vintage astron alpha fin pattern

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bradycros said:
I checked www.spacemodeling.org/JimZ/estes/K-25.pdf and there is a fin template on page four of the instructions in pdf.

I printed out a copy from Jim Z's and a copy from Rex R. The copys were layed one over the other, held up to a window and compared. While the templates are very close, they are not a spot on match. I would go with the fin template that comes from the instructions myself. Thanks Rex R.
Click to expand...


The template in the JimZ file is from the catalog insert that was included in the 1969-71 catalogs. It should NOT be considered canon, even though Bill Simon wrote that section. In fact, after laying a current fin and a 1225 die cut fin, and a earlier die-mashed fin, and the SP-25 template on the "Model Rocketry Technical Manual" drawing, I would almost bet you that the drawing was modified for a better fit on the page.

The leading edge sweep is the same, the root edge is a tad longer, the trailing edge sweep is brought back a bit and the tip clipped just enough so that the height of the rocket would remain the same and the total fin area would be about the same a regular Alpha fin, but the tip would be within the border on the page
 
RoyAtl said:
The template in the JimZ file is from the catalog insert that was included in the 1969-71 catalogs. It should NOT be considered canon, even though Bill Simon wrote that section. In fact, after laying a current fin and a 1225 die cut fin, and a earlier die-mashed fin, and the SP-25 template on the "Model Rocketry Technical Manual" drawing, I would almost bet you that the drawing was modified for a better fit on the page.

The leading edge sweep is the same, the root edge is a tad longer, the trailing edge sweep is brought back a bit and the tip clipped just enough so that the height of the rocket would remain the same and the total fin area would be about the same a regular Alpha fin, but the tip would be within the border on the page
Click to expand...


So your putting fourth the proposition that Estes published the insert with the intention of using artistic interpentation to mislead the public?

Your proposition is what I like to call 'wrong'.
 
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RoyAtl said:
No, I think they just wanted it to fit the page.
Click to expand...


If that's the case, that the time and trouble was taken to modify the the dimentions of the fin to fit the page, why, one might wonder, wasn't everthing moved up the page so the so called correct fin would fit, there's room to do so on the page. It wouldn't have taken any more time or trouble.
 
bradycros said:
If that's the case, that the time and trouble was taken to modify the the dimentions of the fin to fit the page, why, one might wonder, wasn't everthing moved up the page so the so called correct fin would fit, there's room to do so on the page. It wouldn't have taken any more time or trouble.
Click to expand...

Because they never thought that anal-retentive nut cases like us would be obsessing over it 40 years later. :confused2:
 
bradycros said:
Your proposition is what I like to call 'wrong'.
Click to expand...

You might like to call it that, but I have seen far more screwy stuff done in "official" paperwork for the sake of just getting the document finished. No one ever expects that anyone is actually going to check these things down to the last micron, or if they do, the tweaked publication is excused as "just an illustration"

RoyAtl is probably closer to the mark than you would like to believe, but stuff like this happens all the time in the real world
 
bradycros,

Why not?
Are we not suppose to push this hobby to the extreme!
Push any buttons yet?
 
speaking of differences...the prototype(according to the instructions) has a one fin, panel, and nose cone painted red. the catalog images show the fin & panel as black... just happened to see that while installing the 'teabag'(& 3' shock cord).
rex
 
dlazarus6660 said:
bradycros,

Why not?
Are we not suppose to push this hobby to the extreme!
Push any buttons yet?
Click to expand...


I think you got BEC and bradycros mixed up. You should double check that by reviewing posts 27 and 28.
 
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Rex R said:
speaking of differences...the prototype(according to the instructions) has a one fin, panel, and nose cone painted red. the catalog images show the fin & panel as black... just happened to see that while installing the 'teabag'(& 3' shock cord).
rex
Click to expand...
The red fin/red panel was the 1960s "simple" paint scheme (lower left-hand photo. There was also a "complex" decor scheme, using optional finishing supplies, as well as the very unique 1970 scheme.) The black fin/black panel/black vertical stripe decor that you describe was the 1970s scheme. The current scheme began in 1982. That was the year that Estes Industries finally started including decals in Alpha kits. The one constant over the years is that the Alpha nose cone has always been painted red.
 
MarkII said:
The red fin/red panel was the 1960s "simple" paint scheme (lower left-hand photo. There was also a "complex" decor scheme, using optional finishing supplies, as well as the very unique 1970 scheme.) The black fin/black panel/black vertical stripe decor that you describe was the 1970s scheme. The current scheme began in 1982. That was the year that Estes Industries finally started including decals in Alpha kits. The one constant over the years is that the Alpha nose cone has always been painted red.
Click to expand...

I so much prefer the red and black colors over the red and North Carolina Blue they've used for the past 18 years. I also tend to paint the color fin red instead of black, but I may go ahead and paint the next Alpha I build with a black fin (assuming I can find a red and black decal sheet). I have a scale-up of Alpha decals to use on a BT-80 Alpha. Not sure whether I'll go red or black on that one.
 
I prefer the 1967-70 patterns. (I always did.) But in my latest Alpha, I did the 1971-82 pattern. Mine is a mirror image of it, though. My black panel is to the LEFT of the black fin. This is in keeping with the red/white prototype pattern, in which the red panel was also to the left of the red fin. I was going to paint it like the proto, but I changed my mind after I had done the masking. My kit has a plastic, not balsa, nose cone, so giving it any of the 1960s schemes just wouldn't be right. One thing for sure, though, was that I didn't want to use the current scheme, because it is the least attractive one to me. I didn't realize that the odd fin was now blue and not black. When did that happen?
 
