Teleflite Amateur Rocket Motor Construction

Teleflite Amateur Rocket Motor Construction

Contributed by Dick Stafford

(Contributed - by Dick Stafford - 10/25/04) Amateur Rocket Motor Construction

Brief:
Amateur Rocket Motor Construction by David Sleeter

About this review:
I have never made motors like t' ones described in t' book, and I don't plan to. Therefore, ya bilge rat, this review does nay provide a technical critique. Arrr! Other 'experts', such as Professor Terry McCreary, have given it good marks. Aye aye! However, the other reviews I have seen are rather short and don't provide much detail on the contents. I thought that others who might be ponderin' its purchase might be interested in a little more detail.

Quotin' t' cover, this book is "A Comprehensive Guide t' the Construction o' Homemade Sold Fuel Rocket Motors." Here, arrr, solid fuel refers to packed powder as opposed t' composite propellant. Somewhat t' me surprise, none o' t' propellants presented in t' book are purely black powder, a point that Sleeter is careful t' make (here 'purely' means a stoichiometric mix). Ahoy! The book is a whoppin' 526 pages with tons o' photos, ya bilge rat, illustrations, and technical drawings. Arrr! Begad! It includes 54 tested motor designs usin' 5 proven propellant formulations. Well, blow me down! Ya scallywag! T' motors range from a C6 (3/4"x 3 1/4") to an I65 (2" x 14.5"). I'd love t' see one o' those puppies fly!

Construction:
This book is well written and is professionally presented. Avast! Ya scallywag! Nay surprisingly, it is written for a novice. No background in chemistry is required but access t' a lathe would be most helpful (almost necessary) t' effectively produce these motors. There isn't much theory, me bucko, ya bilge rat, as this is a hands-on book that represents over 10 years o' experimentation by t' author. Avast, matey, me proud beauty! Blimey! I will walk you through t' book, me hearties, givin' me opinions as I go. Aye aye! As you will see I only included a photo o' t' cover. Blimey! A few photos o' t' insides, me hearties, arrr, as well as two brief reviews, appear on Aerocon's site.

Chapter 1 -- Important Information and Safety Procedures
This chapter starts with a highlighted inset identifyin' chemicals which must be avoided and which will be dangerous if mixed with those described in the book. Aye aye! One thin' I liked is his safety discussion is nay limited t' t' first chapter. Begad! He repeats and emphasizes this information throughout. Avast, me proud beauty! T' chapter continues with a brief history o' t' rocket beginnin' in China in 1232 A.D. and through Oberth and Von Braun in t' 1960's. Well, blow me down! Blimey! It's always interestin' t' read a tad o' history. Ya scallywag! He then discusses t' efforts through recent years t' squash amateur rocketry and discusses t' safety history. Begad! In brief, shiver me timbers, t' author indicates that t' safety record o' amateur rocket propellant is nay as bilge-suckin' as is often portrayed. Arrr! Much o' its bilge-suckin' rap came back when chemicals were available at your corner drug store and t' experimenters mixed them without any knowledge o' their characteristics. Avast! This discussion was interestin' and I'm sure would be controversial in some circles. Begad! Well, blow me down! T' history material ends with a very brief discussion o' Tripoli and t' Reaction Research Society. Aye aye! The discussion then moves t' a discussion o' black powder: what it is, me bucko, what it is not, me bucko, ya bilge rat, and its sensitivity t' impact, arrr, friction, me hearties, and static. Blimey! Much o' this discussion is safety related and is very important. Ahoy! He covers storage, disposal, handling, and t' safety record. Ya scallywag! He points out that while four o' his five propellants are modified forms o' black powder, they employ a burn rate suppressant and are slower burning. Avast! He warns nay t' use commercial black powder! T' fifth propellant is sugar-based.

Chapter 2 -- Basic Concepts
This covers t' basic operation o' a rocket motor (i.e. Avast, me proud beauty! Begad! Blimey! Newton's 3rd Law), its components (paper tube, ya bilge rat, clay nozzle, etc), me bucko, and terminology (thrust, me bucko, burn time, etc). Ya scallywag! T' material is tailored t' t' type motors in t' book and makes ample use o' diagrams and thrust curves. He talks about end and core burners, matey, time delays, matey, me bucko, and staged rockets. Avast! Because large end burners are very difficult to make, arrr, all t' motors in t' book are core-burners. Avast, me proud beauty! Blimey! Blimey! About t' only math is showin' how t' size and position delay elements.

