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- June 16, 2003 - Volume 1 Number 4 -

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Can the Guy Next Door Build His Own
   Cruise Missile? YES!  [and why that may not be
   the disaster you're expecting!]  - Part I -

   by Larry Cottrill
. . . featuring a jetZILLA EXCLUSIVE:
Bruce Simpson's Response to Part I

   by Bruce Simpson

jetZILLA  JUNE 16, 2003  S P E C I A L   E D I T I O N  -

jetZILLA Online Magazine of Amateur Jet Propulsion Development
    © 2003 Cottrill Cyclodyne Corporation
       [a free subscription e-magazine]
Issue 2003-0616-0104-00                       June 16, 2003
Approx. circulation: Unknown
Publisher:  Larry Cottrill, Cottrill Cyclodyne Corporation, 
                Mingo, Iowa  USA   50168-9500
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I N   T H I S   I S S U E . . .
   Can the Guy Next Door Build His Own Cruise Missile? 
    Yes!  [and why that may not be the disaster 
    you're expecting!] - Part I -
   by Larry Cottrill

   Bruce Simpson Responds to 'Can the Guy Next Door  
    Build His Own Cruise Missile? YES!'
   by Bruce Simpson

   Products, links, ads, etc...

   > Can the Guy Next Door Build His Own Cruise Missile?
     - Part II -

   Who we are, Subscribe, Unsubscribe, Privacy, etc...


 F E A T U R E   A R T I C L E . . .
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Can the Guy Next Door Build 
  His Own Cruise Missile?  YES!
    [and why that may not be the disaster you're expecting!]
  - Part I [June 11, 2003] -
   by Larry Cottrill, Editor, jetZILLA online magazine

Note from the Author: 
All opinions expressed in this series of articles are my own. 
Mr Bruce Simpson was not consulted or interviewed in the
preparation of this article. He may, of course, respond publicly 
or privately at any time, and is especially welcome to point out 
anything he perceives to be in error in my description of his 
activities. This article is not meant to either endorse or 
disparage Mr Bruce Simpson or his ‘D-I-Y Cruise Missile’ project,
and is solely intended to give the public needed information, 
along with another viewpoint, on this topic of interest.


The current spate of interviews with New Zealander Bruce Simpson 
concerning his ‘Do-It-Yourself Cruise Missile’ project has 
brought on a sudden public awareness of the normally obscure 
amateur pulsejet building hobby [an exciting avocation that 
boasts maybe all of 200 participants, world-wide]. Bruce has been 
regarded for some time by those of us engaged in this pursuit as
a genuine authority in the pulsejet hobby field, due to his 
stature as an experimentor and his ability and willingness to 
communicate his detailed knowledge to others, and especially to 
beginners. Bruce has certainly proven that he can be a really 
good teacher.

It came as a shock to many a few months ago when Bruce decided 
to put up a page on his popular Website purporting to educate the
public on how easy it would be for a normally skilled person with
malicious intent to build, from scratch, a small jet-powered 
cruise missile at low cost and without raising any eyebrows when 
procuring the quite ordinary materials needed. The public at 
large was mostly unaware of this project at first, and those not
“in the know” about pulsejet technology greeted the idea with 
understandable skepticism. The Web being what it is, and the 
nature of the project being what it is, public awareness of it 
has grown exponentially. Now, human nature being what it is, so 
has public perception of the project’s credibility.

Bruce is now being touted by the popular media as the only 
living authority on the presumed "terrorist threat" of pulsejet-
powered homebuilt missiles. The rest of the equation is filled in
by a natural and recently heightened fear reaction, especially 
here in the US. Using a bit of imagination, the malicious uses of
such a device are practically limitless: You could spray a 
crowded sports arena with Anthrax or blast a power substation out
of commission with a small conventional explosive; instantly 
pollute the local water treatment plant; in a dry season, start 
massive forest fires overnight. The potential for mayhem is 
seemingly endless.

