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BT Circumferences

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Kruegon

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I'm starting to scale a lot of kits down. I'm also trying to start printing my own decals for the really small stuff. I'd like to build a reliable spreadsheet of the overall circumferences of the BTs. I'm hoping to get a solid list started soon on all the LPR tubes. Especially Estes and MMX tubes.

Does anyone have any info they can share on this one?
 

dhbarr

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Grab the OD list from BMS and calc it?
 

Kruegon

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Grab the OD list from BMS and calc it?
Thought about that, but often, thanks to Pi, it's an unending calculation mathematically. Same as the archer's paradox. But obviously nothing goes on forever like that.

Also, I've noticed that many of the BMS tube sizes actually vary on the larger size compared to Estes tubes. I was just hopeful that the data might already exist somewhere.

It may be that calculating it myself may be the only option. If that be, then it be.
 

Kruegon

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Will this help?

Greg
That's very nice. It'll be very helpful for doing my own calcs on this project. Odds are that'll be my best option for this, but I'm still hopeful the data already exists. Just not convinced.
 

Gary Byrum

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Pretty sure none of what you got was what you were looking for. I already did the math. There is also an upscale chart here, but it's best used in Autocad applications. I was given a formula for determining BT circumferences, but it didn't work for me. I'ts also in the PDF attachment. Hope this helps.

View attachment BT & Fin Specs-Upscales.pdf
 

Micromeister

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All Estes, Centuri & Quest body tube diameters are and have been listed for YEARS all over the net.

As others have mentioned all thats necesary is to calculate using PI. you'll also need to add or subtract a bit for overlap. Somewhere I have lists of all the available tube ID, OD and wall thickness. I'll see if I can find them. I created my own list of ID - OD dimensions used for Up and downscaleing year ago. but It was created before Home computers so it's just on graph paper, expanded as other tubes came along. Circumference is almost never needed in scaling. Diameter and overall length yes.

I'll try to upload the .jpg tube lists I have.

Centuri & Quest Body Tube & Parts list_pg-03.jpg


Estes Body Tube & Parts List_Pg-1.jpg


Estes Body Tube & Parts list_pg-2.jpg


View attachment MM 2b_BodyTubes spread sheet.xls
 
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ratchet01

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A BT circ. chart would be handy for making or scaling BT wraps.
 

Kruegon

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A BT circ. chart would be handy for making or scaling BT wraps.
^ This! That's exactly why I'm looking for the info. It would make it a lot easier to scale rockets properly if the wraps could be scaled to a specific width as opposed to by a % of original size.
 

Micromeister

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^ This! That's exactly why I'm looking for the info. It would make it a lot easier to scale rockets properly if the wraps could be scaled to a specific width as opposed to by a % of original size.
Really! What wraps are you talking about... You can't possibly be talking about those NEVER accurate fin alignment wraps. the only body wrap that might be worth having exact od circumference would be those with corrugation such as the little Joe-II, Saturn-1B or Saturn-V or perhap the Orion.
That said I've build all of them from the ID and OD of the Craft body tubes. All that's needed is the od of the tube and thickness of the material being used as the base wrap x Pi.
I usually add an additional 1/16" to 1/8" as an overlap Just in Case. It really is that simple.
Shoot! even the maunfacturer's allow an overage to allow for excessive glue, etc.

All this talk about circumferences...don't you think if such a schedule were needed or important it would have been made sometime during the past 50+ years?

I don't know of a single Up or Down-Scaler that use % as the basis for their scaling work. Hope this helps a little anyway.

OBTW: Most of the Micro Maxx body tubes are also manufacturered by the same company that makes tube for ESTES. They are all .013" wall tubes with white glassine. T2 = .220" ID - .246" OD. (Makes great Motor Stops & couplings). T2+ = .255" ID, .281"OD. Minimum Diameter motor tube. T2++ = .292" ID, .318" OD, (a Telescoping tube). T3 = .346" ID - .375" OD (a Great Outer Airframe size). T4 = .422" ID, .448" OD, (for larger body models, and of course T5 = BT-5 = .518"ID, .544" OD.
These tubes were originally available only from Totally Tubular, Unfortunately they have sold there stock to E-Hobbies, Balsa Machine Service and others. Used to get quantity discounts on tube, but haven't had to buy in the last several years. Personally I don't stock many of the Old Centuri, Quest or Simroc tubes as they are off size for the standard .013 and .021" wall ESTES tubes.

BodyTube Storage-b_Small Tube boxes 34in_12-01-06.JPG


BodyTube Storage-c-sm_BT-101& overflow_12-01-06.JPG
 
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