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Tau Zero
04-19-2007, 10:58 PM
The first picture below was gonna be really cool, but apparently I have a case of Intermittent Middle Age Shakes. :eek: :confused: :mad: (Never mind that the camera's shutter speed is way too slow, and that it came free with my now-retired Dell printer. :rolleyes: )

EDIT: I took a much clearer picture (#2) outside today. :cool:


+++

I kept thinking that Centuri's PNC-74 was "pointier" than Carl's BC-734P. (For the record, I *love* that shape! :cool: ) So I dragged out my limited collection of Centuri cones and some Semroc counterparts.


Below (left to right), the Centuri nose cones are PNC-73, -74, and -76.
The Semroc cones are BC-723P [PNC-73], BC-735 [closer to PNC-74 than BC-734P], the aforementioned BC-734P [PNC-76?], and BC-730.

Now if my picture had turned out as clearly as I *hoped* :mad: , it would be obvious that:


1) The two cones on the far left [Centuri PNC-73] are basically identical in shape.

2) If you round off the very point of the Semroc BC-735, it's a dead ringer for Centuri PNC-74. (Oops! I even managed to "bash" off the point of the balsa cone while handling it.)


EDIT: The next paragraph was re-edited for picture #2 below.

3) The tip of the [next to the] last cone on the right (Semroc BC-730) isn't quite as round as the BC-734P (which *may* be mislabeled). However, the BC-734 is nearly indistiguishable from the Centuri PNC-76... :confused: which is [second from the] right at 3" long.


The point of all this rambling is, I *think* more accurate Semroc substitutes for these Centuri parts would be:

Centuri -- Semroc

PNC-73 -- BC-723P

PNC-74 -- BC-735

PNC-76 -- BC-734P


The problem with being analytical at work all day is that it spills over into my hobbies when I'm *off* work. (heavy sigh) This all got started when I read the Centuri "Sky Devil" posts, and promptly went downhill from there.


Carl, is your BC-734P (WHICH I LOVE!) supposed to be 3.4" long [Centuri PNC-74?], instead of ~3.0"? I'm not trying to nitpick, (mock sobbing) I JUST HAVE TO *KNOW!*


Or not.


Cheers, as always,

A Fish Named Wallyum
04-19-2007, 11:06 PM
You just need better light. Try taking the pictures outside on a sunny day.

Tau Zero
04-19-2007, 11:27 PM
You just need better light. Try taking the pictures outside on a sunny day.I used a "trouble light," which improved things slightly, but I may try again outside this weekend.

If it doesn't snow like it did today. :eek:


Cheers,

Tau Zero
04-29-2007, 11:07 PM
EDIT: I took a much clearer picture (#2) outside today. :cool: Well, okay, that was *yesterday,* but there you go. :eek: :rolleyes: :p


Cheers,

Carl@Semroc
04-30-2007, 10:35 PM
Thanks Jay! You caught me good this time. Sorry for the long delay, but it has been busy lately and this took more research that usual.

I THINK I know what happened. Looking back through the files, the BC-734P is a true anomaly or in rocket scientist speak, "less than optimal." Centuri produced two PNC-76 nose cones. Both were 3.0" long, but the first was injection molded with a separate shoulder piece and was more pointed. The later PNC-76 was blow-molded as one unit and was about .025" shorter and slightly thicker toward the tip. It is the one that was mass produced and found its way into more kits than the earlier version, like the one you have. I intended to release it as the BC-730P, knowing that most people would not see (and appreciate) the subtle differences.

I had an entry in the spreadsheet for the correct 3.4" long BC-734P that was intended to be a balsa equivalent of the PNC-74 injection molded version. Since it had the same name but was earlier in the file, it kept getting overwritten with the one that should have been BC-730P. So it kept getting left out. I do not have a blow-molded version of the PNC-74 so I am not sure they ever did it. Since several others made the jump from injection to blow-molded, I think it is possible that there are some "in the wild."

