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Apr 06, 2021, 02:54 PM
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moami's Avatar
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Build Log

Composite Electric Bubble Dancer


Hello everyone.
Few years ago I switched from 3D and sport to sailplanes by building an OLYII . It crashed of course after couple of months, but the pure joy of thermalling was unforgettable.
After that I built some flying wing gliders(CO5 and ZAGI), bunch of primitive Dr. Drela supergee based DLGs and learned to work with foam core and glass fiber. Last winter I started to think about building a big glider. BD seems to be a good choice, so started to work on plans in AutoCad and now I think I'm ready to start!
For me it's a trial and error project so I will be glad to receive your thoughts and suggestions.
Last edited by moami; Apr 06, 2021 at 03:04 PM.
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Apr 06, 2021, 07:53 PM
R2R
R2R
St Augustine RC Flyers
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Fantastic project; terrific start.

I’ll be watching with interest.
Apr 06, 2021, 08:43 PM
Registered User
bubble dancer is a great flying plane. My electric changed greatly when the weight when from 35 oz to 40 oz when it came to riding early morning light bubble.

Art
Apr 07, 2021, 04:52 AM
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gliderguide's Avatar
Looking at CRRC, is it not fair to say that basically a solid wing BD is almost a Supra and should perhaps have the Supra foils? Forgive me if I’m wrong... BD foils compensate for covering droop and fly at a lower loading generally. You may struggle to get foam core wings that lite, depending on your layup.

To electrify the BD, you can drop the laminated spar and use a suitable CF tube. Wing joins on mid to tip can be as per the pic. 1.5mm glass sheet plus the butt joint rib to rib is more than sufficient for normal electric loads.

Nice project though. I’ll be following w interest.
Apr 07, 2021, 11:14 AM
Duane, LSF IV
Wazmo's Avatar
The Supra airfoils have the hinge line kink and are designed for full-span camber. The Bubble Dancer airfoils are designed for open structure with film covering. As I recall, there was a slightly different series designed for 3m RES composite - AG24, 25, and 26 I think.
Apr 07, 2021, 02:54 PM
Registered User
If memory serves, there was a guy named Rick who used to make foam "Bubble Dancers" that were almost as light as Mark's, and almost strong enough. They probably were strong enough for electric. He's not around anymore, but maybe he left a thread about it on RC groups. The original Allegro was an RES composite model, but only 2 meters. I don't think I've seen any besides the two prototypes.
Apr 07, 2021, 03:12 PM
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gliderguide's Avatar
http://www.aviatorstudio.com/

This guy did nice work, good build info. More so for traditional BD.
Apr 07, 2021, 03:50 PM
.: Looking for Thermals :.
Ricardo RW's Avatar
What are those for?

And also, what material are you using for the templates? Looks some sort of metal, isn't it?
Apr 07, 2021, 04:17 PM
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moami's Avatar
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Quote:
Originally Posted by R2R
Fantastic project; terrific start.

Iíll be watching with interest.
Thank you my friend
Apr 07, 2021, 04:32 PM
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moami's Avatar
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Quote:
Originally Posted by old1104
bubble dancer is a great flying plane. My electric changed greatly when the weight when from 35 oz to 40 oz when it came to riding early morning light bubble.

Art
According to the calculations I did, I hope to be able to keep the finished weight in the 1300 gr range. Let's see if I succeed
Apr 07, 2021, 04:36 PM
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moami's Avatar
Thread OP
Quote:
Originally Posted by Wazmo
The Supra airfoils have the hinge line kink and are designed for full-span camber. The Bubble Dancer airfoils are designed for open structure with film covering. As I recall, there was a slightly different series designed for 3m RES composite - AG24, 25, and 26 I think.
I chose airfoils based on this page
Apr 07, 2021, 04:51 PM
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moami's Avatar
Thread OP
Quote:
Originally Posted by Ricardo RW
What are those for?

And also, what material are you using for the templates? Looks some sort of metal, isn't it?
In that image I was cutting blocks. The piece you showed is a used battery to add extra weight to my bow.
For templates I use 0.5mm aluminium sheet,I attached paper to it with CA.
Apr 07, 2021, 05:09 PM
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moami's Avatar
Thread OP
Quote:
Originally Posted by gliderguide
Looking at CRRC, is it not fair to say that basically a solid wing BD is almost a Supra and should perhaps have the Supra foils? Forgive me if Iím wrong... BD foils compensate for covering droop and fly at a lower loading generally. You may struggle to get foam core wings that lite, depending on your layup.

To electrify the BD, you can drop the laminated spar and use a suitable CF tube. Wing joins on mid to tip can be as per the pic. 1.5mm glass sheet plus the butt joint rib to rib is more than sufficient for normal electric loads.

Nice project though. Iíll be following w interest.
Thanx gliderguide.
Nice idea!
Unfortunately It is difficult for me to find the CF materials here. So I make my spars by cutting strips from 2mm Thick hardwood veneer. It worked well in my 2.5 m swept flying wings.
Apr 07, 2021, 05:16 PM
.: Looking for Thermals :.
Ricardo RW's Avatar
Quote:
Originally Posted by moami
In that image I was cutting blocks. The piece you showed is a used battery to add extra weight to my bow.
For templates I use 0.5mm aluminium sheet,I attached paper to it with CA.
Thanks, great job you're doing!


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