Fly Electric!

Tiny Treasures

This page is about small light planes, my 'Tiny Treasures'. These indoor/slow-fly/park models are so convenient and such FUN that they are what I fly most of the time, indoor or out, wind or no wind!

These are generally not beginners planes but there is variety of free plans to please everyone from hooligans to the more 'relaxed'. Most of the older designs were intended for GWS 'IPS' motors and nicads. These days you would use CDRom brushless motors and lithium cells for all of these. My older designs are featured on this page and newer designs will open in a new browser window from links below.

Chitti
CHITTI CHITTI BANG BANG Here's one to delight the kids, young and old. Fairly well-behaved now most of the time.
Bounce (43kb)
BOUNCE If you can handle at least mild aerobatics OR WANT EXTREME 3D then this is the plane to die for! It is almost indestructable but is designed for EPP which makes it harder to build.
Mumbo Minor (19kb)
MUMBO MINOR Not quite as good as Bounce but still very aerobatic and 3D capable. Designed for Depron.
Ultimate (33kb)
ULTIMATE The larger version of this plane is particularly good for learning 3D and knife-edge flight with double-length CDRom motors. The smaller version suits single CDRom motors but is less well mannered.
Nutta (19kb)
NUTTA This is the best of the 'pre-CDRom' planes designed for Depron and GWS gear. It is an easily built sports/aerobatic model.
And_Now depron model (22kb)
ANDNOW This is a 'classic' and is still one of the best models to start indoor flying. The roll rate is a bit slow but it is reasonably lively for general sport flying.
Extra 300 depron model (32kb)
EXTRA This is sort of a scale version of Nutta with a good roll rate.
Butterfly depron model (25kb)
BUTTERFLY This is a bit silly and can be a handful to fly but looks great in flight.
Whoosh (23kb)
WHOOSH Truly impressive performance for such a small ducted fan model. Too noisy and fast for indoor.
Drenalyn
DRENALYN Popular in France and but tailess models are not to everyone's liking.
Curtiss Flying Boat
CURTISS A fairly accurate scale model which only suits calm outdoor conditions but does take off from flat water.
NIGHT FLYING Don't stop flying just because the sun set!
DIY motors (22kb)
MOTORS Oh, did someone say CD-Rom brushless motors were quite neat? :-)
Kokam type cells
Lithium cells and charger the 'new' power source.
Plans are provided free for all the models mentioned. As with all my plans you may build the planes, modify them, do almost anything you like, except hold me responsible for anything or profit from the designs. The models are based on DEPRON or EPP and I list every source that I know of on these links. Read the details on a few similar models irrespective of which one you want to build, as each have tips which may help you with the others. Please let me have feedback, particularly if you spot errors or have queries or suggestions.


'Nutta'

Are you a nutter like me? Well then you may also enjoy this stunning little model. As Tim H puts it: "Cool... Have a NuthaNuttaButtaPeanutbuttaSandwichCookie..." but heed Mike Roberge's warning... "Nutta is like an 8 second bull ride"! "After increasing control throws "...she went from a house cat to a tiger. Tearing up the sky. Loops less than the plane length (well almost). Rolls on axis maybe not, rolls to fast to tell. After a 15 min flight with lipoly 700. I had to make myself a drink. Stiff drink!! Flew it in about 10k wind after the flight was over. Thats when I said that was fun." Search for 'Nutta' on the Ezone and you will see how much fun people are having. I fly mine outdoors in winds which are far too strong and have a ball. Rolling circles, tight loops within inches of the ground, touch the tail on the ground inverted... (take your Cyano and accelerator to the field; you will probably need it with these stunts!).

So what's it all about? Well, I wanted something a little 'curvier' than the AndNow. I wanted something which would roll quicker as the AndNow struggles a bit in confined spaces. And if it could be lighter and perform better, then why not! Nutta is about 4.4oz (125g) with two 560 Kokam Lithium-Polymer cells and the excellent Pixie 7 ESC. As on most of these models I am using 6g servos and Receiver with the Carbon Brushed GWS 'IPS' / 150BB motors (currently the 'S2' (3.5:1) with two 560 to 800 Lithiums). You will notice that the controls are fairly large (an understatement!) and move 45 degrees (each way!), so 30 or 40% exponential is definitely helpful to tame the beast. This setup is not for beginners but you can reduce the throws to quieten things down a bit.

