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Elektra I(TM) pulsejet engine prototype with designer Larry Cottrill - Copyright 2004 Larry Cottrill

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The  Elektra ITM  ultra-low-cost valveless  
  pulsejet project -   08 April 2004 - TODAY!
(last content update: 15 May 2004)

'Elektra I' experimental valveless pulsejet in test run - Photo Copyright 2004 Larry Cottrill
The completed Elektra I ultra-low-cost pulsejet prototype

Test Journal and more photos - go to Page 2!


WORK IN PROGRESS LOG
  Preliminary Design
    Concept submitted:   2004-04-08    
    Design complete:   2004-04-08    
  Working Prototype
    Construction started:   2004-04-09    
    Construction completed:   2004-04-17    
    Testing started:   2004-04-19    
    Self-sustained operation:   2004-05-18    
    Testing completed:   - N/A -        
 


E X P E R I M E N T A L
---   R E A D   T H I S   N O T I C E   ---
In viewing this site, YOU ARE AGREEING TO THE FOLLOWING TERMS AND CONDITIONS:
  1. LIMITED LICENSE IS HEREBY GRANTED TO BUILD AND MODIFY THIS DESIGN IN SINGLE UNITS ONLY, FOR NON-COMMERCIAL PURPOSES ONLY, such as for personal education and amusement, and including use of the design as a powerplant for an unoccupied model vehicle, UNDER THE REMAINING PROVISIONS OF THIS STATEMENT OF TERMS AND CONDITIONS:
  2. PRODUCT DESIGNS SHOWN ON THIS PAGE ARE proposed embodiments of INVENTIONS OF LARRY B COTTRILL, and any or all rights may be assigned to Cottrill Cyclodyne Corporation (a for-profit corporation registered in the State of Iowa, USA);
  3. PRODUCT DESIGNS SHOWN ON THIS PAGE ARE UNDER DEVELOPMENT AND THESE PRODUCTS AND THE UNDERLYING INVENTIONS potentially embodied in such products ARE NOT BEING MARKETED NOR OFFERED FOR SALE, pending completion of development efforts and possible patent application;
  4. NO ORDERS ARE BEING TAKEN for any future products shown or described herein, pending completion of development efforts and possible patent application for the underlying Inventions;
  5. NOTHING in the images or descriptions of proposed future products on this page SHALL BE CONSTRUED TO LIMIT the range of embodied applications for the underlying Inventions, NOR IN ANY WAY TO WARRANT SUCH INVENTIONS or any derivative embodiments as to fitness FOR ANY PARTICULAR PURPOSE;
  6. In showing product information on this page, NO CLAIMS OF ANY KIND ARE MADE in regard to performance, manufacturability, marketability, product safety, or fitness for any particular purpose;
  7. In showing product information on this page, NO LICENSE IS GRANTED to duplicate, re-scale, publish, revise or offer these designs to any party on any basis FOR ANY COMMERCIAL USE;
  8. PUBLIC PRESENTATION OF THIS PAGE and the images and descriptions of these proposed future products SHALL NOT CONSTITUTE ANY WAIVER OF PATENT RIGHTS OR OTHER RIGHTS the Inventor or any licensee or assign thereof may have in relation to these Inventions;
  9. BY VIEWING THIS PAGE, YOU AGREE THAT YOU UNDERSTAND THAT THE BUILDING AND TESTING OF JET ENGINES IS INHERENTLY DANGEROUS TO PROPERTY, LIFE AND LIMB, AND THAT THE DESIGNS SHOWN ARE NOT REPRESENTED AS EXPERIMENTALLY PROVEN DESIGNS;
  10. AND YOU FURTHER AGREE THAT ANY ATTEMPT on your part TO BUILD, TEST, MODIFY AND/OR UTILIZE THE DESIGNS SHOWN IS PERFORMED UNDER CIRCUMSTANCES BEYOND OUR CONTROL, THAT YOU ARE BUILDING AND TESTING THE DESIGNS AT YOUR OWN RISK, AND THAT YOU ARE ASSUMING TOTAL LEGAL RESPONSIBILITY FOR ALL DAMAGES OF EVERY KIND THAT MAY BE INCURRED in such building, testing, modifying and/or utilizing them for any purpose whatsoever; AND THAT YOU AGREE TO HOLD THE DESIGNER AND COTTRILL CYCLODYNE CORPORATION COMPLETELY HARMLESS IN REGARD TO ANY SUCH DAMAGES YOU INCUR, WITHOUT LIMITATION.