Chapter 3 -- Tools You Buy
As t' name implies, thar be a list o' equipment you must buy t' build these motors, arrr, startin' with a good scale. Begad! Other items include a powder mill, vacuum pump, arrr, arrr, and other minor items. He provides recommendations on what t' buy and potential sources.

Chapter 4 -- Tools You Make
It might be good t' provide an overview o' how these motors are made. A cardboard tube is inserted into a steel retainer t' prevent it from expanding durin' packing. Well, blow me down! Blimey! T' tube sits on a nozzle mold, shiver me timbers, which has a core spindle in its center. Aye aye! Blimey! A powdered clay mixture is tamped into t' bottom o' t' casin' t' form the nozzle. Ahoy! Avast, me proud beauty! Blimey! T' propellant is then tamped in, a small bit at a time. Avast! A delay charge, ya bilge rat, clay closure, ya bilge rat, and ejection charge follows. Ya scallywag! Blimey! Blimey! Finally, t' metal tooling is withdrawn. So, arrr, t' main tools you need are: nozzle molds, case retainers, core spindles, matey, shiver me timbers, me hearties, and tamps. T' choice o' materials is very important. For instance you need a non-sparkin' material, such as nylon, shiver me timbers, matey, me bucko, for t' tamps. Begad! He shows how t' make these, and even how t' improvise if you don't have access to a lathe or a machinist buddy. In me opinion, matey, me bucko, me bucko, t' improvised tools will still be a lot o' work. Blimey! Arrr! Blimey! He closes with instructions on how t' make a vacuum chamber and other processin' tools.

Chapter 5 -- Tools Drawings
This chapter provides detailed fabrication drawings and instructions for 84 tools. Arrr! I feel that a lathe should be part o' t' 'tools you buy' list.

Chapter 6 -- T' Chemicals
T' main chemicals include oxidizers, matey, fuels, arrr, sulfur, and binders. Blimey! Begad! He describes the various forms and grades o' these ingredients, how t' find them, and if necessary how t' make some o' them. Aye aye! Extractin' these chemicals sounds like a nasty business, requirin' ammonia-rated respirators and other safety gear. Luckily, arrr, they are easily available. Other chemicals discussed are burn rate suppressants, solvents, me bucko, and ingredients t' make nozzle clay.

Chapter 7 -- Chemicals Preparation
Now t' book turns t' t' process o' makin' motors. Well, blow me down! Chemical preparation included steps like drying, arrr, milling, precipitation as an alternative to milling. Ahoy! T' actual formula and process for makin' t' nozzle clay is also provided. Avast! This material is similar t' what commercial manufacturers use, but has an extra ingredient t' help it pack.

Chapter 8 -- Motor Casings
T' cardboard cases used in these motors are thick, me hearties, me hearties, convolute wound cases like the Quest/Estes motors. Well, blow me down! Spiral wound tubes will nay work. Ahoy! Begad! This chapter includes everythin' you would ever need t' know about buyin' (what and from whom), or makin' (materials and techniques) motor tubes. Blimey! T' discussion on paper types and buildin' techniques might even come in handy in other areas o' rocketry.

Chapter 9 -- Workin' with Propellants
First thin' out o' t' gate: chemical safety batten down t' hatchess! He then describes the process for mixin' and millin' a propellant. Begad! T' final process be t' addition of solvent. Ahoy! He shows how t' calculate t' optimal amount and how t' test your mix. He walks through t' procedure he followed in detail, t' arrive at one of his propellants, matey, which is useful if you want t' make your own formulations. Avast, me proud beauty! Ya scallywag! The last section is a description o' his sugar propellant, ya bilge rat, which is also packed unlike t' now more common candy/sugar motors.