I have a simple landing skid this time; my normal landing gear/wheels would add 6g. I've used a hollow 3mm carbon spar for the fuz which has proven to be more resilient than 5x5mm spruce (the spruce also weighs about 3.5g more). It still flies slowly but rolls and loops are excellent. Construction is similar to most of the other models on this page except that the single rib is made from balsa and is attached permanently to the fuz instead of the wing. The wing is not 'pre-formed' in any way but as usual it it best to let the natural curvature of the Depron help you. This approach yields quite a flat wing except for the center bit which follows the rib; this seems to work rather well. This approach also resulted in a smaller gap between the fuz spar and wing so the airleron servo has to be mounted off-centre. To ensure that each aileron moves the same, the aileron horns are similarly off-centre. The wing leading and trailing edge spars are from 2mm carbon and are glued on with Cyano and then secured with a strip of 20mm clear tape wrapped around the spar/edge. This yields a cleaner wing than with the spar attached under the wing in the middle somewhere. Notice how the motor and prop are held with rubber bands (a Futaba servo arm and 2 standard nuts are used behind the prop) on a shortened drive shaft; this approach helps prevent damage to the drive chain and fuz spar on most of these models. I attach the battery with Velcro.

As usual, email me if you have problems (or check the Ezone) and please send me colourful pictures. The plans are provided in the usual Adobe Acrobat and CAD formats. You will notice three full size templates to help address printing errors; use the one which has the most accurate 100mm 'reference line'.

Nutta
20 kb
Nutta
33 kb
Nutta
17 kb
Nutta
29 kb
Nutta
24 kb
Mike Berends' Nutta
Mike Berends
Canada

Axel Huck's Nutta
Axel Huck
8xAAA 200g
Germany
Emmanuel Henris's 'Nutta in a box'
Emmanuel
Henris's
Nutta on hols
Mike Young's Nutta
Mike Young's
Nutta

Is it an Extra or a Nutta?

Hoppy's
Extra/
Nutta thing
130% Nutta
Mel's
130% Nutta
Dual IPS

PDF for 'A4' paper (20kb)
PDF for 'Letter' paper (20kb)
Zipped TurboCAD 6.2 TCW file (18kb)
Zipped DXF file (19kb)
Zipped DWG file (29kb)


'Whoosh'

John Stennard published a design for a single engined 'Fanjet Trainer' which impressed me when I saw it flying. However, his view was that a twin would be even more effective. Suitably inspired, I bought two GWS '50' ducted fan units and set about designing a model. I am pleased to say that this model flies brilliantly. The fans generate impressive levels of thrust (I'm dying to get my hands on their 400 versions!). Please let me have your impressions and configuration (with photos) if you build one.

Whoosh
23 kb
Whoosh
51 kb
Whoosh
25 kb
Whoosh
13 kb
The model is built entirely from 3mm Depron. The wingspan is the same as the AndNow and Extra, namely 700mm (27.5"). However, the wing area is much smaller at 126 sqin so has a good turn of speed. With seven 720mAh AAA NiMHs, two HS50 servos, a GWS 4P receiver and Castle Creations Pixie 7 ESC it weighs 214g (7.5oz). It is naturally slightly lighter with six NiMHs and actually performs reasonably well with these even in a breeze (although I now only use 7). It draws about 6A so flight times are typically between 5 and 7 minutes. It flies well at reduced throttle settings so you can stooge around slowly if you wish. The model is easy to fly and the CG is not critical. Hand launches are extremely stable and it climbs steadily from a gentle launch. It will loop from level flight and rolls are brisk. It will fly inverted and will do an outside loop from this attitude but the cambered airfoil works against you. I have tried a reflexed airfoil but it was not nearly as nice to fly. The battery is changed conveniently through the front hatch. Slide the wing back and forth against its rubber bands to release or retain the hatch. I use the blue $1 Maxell NiMHs (one of the lucky ones to get some from Electronic Goldmine) and charge these 720's at 600mA to avoid excessive heat buildup.

