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  #11  
Old 04-24-2019, 10:08 PM
Jerry Irvine's Avatar
Jerry Irvine Jerry Irvine is offline
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Quote:
Originally Posted by teflonrocketry1
Jerry,

I can't find any information on ST-125 Mini-Max tube; what are its inside and outside diameters?

1.25" x 1.34" LT-125 (ST was my error)

cites:

http://www.oldrocketforum.com/showp...529&postcount=8
LT-125

http://www.semroc.com/Store/Products/BodyTubes.asp
Series 125
LT-12580 1.250" 1.340" 8" 0.045" 0.72 oz 3 oz. $0.00
LT-125300 1.250" 1.340" 30" 0.045" 2.70 oz 18 oz. $0.00
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  #12  
Old 04-24-2019, 10:20 PM
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So Jerry, what were the defects? If we're 3d printing a fin can, it seems like that's the time to fix the defects. What exactly did Lee say?

And thanks for the tip on the Eliminator, Teflon but $40 is a little steep for a fin can and as I have no use for purple tubes and ugly stickers, I'll pass.
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  #13  
Old 04-24-2019, 10:49 PM
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I could easily print a scale coupler for the heavy wall LT-125 (or any other tubing size) in red ABS (similar properties to polystyrene) if you are interested. I could also print the nose cone for LT-125 in ABS plastic. PM me for details. It looks like LT125 is a heavy wall version of Centuri ST-13 tube.

Incidentally, that purple color on the Estes Eliminator tubes can be sanded off very easily and the tubes re-painted in any color. My friend Andrew did that for the Estes Pro Series Prowler kit and it came out looking great; he just couldn't fly a hot pink rocket!

I am also interested in the flaws of the 1340 fin can as these might be easily corrected during 3D printing. One option might be to print the fin can with slots to accept wood or fins made from some other material like G10.
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  #14  
Old 04-25-2019, 04:55 PM
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Jerry Irvine Jerry Irvine is offline
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Quote:
Originally Posted by teflonrocketry1
I could easily print a scale coupler for the heavy wall LT-125 (or any other tubing size) in red ABS (similar properties to polystyrene) if you are interested. I could also print the nose cone for LT-125 in ABS plastic. PM me for details. It looks like LT125 is a heavy wall version of Centuri ST-13 tube.

Incidentally, that purple color on the Estes Eliminator tubes can be sanded off very easily and the tubes re-painted in any color. My friend Andrew did that for the Estes Pro Series Prowler kit and it came out looking great; he just couldn't fly a hot pink rocket!

I am also interested in the flaws of the 1340 fin can as these might be easily corrected during 3D printing. One option might be to print the fin can with slots to accept wood or fins made from some other material like G10.
I would cheerfully make a 1340 kit but think red fin units are unobtanium.

Lee said the fin units had too many stress risers like the transition from the strake to the fin should have had a small curve. The launch lug was a bad idea in hindsight. He would have made it incrementally thicker although still with the draft. The leading edge of the unit gets chipped easily and pulls from the mold irregularly. Curve that with a small radius.

Tech Jerry
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  #15  
Old 04-26-2019, 08:41 AM
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Quote:
Originally Posted by teflonrocketry1
I could easily print a scale coupler for the heavy wall LT-125 (or any other tubing size) in red ABS (similar properties to polystyrene) if you are interested. I could also print the nose cone for LT-125 in ABS plastic. PM me for details. It looks like LT125 is a heavy wall version of Centuri ST-13 tube.

Incidentally, that purple color on the Estes Eliminator tubes can be sanded off very easily and the tubes re-painted in any color. My friend Andrew did that for the Estes Pro Series Prowler kit and it came out looking great; he just couldn't fly a hot pink rocket!

I am also interested in the flaws of the 1340 fin can as these might be easily corrected during 3D printing. One option might be to print the fin can with slots to accept wood or fins made from some other material like G10.


Teflonrocketry1: If you like, I can send you a fin can from an unopened Maniac kit for you to copy, and make any 'improvments.' I would like a coupler for an LT-125 tube. Let me know the cost. I have the stuff to make a 1340.
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  #16  
Old 04-26-2019, 03:08 PM
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Rocketflyer,

I have a fin can from an Estes Eliminator kit that I measured. Is this part much different that the fin can from the Maniac kit?

I measured the fins as being 1/32 of an inch thick, this may be very difficult for my 3D printer to handle. Once I have a suitable 3D drawing for the fin can I was planning on giving the 3D print a try. My first pass drawing with fillets on the fins had some holes in it when I attempted to create a file for the 3D printer so I will have to go back and make some significant corrections/modifications.

I can easily make the transition for the LT-125 tubing (1.34" OD and 1.25" ID) with a 0.25 inch band in the middle and my take on a sturdier shock cord mount in red ABS plastic (similar to polystyrene). Do you need the nosecone?

I have already 3D printed several 1340 nosecones and transitions for Centuri ST-13 tubing which eRockts seems to have in stock; all their LT-125 tubing is listed as discontinued.
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  #17  
Old 04-26-2019, 04:57 PM
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Quote:
Originally Posted by Jerry Irvine
I would cheerfully make a 1340 kit but think red fin units are unobtanium.

Lee said the fin units had too many stress risers like the transition from the strake to the fin should have had a small curve. The launch lug was a bad idea in hindsight. He would have made it incrementally thicker although still with the draft. The leading edge of the unit gets chipped easily and pulls from the mold irregularly. Curve that with a small radius.

Tech Jerry
The draft is for mold release. 3D printed does not need draft.

I am not sure what speed the fins could handle but if you made the whole unit about 1/16-3/32" thick, that might be a good start. Since it obviously is not an original part, it only has to look like it.

Jerry

Last edited by Jerry Irvine : 04-28-2019 at 02:46 PM.
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  #18  
Old 04-28-2019, 11:44 AM
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Quote:
Originally Posted by teflonrocketry1
Rocketflyer,

I have a fin can from an Estes Eliminator kit that I measured. Is this part much different that the fin can from the Maniac kit?

I measured the fins as being 1/32 of an inch thick, this may be very difficult for my 3D printer to handle. Once I have a suitable 3D drawing for the fin can I was planning on giving the 3D print a try. My first pass drawing with fillets on the fins had some holes in it when I attempted to create a file for the 3D printer so I will have to go back and make some significant corrections/modifications.

I can easily make the transition for the LT-125 tubing (1.34" OD and 1.25" ID) with a 0.25 inch band in the middle and my take on a sturdier shock cord mount in red ABS plastic (similar to polystyrene). Do you need the nosecone?

I have already 3D printed several 1340 nosecones and transitions for Centuri ST-13 tubing which eRockts seems to have in stock; all their LT-125 tubing is listed as discontinued.



Teflonrocketry: As near as I can tell, the fin cans are alike. Let me know cost of coupler/transition and nose cone. Paypal work for you? Thank you!
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  #19  
Old 04-28-2019, 11:26 PM
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Quote:
Originally Posted by Rocketflyer
Teflonrocketry: As near as I can tell, the fin cans are alike. Let me know cost of coupler/transition and nose cone. Paypal work for you? Thank you!


PM sent!
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  #20  
Old 04-29-2019, 06:54 AM
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Jerry Irvine Jerry Irvine is offline
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Quote:
Originally Posted by teflonrocketry1
PM sent!
The EJ coupler has loops on both ends. The nose cone has a loop on the end. Their loop was the old bogus round one. The new Estes cutout with thick large stick is much better. Based on my prior post I would make the fins thicket than original by a bit.

Jerry
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