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  #31  
Old 07-07-2017, 02:40 PM
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Originally Posted by blackshire
(I wonder this because in those days, a lot of people around the country had to buy model rocket supplies and building supplies by mail order--that 1969 catalog also offered paint, glue, sandpaper, hobby knives, and Photo-Flash "D" batteries for that reason.)

I ordered some rockets for my daughter from Estes and picked up some epoxy to tip the total into free shipping. Felt like the good old days!




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  #32  
Old 07-07-2017, 05:06 PM
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I was lucky enough to buy a bunch of red and black livery (and therefore, original shaped pnc-50K nose) Alphas three years or so ago on eBay just before I had to stop buying anything on eBay.

I also have two or three yellow card K-25/1225 balsa nose Alphas.

I'm hoping they all made it through the move and didn't get dumped when I missed the deadline. I've seen three or four of them while looking through boxes as I've been unpacking.

There is only one fin shape for the Alpha. That fin shape has persisted since early days (photogrammetry confirming dimensions in an old issue of Model Rocket News, before Astron Alpha was commercially available.) through the die mashed and laser cut versions (proportions were same if dimensions were a few hundredths off) and even the plastic Alpha III.

The aberration that was the Technical Section Yellow Pages Alpha was perfectly understandable as the only way to fit a pattern on the page. It is unfortunate that Carl took that as definitive.

Never liked the light blue of the post red & black decals (would probably have been OK if they were navy blue)

I really wish the old nose shape would return, but I recognize that the current shape has been around so long that many consider it the *real* Alpha shape.
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  #33  
Old 07-07-2017, 06:08 PM
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Originally Posted by A Fish Named Wallyum
Could be worse. You could be new age.


New age is definitely not part of my DNA.
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  #34  
Old 07-07-2017, 06:22 PM
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I don't think it was mentioned, but if it was, I apologize. Are the current plastic nose cones for the Alpha the same profile as the original balsa nose cones?

I seem to remember thinking the nose cones on the Alpha III I used for school builds back in the 90s looked slightly different. I had an old BNC-50K (which I believe is the original Alpha cone) and used that as a model to turn a new balsa nose cone for the Super Alpha kit a few years ago. My kit had the overly long (and rounded tip) plastic nose cone and a shortened body tube to make it roughly the correct length.

I did use the included motor mount parts and decal!
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  #35  
Old 07-07-2017, 06:24 PM
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Roy,

Agree on the nose cone shape. The PNC-50Ks are very close to the balsa original and noticeably different from the later/current one.

On fin shapes: Here are pictures I just took. Note that the die cut fin matches SP-25 (at the outside of the lines) exactly but the current laser-cut fin in Estes kits has a slightly shorter span and different tip sweep. Also shown is the Semroc fin both on SP-25 (clearly a different shape) and on the yellow catalog page (where it matches exactly).

For all of these I tried to line up the root and the leading edge.

I'll worry about Alpha IIIs later....but those fins are VERY close to the original SP-25.

Lee - there have been two shapes of the blow-molded Alpha cones, as alluded to above. The current one is more tapered, the former one is very close to the balsa cone.

On THAT subject: Semroc BNC-50Ks are close but not quite as sharply pointed. BMS BNC-50Ks are closer to the Alpha III cone in shape.....

But as far as I know, the Alpha III shape is the same regardless of version, original red, current orange, clear (Phantom), black (Alpha IV) and (I presume) white or chromed (Quasar). I've never seen a chrome Quasar cone in person.
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Last edited by BEC : 07-07-2017 at 06:46 PM. Reason: replace laser cut picture with one a little closer to the others in size....
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  #36  
Old 07-07-2017, 06:35 PM
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Quote:
Originally Posted by Royatl
There is only one fin shape for the Alpha.
I've see two: The shape as designed by Estes.

And the shape caused by young newbs incorrectly gluing the trailing edge to the tube in a sort of upside down fashion

Doug

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  #37  
Old 07-07-2017, 06:41 PM
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Quote:
Originally Posted by Doug Sams
I've see two: The shape as designed by Estes.

