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Vagabond Fin Edges?

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Kruegon

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My Vagabond fins are almost ready to attach to the body tube. Joined, sanded, and papered. The last thing I need to do is finish the edges.

There's so many angles on this fin. Most are outside angles but two are inside angles. Any suggestions on how to finish the edges? Normally I'd just round them, but with the inside angles, I wasn't sure about trying this.
 

neil_w

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Personally I round everything, regardless of the shape. Examples:
https://www.rocketryforum.com/showt...ond-Cutter-build-thread&p=1520570#post1520570
https://www.rocketryforum.com/showt...hip-Avalon-build-thread&p=1662003#post1662003
https://www.rocketryforum.com/showt...hip-Avalon-build-thread&p=1663463#post1663463
https://www.rocketryforum.com/showthread.php?134261-Biohazard-build-thread&p=1586422#post1586422
Etc.

To be sure, rounding the inside angles requires a bit more care, but it's not really hard. My go-to technique these days for balsa is to wrap a piece of 400 grit around my finger tip, and just run it along the edge repeatedly until the desired shape is achieved, then touch up as necessary. I sort of showed it here: https://www.rocketryforum.com/showthread.php?134261-Biohazard-build-thread&p=1590056#post1590056

All that said: obviously do what you prefer. If ya wanna leave them square, that's OK too. :)
 

Kruegon

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I definitely don't want square on this one. It's too good of a performer. Just wanted to get a pulse check of the community views. Sometimes I learn a new technique or get to see a new perspective. It's Tuesday night. My launch is Saturday at 10am. Can I get this one finished and painted that fast?
 

neil_w

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I definitely don't want square on this one. It's too good of a performer. Just wanted to get a pulse check of the community views. Sometimes I learn a new technique or get to see a new perspective. It's Tuesday night. My launch is Saturday at 10am. Can I get this one finished and painted that fast?
Uhhhhh..... not if you're me. :)
 

Kruegon

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Not if you're me either it seems. To have it ready by Saturday, it would have to be assembled and filleted tonight. I didn't make it. So no chance of primer tomorrow. And I'm not flying this one until it's completed.
 

Leo

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I'm someone who always tries to round the edges. This is less for performance but more for looks.
However there are some rockets that look better with square edges e.g. SiFi models like the Battlestar Galactica Colonial Viper.

When I first started the Vagabond I too had to decide what to do. I quickly decided to take the square route because the way the fins are designed.
In my opinion this rocket just looks real "sharp" with square fins. I really like this rocket. It's simple to build and big. It also looks great in any color you choose to paint it.

 

Forever_Metal

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It's always an opinion about rounding, airfoil, etc...

I think as long as it's done properly (like the vagy above), square vs. round doesn't matter. Clean lines, proper fill and sand, good primer/paint (still learning how to do this myself, even after 20+ yrs.) is all that matters. If performance is your deal, sweet; round and 'foil away.

:2::2:

fm
 

Kruegon

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For my Estes scale kits, I follow the directions exactly. Just my preference. My little John kit said round leading and trailing. So that's what I did. The MIM-104 says leave them square (appears it needs the extra drag), so I did.

Sport rockets are different. They're designed for performance to begin with. So I usually look at what will contribute to that performance.

Now for scratch built scale models, I work for accuracy. I'd rather add nose weight and keep the fins scale. And I work to get the fins shaped as close to original as I can.

I'm looking at the MadCow 2.6" HoJo right now. The fins are flat G10. I'm already looking at options that will allow me to bevel them to scale. Of course I'm also going to compare the fins to the actual missile. I may be working extra hard to get this one true scale. Up to and including upping the motor tube size to get enough thrust after I adjust the scale size of the whole thing.
 

Micromeister

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My Vagabond fins are almost ready to attach to the body tube. Joined, sanded, and papered. The last thing I need to do is finish the edges.

There's so many angles on this fin. Most are outside angles but two are inside angles. Any suggestions on how to finish the edges? Normally I'd just round them, but with the inside angles, I wasn't sure about trying this.

While I haven't built the Vagabond I have built many multi angle finned rockets over the years. With the exception of edges parallel to the air flow (which should be left square) all edges are usually rounded, interior angle edges are not that much different then outer edges with just a little care. I generally use 220 to 360 grit 1/4" and 1/2" Glit sticks in the "tight" areas but a standard folded 1/4" sheet for most of the rest. Once you practice a couple of scrap cut pieces to get the hang of rolling the inside corners it becomes almost second nature. The Interceptor-E and others with multi angle fin/wings and tails just take a little longer to round out. Worth the extra time in good looks, improved Aero & overall performance.

Do you know why most Scoutmasters are on the heavy side? Cause scouting rounds a guy out! LOL

009b2_Interceptor TRWing CloseUp(115dpi)_08-12-06.jpg


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BEC

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When I built mine I rounded all the edges except the trailing edges. When I rebuild it (was an E9 CATO victim) I will do the same.

I understand the aesthetic for square edges, but I can't bring myself to that on anything that's supposed to actually fly.....
 
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