H E A L T H   H A Z A R D
---   R E A D   T H I S   N O T I C E   ---
This project requires WELDING GALVANIZED / PLATED METAL -
ALWAYS OBSERVE THESE PRECAUTIONS:
  1. AVOID BREATHING OF VAPORS from the area heated by welding; do not work with your face directly above the weld area
  2. PROVIDE ARTIFICIAL AIR MOVEMENT TO REMOVE VAPOR if natural breeze is not available
  3. DO NOT WELD IN TIGHTLY ENCLOSED SPACES; work outdoors in moving air if possible
  4. PROVIDE ADEQUATE VENTILATION USING OUTDOOR AIR if you must work indoors
  5. HIGHLY RECOMMENDED: PREHEAT WELD AREAS OUTDOORS AND CLEAN THOROUGHLY WITH WIRE BRUSH to remove plating and ash from weld areas before proceeding with welding
  6. STOP WORK IMMEDIATELY IF YOU DON'T FEEL WELL! Symptoms of inhaling plating fumes may include nausea, sore throat, headache, metallic taste in mouth, general 'unwell' feeling - GET FRESH AIR immediately - If symptoms persist for more than a few minutes, GET MEDICAL ATTENTION!
FAILURE TO OBSERVE THESE PRECAUTIONS CONSTITUTES CIRCUMSTANCES BEYOND OUR CONTROL. BY ATTEMPTING TO CONSTRUCT THE DESIGN SHOWN, YOU ARE ACCEPTING ALL RISK AND YOU ARE AGREEING TO HOLD THE DESIGNER AND COTTRILL CYCLODYNE CORPORATION COMPLETELY HARMLESS IN REGARD TO ANY DAMAGES YOU INCUR, WITHOUT LIMITATION.


   ______________________________________________________________

    I.   O R I G I N A L   C O N C E P T   D R A W I N G
   ______________________________________________________________

Disclosed on Kenneth Moller's Ramjet Forum - 08 April 2004:
    
Elektra I(TM) pulsejet engine - original drawing as disclosed on Kenneth Moller's Valveless Pulsejet Forum - Copyright 2004 Larry Cottrill VIEW LARGE
IMAGE
 
ULTRA-LOW-COST PULSEJET ENGINE - 'Elektra I' The non-scale concept drawing, as disclosed on 08 April 2004. The engine is designed to be fabricated entirely from easily available parts and cheap materials, but does require skilled welding to construct. This engine has now been completed by the author. Drawing Copyright 2004 Larry Cottrill



   ______________________________________________________________

    II.   W O R K   I N   P R O G R E S S   P H O T O   D I A R Y
   ______________________________________________________________


Photo Diary: Building the "Elektra I" Ultra-Low-Cost
Valveless Pulsejet, using ordinary hand tools and LESS THAN
FIVE DOLLARS worth of home improvement store materials 
and a spark plug - PART I
by Larry Cottrill, Editor, jetZILLA Online Magazine
 
          - All photos this page Copyright 2003 Larry Cottrill - 

Table of Contents [Sections I-V below]:
I.  Forming the combustion chamber [09 April 2004]
II.  Welding the basic structure [10 April 2004]
III.  Closing the chamber [13 April 2004]
IV.  The fuel supply tube [16 April 2004]
V. Engine mounts [17 April 2004]

Table of Contents [Test Journal: Sections VI & higher go to Page 2]:


I.  Forming the combustion chamber [09 April 2004]:
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Starting to enlarge the exhaust port knockout hole - here, I'm 
using a large round file to quickly rough out the hole to the much
larger size needed [around 1.25 inches - a little larger than the
OD of the 1-inch conduit exhaust pipe material!]: 