And the shape caused by young newbs incorrectly gluing the trailing edge to the tube in a sort of upside down fashion



....with the trailing edge used as the root. Which is of course why the little die cut dot and the larger laser-cut hole is in Alpha fins now to mark the root edge. Not that everyone pays attention to that.

It's that little hole that convinced me that the current Super Nova two-stager just uses Alpha fin sets.
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  #38  
Old 07-07-2017, 06:42 PM
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Quote:
Originally Posted by LeeR
I don't think it was mentioned, but if it was, I apologize. Are the current plastic nose cones for the Alpha the same profile as the original balsa nose cones?

I seem to remember thinking the nose cones on the Alpha III I used for school builds back in the 90s looked slightly different. I had an old BNC-50K (which I believe is the original Alpha cone) and used that as a model to turn a new balsa nose cone for the Super Alpha kit a few years ago. My kit had the overly long (and rounded tip) plastic nose cone and a shortened body tube to make it roughly the correct length.

I did use the included motor mount parts and decal!
My ~1969 Alpha has a balsa cone with a nice, sharp tip. Similarly, my 1999 Alpha has a plastic cone, also with a nice sharp tip, but the cone is somewhat slimmer just aft of the tip than is the balsa. It has a bit different shape.

My daughter's orange Alpha III cone has a rounded tip, much less pointy than either of the others. FWIW.

Doug

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  #39  
Old 07-07-2017, 07:01 PM
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Quote:
Originally Posted by LeeR
I don't think it was mentioned, but if it was, I apologize. Are the current plastic nose cones for the Alpha the same profile as the original balsa nose cones?

I used to have photos on YORF showing the difference in the nosecones. No thanks to crappy Photobucket, they are not online any more.

So...here they are again.

On left a 2008 BNC-50K from Semroc which is very close if not identical to the profile of the early Estes nose cone, center PNC-50K, on right was the BMS version of BNC-50K in 2008, which is actually the balsa equivalent of the Alpha III nosecone. I threw it in the pic just to show what you'd end up with if you ordered it from BMS at the time.

There was a plastic cone shaped like the balsa one on the left at one time. I've seen them in old Alpha II kits. It is my understanding that they were in X-Ray kits at one time too.

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  #40  
Old 07-07-2017, 09:08 PM
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Quote:
Originally Posted by BEC
Roy,

Agree on the nose cone shape. The PNC-50Ks are very close to the balsa original and noticeably different from the later/current one.

On fin shapes: Here are pictures I just took. Note that the die cut fin matches SP-25 (at the outside of the lines) exactly but the current laser-cut fin in Estes kits has a slightly shorter span and different tip sweep. Also shown is the Semroc fin both on SP-25 (clearly a different shape) and on the yellow catalog page (where it matches exactly).

For all of these I tried to line up the root and the leading edge.

I'll worry about Alpha IIIs later....but those fins are VERY close to the original SP-25.

Lee - there have been two shapes of the blow-molded Alpha cones, as alluded to above. The current one is more tapered, the former one is very close to the balsa cone.

On THAT subject: Semroc BNC-50Ks are close but not quite as sharply pointed. BMS BNC-50Ks are closer to the Alpha III cone in shape.....

But as far as I know, the Alpha III shape is the same regardless of version, original red, current orange, clear (Phantom), black (Alpha IV) and (I presume) white or chromed (Quasar). I've never seen a chrome Quasar cone in person.


The 2016 fin I won't quibble about *too* much, since leading and trailing edge sweeps and root chord are correct.

The old balsa noses were always a bit dodgy due to wear and tear on the plunge grinder. The original plastic nose was a decent approximation. The newer nose is a proper mathematical ogive, but *not* the old shape.

And yes, you're correct about the Alpha III nose. Chrome Quasar was just an Alpha III nose, chromed. As the fins were Alpha III fins, clipped and chromed (though the clipping was probably done at the mold and not post production).
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