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Aug 09, 2021, 04:49 PM
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Build Log

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This is a project I have been working on for a while. It has gone through quite a bit of testing. My flying buddy and I have put this design through it's paces.. First we flew a 2m to test a bunch of concepts. We would then build a 3m applying what we learned and repeat the cycle.

All of that work lead to this. It's a 3m full house with a 2pc wing. Both tail pieces are removable. I did a simple spring and cable system for the tail surfaces but went all the way and did a square wing joiner with a foam core.

The wing surfaces are controlled with a very low profile top drive. It is almost a linear drive but it is slightly proud of the top wing surface.

The pod is RC friendly so no feelers. It really is cavernous, I could put a couple of granola bars on there with my gear so I have a snack when I finally land.

I will snap some detail pics tomorrow. The servo bay covers and the canopy are in the oven right now.
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Aug 10, 2021, 10:10 AM
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Awesome looking plane my man! Great work!
Aug 10, 2021, 02:28 PM
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Thank You Very Much.
Aug 10, 2021, 07:02 PM
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gliderguide's Avatar
Sweet looking bird. More details please!! A drawing, maybe a weight. Always of interest to see a journey like yours.
Aug 10, 2021, 09:06 PM
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Thanks, I will snap some more pics tomorrow. I did it all free hand so drawings aren't really an option unless I get a buddy to draw it in CAD for me. I can share that with a 3S-1300 it is 900 grams. I used the Syner-J airfoils and there are six panels in each wing. I will post up some detail pics tomorrow. I have another one started for a friend of mine so if I think of it I will document the build.
Aug 11, 2021, 01:39 AM
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gliderguide's Avatar
900g is a good weight for a 3m bird. Really good. The original pure bubble dancer was targeted slightly over that as a 3 servo floater so youíve done well. Plus, the SynerJ foils will move pretty well. Sounds like a lot of thought has gone into this. Nice work.
Aug 11, 2021, 01:31 PM
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One of the harder things to sort out was how to make the square joiner tube. A bladder/mold system won't work because it's the ID that Really Matters and that system is better suited to OD critical applications. I could simply wrap the carbon over a mandrel but with no taper removing the mandrel can be problematic.

This is what I came up with. Solid surface material shrinks when chilled so once the tube is cured I put it in the freezer for a little while. Once chilled I can tap the mandrel out quite easily by tapping on the tip I left long.
Aug 11, 2021, 04:50 PM
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Some detail photos. I just added a second screw for the vertical. It is counter suck into the stab pylon. That worked out perfectly.
Aug 11, 2021, 06:10 PM
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gliderguide's Avatar
Nicely done. Iíve used a brass insert to form over for square joiners occasionally. Exactly same issue but I found brass shrinks really good when cold. Very slight radius on the corners will help too and reduce any possible stress points.
Aug 11, 2021, 11:49 PM
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Quote:
Originally Posted by gliderguide
Nicely done. Iíve used a brass insert to form over for square joiners occasionally. Exactly same issue but I found brass shrinks really good when cold. Very slight radius on the corners will help too and reduce any possible stress points.
Thanks, I hadn't thought about how much brass shrinks when chilled. I also had an entire sheet of solid surface to play with. I like the idea of a slight break on the corners. I will do that, super simple to do. I do the same thing for rocket tubes. I use PVC pipe and then full it with ice and water to remove the tube once cured.
Aug 12, 2021, 01:43 AM
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scirocco's Avatar
Quote:
Originally Posted by OhWell
One of the harder things to sort out was how to make the square joiner tube. A bladder/mold system won't work because it's the ID that Really Matters and that system is better suited to OD critical applications. I could simply wrap the carbon over a mandrel but with no taper removing the mandrel can be problematic.

This is what I came up with. Solid surface material shrinks when chilled so once the tube is cured I put it in the freezer for a little while. Once chilled I can tap the mandrel out quite easily by tapping on the tip I left long.
ingenious
Aug 12, 2021, 08:23 AM
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Originally Posted by scirocco
ingenious
Thank You so much. It was a great feeling the morning I came up with with this simple little jig. I made the actual foam core joiner first and then simply sized the tube mandrel accordingly. Fine tuning the width was pretty simple, just slide the wedges. Once I has exactly what I wanted I trimmed one end flush as a reference.
Aug 14, 2021, 11:15 PM
in awe of glide...
Kirkerik's Avatar
Cool!
Interesting placement of the H stab under the Fin/boom. Is this to keep the boom shorter while maintaining the same tail moment?

Have you considered provision for ballast in the wing?

Kirk
Aug 18, 2021, 02:48 PM
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Hi Kirk, Thank You for the kind words.

The stab is underneath for the reason you mentioned and it allows the pull cable to apply up elevator. We have found that if the spring supplies the up elevator it can be easily over powered when the motor is engaged
Aug 18, 2021, 02:50 PM
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Another wing out of the oven. It is white on the bottom.

A buddy wanted my green one so I built this one.


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