Want Cox D8 impulse info !

[ghrocketman]

Does anyone have information defining the total impulse of the early 1970's (circa 1970-71)
Cox D8-0 and D8-3 engines ?
I have several of these and have flown several also; they seem to have MUCH more power than an Estes C5, but not as much (obviously being 18mm) as an Estes D12.
My Mars Lander flies almost twice as high on a Cox D8-3 as an Estes C6-3. :D
Seem to recall (can't remember where from) that the impulse was either 12 or 13 n-sec, but I want the real scoop if anyone has it.
The only info I have found on Ninfinger's site was for A-B-C (but no D) engines.
Does anyone know if Cox produced their own engines or did Estes, Semroc, Centuri, AVI, or someone else make them for Cox ?
The nozzles of the Cox C and D engines appear to be exactly the same as the nozzles on the old AVI C and D engines I have.

[Carl@Semroc]

Does anyone have information defining the total impulse of the early 1970's (circa 1970-71)
Cox D8-0 and D8-3 engines ?
I have several of these and have flown several also; they seem to have MUCH more power than an Estes C5, but not as much (obviously being 18mm) as an Estes D12.
My Mars Lander flies almost twice as high on a Cox D8-3 as an Estes C6-3. :D
Seem to recall (can't remember where from) that the impulse was either 12 or 13 n-sec, but I want the real scoop if anyone has it.
The only info I have found on Ninfinger's site was for A-B-C (but no D) engines.
Does anyone know if Cox produced their own engines or did Estes, Semroc, Centuri, AVI, or someone else make them for Cox ?
The nozzles of the Cox C and D engines appear to be exactly the same as the nozzles on the old AVI C and D engines I have.
They made their own. A rumor at the time was that they paid someone a million dollars for a machine! We had a laugh that maybe we should just sell engine machines instead of rockets!

[Chas Russell]

ghrocketman asked:
Does anyone have information defining the total impulse of the early 1970's (circa 1970-71)
Cox D8-0 and D8-3 engines ?

I was always under the impression that they claimed 13 nt-sec. for the D8's. I did a quick check last night and found a Model Rocketeer magazine dated March 72 that had them contest certified, but did not list impulses for any motors. Also so in the February 74 issue that the MIT Rocket Society had tested some motors and they had the D8's at 11.9 nt-sec. Could not find my Cox catalogs - much to my chagrin - so I don't know if there was a claimed value. They were great motors for heavy models. Lack of volume kept them from having a D8-5.

Chas

[Shreadvector]

Yes, they made them themselves - until the machine "burped" one too many times and set ther rest of the building off. Several deaths, several injuries. Detailed reports were on r.m.r. so Google it. Our NAR section president was actually on the jury for one of the trials.

[ghrocketman]

I actually found a document on Ninfinger that shows that cox claimed these were actually 15 n/sec.
Not sure I believe that any more than an Estes D is 20 n/sec as Estes claims.

Can you give me the link to the info about the Cox engine machine causing an explosion ?
I tried to "Google" it and found a bunch of useless junk.

[Shreadvector]

Go into the Google groups, where you can read the usenet newsgroup rec.models.rockets using a web-browser. Once in the rec.models.rockets newsgroup, search for the following words:

cox death



I actually found a document on Ninfinger that shows that cox claimed these were actually 15 n/sec.
Not sure I believe that any more than an Estes D is 20 n/sec as Estes claims.

Can you give me the link to the info about the Cox engine machine causing an explosion ?
I tried to "Google" it and found a bunch of useless junk.

[Initiator001]

They made their own. A rumor at the time was that they paid someone a million dollars for a machine! We had a laugh that maybe we should just sell engine machines instead of rockets!

Yes, Cox had a motor making machine built for them.

After the explosion/fire, the machine seemed to have disappeared.

Until...

In the early 1990s, we received a call at AeroTech concerning the old Cox motor making machine. It still existed and was nearly intact.

It was in a scrapyard somewhere in Los Angeles.

Some of the AeroTech staff took a plane trip out to LA and checked out the machine. It was partially disassembled but in good shape. The manufacturer's plate was still attached.

Quite a few pictures were taken of the machine.

Back at AeroTech, we debated purchasing the machine. The price was right (Around $10K + shipping, I recall).

We ended up not buying it for a combination of reasons, not the least was the 'regulators' were starting to make noise and we needed the money elsewhere.

As to the machine's current whereabouts, I dunno.


Bob

[Chas Russell]

I did some more digging and never did find an official NAR impulse for the Cox D8's. Cox had advertisements claiming that they were 50 percent more powerful than a C. There was also a new product ad in an issue of Model Rocketry magazine where Cox stated they were rated at 15 nt-sec. I still seem to recall 13 nt-sec. I also go to show my wife pictures of me helping with Standards and Testing in 1970 at the age of 19. She was amused.

Chas