Fly Electric!

'Bubbles'

Top view
34 kb
In-flight shot
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Side view
36 kb

This plane was conceived when brushed Astro cobalt motors were amongst the best we could get and 2000mAh sub-C nicads were revolutionary. It was intended to be an electric version of the 'glow 40' and a more modern rendition of the venerable 'ugly stick' which is such a good all-round sport model. It fullfilled these goals admirably. The name 'Bubbles' was meant to reflect its lighter than air nature, and it proved to be a good flyer even in windy weather.

These days, a small brushless motor would be the best choice together with three lipos. I redesigned the fuz a while back which led to it being smaller to better suit standard wood sizes. It flies well with the original wing but if I were to redraw it I would make the span about 4 inches smaller. Power-to-weight ratios over 1:1 are so easy these days so the 'Tim Hooper enlarged control surfaces' mods would help the hooligans out there.

Since many people have kindly shared their experiences with me, I suggest you review these and decide how you make your Bubbles... (newest at the top).


WHAT OTHERS HAVE DONE...

Stuart Hubbard from Ashhurst in New Zealand has a 52" wingspan Bubbles which weighs 1140g (843g less battery). Powered by AXI 2820/10 with a 3-cell 3650 LiPoly. He opted for a stick fuselage, sheeted with 1.5 mm balsa back to the TE of the wing. Inspired by Tim Hooper's mods he has the larger built-up ailerons, and the rudder servo sitting out in the breeze behind the wing.

Bubbles

Graham Dyer from South Africa says "...flying a Bubbles at the moment, 1150g (40oz), 3S2P 3000mAh LiPo, Axi 2820/12 with 12x6 Prop - Awesome!!"

Brian James from Nottingham in the UK has sent a picture of both Bubbles and Sizzler. Bubbles uses a Keller 25/10 with 10 cells. Sizzler uses the normal Speed 400 6V off 8xAR800's.

Bubbles and Sizzler
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Dave Beeby from Gloucestershire in the UK has an Axi 2820/10 with 8x2600 and an 11x7. Weight is 51.5oz. He says "Performance was very good as expected, with strong vertical climbs possible. I noticed and liked the authoritative rudder. It flies inverted with no elevator correction necessary."

Dave's Bubbles
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VALERIANO from Spain uses an Axi 2820/12 with an 11x7 and 10 cells. Sorry I can't translate his whole email.

VALERIANO's Bubbles
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VALERIANO's Bubbles?
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Anyone for 'Suds'? Phil Philipp in Texas produced this 46.5"/467 sq in wing area version for an Astro 035G. AUW was initially 48oz with 7x2400's swinging an APC 11x7. "VERY impressive performance" is his verdict. He improved performance with 8xCP1700's, but now uses a 4200 LiPol pack with a 9x6. "The plane almost jumps off of the ground now and will climb almost vertical to out of sight". He has an innovative wing attachment and parts were laser cut from scaled down Bubbles drawings. He shared some sage advice from Bob Benjamin who pointed out that the U/C should be under the leading edge of the wing for better handling off smooth surfaces (I fly off grass hence the forward position). Contact Phil if you are interested in a kit (USA only due to P&P costs).

Laser cut parts for Suds
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Phil Philipp's son of Bubbles 'Suds'
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Interested mounting of wing
33 kb

Hannes Illipe from Kungsbacka in Sweden has added a canopy to the plane which transforms its looks a bit and adds very little weight. Hannes gets 10-15minutes with his Axi 2820/10 on 10x3300 NiMHs and an APC 10x5

Hannes Illipe's Bubbles
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Where's the cat hiding?
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Allard Walker from Cape Town says: "Building seemed to take no time at all, and flying has been an absolute joy...I've got a Kontronik Fun 480 on a 3.7 gearbox swinging an 11*6 prop on 8 cells - and power is "sufficient" - with a CP1700 pack in her she has over the magical 100 watts per pound and will generally hang on the prop for quite a while...she's become my favourite Sunday model by a long shot!"

Sheldon Young's Bubbles
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Side view
23 kb

Sheldon Young from Canada has now built his second Bubbles. He has upgraded from a basic Master Airscrew 05 motor to a Mega 22/20/2 driving an APC 13x6.5 through a 3:1 MEC SuperBox with 8x2600 NiMh's. As expected at just 49oz "Unlimited vertical is fun!". Sheldon has removed one wing bay to improve performance and made a number of other mods to reduce weight (which I will incorporate as soon as I get the chance). He suggests the standard wing is better if you want a slow flyer (or your model is heavier), while the smaller wing improves responsiveness if you keep the weight down as he did. You can read more here.

