Doug:

My research indicates there was a BP mini-Max series and then a Composite Mini-Max series just prior to the Enerjet debut.

hth

terry dean
nar 16158

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"Old Rocketeer's don't die; they just go OOP".....unless you 3D print them.

Doug,

The Mini-Max motors used BP as did the earlier Hercules/Atlas motors.

The Mini-Max and Enerjet motors were both in the 1970/71 Centuri catatlog.

By 1972 the Mini-Max motors were no longer in production.

Bob

Nope, Mini-Max was a big honkin black powder motor series.

Enerjets were the only composites.

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Roy
nar12605

Mini - Max were BP -Coaster had made the Atlas/ Hercules for Centuri, Centuri later bought the presses from Coaster and tweeked the design slightly to make the Mini- Max line. Enerjets were composites made by Rocket Development Corp. - Centuri bought that company and redesigned the Enerjet line

Now in the 1962 catalog it says "watch for new Mini- Max engines" http://www.ninfinger.org/~sven/rock...62/62cen12.html so it's a name Lee Piester had in mind for a while . A recent article (I think Launch magazine) it was stated that a composte Mini Max motor was under develoment at that time, it was never sold

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Dale Greene

Mentor, Penn Manor Rocket Club
VISIT SPAAR
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The Old West
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" Speaking the Truth in times of universal deceit is a revolutionary act. " George Orwell

The Mini-Max motors were definitely BP and replaced the Atlas/Hercules series.
The only composites Centuri offered were the Enerjet E24, F52, F67, and 'professional' G-something.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

Why did these motors go out of production? Why did Estes not produce Es until the 1990s?

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Rich Holmes
Camillus, NY
Secretary / newsletter editor
Syracuse Rocket Club

http://richsrockets.wordpress.com

The sequence is a bit backwards: The Centuri BP large scale motors were originally called Atlas and Hercules. THOSE were then replaced by the 'improved' BP motors called Mini-Max around '67 or so.

Earl

__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

I'd read that the production equipment for the Mini-Max line motors was destroyed "by lightning" in the early 70s.

I've also read that they weren't terribly reliable.

There was also the problem of shipping. If you read the old catalogs, you'll see references to a special shipping form. The motors had to go by Railroad Express, an expensive and not always handy method.

(I don't know how FSI got away with shipping its E and F motors by mail.)

I imagine that Estes simply didn't want to get involved with all that.

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NAR #27085 - Oregon Rocketry - SAM

I think Lee Piester stated in the Launch Mag article that a combination thunderstorm/accident caused a fire at the Mini-Max motor facility around the '71 timeframe. Centuri had just recently rolled out the Enerjet composites within the previous year, so they decided not to try to restart the large BP production facility for the Mini-Max stuff and just focus on the new Enerjet composites.

What I hated was that not only did they stop the Mini-Max motor production, they stopped making the Mini-Max kits, which I thought were just as good if not better in design and construction (heavy walled tubing, etc) than the Enerjet kits that were issued a bit later. The Enerjet kits basically all used the standard Centuri low power body tubes. Not 'bad' kits per se, but I wished they would have at least kept the Mini-Max kits, even if they dropped the large BP motors.

Earl

__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

It would not surprise me if FSI just shipped the 27mm E and F motors completely ignorant of any ridiculous regulations.
I can understand disallowing BP motors from being shipped via air; ANYTHING more than that for individuals or businesses is STUPID OVER-REGULATION.

__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !