Estes Super Alpha

[pokerace721]

For the next few weeks, we will supply your choice of a BNC-60K or BNC-60KP balsa nose cone free with your next order to upgrade your Super Alpha from plastic to balsa.

Just put a note in the comments section like "Super Alpha Upgrade BNC-60K" (or KP.)

is there any difference between the two nose cones?

 

[bradycros]

Do NOT use the fin template from that guide if you want to clone the Alpha *KIT*. It is NOT the template from any version of the kit, and was probably drawn the shape it is in order to fit in the space that they had in the catalog.

You need to contact Carl McLawhorn at Semroc and give him the benifit of your expertise. I bought a set of lazer cut fins for the K-25 from Semroc to clone an Alpha. The fins sent to me match that template. Since Carl's dealt with these kinds of details many times, I'll go with his expert opinion.

But thanks anyways.

 

[bradycros]

is there any difference between the two nose cones?

Yes. You can compare the two by going to:

www.semroc.com/Store/Scripts/prodView.asp?idproduct=2735

and

www.semroc.com/Store/Scripts/prodView.asp?idproduct=2736

 

[Marc_G]

I prefer the rounded one (kp ).

Gotta love SEMROC. Before Carl's post I was contemplating ordering some stuff from "somewhere" out a list of about four vendors. His post incenfivized me to place the order with Semroc. I placed it saturday night and got the comforting autoreply confirming the order. In the morning--EASTER SUNDAY -- I got an email clearing up an ambiguity about the order (thanks for checking!) And it went out today. Absolutely first rate customer service. I bet that free cone promo nets some great returns. Genius way to take advantage of the discussion re: super alpha.

Marc

 

[RoyAtl]

You need to contact Carl McLawhorn at Semroc and give him the benifit of your expertise. I bought a set of lazer cut fins for the K-25 from Semroc to clone an Alpha. The fins sent to me match that template. Since Carl's dealt with these kinds of details many times, I'll go with his expert opinion.

But thanks anyways.

With all due respect to Carl, I think he made the mistake that we all originally did in assuming that the Estes Technical Manual insert in the '69-'71 catalogs accurately reflected the K-25 Astron Alpha kit. But unless someone produces a 1967 vintage K-25 kit whose pattern matches it, I'll go with the mid 70's K-25/#1225 pattern sheet (SP-25). Other than the '69 Estes logo, it looks just as I remember the patterns from the Alpha kits I built in 1968.

I have, written down in many places, that the root of the fin is 2.25", the tip is 1.25", and the span of the fin is 1.6". That corresponds exactly to the SP-25 pattern, and to the die cut fins from mid-80's Alpha kits.

In TR-11, Dr. Gregorek, on page 42, gives dimensions of root:2.25", span 1.6", and tip 1.20", the only difference.

In contrast, the pattern from the manual, while having a root of 2.25", has a span of only 1.5" and a tip of 1.4". While it may seem slight, it is quite a noticeable difference visually.

The photos show comparisons between a die cut fin from a mid-80's Alpha kit, and the SP-25 from a mid 70's kit, and page 58 from the 1971 Estes catalog (which is what is shown on JimZ's site).

I have pictures of Alphas from the April '66 Model Rocket news which I'll scan and measure tomorrow, but they appear to correspond to the SP-25 pattern.

 

[BEC]

I have pictures of Alphas from the April '66 Model Rocket news which I'll scan and measure tomorrow, but they appear to correspond to the SP-25 pattern.

As one of the participants in these "Alpha fin variation" discussions I'm going to be really interested in what you find. Thanks, Roy.

 

[Carl]

The more I look at this, the more mysterious it is. It looks like there were at least three versions of the early balsa Astron Alpha. In April 1966 MRN, the photos clealy have the 1.29" tip, 1.6" span, and 2.8" sweep. This is very close to the SP-25 pattern. This model had the RA-2050 rings since the AR-2050 was not released. The later catalog version had a 1.44" tip, 1.49" span, and a 2.58" sweep. The later die-cut version had a 1.23" tip, 1.68" span, and a 2.78" sweep. The fins were all different on the die-cut sheet, so the averages are given.

The first published fin span of the Astron Alpha in 1966 was 4.2" which matched the 1.6" span fins (1.6" * 2 + .976"). In 1966 the published spec for the fin span was changed to 4.0" which matched the catalog version of the fins (1.49" * 2 + .976"). It is interesting that most of the photographed models in the catalogs during the early 70's used the catalog version of the fins and not the version that was in production at the time.

The later die-cut fins were the largest of the group, but the earliest fins made the Alpha 12.3" long instead of the 12.25" that was usually published.

I went with the catalog version for our FES-K25 fins because they were the best known. I should go back and release the FES-K25F to match the 1966 version and the FES-K25L to match the later version. The later version should have all three slightly different fins to match the original die-cut sheet.

 

[Marc_G]

Showed this fin-span discussion to my wife; she thinks we're a bunch of geeks with too much time on our hands. "Who cares about 0.2 inch difference on fin span on a 40 year old model?" :bangpan:

 

[pokerace721]

I think the Alpha would fly pretty good with canted fins or install fin tabs to allow it to spin...great design for it.

 

[bradycros]

The more I look at this, the more mysterious it is. It looks like there were at least three versions of the early balsa Astron Alpha. In April 1966 MRN, the photos clealy have the 1.29" tip, 1.6" span, and 2.8" sweep. This is very close to the SP-25 pattern. This model had the RA-2050 rings since the AR-2050 was not released. The later catalog version had a 1.44" tip, 1.49" span, and a 2.58" sweep. The later die-cut version had a 1.23" tip, 1.68" span, and a 2.78" sweep. The fins were all different on the die-cut sheet, so the averages are given.

