Estes BNC-60AH vs Semroc BNC-60AH How close a match?

Thanks to Gerry Fortin's website, I've finally been able to confirm that the Estes OMEGA K-52P was released in 1970 with a balsa nosecone. Sometime later, possibly 1971, it was switched to a one piece plastic PNC-60AH. There is still also the chance that it was released (possibly with a yellow hang tag) with the two-piece version of the PNC-60AH that matches the Citation Der Red Max.

I'm now very interested in modeling the 1970 version of the K-52P, and as I don't have an original Estes BNC-60AH, I'm thinking that I need to score a Semroc BNC-60AH. According to the 1970 Catalog the Estes cone was 6 5/8" (6.625") whereas the Semroc is given as 6.6". I'm curious though about how different they truly are.

Does anyone have one of each to compare them?

I think I have one at home, I'll check. I was going to do a replacement cone for my Der Green Max, but lost the rocket to a carrot field before using the balsa cone. I should be able to do a side-by-side with a modern PNC-60AH, you can judge from there. I would bet, though, that the call out of 6.6" is the same size, simply with fewer decimal places indicated.

(I'll beg your pardon in advance. I'm feeling exceptionally snarky this morning and if I don't get it out of my system it's, you know, unhealthy. :blush



I understand that to Klingons .025 inches, .64 millimeters, makes all the difference.

Just because there's a .025" difference in length doesn't mean that they are overall the same shape. One may have a blunter tip, or a thickness along the curve that the other lacks (think fat ogive vs ogive).

K'Tesh said:

Just because there's a .025" difference in length doesn't mean that they are overall the same shape. One may have a blunter tip, or a thickness along the curve that the other lacks (think fat ogive vs ogive).

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Quite right, the overall shape could be just that much off, especially with wooden parts made on different equipment, decades apart. And if it matter to you it matters.

Note to self: less snark; snarky ain't smarty.

You'll have to decide how useful this is to you. I found my BNC-60AH, but based on its packaging, I think I bought it from BMS rather than Semroc. So that's another variable. But here it is next to the modern PNC-60AH, on a Der Red Max:


It appears that the profile at the tip is somewhat different, insomuch as the plastic version is more conical at the tip, whereas the BMS cone has a little more meat on it there. The actual tip of the balsa cone is somewhat rounder too. Another thing to note - the BMS cone is just about 5mm shorter. That makes it slightly less than 6.5" long, though BMS also claims a 6.6" length. That could be part to part variation, depending on the process of how these balsa parts are turned - I'm guessing they will be less consistant than the molded version. To that end, I've always considered that reproductions of balsa clone parts (including fins) don't have to be as precise for the sake of cloning, simply because they will have a lot of variation just due to different sanding and prep from builder to builder, especially when cloning earlier models.

Thanks for that Rick!

Man, if I ever won the Jackpot, nobody would stand a chance against me on Ebay when one of these (K-52P's) came up for sale (until I'm satisfied that I've got all variants covered).

Got this fron Sheryl this morning:

Not sure if you knew but Carl had talked to Vern about the balsa cones they made. Vern told him they would start out with one shape/size and after many cuttings, the size and shape would change with the cutting wheel getting dull. So one kit would have several different looking cones, depending on how many they cut at a time.


Know this won't help you with BNC-60AH but Carl programmed our cones to be cut to be a close match to the original.

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I don't know about you all, but that's about an authoritative answer as I could hope for.


Thanks All!
Jim

OK... I finally got my hands on an Estes PNC-60AH that was injection molded. I just compared it to a modern PNC-60AH blow molded nosecone, and the difference in exposed length is...


3/32"

That's right folks, 3/32". I took each and put it in a body tube, put that into an aluminum angle, slid them so that they (and the aluminum angle) were flush against a flat surface (a piece of tile), and marked the body tube/nose cone joint on the angle.
The old version is 2mm shorter, and more than twice as heavy (eye bolt included).

Old (Injection molded, two-piece, (white))
Exposed Length: 6 5/8"
Weight: 1.45oz (painted, with shock cord mount)


New (Blow molded, one-piece, (white))
Exposed length: 6 23/32"
Weight: .6oz (painted)