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Note for the Scratch Builders

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Woody's Workshop

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Estes no longer lists BT-56 tubes.
I've only found 1 vendor online that has any, and are on sale.
eRockets still stock Totally Tubular in BT-56.
I imagine once current stock of Estes BT-56 nose cones are sold out they will drop them too.
On a good note, Uncle Mikes Rocket Shack on ebay, not on his site, has dropped his single engine mount kits that fit BT-56 to $1.25 each.
Good time to stock up for those Centuri kits you always wanted to clone.
I hope my brother gives me some cash for xmas when he gets here tomorrow.
 
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Pepe Le Pew

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Woody, I have had to roll my own tubes when I cannot find a size I need. It's is a pain in the a.. but I manage! Thanks for the heads up!
 

Gary Byrum

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I never really got it about a BT 56. It's only a smidgen bigger than a 55 and hardly noticeable. So I've never used them. Won't be any great loss for me.
 

cavecentral

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What is the difference between BT-55 and BT-56? Even BMS doesn't have BT-56. I doubt I'll need one unless I find a cone or tube that is slightly off an not know why.
 

mwtoelle

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Use Semroc ST-13 instead. BT-56 was the Estes name for it after Centuri was shut down in the early 80s. eRockets is still selling ST-13 in lengths up to 30".
 
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hcmbanjo

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What is the difference between BT-55 and BT-56? Even BMS doesn't have BT-56. I doubt I'll need one unless I find a cone or tube that is slightly off an not know why.
mwtoelle is right.
The BT-56 is a carry over from Centuri, the ST-13.
The Estes BT-55 is 1.325" diameter, the Centuri ST-13 was 1.34" diameter.
After the Centuri line was stopped, Estes kept the tube size to use the (Centuri) Enerjet 1340 nose cone and fin can.
That nose cone, fin can and BT-56 (ST-13) was used more recently in the Eliminator model and some earlier rockets.
Centuri also used the fin unit in the Argus ARTF model.
 
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Tramper Al

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Even from Estes there is still a lot of BT-56 being sold - look at all of those 1.35 inch diameter E2X and RTF kits. If you want to buy plain white BT-56 tubes direct from Estes, the small TARC assortment contains a couple, as well as their engine mounts for 24mm and 29mm. It's not a bad time at all to be a BT-56 scratch builder. With the Eliminator out there, even the 1340 fin can will be common for quite a while yet.
 

Gary Byrum

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Thanks Gary - it's corrected now. Writing up this post I had BT-56 on my mind.
No worries. You did have me double checking my life long parts notes though.....Hahaha
On another note about BT 56 tubes, I'm pretty certain that I have ordered what were supposed to be 55 couplers from a vendor, and got 56 sized instead. I still have some of those too. I just wet em and peel off the outer most layer of paper and slick the surface up where I can use it in a BT 55. When parts are so close to being alike, where the vendors can't tell them apart, I have to question why they were manufactured in the first place. I'm sure someone had their reason.
 

Tramper Al

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When parts are so close to being alike, where the vendors can't tell them apart, I have to question why they were manufactured in the first place. I'm sure someone had their reason.
As alluded to above, BT-56 was created because of the merger and history of Centuri's #13. And to its continued parallel existence we owe the availability to this day of the excellent Enerjet fin can and nose cone that would otherwise have died out in the early 1970s.
 

Gary Byrum

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..........And to its continued parallel existence we owe the availability to this day of the excellent Enerjet fin can and nose cone that would otherwise have died out in the early 1970s.
You have to forgive this old school dood regarding things like plastic fin can assemblies. It robbed the kit/build of a specific part of the craftsmanship. It's right up there with laser cut fins (in my opinion). I guess when you grow up doing things where your skills were exercised more, that's what you get used to. When a rocket gets too easy to build, may as well let the little folks have at em. Besides, I've always hated dealing with gluing plastic to paper or wood. I trust good wood glues to do their job keeping my wood stuck to the paper.
 

K'Tesh

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Why do I feel that I somehow inspired this thread?

To my knowledge, Estes only has a few nosecones for the BT-56, the EnerJet Egg Crate's nosecone (part number unknown), and the PNC-56A (aka Part Numbers 072015/072013/060312/060340) which have their origins with Centuri, Tim Van Milligan's Omloid, and the AstroCam 110 based cameras.
 
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Woody's Workshop

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Hey K'Tesh,
You didn't exactly, inspire the thread.
I was just roamin and noticed a vendor had the Estes BT-56 on clearance.
Prompted me to investigate the Estes site to check availability, not listed.
Further searching lead me to sales of single engine mounts for the BT-56 tubes on clearance sale at Uncle Mikes Rocket Shack.
Thought I'd put it out there for the scratch builders and cloners.
IF I get my hands on some cash, I'm buying a bunch of EM's.
Uncle Mikes also has discounts on centering rings.
I haven't checked my stock yet, but I don't think I very many, if any, BT-56 centering rings.
And I know there is cloning in the future that is going to require these items.
Today, I found out that the Phoenix Bird was originally done in BT-56 by Centuri, unlike the Estes on that is BT-55 based.
I then found a place that makes the Eliminator (Enerjet) Fin Can.
I just try to share what I find so everyone know, and it gives a reference in the future if your looking for something.
 

Tramper Al

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I then found a place that makes the Eliminator (Enerjet) Fin Can.
I just try to share what I find so everyone know, and it gives a reference in the future if your looking for something.
Hang on, you found a place that makes the Enerjet Fin Can today? Other than Estes/China in yellow (though I think recently discontinued there too)?

EDIT: OK, I see your link. While that is a BT-56 fin can, it does not seem to be designed to replicate the 1340/Eliminator model. No launch rod tunnel, for one thing.
 

hcmbanjo

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While that is a BT-56 fin can, it does not seem to be designed to replicate the 1340/Eliminator model. No launch rod tunnel, for one thing.
Well, the fins are different and lacks the molded launch lug.

1340 Fin Can A.jpg 1340 Fin Can B.jpg
 

dhbarr

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Looks extremely similar to the Quest Falcon fincan.
 

Tramper Al

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Well, the fins are different and lacks the molded launch lug.
Right. There are many other (later) plastic BT-56 fin units from Estes in build kits, of course. As in the BT-56 helicopter nose cone models, Mach 12, Delta II, etc. and then a whole slew of RTF models. I have no idea what this 3D printed unit is meant to be.
 
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