The plane took just one evening to make but the motor and servo mountings took another evening or so. Make a cardboard template for the fuz side and cut two from Depron. Decide on the width to suit your radio gear and batteries and cut lengths of Depron for the top and bottom of the fuz (mine are 19mm). I made these parallel for simplicty but you could taper them towards the rear if you wish. Glue the top and bottom to one fuz side first and then do the other. I used a foam-friendly contact adhesive (UHU 'Creativ for Polystyrene foam') but PVA 'white glue' or Odorless Cyano would do as well (and probably give you a straighter fuz as you would be able to check alignment). I left the nose open on first flights for ESC cooling, but experienced no problems when I later added a rounded block of Depron to the front.

I rolled the Depron wing over a curved surface to create the indicated airfoil shape. This was mainly to ensure that that fan mountings did not 'fight' the wing curvature. Early photos below show Depron mountings; these have been replaced with liteply/balsa and a single rubber band to allow the fans to flex and even pop off when you land on long grass. I'm now using 3mm hollow carbon tube in the front and 2mm solid at the rear to strengthen the wing. These are only held on with 20mm self-adhesive tape but I would recommend gluing the rods to the wing first. I started with 2mm at the front which worked fine most of the time but was not really rigid when pulling high G's. The ailerons are hinged with the same 20mm tape and follow the curvature of the wing. Control horns are from 1/32" ply, reinforced with a 15x15mm 1/64" ply base glued to the Depron surfaces.

My fan units came in a box which indicates that the blades are 20x20x3. The GWS web site indicates that 20x 30 x3 are available as well as 5 blade options. I've not tried these. My motors are "CN12-R-LC" and again other options are likely to emerge over time. GWS claim 73g of thrust from 7.2v. Two motors will generate 146g which compared to an AUW of 214g is a fairly good thrust to weight ratio of 60%. I've not measured these but can say the good performance would seem to bear out their claims. Even with 7 NiMHs, the motors are barely warm at 14'C ambient temperature. This is probably because there is good airflow over the motors particularly as the plane flies quite fast for its weight and probably allows the motors to unload. I have now removed the heat sinks which come as standard to save the extra 6g.

Whoosh
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Whoosh
25 kb
Whoosh
26 kb
Whoosh
21 kb
Original depron motor mounts
17 kb
Whoosh
27 kb
Revised lite ply and rubber band mount
17 kb

Plans:
The plans comprise a one page 'overview' and a four page 'template'. The 'overview' shows the entire drawing at a reduced size and gives you some of the dimensions. The 'template' pages have to be glued together and give you full size drawings of the fuz and other more complex pieces. Because Adobe Acrobat PDF files print to different sizes on different printers, I have created three different sizes for the 'template' pages: normal (100%), smaller (95%) and larger (105%). I have also formatted the PDF pages for A4 and Letter paper sizes. So download the correct version for your paper size and read on...
'A4' PDF self-extracting zip file (120kb)
'Letter' PDF self-extracting zip file (120kb)
Open your file on your PC after downloading it. Print the first page of the '95%', '100%' and '105%' template files and measure the "100mm reference line". Use this to determine which is the most accurate. Use a photocopier to correct any further errors if you wish, or email me if you experience problems. I also provide the original TurboCAD 6.2 (21kb) file and a DXF (25kb) version.


'And_Now'

'And_Now?' (or 'White Thing' as we often call it) is a stunning little model, indoors or out. You can get exciting performance indoors on 7 cells and fly in 10 knot winds outdoors on 8 cells. 7 minute flight times are common with 300mAh NiMH's. The model draws a great deal of attention from both the general public and modellers alike. Need more convincing? Search the Discussion threads on the EZone. It's a more forgiving model than the Extra, and with its generous wing area handles lower power settings. The plane is a natural evolution from the PicoStick/LiteStick as most of the 'hardware' can be reused. It will give most people more than enough aerobatic capability although it is tame by comparison with the Extra and Nutta!

