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Old Nov 09, 2014, 09:39 PM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
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Bubble Dancer #1.5 - The rebuild.

Hello all,

In 2011 I finished my first Bubble Dancer - for the sake of this narrative, we'll call it "BD#1" - and I enjoyed flying it for most of that summer.

To make a long story short, my battery pack had a disagreement with the charger, which resulted in the receiver having a disagreement with the transmitter, which resulted in BD#1 having a disagreement with the ground. It locked up at 400 feet and went in absolutely vertical from there! (I will vouch for Dr. Drela's fantastic wood structure design, as the only damage was a slightly crumpled fuse pod and the rudder splitting from the fin at the hinge - that's it!)

I spent 2012 and 2013 making a new fuse mold and my whole-wing jig. Then, as posted here, BD#2 emerged from the shop in June of 2014.

I have been flying BD#2 all summer and while it is extremely light and a total joy to fly, it does suffer when the wind starts to kick up. So I thought it would be neat to revive BD#1 as my windy-day plane since I built it without the use of a scale, and as such it is about 30% heavier than BD#2.

I pulled one of my fuse pods off the shelf, added a boom and built up a new vertical fin. After that, it was a simple covering job.

So from the shop today emerges BD#1.5!

One item of note: BD#1 was an extended tip plane, which when coupled with its greater weight, I always felt needed a bit more rudder authority than it had. So I tried something different on this rebuild - I scaled up the plans 5% to see how that affects the controllability. You will see in these pictures 2 vertical fins being built simultaneaously: one is normal-size for the in-process BD#3, and the other is the 105% for BD#1.5.

I thought I'd post these pictures on RCGroups, since I'm not sure I'm going to include them on my website - aviatorstudio.com, as it is mostly just a covering job - the only real news here is the wacky covering job I gave it.

As always, my desire is to do what I can to promote building... thanks for letting me share!

Mark
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Old Nov 10, 2014, 01:35 AM
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TLHover's Avatar
Australia, NSW, Wauchope
Joined Jan 2012
337 Posts
I admire your building work Mark.
And I must add you have inspired me to want to build one of these beautiful gliders.
Thank you, Tim
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Old Nov 10, 2014, 04:01 AM
Registered User
Romania, Dolj, Craiova
Joined Sep 2007
15,440 Posts
If one day you want to sell one of your retired birds, even partly damaged, I still have two kidneys
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Old Nov 10, 2014, 09:26 AM
Registered User
Joined Nov 2010
281 Posts
Mark...Love the 1.5's new graphic's. Please post results/thoughts of rudder change you get a few hours air time in. Thank's for all the work you have put in and generously shared on the design. A group of us are working on a "Bigger Bubble" and can truly sympathize, relate and appreciate all your effort, dedication and time.
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Old Nov 10, 2014, 03:16 PM
kak8
Joined Jun 2005
324 Posts
How do you keep the spoiler absolutely down? I had to glue some small magnets and iron washers.
Balsa spoiler starts to bend after ironing the covering. And the top of the hinge.

I want to build a new one when I look at your beautifull work.
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Old Nov 10, 2014, 05:25 PM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
Hi Tim,

Cool! Go for it! Building one of these is a great challenge and skill builder. (At least it was for me - and I certainly have gained much from the journey.)

By the way, I just looked on the map to see where your town was... I flew my "office" (a Challenger business jet) to Sidney and Cairnes in 2008... Looks like I flew over your town!

Mark
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Old Nov 10, 2014, 05:45 PM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
Hey renatoa,

Based on what happened to BD#1, slightly damaged might be wishful thinking... I guess that if I'm going to break something, I should do it definitively!

My wife says, "are his kidneys in good shape?"

See yah!

Mark
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Old Nov 10, 2014, 07:10 PM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
Capt. Gary,

Thanks! I too am eager to see how (if?) the bigger rudder will do much. As Mark Drela has stated over and over, the best thing to do is to keep the extremities light... Not much I can do on that score with this bird at this point, but we'll see how the bigger rudder works. It may be awhile before I can fly it as winter is bearing down on me and I won't be able to fly anyways for a while due to work.

I have been following your "Bigger Bubble" thread and will be interested to see your results! Post pictures when you can!

