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Old 09-08-2016, 02:55 PM
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Earl Earl is offline
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Quote:
Originally Posted by jbuscaglia
G. Harry wrote some articles on the "Early Days" that I remember reading in The Model Rocketeer back in the late '70s when he was the editor. I believe that similar articles may have also appeared previously in Model Rocketry Magazine. In one, Harry mentions that they switched to 18mm when they went to Brown because the cost would be much less since they could use existing tooling.


That's what I recall from that series 'NAR Roots' that Harry wrote in the latter 70s, in the NAR magazine. As I recall, Harry said that Orv could make maybe a couple hundred motors per night at home, but that was not going to be enough for their hopeful sales once MMI went full commercial. Brown said he could make them the same size (13mm) if they wanted, but (as you alluded), he could make them cheaper by using the 18mm tubes from his standard fireworks stuff. So, 18mm it became.

Some years later of course, various manufacturers came back out with 13mm stuff, one in the mid-60s or so that only lasted a year or two (forget their name), and then with MRI/MPC, Estes, and Centuri. I guess the Centuri minis were probably closer -- overall-- to the original Carlisle motors, considering their original longer length.

So, Harry said in those articiles, that, somewhat unknowingly in that one simple decision, they 'set the standard' for model rocket motor size that most manufactures would follow for decades. But, I recall seeing somewhere a comparison photo of an original Brown motor side by side with 'modern' 18mm motors, and I swear that Brown motor appeared to be a bit shorter than the current-day standard. But, coulda just been the photo.

Earl
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