Enlarging the exhaust port with large round file (c) 2004 Larry Cottrill


A large half-round is needed, though, to really get the
hole smooth and uniformly round [as near a perfect circle 
as you can make it]: 

Smoothing up the exhaust port with large half-round file (c) 2004 Larry Cottrill


Creating the port for the intake stack - Make a punch mark in
the middle of the rounded corner. Then, start the hole with a 
small, fast hand drill with a very small twist drill in the chuck 
[3/32-inch diam. shown] and a few drops of light oil. Your twist
drill must be good and sharp to start without skidding off: 

Starting the air intake port with small hand drill (c) 2004 Larry Cottrill


Re-drilling the stack port - Use the biggest drill you have, and make 
sure the box is well anchored in the vise. Take it slow, and gradually work
through the steel, using added oil as needed. This is a 3/8-inch twist
drill in a big, slow 1/2HP gearhead drill: 

Enlarging the intake port with large, slow drill (c) 2004 Larry Cottrill


Enlarging the intake stack port, using the full-round file. This
is a LOT of work, but it just needs to be big enough for the 3/4-inch
conduit to slip through. Then, re-work it at the top and bottom to
make it slightly elliptical, so the conduit will fit at the steeper
angle [about 60 degrees] shown in the drawing: 

Enlarging the intake port to its final size with the full-round file (c) 2004 Larry Cottrill


Making the spark plug hole - since I planned to use a miniature plug,
I just used the two-drill technique once more to drill a 3/8-inch hole,
then enlarged it slightly with the full-round file. The drilling and 
filing have to be done with great care, so the knockout won't be bent
out of shape. It will end up being welded into the box. [NOTE: If 
you use a bigger plug, like a lawnmower plug, just remove the 
knockout instead]: 

Finishing the spark plug hole with the round file (c) 2004 Larry Cottrill


After about an hour's work, here's the finished combustion chamber, 
all ready for welding: 

Finished comustion chamber, ready to weld (c) 2004 Larry Cottrill



II.  Welding the basic structure [10 April 2004]:
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I started the welding by simply sealing up the knockouts in the
center of the cover plate and in the center of the wide face of
the box - only the slightest amount of filler rod is needed to 
get started, then just work the puddle around the knockout: 

Sealing up the large knockouts by welding (c) 2004 Larry Cottrill


The smaller 'Romex' knockouts are more difficult, because in this
case, there are some real gaps to be filled: 

Welding up the smaller knockouts (c) 2004 Larry Cottrill


After carefully welding the spark plug knockout to the box, the 
spark plug nut is precisely aligned over the hole, and secured with
Vise Grips(TM) pliers while tying the nut down with a couple of 
small tack welds: 

Tack welding the spark plug nut over the hole (c) 2004 Larry Cottrill


After tacking, remove the tool and work carefully around the nut
to get it fully welded in, using filler rod as required. Then,
file the top of the nut back to a smooth surface: 

Smoothing up the exhaust port with large half-round file (c) 2004 Larry Cottrill
Unfortunately, the threads will have to be cleaned up by running 
a tap of the correct size through the nut.

Now, clamp the box in a vise and position the tailpipe [cut from
1-inch diameter rigid steel conduit] in place, and make a single
large tack weld, leaving about a 1/16-inch gap between the pipe 
and the edge of the slightly oversize hole: 

Making the first tack weld between the exhaust pipe and the chamber (c) 2004 Larry Cottrill
Then, carefully align the pipe with the chamber and make another 
tack weld opposite the first one. Next, make two more at 90 degrees
from the first two, being careful to align the pipe as accurately
as possible!


