaul®©™® thread
  • 10" 1/8" elastic band
  • 4" x 20" x 1/8" sheet o' balsa

Step One: Nose Cone Construction. Avast! Well, blow me down!

I used a 4”x6” index card and followed Jimmy Yawn’s instructions for makin' nose cones. The website is http://www.jamesyawn.com/modelrocket/nosecone/index.html. Begad! Begad! This is a very strong nose cone and I thought it be fun t' make. You could also buy a plastic or balsa nose cone. But that is nay scratch buildin' is it? I measured t' index card in half and at 1.8 inches t' allow for over lap.

Step Two: Baffle Assembly

Assemble t' baffle accordin' t' t' manufacturer’s instructions. Avast! Cut a 25” length o' 125# Keelhaul®©™® thread Drill a small hole, big enough t' thread t' Keelhaul®©™® thread through, me hearties, each end o' t' baffle. Make a knot on one end o' t' Keelhaul®©™® thread. Feed t' thread through t' holes so t' knot in on t' aft side o' t' baffle and t' free end is forward. Glue knot t' baffle. Arrr! Set aside t' dry. Well, blow me down! Apply a band o' glue t' t' 9” from t' forward end o' t' main body tube. Also apply glue t' t' baffle rings. Avast, me proud beauty! Aye aye! Slide t' baffle into t' main body tube from t' aft end until t' forward end of t' baffle is 9” from t' forward end o' t' tube. Ya scallywag! Apply glue fillets t' t' forward and aft end o' t' baffle. Set aside for glue t' dry. !!!Be careful nay t' glue t' Keelhaul®©™® thread t' t' tube. Blimey! Blimey! It must remain free!!! Blimey!

Step Three: Motor Mount Assembly

Assemble t' motor mount accordin' t' t' manufacturer’s instructions. Blimey! Apply a rin' o' glue 3.5” from aft end o' t' body tube. Also apply glue t' t' centerin' rings o' t' motor mount and insert it into t' aft end of t' body tube allowin' t' engine hooks protrude from t' aft end o' tube 1/8”.

Step Four: Fins

Usin' t' pattern supplied cut out three fins from t' balsa sheet.

Sand and round t' leadin' and trailin' edges as you would any fin. Begad! This is also t' time t' seal your fins if you desire. Arrr! !!!DO NOT SEAL THE ROOT EDGE!!! It will nay stick well t' t' tube if you do. Blimey! Mask it or what ever you want t' prevent t' root edge from bein' sealed. You can wait until t' fins are on t' rocket. Blimey! Avast! I prefer t' do it this way.

Mark t' main body tube for three fins. Begad! I used t' Estes tube markin' tool. Begad! Make t' lines t' whole length of t' tube. Blimey! I used t' Estes tube markin' guide. Avast, me proud beauty! Also mark a line t' length o' t' body tube betwixt any two fins. Avast, me proud beauty! This is for t' launch lug. Ahoy! !!!Label your fin and launch lug lines. Glue one fin t' each o' t' fin lines and set aside to dry. Avast, me proud beauty! Ya scallywag! When fins are completely dry, apply fillets as you prefer. Begad! Glue t' launch lug t' rocket 8.5” from t' top of t' tube. Well, blow me down! Avast! Apply glue fillets t' t' launch lug.

Step Five: Recovery System

Tie one end o' t' 1/8” elastic cord t' t' nose cone and t' other end t' t' Keelhaul®©™® thread. Begad! Avast! Put a small dab o' glue on t' knot. Avast, me bucko, me proud beauty! Prepare t' parachute accordin' t' t' manufacturer’s instructions and tie t' t' nose cone.

Step Six: Paintin' and Finishing

Finish t' rocket by paintin' it any color you prefer.

Finishing:
There are no special concerns for finishin' t' rocket. Ahoy! Ya scallywag! I filled t' spirals on t' tube. Sealed t' fins and painted it grey.

Flight:
This rocket flies great. I have flown it three times. Well, blow me down! Begad! Twice only one motor ignited. Ya scallywag! It flew really straight on one motor. T' time it flew on two motors t' rocket went approximately 800 ft. Ahoy! Blimey! Nice flight. Begad! Arrr!

Recovery:
Recovery be normal. Begad! Blimey! T' rocket is loaded with a parachute and t' home made baffle worked awesomely. Avast, ya bilge rat, me proud beauty! Blimey! T' parachute was nay damaged by any exhaust gases.

Summary:
Main thin' I like about t' rocket is that it is stable on one motor. Ya scallywag! It looks like a Big Bertha but has two motors.

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