DynaJet static run with pressure gauge tube in exhaust pipe - photo (c) 2003 Cottrill Cyclodyne Corp. VIEW LARGE
NOISY  HOBBY  OR  HOMELAND  TERROR? A small pulsejet going full roar 20 seconds after cold startup. The thin, bent stainless steel tube inserted into the tailpipe [secured in vise at left] is part of a gas velocity measurement experiment. The engine shown is a standard DynaJet running white gasoline as fuel. This is a fairly small engine, only 21 inches [535mm] long x 2.5 inches [64mm] maximum diameter and weighing 1 lb [approx. 0.5 kg], but many homebuilt engines are much larger. Some types of pulsejets can be homebuilt very simply and inexpensively, with minimal tooling and virtually no machining! Photo Copyright 2003 Cottrill Cyclodyne Corp. IS IT REALLY POSSIBLE? What would you need to do to bring such a scheme to fruition? Well, after some careful planning and design work, you’d have to accomplish, basically, the following: - Build a large, fast, rugged model airplane of sufficient size to carry the deadly payload [and necessary fuel and equipment] successfully to the desired target site - Build a working jet engine out of new and/or scrap metal [mostly some kind of sheet metal, assembled by welding] - Build a guidance system [could be radio controlled, pre-programmed dead reckoning with gyro guidance, GPS guidance, or some combined system] - Build a launching device to get the model up to speed quickly when finally needed [this could supposedly consist of a fast car, van or small truck] - Perform extensive testing, without detection - At the chosen moment in the wee hours, make a fast run down the road and launch your device at the intended target; then beat it back home and wait for the media coverage to start Bruce’s now-famous “construction diary” site page clearly lays out his version of this sequence, broken down in greater detail, under the ‘Project Milestones’ heading. The subheadings will be turned into links to detail pages as the project moves forward. [The link to this page on Bruce’s site is listed at the bottom of this article.] It seems obvious that, at least in Bruce’s capable hands, such a plan is feasible. SO, WHAT’S WRONG WITH THIS PICTURE? EVERYBODY involved in the pulsejet hobby knows you can do this. Probably, every R/C [Radio Control] airplane jockey can at least envision doing it, by assuming that the engine part of the system can be made feasible. It's just a gluing together of lots of over-the-counter technology, put together in a way guaranteeing that everything will work. There is really not much question that it is possible, and that Bruce will succeed at doing it. But here’s the problem with all this: Bruce will get it to work almost entirely because he is Bruce Simpson, with a lifetime of skills and experimentally gained knowledge that make success in such a venture extremely likely. That’s the kind of success an independent terrorist would want, but in the case of a pulsejet powered missile, it’s really not what they’re very likely to get. Here’s why: 1. Just because you can design a pulsejet doesn’t mean you can build it 2. Just because you can design an airframe doesn’t mean you can build it and get it flyable 3. Just because you’ve built the engine doesn’t mean you can run it 4. Just because you can get it running doesn’t mean it will perform well enough to deliver the payload 5. Just because you can get it running right doesn’t mean you can launch it 6. Just because you can launch it doesn’t mean you can pilot it 7. Just because you can pilot it doesn’t mean a robotic system can pilot it to the intended target point I’ll try to substantiate all these claims in Part II. FEELING THE EFFECTS The real danger here is not that professional terrorists will suddenly enlarge their vision to include cheap pulsejet-powered missiles -- they have access to much better technology than this -- but rather, that any malcontent with a grudge against someone [usually 'The Government' or some offending people group] and some money to spend now can imagine he has a place to go to get the ‘recipe’ for something he never could have considered before. Bruce claims that he will never reveal quite as much technical data as would be needed for someone to actually accomplish the terrorist’s goal, and I believe his intentions are good -- but this is making a big assumption about the inability of someone else to ‘fill in the blanks’ in the pattern of something that’s being described in a relatively high degree of detail. I have already received credible reports of pulsejet hobbyists being treated as persona non grata when they shop at the local hardware store for a small spark plug or some scraps of sheet metal, just because they mention they are working on their own pulsejets. In view of Bruce’s newfound credibility with the general public, I guess this is understandable, but this kind of ‘censorship’ is NOT productive in terms of dealing with the perceived threat, and it is NOT necessary. The real threat CAN be understood and dealt with. I’ll cover the real nature of this threat in Part III. And finally, in Part IV, I’ll talk about what we in the pulsejet community can do to educate the public and prove ourselves responsible citizens in the continuing enjoyment of our unusual hobby. Bruce Simpson’s ‘Construction Diary’ page can be found at: -- End of Part I –- _____________________________________________________
    Larry Cottrill with Reynstodyne Shark[TM] engine prototype - Photo Copyright 2003 Cottrill Cyclodyne Corporation
  Photo Copyright 2003 Cottrill Cyclodyne Corp.
Larry Cottrill is Editor of jetZILLA online magazine and Director of Product Development and CEO of Cottrill Cyclodyne Corporation of Mingo, Iowa, USA - striving to create the world's smallest, safest and most practical hobby jet engines. You may contact me concerning this article at: This article first appeared in jetZILLA ezine, Special Edition, June 13, 2003. Permission is hereby granted by the author and publisher to freely distribute this article, so long as you agree to use the article in its entirety, without alterations or additions, including this resource box. Do you write articles? Click Here To Learn How You Can MASSIVELY BOOST Your Exposure for FREE! The author is a member of the free Writer's Viral Syndicator and sponsored by ad-CLiX Traffic Exchange Network _____________________________________________________ Don’t miss the remaining articles in this series! Simply subscribe [at no cost] to jetZILLA online magazine – just send a BLANK email: Be sure to do this from the system where you want to receive each email edition of jetZILLA. You should receive a validation email immediately.