Sheldon Young's Bubbles
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Side view
23 kb

Steve Boxer from Long Island New York enjoyed building his Bubbles. He chose an Endoplasma with the standard 'Gary Wright' setup on 10x2400 NiMHs. 58oz for his 54" wing version. He found the model to be stable at slow speeds and "pretty fast" at full throttle. You can read more here which includes a parts list (I've not checked it but thanks Steve). Neat looking nose graphics...

Steve Boxer's Bubbles
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Steve Boxer's Bubbles
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Do I smile or cry? Ralf Muskens from the Netherlands credits Tim Hooper for inspiring this Bubbles. Initially 2150g (75oz) with 10 RC2000's, an Ikarus X-500-4 and 12x6"APC prop. Ralf says this worked great and he enjoyed 6 minutes of "pure fun". He says "the plane can do any aerobatics and lands like a dream". However, the motor died after 20 flights so he converted it to a glow engine, a Saito .56 4-stroke. The weight is now 2300g (81oz) and is the envy of his club mates. So, Bubbles with a 'smelly' up front; do I smile or cry?

Ralf Muskens' Bubbles with the Saito
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Ralf Muskens' Bubbles with the electric motor
19 kb

Ken Davies from the UK with another AXi 2820/10 powered version which he describes as 'brilliant'. With 8x1600 and a 11x7 prop it weighs 52oz and he gets 6-8 minutes of "pure indulgence" as he calls it.

Ken Davies' Bubbles
18 kb

Brett Preisig from Parkes NSW in Australia has achieved success with his AXI 2820/10 brushless version. 10x2400 CP cells turns a 10x6 for over 12 minutes. 61 oz (1725g) is a nice weight. Brett finds the model is stable and handles well, even in "very windy" conditions. "Loops and rolls were all fine and a sinking knife edge was possible for a few seconds". He would recommend the model to anyone who enjoys building and has progressed past the trainer stage.

Brett Preisig's Bubbles
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Brett Preisig's Bubbles front view
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Brett Preisig's Bubbles in flight
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I think it's fair to say that Tim Hooper from Telford in the UK is very fond of his Bubbles and probably does more to promote it than I do. His also started life with an Astro15G and 12 cells which came in at 66 oz. One of his many telling comments: "any doubts he (a fellow ic clubmate) may have had about e-flying are now thoroughly laid to rest!". Two years later the model still flies great but he's increased the size of the control surfaces and has gone brushless with an LRK 350/15 outrunner, Hacker 70A ESC (with BEC), 8x3300 NiMH cells turning an APC 12x6 to save 10oz. Sounds impressive to me! Read about Tim's vertical takeoffs here.

Tim Hooper's Bubbles from the front
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Closeup of Tim Hooper's Bubbles
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Improved colour scheme by Tim Hooper
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Gunter Losse from Germany has built this one. 1.5kg (53oz) with Kontronik 400-40 brushless motor, 4.4:1 gearbox turning an Aeronaut 10x8 CAM folder. Just 6 x 1900mAh cells drawing 19A. Although Gunter would like more power he says he enjoys the model. He's been experimenting using the ailerons as flaps. Lightening holes in ribs too, I see.

Gunter's Bubbles
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Gunter's Bubbles
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Luc Van Ammel from Kalmthout in Belgium tells me his fellow club members are amazed at the performance he gets from his 77oz (2.2kg) version. Speed 700 Neodym, 12 cells, 2.7:1 SpeedGear and 12x8 prop. "Average flights with some aerobatics (loops, rolls, immelmans and split-s ) are 8 minutes". He points out that this is equal to the typical glow '40' flight time. He gets 10 minutes just crusing around.

Luc's Bubbles
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Luc's Bubbles with Helene
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Luc's Bubbles showing the motor setup
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John Moyler from Reading in the UK has built his Bubbles to plan and achieved a slightly lower weight than mine, 60oz. He used 2mm Lite Ply instead of 3mm. He says "I was very impresssed with the way it flew". He also uses an Astro 15 on 12 cells. He's currently averaging 8 minutes from 2000 Nicads.