The first published fin span of the Astron Alpha in 1966 was 4.2" which matched the 1.6" span fins (1.6" * 2 + .976"). In 1966 the published spec for the fin span was changed to 4.0" which matched the catalog version of the fins (1.49" * 2 + .976"). It is interesting that most of the photographed models in the catalogs during the early 70's used the catalog version of the fins and not the version that was in production at the time.

The later die-cut fins were the largest of the group, but the earliest fins made the Alpha 12.3" long instead of the 12.25" that was usually published.

I went with the catalog version for our FES-K25 fins because they were the best known. I should go back and release the FES-K25F to match the 1966 version and the FES-K25L to match the later version. The later version should have all three slightly different fins to match the original die-cut sheet.

Well... there ya go. Thank you for the information Carl.

 

[BEC]

The later version should have all three slightly different fins to match the original die-cut sheet.

Ah....so we can have that nostalgic "gotta stack sand 'em to make them match" experience that is so lacking in kits with laser cut fin sets ....

 

[RoyAtl]

And I still have to insist that there is only one version of the kit Alpha (as far as fin-shape goes). I.E. all versions of the Alpha kit (even the Alpha III!) were based on the one pattern. Of course, you should allow ±~0.05" variations as part of the "do I cut inside the line or outside the line?" and variations between die-cut and die-mashed :wink:.
The important thing is they keep the same ratio (shape).

I assume that the "Catalog Alpha" you're talking about is just the drawing in the '69-'71 catalog technical section, because I've never seen a photo of an actual Alpha that looked like it used those fins. Again, I bet you can chalk that up to Gene Street's discretion. To me, it is obvious he shortened the span, but then extended the chord to keep the same fin area. But then, I also think he could've used the regular SP-25 pattern without problem. Unless Bill Simon knows what Gene's reasoning was I suppose we'll never know. Of course, it is Bill Simon's design, so he would be the ultimate authority anyway.

 

[Rex R]

I happened apon a kit w/ the balsa nose...when I went looking for a rocksim file I didn't find any. so here are two versions(.ork open rocket) a stock version and a 24mm version, enjoy.
rex

View attachment salpha18.ork

View attachment salpha24.ork

 

[powderburner]

(snip) she thinks we're a bunch of geeks....

Geeks? Is that supposed to be a news flash or something?

Hey, I think it's a lot more fun being a geek, and having half a clue how stuff works and how I can make it work for me. My wife has never complained; she gets things custom made for her that aren't even for sale in the stores.

It's usually the people who don't have "their own" geek that try to make fun of us....because they are jealous!

 

[powderburner]

Thank you SEMROC! (I got my free nose cone!)

I placed my order a couple days ago and my local post office (amateur operation) delivered it Saturday. F A S T service!

Only problem was that the mail carrier put half the box into my mailbox and left the door open with the other end sticking out, and we were out of town for the weekend (San Antonio), and just my luck we had some major thunderstorms while I was gone. Absolutely none of this was in any way the fault of SEMROC, but I got home tonight to find a soggy box (and matching soggy pile of mail) sticking out of my mailbox.

So, let me tell you about SEMROC quality, even in their shipping. NONE of the items inside the box was damaged in any way because SEMROC had packaged everything sealed inside plastic bags. All items are just fine, despite the best efforts of my wonderful local mail carriers.

Again, thankyou to SEMROC! I don't know why you took on fixing an Estes problem (and I hope they are kicking themselves for missing the opportunity) but I am happy that you did.

Now, back to the original thread on Super Alpha builds----

 

[o1d_dude]

Speaking of Super Alpha nosecones, I was in one of LHSs today and spotted a Super Alpha kit on the rack. When I checked the bag it had a really nice balsa nosecone.

Don' t give up hope! They're out there.

 

[modus.ponens]

I bought my son a Super Alpha kit for Christmas and its been sitting in the bag driving me crazy. I was at the LHS (R/C country) recently and bought one for me, plus some extra couplers and BT60 and larger engine mount. I'm going to see if I can stretch it out a bit and make this a dual deploy with my Raven II. Both kits have balsa nose cone.

 

[o1d_dude]

Those Super Alphas fly very nicely on 24mm motors. Mine had such a dense balsa nosecone I didn't need to add any weight for stability.

I'll bring mine out to the next SARG launch so you can take a look at it.

 

[qquake2k]

Those Super Alphas fly very nicely on 24mm motors. Mine had such a dense balsa nosecone I didn't need to add any weight for stability.

I'll bring mine out to the next SARG launch so you can take a look at it.

I can vouch for the quality of Old Dude's Super Alpha. Amazing finish on that beautiful bird!

 

[SMR]

Speaking of Super Alpha nosecones, I was in one of LHSs today and spotted a Super Alpha kit on the rack. When I checked the bag it had a really nice balsa nosecone.

Don' t give up hope! They're out there.

I am still undecided whether or not to desecrate that beautiful balsa nose cone with paint!

 

[bradycros]

Those Super Alphas fly very nicely on 24mm motors. Mine had such a dense balsa nosecone I didn't need to add any weight for stability.

I'll bring mine out to the next SARG launch so you can take a look at it.

This here fella at CIT says he's gotta know which style fin set came with your Super Alpha. The one your "not" spos'ta use or the 'other' one?