Looking through the chamber at the exhaust stack held in place
by the four tack welds [note the clearly visible space between the
chamber exhaust port and the pipe end]. The finished spark plug
mount is also clearly seen here, in the middle of the nearest wall
[i.e. the front end] of the chamber: 

View of the tack welds joining the exhaust pipe to the chamber, before finishing the welded joint (c) 2004 Larry Cottrill


After finishing the complete weld between the exhaust pipe and
the chamber, the intake stack is cut to size, carefully positioned
and tack welded in at one point only: 

Tack welding the intake stack to the chamber (c) 2004 Larry Cottrill


The stack is carefully aligned, and the angle checked to make sure
that the angled cutoff is accurately positioned. Then, after a couple
more tack welds and re-checking, it is welded solidly in place. It's
good to have the vise available for positioning the work so that the
entire joint is easy to reach: 

Finish welding the intake stack to the chamber (c) 2004 Larry Cottrill


The combustion chamber section of the Elektra I engine, all finished
except for welding on the side cover plate: 

Finished comustion chamber, fully welded except for the cover plate (c) 2004 Larry Cottrill



III.  Closing the chamber [13 April 2004]:
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The cover plate is attached to the side of the chamber by means of 
the two screws. Start the welding process by tack welding the cover 
plate at points near the corners: 

Tack welding the cover plate to the left side of the combustion chamber (c) 2004 Larry Cottrill


Now, remove the two screws holding the plate to the box and finish 
weld the edge of the cover plate down to the box wall, working from
tack weld to tack weld. There is enough overhang at the edge of the
coverplate to make almost the entire weld without filler rod -- the 
rod is only needed when you get to the corner voids: 

Finish welding the comustion chamber, adding filler metal only at the corner voids (c) 2004 Larry Cottrill


The finished combustion chamber section of the Elektra I engine, left side
rear and top view: 

Finished comustion chamber, left side view (c) 2004 Larry Cottrill


The combustion chamber section of the Elektra I engine, right side front
and bottom view: 

Finished comustion chamber, right side view (c) 2004 Larry Cottrill


The combustion chamber section of the Elektra I engine, closeup right
side view with spark plug threaded in, just to see how it looks: 

Finished comustion chamber, closeup right side view with spark plug (c) 2004 Larry Cottrill



IV.  The fuel supply tube [16 April 2004]:
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The original fuel supply tube is designed to drop into place and 
be held by gravity alone. It is .125 inch OD copper tubing, with a 
1/4-inch compression fitting bonded on with J-B Weld epoxy. It 
slides loosely into a short section of .25 inch OD stainless tubing,
bonded inside the intake tube with J-B Weld. A notch in the near 
side of the intake tube rim keeps it in alignment and prevents it 
from vibrating out of place. This crude design allows for great 
flexibility in experimenting with different fuel schemes: 

Finished fuel delivery tube shown being dropped into place in the intake tube (c) 2004 Larry Cottrill



V.  Engine mounts [17 April 2004]:
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The two identical engine mounts are cut from a single hardware piece
called a 'fence rail bracket' - I used the jeweler's saw because it is 
a favorite tool, but a hacksaw would have made quicker work of it [the 
only other work needed before welding the mounts is to drill out the 
holes to a larger size to fit the mounting bolts]: 

Cutting engine mounts from 'fence rail bracket' hardware (c) 2004 Larry Cottrill


Jigging the engine and mounts for tack welding - I used a scrap of flat 
wood, though metal would be safer. To protect the wood from the torch 
flame while tack welding, I covered as much as I could with the sheet 
metal scraps shown. The engine itself is supported level by a brick 
placed under the tailpipe: 

Jigging the engine and mounts into proper alignment before tack welding (c) 2004 Larry Cottrill


Initial joining of the mounts to the engine, using just a couple of 
small tack welds - the wood base got scorched in a couple of places; 
if you use wood as I did, keep your fire extinguisher handy! After 
the tack welding is done and the piece cools, unbolt it carefully 
from the jig and do the finish welding, handling carefully so the 
alignment isn't accidentally altered.

Tack welding the engine mounts to the combustion chamber (c) 2004 Larry Cottrill


After finish welding the mounts and attaching the fuel pipe and 
spark plug, we get our first look at the finished Elektra I pulsejet
prototype: 

The Elektra I(TM) ultra-low-cost valveless pulsejet engine prototype, completely finished (c) 2004 Larry Cottrill

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Page updated: 19 Jul 2004

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