Perusing thru the old Centuri catalogs, I was curious what the Centuri Mini-Max motors were like. Were they reliable? Semroc has reproduced most of the Mini-Max rockets, I just wished I those motors were still available if they were any good.
Tell me about Centuri Mini-Max motors.
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Bazookadale
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I flew a few of them and had no problems, but they did have a bad reputation. I don't think the NAR ever certified them(could be wrong) because I wasn't allowed to fly them at PITTCON 1970. What I remember most was the huge piller of flame - just awesome
rocketguy101
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In '73 or so, I found a bargin bin table of motors, and saw this F55-0 Mini-Max motor and a bag of F100-0s.
Here are some pics of the Mini-Max:
This was a huge motor back in the day!
Here are some pics of the Mini-Max:
This was a huge motor back in the day!
rocketguy101
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The nozzle is huge!
rocketguy101
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I believe the $2.25 marked on the motor is what I paid for it!
rocketguy101
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9 inches long x 1.13 inches dia
228.6 mm x 28.7 mm
the nozzle opening is about 0.57 inches (14.5 mm)!
rocketguy101
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Originally posted by dlrflyer
Wow, I knew they were 29mm, but I didn't know they were 9" long.
Are you sure? I thought they were about 5" long.
I stand corrected--I mis-read the grid on my cutting matt (see 1st pic)-- with a tape measure, I get 7.75" (197 mm)
denverdoc
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I launched a dozen between 68 and 72. Never had a failure. The corresponding kits included some fiberglass tape to reinforce the fillets IIRC, but otherwise pretty standard materials and building tecqniques. Best flight was not in one of those but an Estes Arcas--just wrapped the mini-max motor in tape to fit the BT-55. That was the first rocket I flew that simply vanished a couple of seconds after liftoff. It was a pain to get them--something like rail or bus only limitation. In fact the kit and motors was a xmas gift now that I think about it. Even my dad was impressed by the F flights.
JS
Stefan_Jones
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A little more:
Mini-Max motors were descendents of the Coaster motors.
They offered an early, early version of the Aero-Dart, but no motors, in 1962. I built a clone of the model based on the picture and catalog dimensions:
https://home.comcast.net/~stefan_jones/aerodart_i_lo.jpg
Centuri started carrying big motors early on, as far back as 1964. The catalog of that year had another version of the Mini-Max, which I also cloned:
https://home.comcast.net/~stefan_jones/aerodart_ii_lo.jpg
In '65 or so the long burners and short burners were called Atlas and Hercules.
The big motors were labeled Mini-Max by 1966. The last catalog to offer them was 1971. That was the first Centuri catalog I bought, and the thought of giant F motors that had to be delivered by railroad boxcar blew my nine year old mind. (I learned a few years ago that Railroad Express did local deliveries by truck, so you didn't actually have to hang out by the depot.)
The Semroc clones of the "Mini-Max" era kits are really great. The Explorer flies beautifully on an E9.
Mini-Max motors were descendents of the Coaster motors.
They offered an early, early version of the Aero-Dart, but no motors, in 1962. I built a clone of the model based on the picture and catalog dimensions:
https://home.comcast.net/~stefan_jones/aerodart_i_lo.jpg
Centuri started carrying big motors early on, as far back as 1964. The catalog of that year had another version of the Mini-Max, which I also cloned:
https://home.comcast.net/~stefan_jones/aerodart_ii_lo.jpg
In '65 or so the long burners and short burners were called Atlas and Hercules.
The big motors were labeled Mini-Max by 1966. The last catalog to offer them was 1971. That was the first Centuri catalog I bought, and the thought of giant F motors that had to be delivered by railroad boxcar blew my nine year old mind. (I learned a few years ago that Railroad Express did local deliveries by truck, so you didn't actually have to hang out by the depot.)
The Semroc clones of the "Mini-Max" era kits are really great. The Explorer flies beautifully on an E9.
shockie
High Plains Rocketeer
The Coaster EF motors originally derived from pyrotechnic BP skyrocket motors. They were either made with air-hammers or gang-rammers. I was told this myself by Menford Sutton. No such luck as a MABEL and automated production. Therefore, since QC was low, some worked great and others not so great. If you read the old modeling magazines of that era, they were hit and miss at best. The original Coasters didn't even have a delay train and ejection charge. They used a fuse and squib as a delay train and an ejection charge. In 1959, The Coasters suddenly appeared with integrated delay and ejection charges and Orv Carlisle slapped them with a Cease and DeDesist orderor violating his model rocket patent. It was ignored. In the 63-to-65-time frame Coaster was absorbed by Centuri. The new Atlas-Hercules and the later Mini-Max were all made with gang-rammers, which is pyrotechnic fireworks technology.... They finally figured out how to make them using independent hydraulic rammers which improved the QC but the deserts around Phoenix Az is littered with the carcasses of thousands of BP atlas-hercules-mini-max rejects.
