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  #61  
Old 03-27-2021, 03:06 PM
jdbectec jdbectec is offline
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Strangely enough my recollection of the D8-0 8's was they did not completely filll the case
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  #62  
Old 03-27-2021, 05:06 PM
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Quote:
Originally Posted by georgegassaway

Oh, actually..... maybe pellets is misleading. Since the fire happened in 1970 when they were doing pellets. But most (if not all?) D8's were made after. This begs a big question oddly left out of this thread.... did Cox just "go back to normal" and make engines in the same place, taking some better precautions? Or did they move engine operations, or even outsource the engine making as Quest did after their fire?

The pellet method might have gone away after that 1970 fire. In which case, they could fill the D8-0 to the brim with loose BP (well, perhaps a double press process), without the limitations of how much space 5 or 6 pellets would take.



It was established earlier that the explosion occurred on or about June 11, 1971. All the manufacturing dates we've seen pictured are before that date.

If they outsourced after, who would they have outsourced to at that time?
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  #63  
Old 03-27-2021, 07:28 PM
shockwaveriderz shockwaveriderz is offline
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Quote:
Originally Posted by Royatl
It was established earlier that the explosion occurred on or about June 11, 1971. All the manufacturing dates we've seen pictured are before that date.

If they outsourced after, who would they have outsourced to at that time?


Well we know it wasn't Estes/Centuri. So that basically leaves MRI/MPC/AVI . No way it was FSI. I thought I had read somewhere sometime that MPC produced their engines after the explosion/fire. I have no evidence to back it up.
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Last edited by shockwaveriderz : 03-27-2021 at 07:50 PM.
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  #64  
Old 03-27-2021, 07:51 PM
shockwaveriderz shockwaveriderz is offline
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Quote:
Originally Posted by Royatl
It was established earlier that the explosion occurred on or about June 11, 1971. All the manufacturing dates we've seen pictured are before that date.

If they outsourced after, who would they have outsourced to at that time?


Announced at the January 1971 HIAA Trade Show.

The big news from Cox was the announce-
ment of a new engine - a D in the standard
18mm X 70mm, "A, B, C-type," casing. The
D's - a D8-0 and a D8-3 - are expected to
be available before summer. The total impulse

of the new Cox engine is 15.00 newton seconds
making it a mid-range D. The engine has an
average thrust of 8 newtons and a burn time of
1.87 seconds. Total weight is 24.2 grams for
the booster and 26.2 grams for the D8-3.

They were both on the NAR Certfication list as of January 31,1971.


New from the L.M. Cox Company is
the Cox D8. This is the first commer-
cially available D engine in a standard
18 mm. x 70 mm. casing. Although only
(only?) 15 newton-seconds - 20 newton-

seconds is the maximum total impulse
for D engines - these engines are ex-
cellent performers. Having 50% more
power than previously available in a
standard engine casing, they offer many
possibilities in Boost Glide, Rocket
Glide, Plastic Model. Scale, and Egg

Loft events to say nothing of high per-
formance sport flying. Weighing in at
25.5 grams, the new D is available as
types D8-3 and D8-0. Why aren't there
any longer delays? Simple - they won't
fit into the casing !

Doug Malewicki of Cox informs us that
early production versions of the Cox D8
engines, as well as other Cox engines, were
manufactured in an 18 mm outer diameter
tube. Adding the paper wrapper made it

impossible to fit the engine into a BT-20
or Centuri No. 7 tube, though there was no
problem fitting it into a Cox model. To
eliminate this problem, and make Cox en-
gines fit all available standard size rocket

kits, Cox is now manufacturing engines which
measure 18 mm including the paper wrapper.
Unless your hobby shop has very old engines
on display, you should have no problem with
fit on any engines you purchase today. In-
cidentally, Doug reports that he flew many

models at NARAM-13 using Cox engine
BT-20 tubes, and he encountered no diffi-
culty with the fit.
Cox is presently changing the tooling to
allow completely automated production of
the D8-0 and D8-3 engines. As a result,

these engines may not be available in some
stores until early in February (1972). At that time,
however, the automated equipment will allow
high-speed production to meet the large
demand for this engine.
Attached Thumbnails
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Name:  Cox D8.jpg
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Size:  87.0 KB  
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Last edited by shockwaveriderz : 03-27-2021 at 08:31 PM.
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  #65  
Old 03-27-2021, 08:33 PM
Initiator001 Initiator001 is offline
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I have examples of unfired Cox D8-0 and D8-3 motors.

Here's some pictures of each. I have broken the pictures up into multiple posts.

This set of pictures shows a side view of the casings (Note dates) and their forward ends. The D8-3 has a paper cap while the D8-0 has some sort of coating/slurry.
Attached Thumbnails
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Name:  Cox 001 D8-0 & D8-3 Side View.jpg
Views: 48
Size:  32.1 KB  Click image for larger version

Name:  Cox 002 D8-3 & D8-0 Forward Ends.jpg
Views: 61
Size:  24.0 KB  
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  #66  
Old 03-27-2021, 08:36 PM
Initiator001 Initiator001 is offline
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Here is a depth measurement of the D8-0 motor.
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Name:  Cox 003 D8-0 Depth.jpg
Views: 31
Size:  65.7 KB  Click image for larger version

Name:  Cox 004 D8-0 Depth Closeup.jpg
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Size:  31.8 KB  
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  #67  
Old 03-27-2021, 08:37 PM
Initiator001 Initiator001 is offline
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Here is the depth measurement of the D8-3 motor.
Attached Thumbnails
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Name:  Cox 005 D8-3 Depth.jpg
Views: 20
Size:  62.0 KB  Click image for larger version

Name:  Cox 006 D8-3 Depth Closeup.jpg
Views: 25
Size:  57.6 KB  
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  #68  
Old 03-27-2021, 08:42 PM
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Ez2cDave Ez2cDave is offline
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Quote:
Originally Posted by Initiator001
I have examples of unfired Cox D8-0 and D8-3 motors.

Here's some pictures of each. I have broken the pictures up into multiple posts.

This set of pictures shows a side view of the casings (Note dates) and their forward ends. The D8-3 has a paper cap while the D8-0 has some sort of coating/slurry.


You know, that shiny surface on the D8-0 makes me wonder if those motors were "pressed wet" ( damp / moist BP ) and then allowed to dry / cure ?

Dave F.
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  #69  
Old 03-27-2021, 08:48 PM
Initiator001 Initiator001 is offline
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Quote:
Originally Posted by Royatl
It was established earlier that the explosion occurred on or about June 11, 1971. All the manufacturing dates we've seen pictured are before that date.

If they outsourced after, who would they have outsourced to at that time?


Cox motors were not outsourced. No information has ever come to my attention that proves otherwise.

My 'latest' production date on a Cox motor is a B6-6 dated 6-7-71.

My D8-0 is dated 5-14-71.

My D8-3 is dated 5-27-71.

My earliest is an C6-6 dated 8-12-70.
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  #70  
Old 03-27-2021, 08:51 PM
Initiator001 Initiator001 is offline
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Quote:
Originally Posted by Ez2cDave
You know, that shiny surface on the D8-0 makes me wonder if those motors were "pressed wet" ( damp / moist BP ) and then allowed to dry / cure ?

Dave F.


It has been speculated that Cox motors used a much higher water percentage during the pressing process.
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