John's Bubbles
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John's Bubbles
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John's Bubbles
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Wayne Haycock who lives in Doxey, Stafford in the UK has succeeded with his Bubbles. 84oz with a Speed 700, 12x8 prop and 12x2400 Nicads. He writes: "I get 7 mins of out and out aerobatics with me only throttling back at the top of a loop or stall turn; all in all Bubbles is just brilliant".

Wayne's Bubbles
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Wayne's Bubbles
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Here is Frank Langford's example. He's from Nottingham in the UK and describes this as his first real model after returning to modelling after a long break. He's using an Overlander Typhoon motor (600/650?) turning an 11x7 through a 2.3 gearbox. 10x2100 Nicads plus a 600mAh NiMH Rx pack yeilds an AUW of 62oz.

Frank's Bubbles
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Frank's Bubbles
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Dominic from Kehl in Germany has built another very light version at just 1568g (55.3oz); I see an extra few lightening holes in one of the photos. He uses 14 x 2000mAh cells and a home-made 'LRK' brushless motor which swings a 14x4 APC prop. Dominic tells me the plane can do any manoeuver, including torque rolls!

Dominic's very light Bubbles
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Front end with some extra lightening holes
31 kb
Home-made LRK brushless motor
16 kb

Lew Weaver in Scotland was the first to tell me of his success with a 57oz Speed 600 version on 8 cells. First reactions were: "ROG, loops, rolls, inverted etc all OK". He later converted to an Aveox 1010/3y 4:1 on 13 cells and described the performance as "sparkling", giving >10mins on 2000 cells with moderate aerobatics. My sources reveal that he is now using an AXI 2820/10 brushless which turns an 11x9 on direct drive with 8 cells at 31A. Floats from my 'foam special' design "worked OK" he says, but I sense that they need to have a larger volume if the model is any heavier than 4lb.

Lew Weaver's Bubbles which he calls 'Skoosh'
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Side view of Lew's 'Skoosh'
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On floats
11 kb

PLANS etc:

The model has been improved over the years and we are now up to version 'J' (dated Nov'02). The plans for this version are available in a two primary formats, Adobe Acrobat ('PDF' files) and CAD. The PDF file format provides outstanding quality in a tiny file size so everyone can print them without special software. The only problem is that they print to slightly different sizes on different printers. So I have created three sizes: 95% (smaller), 100% (normal) and 105% (larger). Print the 'Test' page first, measure the 200mm lines, and select the version which is the most accurate or best suits your intentions. I suggest that you favour a smaller size if you intend lower power levels, and a larger version if you want greater weight carrying ability. Note also that there are two paper sizes, 'Letter' and 'A4' so please select the correct paper size. I am aware of one small error on the plans (the composition of the wing spar) which is discussed in the Construction Guidelines. Please let me know if you spot others.

The '100%' A4 plans print onto 36 sheets (some of the other options may require more). To aid gluing this number of sheets together, they are assembled into 4 separate sections/files. To help you download them, each set of 4 files are zipped into a single file. The second file type is CAD. These are available in the native TurboCAD 6.2 (which I use) and the DXF export. These files are also zipped.

If you've not already noticed elsewhere on this site, the plane was originally designed to carry an inboard camera (up to version 'h' which can be provided), and is impressive off water on floats (more free plans available). Please also notice the additional links/information beneath the file download options. The Construction Guidelines are highly recommended, and the close-up photos might clarify things for you. Please note that I have experimented with many file formats and settings in order to provide files which can (hopefully) be opened and printed accurately anywhere in the world. If you experience difficulties with any of these versions (or spot errors or have any questions), please let me know and I will try to solve the problem.

FREE PLANS
& more info
'Test' 95% 100% 105%
'PDF' A4 paper 2kb 75kb 75kb 75kb
'PDF' Letter paper 2kb 75kb 75kb 75kb
CAD 'TCW' version - - 83kb -
CAD 'DXF' version - - 108kb -
18 Close-up Photos (186kb) - - - -
Construction Guidelines - - - -
Key Stats (original fuz) - - - -
Component Weights (original fuz; Excel 22kb) - - - -

PLEASE NOTE:-

You may build the plane, modify it, do almost anything you like, except hold me responsible for anything or profit from my design. I have no association with or warrant any of the products mentioned.

Please send me an email if you build Bubbles. I look forward to your comments and like to publish your advice to help others. Photos would be great (< 100kb), along with your plane's vital statistics (eg: motor, gearbox, prop, batteries, weight, etc.).


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