I sent you a couple of the REAL, new, improved, "more gooder" BC-734P cones today. Sheryl is getting the stock corrected tomorrow, so we should be right back there where I THOUGHT we were a few weeks ago!

The Centuri Cross-Reference is still good. It just does not have the distinction between the two versions of the PNC-76 replacements.

Thanks again, Jay!

Tau Zero
04-30-2007, 11:11 PM
Thanks Jay! You caught me good this time. (chuckling) I didn't intend to "catch" you, Carl! That was just a side effect of my "analytical exorcism!" :eek: ;) :D


I sent you a couple of the REAL, new, improved, "more gooder" BC-734P cones today. Sheryl is getting the stock corrected tomorrow, so we should be right back there where I THOUGHT we were a few weeks ago!

The Centuri Cross-Reference is still good. It just does not have the distinction between the two versions of the PNC-76 replacements.

Thanks again, Jay!Please feel free to keep the BC-730P available! And thanks (as always) for going "above and beyond" for *all* of us incurable Semroc fans!


Cheers,

Tau Zero
05-01-2007, 09:36 AM
The point of all this rambling is, I *think* more accurate Semroc substitutes for these Centuri parts would be:At least, after I get done updating them (the links below are "clickable"):

Centuri -- Semroc

PNC-73 -- BC-723P (http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=918)

PNC-74 -- BC-734P (http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=1459)

PNC-76 -- BC-730P (http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=919)


Cheers,

Tau Zero
05-02-2007, 10:57 PM
I sent you a couple of the REAL, new, improved, "more gooder" BC-734P cones today.PNC-74 -- BC-734P (http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=1459)Check out the contents of the Semroc box that turned up on my desk at work today.

--How cool is *that?!?* :D :p


Cheers,

A Fish Named Wallyum
05-02-2007, 11:06 PM
Looks like two scratchbuilds to me. One can be the Snake, the other the Arrow. :rolleyes: ;)

Tau Zero
05-02-2007, 11:40 PM
Looks like two scratchbuilds to me. One can be the Snake, the other the Arrow. :rolleyes: ;)ROTFL!

--*Nice.* (I bought the CD today, and I'm listening to it now. "Brought to you by the letter 'ssssss'" :eek: :D )


Actually, I think one of them will be, (whispered) "Stiletto."

http://www.ninfinger.org/~sven/rockets/nostalgia/72cen014.html


...with Bill (Vanel) Cooke's "reversed" paint job :cool: :

http://forums.rocketshoppe.com/showthread.php?t=432&highlight=Stiletto


Cheers,

A Fish Named Wallyum
05-02-2007, 11:45 PM
Actually, I think one of them will be, (whispered) "Stiletto."

http://www.ninfinger.org/~sven/rockets/nostalgia/72cen014.html


...with Bill (Vanel) Cooke's "reversed" paint job :cool: :

http://forums.rocketshoppe.com/showthread.php?t=432&highlight=Stiletto


Cheers,

I like the look of Bill's bird. Where's he gotten to? :confused:

Tau Zero
05-07-2007, 12:51 AM
I do not have a blow-molded version of the PNC-74 so I am not sure they ever did it. Since several others made the jump from injection to blow-molded, I think it is possible that there are some "in the wild."I was poking around in some printouts of Centuri plans from JimZ when I came across this blow-molded PNC-74 "sighting" in the second (non-"K" version) of the Excalibur:

http://www.dars.org/jimz/cen5008.htm

It's in the exploded view on the 4th page, listed as "c".

To my eye, the 1972 catalog model appears to have a PNC-74 nose cone (as, apparently, does its neighbor, the Bandito):

http://www.ninfinger.org/~sven/rockets/nostalgia/72cen020.html


...*although* the kitcard illustration looks like it uses a PNC-76. :confused:
(I have the PDF file, but can't figure out where I found it. I don't think it's the version on YORP. :o )


Analytical *and* obsessed,