Foamboard B-52 - Powered by GREMLINS!

nautilusroom · May 29, 2019

Mid7night said:
If you already saw videos of this flying on my channel and just want PLANS, they are posted here in the RESOURCES section! Look also for the motor-mount ducts if you want to print your own.

Plans: https://forum.flitetest.com/index.php?resources/b-52-7ft-foamboard-edf.45/

Motor Mount Duct: https://forum.flitetest.com/index.php?resources/3d-printed-edf-duct-1106-gremlin-motor.46/

If you want to know more about the journey I took...read on.

After having some fun with my Gremsicle (popsicle-frame quad with Gremlin parts), I got tired of fiddling with it and wanted to do something different.

I had at least eight 1106-4500Kv motors and Emax 12A Bullet ESCs, and a coworker suggested the B-52. I ran some quick scaling math based on the B-52 engine diameter and the smallest 4-blade props I could find (1.9"), and arrived at a scale wingspan of SEVEN FEET. I don't know why, but I thought it'd be smaller.

But now I was hooked, so I immediately began modeling it up.

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I also modeled a custom motor mount and "fan" duct for my little "Gremlin EDFs". They're almost the same size as a standard 50mm EDF, but since they use a tiny 1106 motor for power, they're a lot lighter.

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Having just sold off my own 3D-printer, I turned to my friends in the FT chat and Nicholas Simpson came through ... and printed WAY more than I needed for me! Thanks man!

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Despite its sheer size and needing roughly 13 sheets of foamboard, the pieces are all really very simple, and so construction took off pretty quick.
The fuselage went together the fastest, but then I had to shift to the motor pods.

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It was actually the motor pods themselves that took the most time to assemble. Doing one was easy, but doing it seven more times became a bit tedious.

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With the pods done I could continue on the wing:

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Once the wing was done I had to figure out how to hold onto it! I made a wing-hold-down strap using a velcro battery strap, some filament tape and some BBQ skewers.
I wrapped the strapping tape around some paint sticks that I glued into the fuselage at the front and rear of the wing saddle.

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Then it was finally ready to go together!

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Oh yeah ... Landing gear. To keep it light I used only four wheels, and used BBQ skewers for axles. The wheels were held in simple cradles that were pinned onto the fuselage using a few more skewers:

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Then finally: MAIDEN FLIGHT DAY!! We went back out to Prado Airpark, the same place I flew the Valkyrie. It has a beautiful 800ft paved runway, and early in the morning it's calm and gorgeous weather.

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Even with EIGHT motors pushing it along, and it only weighing 4lbs-13oz RTF; I was still a little concerned it might not get off the ground. We now know that was not a problem.

Here are videos from the day. In the maiden livestream, takeoff is around the 20-minute mark.

These two are the third and last flight of the day:

I can't thank you all enough for following along, and especially those who tuned in for the livestream! That was fun, I hope to do more of that in the future.

If you download the plans and attempt a build, please share your progress here and don't be shy about build questions!

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