 jetZILLA  E X C L U S I V E !
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Bruce Simpson Responds to
  'Can the Guy Next Door Build 
   His Own Cruise Missile?  YES! [Part I]'

    Bruce Simpson with his Lockwood engine prototype - photo used by permission
  Photo by Bruce Simpson - used by permission
Bruce Simpson is an experimenter who lives and works in New Zealand. He has been heavily involved in pulsejet design and experimentation for about the last three years. _____________________________________________________ Note from the Editor: When I notified Mr Bruce Simpson of my intent to publish Part I of a critical series of articles, he kindly offered this immediate response for publication. What Bruce gives in these comments is an interesting look at why he sees this controversial project as legitimate, timely and important. - Larry Cottrill, Editor _____________________________________________________ Since the media decided to catapult my low-cost cruise missile (LCCM) project into the public eye, I have received a raft of feedback from all around the world. Of the more than 3,000 emails I have received, only eight have been critical or voice strong concerns over the effect this project will have on either terrorism or individual freedoms. The vast majority of respondents have been congratulatory or very positive in their endorsement of the project and its goals. Many also mention that they are now intrigued by pulsejet engines and want more information about them. I suspect that this little project has probably introduced thousands of people to pulsejet engines and will likely result in a significant surge in the number of kids and adults who haul out that old Dynajet or decide to try and build one for themselves. It's worth remembering that people tend to fear most that which they don't understand. By making pulsejet technology more widely understood I strongly believe that this project is encouraging a healthy interest in the subject. I've also strongly stated that I'm opposed to any knee-jerk reactions on the part of authorities. I doubt very much whether they will attempt to ban the raw materials or other resources that amateur pulsejet builders use. To do so would be as ridiculous as banning fertilizer or diesel oil because they could be used to make a bomb. My single largest hope is that by publicizing the fact that an LCCM is possible, any terrorists contemplating such an undertaking will now realise that people will no longer be oblivious to their activities. The blanket of secrecy and obscurity has been lifted and that makes their chances of succeeding a lot lower. It's also worth appreciating that although the LCCM is a project that any second-year university student could undertake, it's not the kind of thing that school kids will be able to reproduce in dad's garage. A certain amount of intelligence, plus skills in the area of electronics, software design, engineering and aerodynamics is required -- and there aren't that many people with this mix of discplines under their belt. Let's not forget also that the test could turn out to be an embarrassing catastrophe. If the LCCM slumps from its launch ramp into a ball of flame just a few feet away then it's likely that nobody will be worried about pulsejet-powered "flying bombs" for some time. - Bruce Simpson June 12, 2003

"To God Alone be the Glory"
- Johann Sebastian Bach 1685 - 1750

P R O D U C T S   A N D   S T U F F  . . .
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V i s i t   O u r   F r i e n d s  . . .

   Bruce Tharpe Engineering - 8622 E Evans Creek Road, 
      Rogue River, OR 97537  Phone: 541-582-1708. 
      Assembled fuel bladders, pulsejet model plans and 
      MUCH more.   email:

   ModelFlight - United Kingdom 
      A top-notch magazine for model flyers -- check out 
      the 'Gallery' section for photos of some absolutely 
      beautiful aeromodeling work from all over. Lots of 
      scale stuff. Good construction hints, reviews, etc. 
      All kinds of aeromodeling represented, including the 
      occasional jet craft.    

V i s i t   O u r   O w n   L i n k s  . . .

   Tools for Marketers / Webmasters [ TfMW ] -
     Page 2 [ complete product catalog ] -    

   Cottrill Cyclodyne SFOATM Pulsejet Engine Design / 
      Development Page - where "Steel Floats On Air"!    

   Cottrill Cyclodyne Corporation Site Directory -    

   jetZILLA Initial Press Release [ return to the 
      jetZILLA home page, then select from 'Archived 
      Editions' ] -    

M a k i n g   M o n e y   o n   t h e   'N e t  . . .

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C O M I N G   I N   T H E   N E X T   E D I T I O N . . .
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   > Can the Guy Next Door Build His Own Cruise Missile?
     - Part II -
A L L   T H A T   B O I L E R P L A T E . . .
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T h e   W e b   E d i t i o n  . . .
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  Larry Cottrill with Reynstodyne(TM) Shark(TM) engine prototype after early test firing - Photo Copyright 2003 Cottrill Cyclodyne Corporation
  Larry Cottrill with ReynstodyneTM SharkTM engine prototype after early test firing
Photo Copyright 2003 Cottrill Cyclodyne Corporation
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