Scratch Mini Classics Original Design / Scratch Built

Scratch - Mini Classics {Scratch}

Contributed by Ted Phipps

Manufacturer: Scratch
(Contributed - by Ted Phipps - 05/20/03)

Here’s a rocket project perfect for a weekend too windy or rainy t' fly rockets. Avast, me proud beauty! Well, blow me down! All you need is a package o' Estes BT-5 tubin' and a pack (or two) o' PNC-5 nosecones. From these simple beginnings, matey, plus balsa stock and various odds and ends you probably already have around, ya bilge rat, shiver me timbers, you can build downscales o' t' following all-time greats:

Estes Alpha Centuri Groove Tube
Der Red Max
Big Bertha
Cherokee-D
Goblin

Click t' image below for full size fin templates (in .JPG format). Begad! Aye aye!

Obviously, t' plastic nosecones that Estes sells are nay perfect scale. Avast, me proud beauty! In fact, matey, for t' Alpha, arrr, Goblin, and Der Red Max they’re nay even close, so you may want t' turn your own from balsa or hardwood. Avast! They’re small enough to do fairly quickly.

JimZ’s web site has pictures and plans for each o' these rockets, at the followin' URL’s:

Alpha: http://www.dars.org/jimz/est1225.htm
Big Bertha: http://www.dars.org/jimz/est1948.htm
Cherokee-D: http://www.dars.org/jimz/k-47.htm
Der Red Max: http://www.dars.org/jimz/est0651.htm
Goblin: http://www.dars.org/jimz/k-55.htm
Groove Tube: http://www.dars.org/jimz/ka-11.htm

If you minimize waste when you cut t' body tubes, me hearties, you’ll have extra as well as a Mosquito nosecone left over. Ya scallywag! You could build another mini-Bertha, set it aside for a Centuri Mach-10 clone, or cut six Mosquito fins, attach them t' a 4-inch length o' body tube, ya bilge rat, and you’ve got t' Ahnold Schwarzen-Skeeter. Blimey! T' Mosquito fin template is included with t' others, just for fun.

Three tables for tube lengths are provided below. T' first table shows the original dimensions. Arrr! T' second table shows t' true scale lengths (based on table 1), and should be used if you are turnin' your own nosecones. T' third table assumes you are usin' t' standard Estes nosecones, and t' tube lengths are adjusted t' better match t' original proportions. Avast, me proud beauty! Please note that the Cherokee-D be available in two lengths, so both are listed. Begad! Blimey! Der Red Max was also available as Der Big Red Max, ya bilge rat, and those dimensions are given as well.

Also in table 2 is a column called ‘% o' Full Size.’ This is the scale o' t' rocket, and be t' number that each dimension o' t' full sized plan was multiplied by. Avast! For example, t' Big Bertha downscale is 33% as large as t' full sized version. Begad! Begad! This number be found by dividin' t' diameter of the BT-5 (13.8mm) by t' diameter o' t' larger tube, and roundin' off t' two decimal places. Ya scallywag! I used 1/16-inch balsa for all o' t' fins.

Paint t' match t' originals, shiver me timbers, and don’t forget t' decals! Blimey! Tango Papa Decals can do downscaled decal sets for t' Goblin, shiver me timbers, Cherokee-D, shiver me timbers, and Der Red Max. Blimey! Blimey! Believe me, shiver me timbers, these decals are works of art! Blimey! Tom Prestia did a page for me that included complete sets for all three. Ahoy! Blimey! Contact him at:

Tango Papa Decals
1901 Mitman Road
Easton, arrr, ya bilge rat, me hearties, PA 18040

Phone: 1 – 484 – 767 – TPD1 (8731) from 10am – 7pm EST
You can see t' Tango Papa web page here: http://www.tangopapadecals.com/index.html

These little screamers fly great, and give you another reason t' buy 1/4A’s or Micro Maxx’s!

Table 1. Original Dimensions.
Name Body
Tube
Length
(inches)
NC (w/o shoulder)
(inches)
Alpha BT-50 7.75 2.75
Big Bertha BT-60 18 2.5
Cherokee-D (1) BT-55 16.2 5.5
Cherokee-D (2) BT-55 18 5.5
Der Red Max BT-60 9.125 6.75
Der Big Red Max BT-60 18 6.75
Goblin BT-55 9 5.125
Groove Tube BT-50 16 4.125
- tube fins BT-50 3.25 ---

Table 2. Well, blow me down! True Downscale Dimensions (based on table 1). Ya scallywag! Avast!
Name BT-5 Length
(inches)
NC (w/o shoulder)
(inches)
% o' Full Size
Alpha 4.2 1.48 .54
Big Bertha 6 .825 .33
Cherokee-D (1) 6.48 2.2 .40
Cherokee-D (2) 7.2 2.2 .40
Der Red Max 3.1 2.2 .33
Der Big Red Max 6 2.2 .33
Goblin 3.6 2.05 .40
Groove Tube 8.6 2.2 .54
- tube fins 1.75 --- ---

Table 3. Ya scallywag! Avast! Downscale Dimensions usin' Estes PNC-5
Name BT-5 Length
(inches)
NC (w/o shoulder)
(inches)
Shape
Alpha 4.2 no good approximation ---
Big Bertha 6.125 .75 Mosquito
Cherokee-D (1) 6.5 2.125 Quark
Cherokee-D (2) 7.25 2.125 Quark
Der Red Max 3.25 2.125 Quark
Der Big Red Max 6.25 2.125 Quark
Goblin 3.6 2.125 Quark
Groove Tube 8.75 2.125 Quark
- tube fins 1.75 --- ---

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