04-05-2020, 08:39 PM
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Master Modeler
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Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
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Quote:
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Originally Posted by ghrocketman
The Argus fin unit was the original Enerjet fin-can.
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First, I want to apologize for my delayed reply here. I knew that about the Centuri Argus & Phoenix Bird kits’ (and several Estes kits’) Enerjet-origin plastic fin unit (and so did Roy Houchin, for whom I'd also posted the Argus query), but I'm glad that you mentioned that fact nonetheless. We graybeard (and gray forelock, mane, and tail) space modelers know these things, but many younger ones do not, and mentioning such things helps to fill in their model rocketry historical knowledge.
Quote:
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Originally Posted by Earl
Ok, here are tube lengths from an open Centuri Argus kit:
Bottom tube: ST13 12"
Middle tube: ST8 5.5"
Top tube: ST7 7"
All your other callouts I think are correct. The Estes Yankee kit used a very similar 'looking' cone to the Centuri PNC-71 cone (used in this kit and, as you pointed out, the X-24 Bug kit and for the plastic pod cones on the Orion kit...and a few other kits), but it is not quite the same. I got some of the Estes cones about 10 years ago thinking I could use them for an Orion clone, but they just did not quite do it for me.
And as GH pointed out, the fin can is the original one developed for the Enerjet 1340 sounding rocket and used in quite a number of kits over the years. Wow, that fin can is approaching 50 years old.
Earl
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Thank you! I just sent a link to Roy as well. Indeed—the conical Centuri PNC-71, and the Estes PNC-20[?] (in their Yankee kit, and also in a few Estes RTF rockets) are very similar nose cones. (Their included angles—and their rounded nose tip radii—may even be identical, or very nearly so.) The only significant difference between them, of course, is their “outer edges’ diameters” (0.759” for the Centuri PNC-71, versus 0.736” for the Estes PNC-20[?]). (If one made a duplicate Estes one, with its length extended slightly so that its base’s outer diameter [*not* the tenon’s <shoulder’s> diameter] matched the 0.759” outer diameter of the Centuri/Semroc #7 / ST-7 tubing, its shape might be identical to that of the PNC-71, or so close that it wouldn’t matter [like the virtually-identical Centuri PNC-54 and the Estes Gnome kit’s nose cone; both are 4:1 tangent ogive nose cones for #5 / BT-5 tubing].) |