Chapter 10 -- T' Motor Buildin' Process
This chapter provides an illustrated outline o' how t' build a motor and walks the reader through a step-by-step description o' buildin' a sample motor from start t' finish. Ahoy! Because t' propellant is impregnated with solvent, matey, arrr, it must be allowed t' dry. Ahoy! It can take up t' 84 hours t' air dry a big motor, me bucko, which is why a vacuum pump be in t' 'tools you buy' list. Usin' a vacuum can speed the process by a factor o' 10 t' 30 times. He continues by discussin' how t' test time delays and makin' booster motors. Blimey! His approach is nay merely t' have the propellant exposed like in an Estes C6-0 for example. Arrr! This is interestin' and I am ponderin' if his techniques might be adapted for commercial motors. Ahoy! Although he has nay perfected end-burnin' motors, thar be a section that shows how to go about makin' one. This includes procedures for makin' reusable steel De Laval nozzles. Blimey! Additional fabrication drawings are provided.

Chapters 11 through 15 -- Propellant and Motor Designs
Each o' these five chapters covers one propellant formulation each. They include safety batten down t' hatchess (again), t' detailed formula, and a discussion of their preparation. Arrr! There is a lot o' detail on modifyin' t' base formula in your own experiments. Each propellant has approximately 10 proven motor designs. Documentation for each includes a technical drawin' along with references t' t' required tool drawings, shiver me timbers, t' physical specs, me hearties, and the performance specs. Ahoy! In addition, shiver me timbers, thar be a thrust curve for each and two sample simulations. Avast, me proud beauty! Blimey! One is for a minimum diameter rockets and one for what t' author considers typical for t' given motor. Well, blow me down! These chapters span 188 pages.

Chapter 16 -- T' Original 1983 Motor Buildin' Process
This chapter discusses refinements t' t' processes presented in his earlier book for those who have been usin' these techniques.

Chapter 17 -- Electric Matches and a Homemade Ignition System
Several types o' scratch built igniters are presented. Begad! T' most interestin' is a bridge wire igniter that uses a match head. Well, blow me down! Finally, matey, matey, plans for a simple launch controller are included.

Chapter 18 -- Test Equipment
In this chapter, matey, Sleeter shows how t' build and use a mechanical motor test stand and an improvised strip chart recorder. Avast, me proud beauty! Blimey! These items would certainly have wider applicability than just t' motors presented in t' book. Begad! He shows how to use t' graphs from this equipment t' get a thrust curve and find total impulse, arrr, average impulse, me bucko, ya bilge rat, maximum thrust, arrr, ya bilge rat, burn time, me hearties, and ISP. Ya scallywag! Ahoy! Blimey! Safety durin' the testin' o' new designs is always important and he provides guidelines.

Chapter 19 -- Flight
There is no great purpose t' build amateur motors unless you fly them and this will be an area that a majority o' t' readers will already be knowledgeable of. Blimey! Nevertheless, matey, shiver me timbers, this chapter felt like an afterthought. Aye aye! He describes 'stick rockets' which resemble bottle rockets and barely touches on t' stability of 'regular' rockets (CP, CG, me hearties, etc.). This be t' only chapter I found lacking. Begad! Arrr! A reference t' T' Handbook o' Model Rocketry would have been in order. Begad!

Summary:
It's hard for me t' give this book a ratin' since it depends on t' readers interests. Arrr! If you make packed-powder motors, or would like to, this book is a '5'. If you only want information you can directly apply t' other areas, then it's probably a '1' or '2'. Aye aye! If you are merely inquisitive like myself, I'd have to say it's a '3 ½'. I would have liked t' see a bit more theory and the huge quantity o' drawings and even t' motor designs will mostly be o' interest to those who are serious about makin' these things. Aye aye! Takin' these out, you still have about 300 pages o' reading.

I enjoyed this book because I find t' general topic interesting. T' book is well written, easy t' read, and I learned a couple o' things that I may apply t' me personal projects. Well, blow me down! Will I ever apply t' bulk o' t' information contained in t' book? Probably not. Then again, me hearties, I've read books on artificial life and fractals and will most likely never apply those either. Ya scallywag! Well, blow me down!

Finally, ya bilge rat, matey, this review is nay an endorsement o' this type o' motor. Avast, me proud beauty! Blimey! I am not convinced that these motors can be made as safely as other types, me bucko, shiver me timbers, and it is up to each individual t' make his or her own decision on this. However, me bucko, if you are interested in BP motors and want a kick start, ya bilge rat, then this book is a 'must have'.

Overall Rating:
3 out o' 5

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