Nytrunner
Pop lugs, not drugs
For the wiring tunnels on my Pro series Patriot, i found it helpful to use an xacto to rough in the shape before sanding. Reduced the sanding time immensely
My Madcow 2.6 Bomarc build thread
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For the wiring tunnels on my Pro series Patriot, i found it helpful to use an xacto to rough in the shape before sanding. Reduced the sanding time immensely
Thanks- nice looking rocket! I currently do not have access to a 3D printer, but I do keep looking at them...
I'll remember that for next time, although the balsa is pretty soft and sanding didn't take too long. I just got a little carried away with it.
Actually, is there a 3D printer that does better for rocketry? I guess I'm thinking more about the material used, I have not done any research, but I do know some plastics work better than others. Likely there is a 3D printing group here...
KevinM
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I wasn't being overly "choosy" about that, and I'm certainly not the best guy to ask as I've not played around with it much... I was just taking up an opportunity to finally make use of our Mechanical Engineering dept's long standing offer that I "had to try printing something for one of my models"... The machine is one of the common FDM types, and I think the material printed with was PLA. (It's not ABS.) The machine was also set with a reasonably coarse print scale so there were considerable "ridges" in the resulting part, but all four parts (2x inner shock cones and outer cones) were printed vertically, so at least the "unwanted features" came out as concentric rings instead of longitudinal lines of varying thickness. After a couple of coats of high-solids primer and a good deal of sanding and I thought they came out looking pretty good. (With a finer print pitch I'm sure less finishing work would be required, but I wasn't about to get picky about the machine setting on this job!) See for yourself the finished parts below...
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Wow, very nice! If you find the file, let me know- my niece in Florida does a fair amount of 3D printing, maybe I can convince her to do these...
Not sure but I think at point it came with a balsa nose cone
KevinM
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Wow, very nice! If you find the file, let me know- my niece in Florida does a fair amount of 3D printing, maybe I can convince her to do these...
Done! Hopefully this works right. The forum wouldn't let me upload the model files natively so I buried them in a .ZIP. (And this way anyone can download them.) You'll find three solid model files and one DXF. One of the model files shows the inner and outer cones assembled in their relative placements. There's also a stand alone "inner" and "outer" file meant for printing. Finally, the .DXF file has the little bits that are meant to hold the inner and outer parts in place. (I cut these out of G10 and CA'd into place after a little bit of initial prime/sanding.) If you're a hot-shot at 3D modeling (or at least better than me) you could incorporate the standoffs into the outer cone and simplify the assembly.
These aren't meant to be perfect, but they look the part and will hold up better than the included balsa parts. Enjoy!
KMc
Thanks, truly appreciated!
Well, I still had some balsa work left, needed to plank the pod fins on both sides, then airfoil. While I had those under flat weights, I remembered I still had to epoxy the motor mount in. One batch for centering rings, using a dowel to smear some just past the tail fin slot, after partially inserting the motor mount, added another smear just inside the tube and finished inserting the mount. After that cured for an hour, I mixed another batch and poured it in the rear to both secure the mount and protect the ring.
Glued in the tube coupler, tacked the pod fins on with some medium CA glue, then added 30 minute epoxy fillets. Ok, adding- one left to do.
And by glued I used epoxy for the coupler too.
And by glued I used epoxy for the coupler too.
I remembered to add tape to the fin side for the last pod fin to main tube fillet. After cure I then tacked the pods on with medium CA and added fillets. Initially struggled with these as the pod tube was too short for my holder, then I added the aluminum angle and problem solved.
The pods are decorative so they don't need to be super strong. Just be sure to anchor your nose weight. I have heard stories that will turn you white when that has not been done.
The beast is a bit much for 1/4 inch rod, especially around folks who weren't around in the olden days .
The beast is a bit much for 1/4 inch rod, especially around folks who weren't around in the olden days .
Understood about the pods being decorative, I don't like how wood glue does fillets, and wanted to try out the BSI 30 minute epoxy. I normally use rocketpoxy but trying out alternatives. Got final fillets on, and attached ramjet points...
