Scratch Mini Classics Original Design / Scratch Built

Scratch - Mini Classics {Scratch}

Contributed by Ted Phipps

Manufacturer: Scratch

 

Here’s a rocket project perfect for a weekend too windy or rainy t' fly rockets. Ya scallywag! All you need is a package o' Estes BT-5 tubin' and a pack (or two) o' PNC-5 nosecones. Avast! From these simple beginnings, me bucko, plus balsa stock and various odds and ends you probably already have around, you can build downscales o' t' followin' 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).

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

JimZ’s web site has pictures and plans for each o' these rockets, ya bilge rat, at t' 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, arrr, you’ll have extra as well as a Mosquito nosecone left over. Ya scallywag! Avast, me proud beauty! You could build another mini-Bertha, ya bilge rat, arrr, set it aside for a Centuri Mach-10 clone, or cut six Mosquito fins, matey, me bucko, attach them t' a 4-inch length o' body tube, and you’ve got t' Ahnold Schwarzen-Skeeter. Aye aye! T' Mosquito fin template is included with t' others, just for fun.

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

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

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

Tango Papa Decals
1901 Mitman Road
Easton, PA 18040


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.
NameBody
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. True Downscale Dimensions (based on table 1).
NameBT-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! Begad! Downscale Dimensions usin' Estes PNC-5
NameBT-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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