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Mighty Mini VariViggen

#1
I've been working on this project in bits and pieces since last spring, so I thought it was finally time to make some plans and build a prototype. For those of you who don't know, the VariViggen was Burt Rutan's first homebuilt design, so it's basically the parent of the VariEze and LongEz.
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This will be Mighty Mini sized, so a 20 inch (508mm) wingspan and run off of an 1806 and 2S or 3S. I'm not quite sure if 2s will be enough power since this is a little bigger and a bit heavier (more formers) than the FT LongEz

Anyway, here's my CAD progress so far. I started designing this in Inkscape, then got confused and decided to learn how to use Fusion 360 and continue it there. :)
Screen Shot 2021-01-24 at 21.07.28.png


The wing is just going to be a flat plate, so nothing too complicated. I'm planning to do a posterboard turtledeck and cockpit if that doesn't turn out to be too difficult. Since I recently got an Ender 3 Pro, I might make additional 3D printed parts, (say, engine intakes/exhaust, a better cockpit, etc.) whenever I get that fully operational.

Oh, and I'll probably add a prototype paint scheme poll some time, when I get some ideas for that.
 
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#3
Update: I got the tabs for the tail feathers done and finished almost all of the formers. Still figuring out how to do the lofting for the turtledeck and nose, so any advice on how to do that would be great! I'm having trouble limiting it to just the section of the nose I want to be lofted. (Just that curved part on the top, down to where the wing meets the fuse.)

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I really need to decide where to put the hatch. Maybe part of the top comes off...
 
#4
This isn't a design update because there isn't anything to report, but I thought I'd fill a post with useful links and history, and what I'll be working on when I get back to the CAD. I'm hoping to have the plans done by the end of the weekend, and build and fly a prototype as soon as possible.
This will be Mighty Mini sized, so a 20 inch (508mm) wingspan and run off of an 1806 and 2S or 3S. I'm not quite sure if 2s will be enough power since this is a little bigger and a bit heavier (more formers) than the FT LongEz
It will also be 4 channel, so both elevons and dual rudders. 4 servos in total, because I couldn't think of a way to make the rudders work on ones servo without using a flexible pushrod that I don't have or putting the servo below the wing, where it would be ripped off during every landing. The hatch is definitely going to go on the top rear, and there will be space under the forward turtledeck formers to move electronics forward. I'm sure there will be plenty of space for everything, it will just be a question of how to access it all.

Okay, as I said in the first post, the VariViggen is the ancestor of the VariEze and LongEz, if not all of Burt Rutan's designs. There are actually two versions, the standard VariViggen and the SP, with winglets.
https://www.eaa.org/eaa-museum/muse...llection-folder/1972-rutan-variviggen---n27vv
https://en.wikipedia.org/wiki/Rutan_VariViggen

Balsa plans I used:
https://aerofred.com/details.php?image_id=101385&mode=search&sessionid=hrcbdjeq7o1t81rsmkloemjg65
 
#5
This isn't a design update because there isn't anything to report, but I thought I'd fill a post with useful links and history, and what I'll be working on when I get back to the CAD. I'm hoping to have the plans done by the end of the weekend, and build and fly a prototype as soon as possible.

It will also be 4 channel, so both elevons and dual rudders. 4 servos in total, because I couldn't think of a way to make the rudders work on ones servo without using a flexible pushrod that I don't have or putting the servo below the wing, where it would be ripped off during every landing. The hatch is definitely going to go on the top rear, and there will be space under the forward turtledeck formers to move electronics forward. I'm sure there will be plenty of space for everything, it will just be a question of how to access it all.

Okay, as I said in the first post, the VariViggen is the ancestor of the VariEze and LongEz, if not all of Burt Rutan's designs. There are actually two versions, the standard VariViggen and the SP, with winglets.
https://www.eaa.org/eaa-museum/muse...llection-folder/1972-rutan-variviggen---n27vv
https://en.wikipedia.org/wiki/Rutan_VariViggen

Balsa plans I used:
https://aerofred.com/details.php?image_id=101385&mode=search&sessionid=hrcbdjeq7o1t81rsmkloemjg65
love the look... please go with the paint job in the first pic of the real thing

View attachment 190289
 
#7
Ok, I'm done with the Fusion design! This is it:
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Next up is to get all the faces into Inkscape and build a prototype to work out how the motor mounts and how long that front foam panel should be, since I wasn't able to figure those out easily in Fusion. Oh, and put it into a cg calculator to help estimate the up thrust angle.
 

The Hangar

Fly harder!
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#9
#10
Okay, I had to uninstall and reinstall Fusion to make it work, but I started to export the faces as .svgs through the Shaper Origin extension, and put them into Inkscape. Hopefully I'll finish plans tomorrow and start building the prototype soon after that!
 
#13
Update: First, the good news. I got all the flat parts into Inkscape and corrected the Shaper Origin extension's errors, and I'll start building in a couple of days!
Screen Shot 2021-02-13 at 21.10.57.png

Now for the bad news. None of the extensions I tried to flatten the turtledeck worked. Since that was the whole point of using Fusion, I'm going to go back to Inkscape + guesswork for my other designs coming in the near future. Anyway, I can still make some templates for the turtledeck and scan them in while I build, but that will slow this project down somewhat.