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Originally Posted by SolarYellow
I'd also be curious to know whether the NC has changed since being introduced as plastic. The blow-molded NC in the now-just-discontinued-again kits has some particular, unique geometry. It makes up- or downscaling it by substitution of another COTS nose cone essentially impossible if you want it to look right. Wondering how far back that goes.
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Using the catalogs as a guide, towards the end of the original kit's release, Estes Catalogs gave a visual cue in the form of icons below each model's description - the icon on the Goblin's still shows that the model was using the BNC-55AO clear to the end of its initial run. The plastic NC was for the modern era version only.
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Originally Posted by SolarYellow
On the other hand, this is getting seriously OCD. The old instructions at JimZ show clearly, visibly different NC shapes on different rocket photos in the same instruction document in the balsa era. I gather from that that the balsa cones were pretty inconsistent, as in all over the place. Or perhaps just ended up that way after different builders were done sanding and filling them.
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I currently have beside me my pair of Goblins - my modern plastic NC beast, and my barn find 1970 Freebie Kit that I recently restored, and I can see what you're on about the difference between the plan's kit photos and reality - as a former art director and kit manufacturer, I can give you a simple answer to this issue - what is pictured on the plans is the prototype with a hand-carved nose cone, as the first kit to use the BNC-55AO was the Goblin. The taper matches more closely to what came out with the PNC of the resent kit. To drive home this 'error', if it really is one (Prototypes always differ from their final design specs), is that in 1973's catalog, where all the rockets are rendered in paint, the artist obviously used the same pre-production photo as a guide, as the NC has the same flat inch or two before curving inwards at the tip. To drive home the fact that this was the case, a few pages down the line, we find a picture of the other rocket using the BNC-55AO at the time, the Astron BANDIT, with a nearly perfect shape, though not happily rendered, as you can see where the artist attempted to fix a curve error in the NC/Payload section of the rocket, and did not color match it well.
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Originally Posted by SolarYellow
Also, just to note it, there's more different in the older vs. laser cut fins than the size. The laser cut fins have visibly more sweep and I think a little taper. I have not yet put scans of both in AutoCAD to quantify the differences, though.
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Shape wise, I didn't see visually at first between these two beside me - making a simple paper template using a PostIt note and tracing the 1970 model's fin, then laying the laser cut version over it, there is a slight variation - Root edge, trailing edge and outer edge are all the same, but the leading edge, which has the same length along the root edge, tapers down ever so slightly at the outer edge by about 3/32 of an inch. Now this could have many variables for this issue - all classic Goblins used a template to make the fins, and the former owner couldn't cut straight - tracing a template to the balsa is always larger than planned, as the width of the pencil/pen's point would add thickness, and who cuts balsa on the inside of a traced line anyway? No one, I tell you, NO ONE!
The one thing I did notice while examining these two beside me, is the fact that the original model uses thicker balsa. The modern version is using 3/32" balsa for its fins, while the classic is 1/8". Note that in my restoring of the 1970 model, the fins were original and never flown, as the original owner had not installed an engine mount (unless he was trying to fly this thing on a 29mm - I think not). It arrive to me painted in Day-Glo Pink, with the balsa simply painted, not sealed beforehand, leaving the model with a bad case of balsa beard. I carefully removed all the fins since the numb-nuts also hadn't rounded the leading or trailing edges, and the glue was sub-par anyway. As for the engine mount, I dug out some spare CR-5055s, a section of BT-50 tubing and an EB-50. I purposefully did not add the engine hook, as it would get in the way of allowing the rocket to stand on its fins properly, and any good rocket fiend worth their salt knows how to friction fit an engine.
https://www.oldrocketforum.com/atta...tid=68025&stc=1