BT-55 vs BT-56 Tubing

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JRThro

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Can anyone compare from experience the sizes of BT-55 and BT-56 body tubes? They are almost the same size, but not exactly. I have a rocket with a BT-56 body. I'd like to extend it with a BT-55 tube, but... can I do that? And will a normal BT-55 sized tube coupler work? Or do I have to find another BT-56 tube somewhere?

Thanks in advance.
 

lalligood

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I guess it depends on the look you are going for...

BT-55 should fit just inside the BT-56--you could go so far to say that BT-55 is THE coupler for BT-56... So that would leave you with a peculiar looking "transition" between the tubes. Might want to hunt down some BT-56 to keep everything looking smooth ;)

FWIW, I know that Sunward Aerospace uses BT-56 as the main tubing for their kits.

HTH,
 

JRThro

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Originally posted by lalligood
I guess it depends on the look you are going for...

BT-55 should fit just inside the BT-56--you could go so far to say that BT-55 is THE coupler for BT-56... So that would leave you with a peculiar looking "transition" between the tubes. Might want to hunt down some BT-56 to keep everything looking smooth ;)

FWIW, I know that Sunward Aerospace uses BT-56 as the main tubing for their kits.

HTH,
Hey, I was trying to do this the easy/lazy way!

Also, the ID and OD of BT-55 and BT-56 are, from Sven Knudsen's page at https://www.ninfinger.org/~sven/rockets/body_tubes.html, as follows:
BT-55 ID=1.283"
BT-55 OD=1.325"
BT-56 ID=1.304"
BT-56 OD=1.346"

So I don't think a tube with an OD of 1.325" will fit inside a tube with an ID of 1.304" anyway, unless you have a way to shrink one of them somehow. ;)

I won't disagree that the "right" thing to do would be to go ahead and get the right size BT; I'm just not convinced the the difference between the BT-55 and BT-56 is great enough to justify having to use a BT-56.
 

Stymye

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It's not a very common size but

If your repairing an astrocam or building a rastrocam you need bt-56.. If you have a leftover eliminator/maniac fincan or nosecone you need a bt-56...theres quite a few that use bt-56, like the sky winder ,heliocopter,and the chrome domes,cosmic cobra

so I bought a pack of estes bt-56 and suprisingly have used 2 tubes so far

the od of a bt 55 depends on the manufacture .. but you could always slit the bt 55 to fit as a coupler.
 

JRThro

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Originally posted by stymye
It's not a very common size but

If your repairing an astrocam or building a rastrocam you need bt-56.. If you have a leftover eliminator/maniac fincan or nosecone you need a bt-56...theres quite a few that use bt-56, like the sky winder ,heliocopter,and the chrome domes,cosmic cobra

so I bought a pack of estes bt-56 and suprisingly have used 2 tubes so far

the od of a bt 55 depends on the manufacture .. but you could always slit the bt 55 to fit as a coupler.
Where did you find the BT-56's?

What I want to do is extend my Estes Stars & Stripes (from their starter kit). It just seems too short to me, esthetically speaking. And the CG seems to be really far back on the body, just from balancing it on my finger. Also, the nose cone, the shock cord, the streamer, and even the *outside* of the forward end of the body tube have all gotten pretty darned scorched, which I don't like.
:cool:
 

lalligood

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Originally posted by JRThro
Hey, I was trying to do this the easy/lazy way!

Also, the ID and OD of BT-55 and BT-56 are, from Sven Knudsen's page at https://www.ninfinger.org/~sven/rockets/body_tubes.html, as follows:
BT-55 ID=1.283"
BT-55 OD=1.325"
BT-56 ID=1.304"
BT-56 OD=1.346"
BUSTED! I think... :rolleyes:

OK, so I pulled the information out of the sky, BUT I was basing it on my experience with building my Richter Recker, which uses a piece of BT-69 to hold the 3 BT-50 MMT tubes & all slides (rather conveniently I might add) into the main airframe BT-70. I thought that BT-55 would fit the same way inside BT-56...

I apologize for giving false information. :eek:
 
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