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Woody's Workshop 02-04-2017 06:42 PM

So the very first Alpha used a BT-50 9" long?
The only one's I've seen (or built) were BT-20.
I'll have to scratch build one soon of a BT-50 version.
Do you have a part number or a BNC number?

al_packer 02-04-2017 07:03 PM

Quote:
Originally Posted by Woody's Workshop
So the very first Alpha used a BT-50 9" long?
The only one's I've seen (or built) were BT-20.
I'll have to scratch build one soon of a BT-50 version.
Do you have a part number or a BNC number?


BT-50 was 0.950 I.D., 0.976" O.D., at least up until I departed in 1977. That just happened to be the size of a stock mandrel that Euclid Spiral Paper Tube Company had. The nose cone was a BNC-50K.

vcp 02-04-2017 08:28 PM

I have an Alpha, in pristine condition, flown once, that is 47 years old.

stefanj 02-04-2017 08:35 PM

Quote:
P.S. My favorite science fiction book: "The Stars my Destination" by Alfred Bester. It would make a great movie if someone like Tim Burton took on the project.



"Gully Foyle is my name
Terra is my nation
Deep space is my dwelling place
The stars my destination."

I had the pleasure of meeting Bester, at a SF convention in 1980. I feel very proud to have gotten a laugh out of him.

tbzep 02-04-2017 08:42 PM

Quote:
Originally Posted by Woody's Workshop
So the very first Alpha used a BT-50 9" long?
The only one's I've seen (or built) were BT-20.
I'll have to scratch build one soon of a BT-50 version.
Do you have a part number or a BNC number?

All the Alphas, Alpha III's and Alpha IV's are BT-50. You're just getting the numbers mixed up a little. BT-20 is the size for 18mm motor mounts (1/2A - C)

dwmzmm 02-04-2017 08:44 PM

1 Attachment(s)
I just remembered my dad took a slide picture of my very first model rocket launch, that of the Astron Alpha along with the red Electro Launch pad. This was at the CW Ruckel Jr. High School in Niceville, FL (summer of 1969). Engine used was the 1/2 A6-2; I failed to use enough recovery wadding as the parachute was mostly melted. Before launch, my mom was so scared of the engine "blowing up" that she locked herself in the car. :chuckle:

Woody's Workshop 02-04-2017 09:52 PM

Quote:
Originally Posted by tbzep
All the Alphas, Alpha III's and Alpha IV's are BT-50. You're just getting the numbers mixed up a little. BT-20 is the size for 18mm motor mounts (1/2A - C)


You are correct.
I must be tired.

BEC 02-04-2017 10:47 PM

Quote:
Originally Posted by al_packer
Let's start with (3), because that's where the design started. I free-handed that shape on the nose cone lathe in Vern's garage, probably a year earlier, just making a shape that I liked. Then when the call for a new beginner's model came down, I picked the nose cone up off my kitchen table, grabbed an 18" length of BT50, and (1) cut it in half (shipping considerations for the final kit limited me to 9"). and stuck the nose cont on one end. The fins (2); well, I wanted the CP back fairly far for max stability, so a swept design was the logical choice. Straight tips meant the fin would be easier for the builder to cut from the balsa sheet, and the taper was for appearance and structural considerations. I drew a shape, then changed it to get the look I wanted and poof--I had something Vern would like.


Interesting about the nose cone. The BNC-50K was already in use on the X-Ray, Farside (not X), Cobra and Drifter....or was that the already-in-stock nose cone that was closest to your free-handed one when you started looking at actually producing it?

I've located the instruction sheet from my first Alpha kit....but of course the SP-25 is long gone.

BEC 02-04-2017 10:54 PM

Quote:
Originally Posted by al_packer
BT-50 was 0.950 I.D., 0.976" O.D., at least up until I departed in 1977. That just happened to be the size of a stock mandrel that Euclid Spiral Paper Tube Company had. The nose cone was a BNC-50K.


So just like the story GHS recounts in a couple of his writings of a stock firework tube setting the diameter of the most common model rocket motor (18mm), a stock mandrel drove the size of the next common size up (24mm) since the Estes "Mighty D" had to fit in BT-50, and I surmise (but don't know) that all the follow one motors (Estes Es and C11s, and 24mm composites) are all that diameter to be compatible.

I love how this stuff all connects together.

Ltvscout 02-04-2017 11:10 PM

Quote:
Originally Posted by al_packer
Thanks, guys and/or gals for posting your Alpha memories.

Thanks for stopping by, Bill, and enlightening us with the background of the Alpha.


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