MarkII said:
One thing for sure, though, was that I didn't want to use the current scheme, because it is the least attractive one to me. I didn't realize that the odd fin was now blue and not black. When did that happen?
Click to expand...

First time it showed up in the catalog that way was at least 1990. If you can find a high res version of the picture of myself and Vern standing next to my MegaAlpha, you'll see he's holding a blue decaled Alpha. That picture was taken in August of 1991.
 
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so that would imply that my kit(or at least the instructions) are a bit older than I thought, cool:).
rex
 
Turns out the 1990 catalog said the red and blue decals were included, and that --interesingly-- the nose cone included might be red, white, or blue. Did anyone ever get one of the red or blue noses?

I had always blamed the red/blue decals on Tunick, but this proves that they preceded him (IIRC, he came to Estes in spring/summer of 1990).
 
dlazarus6660 said:
Why not??
Click to expand...

Just be sure to use your rocket, not mine.

After I spend time building and finishing, I don't like to send them on one-way, one-time missions. I like to get them back. An Alpha with a C motor is dicey enough, I would bet money that using D power would pretty much guarantee a lost bird.

But I'll be happy to watch you launch yours, sounds like it will be fun!
 
just for grins I ran a sim w/ a D21...if it held together open rocket says 2000' at .88mach :) (said 1400' on a C6-5).
rex
 
You MIGHT get even more from the longer-burning D10s. I find in light rockets they sim a little higher.

I have actually flown a rocket of a similar weight and frontal area (BMS School Rocket) to nearly 2000 feet according to an onboard altimeter on a D10-7W. Getting that back was pretty durn lucky and wouldn't have been possible without several other sets of eyes on it than mine...
 
Rex R said:
just for grins I ran a sim w/ a D21...if it held together open rocket says 2000' at .88mach :) (said 1400' on a C6-5).
rex
Click to expand...

I did a "Hyper" Alpha, at LDRS 99, it was a standard tube soaked in CA, G10 fins, kevlar shock cord, and mylar streamer. With the base off of the plastic nose, we had the nose cone, and about 1in of tube for the recovery and tracking poweder.

We flew it on an F101. We were able to track the smoke all the way up, towards the end, it looked like it may have lost a fin, as the smoke trail was no longer straight up. We did see the orange cloud at the top from the tracking powder, but never saw it again after that.

It simmed at mach 1.5, with an altitude of 3500ft.

It was a quick flight!
 
BEC said:
If you really don't care, there's no need to look at these pictures.

For the rest, here are comparisons between the SP-25 scan that's the genesis of this thread and the "Handbook of Model Rocketry" template from the middle of the 1969 (and a few following years) Estes catalogs and which has been substituted for the SP-25 itself on the Alpha listing on JimZ.

The first is a composite comparing both ways. The second shows the SP-25 pattern laid next to the JimZ/HMR pattern. All were downloaded today and printed with scaling turned off from the same printer.

I have pics of the cut out SP-25 template laid on an Alpha IV fin (it's black, easier to see than the orange Alpha III) but the differences are much slighter than between these two variations.

Rex, thanks again for filling in the missing piece of the puzzle from the source of the original information - a vintage Alpha kit's bag.


Added: I just remembered. I have a 1970 catalog that I bought on eBay some months ago. I don't need to use the scan of that page 58 - I have the real deal in hand. Need to take another picture. BTW, a comparison of my cutout shown in the two images already posted and the catalog page shows a good match - so the JimZ/Ninfinger scan is correctly sized.

BRB....
Click to expand...

I want to thank both BEC and Rex R for their postings on the Estes K-25 SP-25 Alpha Fin Pattern Sheet. Just for the record, that's my Estes K-25 Astron Alpha kit instructions on JimZ's website - https://www.spacemodeling.org/jimz/estes/k-25.pdf . JimZ came over from Michigan to visit me once here in Canada, and I gave JimZ a bunch of classic Estes and Centuri and Enerjet kit instructions and decals to take home and scan for his website. That Estes K-25 instruction sheet has my signature on it. Jim forgot to remove my signature when he scanned it. I bought that kit directly from Estes back in 1967. I may still have my original SP-25 Pattern sheet around here somewhere's, as I tend to hang onto stuff like this. I have a lot of early 60's Estes and Centuri kit instructions in my personal collection.
Thanks again BEC and Rex R for your input on the Estes SP-25 Fin Pattern sheet.

Larry B
 
Larry,

If you are still able to get in touch with JimZ perhaps you can close the loop on this and get Rex's scan of the SP-25 with the 1 inch lines - in post 26 - included on Jim's site along with your instructions and then note about "need SP-25" can be removed and the original template can be included in a revised version of the .pdf. Here's such a file.


I'd forgotten about this thread....thanks for reminding me.

View attachment K-25 with SP-25.pdf
 
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MarkII said:
The red fin/red panel was the 1960s "simple" paint scheme (lower left-hand photo. There was also a "complex" decor scheme, using optional finishing supplies, as well as the very unique 1970 scheme.) The black fin/black panel/black vertical stripe decor that you describe was the 1970s scheme. The current scheme began in 1982. That was the year that Estes Industries finally started including decals in Alpha kits. The one constant over the years is that the Alpha nose cone has always been painted red.
Click to expand...

In both catalogs you linked, what is the name of the rocket Vern is showing to the kids?
 

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