Mark
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Old Nov 11, 2014, 03:47 AM
Registered User
Romania, Dolj, Craiova
Joined Sep 2007
15,440 Posts
Quote:
Originally Posted by Mark Haley View Post
Hey renatoa,

Based on what happened to BD#1, slightly damaged might be wishful thinking... I guess that if I'm going to break something, I should do it definitively!

My wife says, "are his kidneys in good shape?"

See yah!

Mark
Sure, daily cleaning with single malt
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Old Nov 11, 2014, 10:49 AM
Registered User
Joined Nov 2010
281 Posts
Mark…Thought I smelled pilot. Website is a bit of a giveaway. Almost got ran over by a Challenger flying into EAA Oshkosh a couple years ago. He was closing on us quite impressively on final. Our little PC-12 NG comes in over the fence a bit slower. Back on topic. Will try and send you a few working drawings, as they appear, if I can get them into a workable format for your perusal and amusement. Thanks again for all the time and effort. We still refer to your website and use it as a teaching aid, both stateside and in Germany, when the summer interns are “tasked” building Bubble’s.
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Old Nov 11, 2014, 11:05 AM
3 Sons - Legos and Lift
2motheus's Avatar
Grand Rapids, MI
Joined Apr 2004
567 Posts
Shall we tell him that the power cord behind his workbench is crooked? (There's got to be something for an old flying buddy to pick on.)

Great work, as always.

Tim
http://onewinch.com
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Old Nov 11, 2014, 11:36 AM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
Hey Viejo,

Crooked?!

Man, I spend so much time Photoshopping my gliders so they look good that there's no time left over for cleaning up the shop peripherals!

See yah!

Mark
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Last edited by Mark Haley; Nov 11, 2014 at 12:09 PM.
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Old Nov 11, 2014, 12:08 PM
build what you fly!
Mark Haley's Avatar
United States, NH, Goffstown
Joined Jun 2011
55 Posts
Kak8,

You asked about how I get the spoiler absolutely down...

I've been pondering on that question since you posted it yesterday... So I spent some time hunting around on my computer for any unpublished pictures that I might have taken to see if I had any that shed more detail on what I have done on mine. The best I could come up with were the ones that are already posted on my website both on the BD#2's wing construction page, but more specifically on the BD#1's center panel and covering pages.

Probably the biggest help was picking a good "c" grain plank of balsa to begin with - something that is well in evidence on the picture that is posted above where all the covering is off the wing. I then shape the plank in place as it sits in the spoiler bay.

Beyond that, the bottom covering goes on first and then the top - I leave about a 1/8 inch overlap at the rear of the spoiler (top and bottom) ensuring that there is no gap. The top and bottom overlap are sealed to each other, by heating a metal straight-edge placed up against the rear of the spoiler. This is the method recommended by Dr. Drela. The detailed description is here on my original build... scroll almost to the bottom of that page.

So the covered spoilers sit flat in the bay on their own, the final bit is just making sure that I hook up the servo to control horn (or semi-circle as the plans show) with exactly the right length of wire. I've been fortunate in these installations, as the spoiler pulls exactly flush into the bay when retracted.

That's probably not much help, as I don't have any magic trick to share, but it's what I've done and seems to have work out reasonably well.

By the way, building a new one... yeah, seems to be an affliction I have!

Mark
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Old Nov 11, 2014, 02:12 PM
Dragons, WindMills, all Same
jcstalls's Avatar
United States, IN, Indianapolis
Joined May 2002
4,381 Posts
Hi,
Some ways I have reduced the warping with spoiler.
Quickest is to laminate 1/64th ply on one side of existing spoiler.
Also laminated glass/kevlar/CF cloth on the bias on existing spoiler.
Make one with at two layers of balsa with cloth on bias between layers. Sand underside to desired taper.
Point is to reduce the twisting that creates the warp of a single piece of balsa that has heat shrink film attached.
Try em, you make like it.

Jared
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Old Nov 11, 2014, 10:42 PM
kak8
Joined Jun 2005
324 Posts
Thanks Mark and Jared for some sneaky ideas :-)
The last touch with iron on the hinge, to make it perfectly flat, has bent my spoiler most :-)
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