Will be using rail buttons for this one.
Wing and tail attached, I used rocketpoxy to get a good layer where the wing attaches- ran a line all the way up the tube then remembered only part of the wing's underside touches the tube. so I scraped most of the extra forward to get a good thick layer assuring good contact between wing an tube. drizzled a nice amount through the tail slot onto the motor mount plus added a layer to the bottom of the tail and inserted it, pressing it into the epoxy. Drizzled a bit more into the gap between the tail an tunnel, made a little mess and cleaned it up with a bit of acetone and shop towel. Tomorrow I will add the 'rivets' to the main wing before adding the upper tube.
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For what it's worth, I can't really justify buying a 3D printer for my limited printing needs. I've been using Craftcloud > https://print.all3dp.com/ > to sent out my stl files to get them printed. For small parts, the prices are decent and the turnaround is pretty good. The choice of materials is extensive.
Thanks for the link. I still do not have one for the same reason, although costs have apparently dropped some since I last looked...
With the wings epoxied on, it's time to add the reinforcing pegs, what I've been referring to as rivets- this adds strength as the forces acting on the wing can be intense. I dipped the dowels in some 15 minute epoxy before inserting the into the drilled holes.
I went with epoxy clay on the dowels inside of the tube.
Tacked the centering ring that keeps the parachute and it's weight forward in the tube with some thin CA as it wicks under after I centered it manually. Also wicked some thin CA into the top of the tube for added strength. Mixed up some 30 minute epoxy to add the upper tube. Before slathering the inside of the tube I made sure to drop the shock cord out the rear after tying the nylon cord to the kevlar. This will keep it out of the epoxy and then allow me to fish it back through the aforementioned centering ring. Again a drop of thin CA to stop the cord from fraying. Sliding the tube on will push the epoxy into a nice fillet on the ring. Stood it upside down for a couple of minutes to let the epoxy run up the tube some the stood it on it's tail to cure overnight. I still need to glue the upper tunnel onto the upper tube portion, the instructions say use Zap- I am unfamiliar with that, research can wait until tomorrow. I need something to keep me busy while I WFH, shift for the week starts... Actually kidding, I stay busy all day long doing my job from home, I take it quite seriously. 
Actually kidding, I stay busy all day long doing my job from home, I take it quite seriously.
I know next to nothing about CAD files, I downloaded ABViewer to see the files. I can't see anything when I open the dxf file, any advice? Also, I do not see the pointy center cone. maybe a viewer setting?
Ah, Zap is CA glue. I was going to use wood glue, but maybe some medium or thick CA would do better, at least take less time to set up. It isn't structural at that point. I will consider it.
KevinM
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I'm surprised ABViewer isn't showing you anything. (I'm not familiar with it, but I looked it up and it ought to be able to open the files just fine.) The DXF file was exported from AutoCAD2014, the three SLDPRT files were generated in some flavour of SolidWorks. I've double checked that I can open all of them up, so the files should still be OK.
Have you tried opening ...intake_model.SLDPRT files in ABViewer? That's the file that "shows" how the two parts go together. ...intake_inner_model.SLDPRT is the center cone, and ...intake_outer_model.SLDPRT is the outer part of the intake.
I can try posting the line drawings in the native AutoCAD format (.DWG) but I think that may be less generic than posting the .DXF. I'm not sure what to suggest for the 3D model files. (I'm a rookie too!)
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I can see the objects from the sldprt files, just unsure why I do not see the actual center cone. The dxf file opens but I can not see anything in the viewer window. Tobor is suggesting alternative viewers, will give those a try when I'm off my work shift later tonight. Thanks for the reply.
Thanks Tobor, I will give those a try when I get a chance.
I did glue the forward tunnel to the body tube using medium CA glue. Aside from attaching the nose cone and parachute, I need to prepare for paint and decals. I will be using some CWF to smooth out the wing, tail, boom, and perhaps spirals, then primer and paint. That will all wait at least until Sunday when I start my weekend.
grouch
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Nice job all the way around!
Thanks!
