Bolt-On Fins

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What body size... and what motor?

How does the flanged part attach to the body tube?
It is an AT Arreauxbee Hi kit, 2.6” dia body tube, mid power, 24/29 mm motor mount.

The brackets clamp very snugly, but to make sure the fins don’t fall off in boost, I inserted bolts at the base between the fins. No glue.
 
It is an AT Arreauxbee Hi kit, 2.6” dia body tube, mid power, 24/29 mm motor mount.

The brackets clamp very snugly, but to make sure the fins don’t fall off in boost, I inserted bolts at the base between the fins. No glue.
Should make for an interesting test mule. What motor do you plan to fly it on?

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Building a 4" LOC IV for my Level I. Using 4mm bolts for the larger rocket.

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Didn't see any reason to cut off the fin tabs. They should serve as a backup to the clamping force to keep the fin assembly from sliding off the back.

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Spare fin for field repair if necessary.

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Using the brackets as a guide to drill holes in the fins.

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Here is my STL file for those interested.
 

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make pockets / slots on the motor tube, so that the tabs 'fit into' / add some structure to the assembly.. (So they aren't just dangling / looking pretty)
 
LOV IV fin design was known to do that; bad Idea ; I had the Hevey Duty Beuty that had 4 24mm engine mounts around the 29mm mount. Still had the same bad fin design that went below the body tube.
 
View attachment 567274

More heresy from the apostate who uses packing tape and hot glue.

3D printed. No alignment jig necessary. Nylon bolts. Hard landing damage to fins easily repairable in the field.
Me Like!

The only thing I'd consider calling heretical is how the fin can is larger than the body tube. And that's got nothing to do with the bolt-on fins, as I see it in a whole lot of printed fin cans. Why, when it would be so easy to print a shoulder?
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Me Like!

The only thing I'd consider calling heretical is how the fin can is larger than the body tube. And that's got nothing to do with the bolt-on fins, as I see it in a whole lot of printed fin cans. Why, when it would be so easy to print a shoulder?
View attachment 584731

I have no issue with the fin can being larger. On my field, that is plus because it keeps the rocket at a lower altitude, but I see the concern.
 
Here’s a 4” 3-D printed fin can made of ABS with bonded fins using acetone. I also printed a boat tail for a 54mm motor mount, not shown. Came out very solid and has flown on some spicy motors. 8238E0A2-DCF5-4283-B291-C13C182F0A63.jpeg3714F8D3-4FC1-43FB-8727-FF6C3374DF18.jpeg572916A1-2FEF-45DC-B714-AF8FCE7ACDBE.jpeg
 

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    F22466DC-E065-409E-B6DB-FB547265B63C.jpeg
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Me Like!

The only thing I'd consider calling heretical is how the fin can is larger than the body tube. And that's got nothing to do with the bolt-on fins, as I see it in a whole lot of printed fin cans. Why, when it would be so easy to print a shoulder?
View attachment 584731
Sure, that could be done. Would have to think about how it would integrate with the motor mount.

But the philosophy behind my heresy is quick and easy. I don’t care so much about performance or appearance. So I like to avoid fiddly things like paint, glue, alignment jigs, etc.
 
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