Summer Build off Contest: "MAGIC DART"

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Gary Byrum

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This is just a 2-D drawing, but you get the idea. It's 47" tall and building will start after I get over the NSL burnout. I'll have pics and brief details to offer when I get started. This also shows some fin deco options for the finishing. None of these are concrete though, just some renderings.

Magic Dart.jpg
 

dhbarr

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This is just a 2-D drawing, but you get the idea. It's 47" tall and building will start after I get over the NSL burnout. I'll have pics and brief details to offer when I get started. This also shows some fin deco options for the finishing. None of these are concrete though, just some renderings.

View attachment 292499
Bullseye!
 

dixontj93060

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Not participating in this contest, but love the creativity that it is fostering... The V Guitar, the Boddl, the Spin Fin, all good, but this entry's gonna be tough to beat!!!

Note: just read the rules, I'm thinking I would have time to participate given how well my hip replacement recovery is progressing--just have to see.
 
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KenECoyote

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I think it's destined to lawn dart. :wink:

Looks great and leaves a whole pallet of design possibilities on the fins! You should make a personal launcher using a real dart board for the base. :)
 

DocBrown

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Looks great she is going to be a beauty. Interesting design also.
 

Gary Byrum

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Thanks a bunch guys. This is encouraging.

To dixontj: FWIW, the rules would apply to everything in my fleet.
 

Screaminhelo

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Technically, you are cloning an existing design.

Just yanking your chain, this is an AWESOME idea and I am a bit jealous that I have never thought of it before. I'm going to have to do one of those! I see a 24mm MD with a BT-2 point.
 

Gary Byrum

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I'm going to have to do one of those! I see a 24mm MD with a BT-2 point.
After the trace & scale, the nearest reasonable tube sizes were, BT 50, up to BT 60 and the point/tip was a BT 5. The next size up would have been BT 55, 70 & 20, towering at 64". I wanted to get good flights using D12 motors, so I opted for the lesser size. I prolly could do the bigger one with said motors, but I'd have to make the fins 2 piece. My chosen version can fit the fins on 6" wide balsa.
 

jqavins

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Very cool. I've been thinking for years about an upcale one of these:
04widdy.jpg
Maybe next summer's build off.
 

Gary Byrum

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Let's Begin.

After scaling the trace I did, I thought the fins were going to be way oversized, so for rocketry purposes, I brought them down a notch or two. Of course, I’m going to have to turn the tapered part of the barrel and the point/tip, but this is usually par for the course when I scratch build. The main airframe is a BT 50 tapered to a BT 60 to a BT 20 tip, and should top off at just under 47”.

Since this is still in the designing stage, I am crossing new territory with chute deployment. I don’t like stuffing chutes in BT 50’s, so I’m going to pull it out of the BT 60. At the separation point, I’m considering a barf baffle inside the BT 50 allowing me around 3” of barf in there. The shock cord will prolly be 36” or better, and there’s a chute rip cord also. The chute, of course, isn’t tethered to anything but the BT 50 and should pull out first, followed by the remaining shock cord. Once the laundry is loaded, the upper airframe simply slips on to the 3” coupler. This is just a concept right now. I want LW’s opinion on it before I commit.

Magic Dart Coupling.jpg
 

neil_w

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That's pretty close to a zipperless design, right?

What do you use for the barf baffle? A 20-50 centering ring, or something fancier?
 

Gary Byrum

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That's pretty close to a zipperless design, right?

What do you use for the barf baffle? A 20-50 centering ring, or something fancier?
I've never built with zipperless in mind. Is that how it's done? I usually custom make baffles when I need one. Just circle cut some hard stock to fit snugly and perforate with either a hole puncher or drill small holes for smaller disks. Just glue them in. Heavy 1/8" poster board works great.
 

Gary Byrum

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OK, so there have been some tweaks to the original deployment plan. To give myself adequate room in the "Tunnel-O-Barf", we shove the barf baffle all the way down to the BT 50 tube coupler as pictured, and mount the shock cord to the forward CR, and to the top of the BT 60 airframe. These relocations will make installation a breeze. Most of the excess shock cord and the barf will now share the same place. We don't want a chute tangle with the shock cord now do we.....I suppose now, it's time to get some parts cut and produce the opening photo showing all them goodies going into this build.

Magic Dart Coupling.jpg
 

Gary Byrum

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Here is everything I'm going to need basically. Balsa blocks for turning and the templates, 4 tubes, 2 couplers, CR's & motor block, some stretchy and not stretchy laundry materials, fin template and an unglued shroud/transition (for those who just can't stomach the word "tranny") Now I gotta find time to slap this baby together.

Parts.jpg
 

K'Tesh

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After the flight who's gonna have to go out and fletch it for you?
 

Gary Byrum

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For starters, I wanted to mop the inside of the BT 50’s with CA because the whole design made them look vulnerable. If it weren’t for that payload/grip shaft, I’d leave them alone. I got busy thinking of an idea that would be really efficient to coat the inside of the tubes, so I took some upholstery foam and cut it to fit the tubes. Mounted it with a screw and went to it. That thing worked extremely well. Gave me a perfectly smooth application. This is what it looked like after it swelled twice its size. Got my fins cut also.

Schwabb.jpg

Fins.jpg

It’s a slow go with Magic Dart this week, between work, house work and prepping for the ROSCO launch this weekend. There were chutes to restring and misc. fixer-uppers to deal with.
 

Gary Byrum

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I got the “SHROUD” together which was a great fit. Then it got a CA treatment. Had to custom fit one of the CR’s inside of the 60 coupler. It’s only helping to keep the 60 coupler centered and will provide extra strength to the coupler when I glue it to the shroud assembly. Got the barf baffle mounted on the 50 coupler. That CR with the elastic & teabag mount, along with that 35# woven fishing line wrapped around the dowel are prolly the most complex part of the build. The teabag mounts on the inside of the 60 coupler, the fishing/rip cord will be cut from the rest of the dowel and secured on the underside of the same CR. The whole coupler rig will then be mounted to the shroud assembly. I used 2 CR’s for that shroud so it would be flush with the edge. This is what the recovery coupler will mount to. A nice tight fit.

I will say, because I use paper trannys…(OOPS), these projects go in various directions. I’ve never mounted recovery gear this way.

CRs & Couplers.jpg
 

Gary Byrum

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Motor block went in tonight and the fins got mounted. The stripes on the airframe is what the CA did to it. The tube inside is slick as glass and so is the exterior. That tube is tough as nails.

Fin Mount.jpg
 

sed6

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Fantastic design, love it! Any chance you have a sim file you can share?
 

Gary Byrum

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Fantastic design, love it! Any chance you have a sim file you can share?
The only thing I use is Autocad. If you like, I can make a parts list and generate scaled templates for the fins and turning templates. Lest you forget, there are two parts of this build that are custom turned on a lathe.
 

neil_w

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If you like I could make an OR file for you, given dimensions and details and such.
 
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