'Und_Nu?' is the original name for the model. It was designed by Michael Bohm and discovered on the excellent Klaustrophobia site. My drawings include a few improvements to his brilliant design. The fuz is now based on the above-mentioned Pico Stick which is as light and simple as you can get. And with Depron flying surfaces, it only takes 2 hours to build and is extremely robust. It does not require the most hi-tech motors. It is a model which is really hard to beat. The model should weigh less than 170g (6oz). The wing area is 277 sq in which results in a wing loading of 3.1 oz/sq ft. I use 8x300mAh NiMHs, the GWS R-4P Rx (with half the aerial removed), Schulze 08 ESC and 2 Hitec HS50 servos. You can add a working rudder but it is not needed for normal flight. The take-off run is about 1 inch off grass! Here are a few different versions which illustrate the principles:

Flying inverted outdoors
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ROG take-offs no problem
34 kb
Outer ribs are not needed
10 kb
Flying indoors too
41 kb
Motor mounting
28 kb
Bottom view
18 kb
Front view
16 kb
Middle view
16 kb
Rear view
14 kb
Servos
21 kb
The motor used by most for this model is the '150' size available from GWS (the 'IPS' size used in the LiteStick/PicoStick/Tiger Moth). Multiplex, Alpha, and other makes are available and appear to be identical to the GWS. There are at least three motor options. The 'Carbon Brushed' (DC) version is the best with the 'Deluxe' (DX) a close second. Both have good magnets, similar power and are usually accompanied by gearboxes that have 2 bearings on the prop shaft (often labeled 'BB'). The 'Standard' version will work but don't buy it if you have a choice (it has weaker magnets and bushes instead of bearings).

The gearboxes which come with these motors have many different ratios and your choice depends on the number of cells used. To keep it simple, buy either the 'A' (5.8:1) or 'B' (7:1) 'DC' version with 8 Nicad or NiMH cells. The cells would typically range from 120-180 Nicads to 280-300 NiHM's (NiMH's will normally give longer duration). The prop would normally be a GWS 10x4.7 or 9x7.

Two newer gear ratios are now also available. These are the 'S2' (3.5:1) and 'S1' (4.1:1). These suit smaller cell numbers and I have seen spectacular performance from an S2 on 7 cells. Consider the 'D' (9.6:1) ratio if you want to use 3 Lithiums. A geared Speed 280 is another option but the overall weight and wing loading will be higher. Although the easiest way to mount the motor is to push it on to the front of the fuz stick (as GWS have designed it to be done), the motor takes some abuse and usually breaks eventually if you crash into walls and things. A more enduring approach is make a 20x30mm 1/32 ply or 6mm balsa 'mounting plate' and to strap the motor to the stick with a couple of rubber bands. This gives it a bit more flexibility which also helps stop the fuz stick from breaking. A 'prop saver' where the prop is only retained with a rubber band is another aid to resilience.

The design is based on 3mm (1/8") Depron which is a very dense foam. This provides the perfect balance between flexibility and rigidity for models like these. Note that Depron usually has a 'grain'. The wing does not have to be preformed in any way if you use the natural curvature of the Depron in the right direction. Add two extra wing ribs at the ends of the spar if you go for higher power settings or find the wing twisting at higher speeds (remember it's meant to be a 'slowfly' model!). I list every source of Depron that I know of on my links page. I also have a small section here about some other uses for Depron. You will need a little Cyano to build the model, and copious amounts later if you crash as often as most of us do! 'Odorless' Zap is foam-friendly, as is 'Grip' cyano activator to speed up field repairs. Note that the occasional mid-air collision and inverted landings contribute to our normal attrition rate; the plane holds together exceptionally well under less arduous conditions. Even with our abuse, there are few components that Cyano can't repair in a couple of minutes.

Plans are in various formats but the 'pdf' version should be the easiest. The 'DXF' version is only needed for the CAD guru's. The pdf plans should print to scale on one page and most dimensions are noted for you to build one. The wing starts 60mm from the front of the spar. The dowels for attaching the wing are usually 5mm ahead of and behind the wing itself. Start with the CG about 65mm back from the leading edge of the wing and move back 5 or 10mm to improve roll rates, elevator sensitivity and inverted flight characteristics. Once you've crashed a few times and seen how resilient the model is you will also discover that most dimensions are not critical so don't worry if you need to change a few things. Don't bother beefing up the design to make it stronger; all you will do is add unnecesary weight. Email me if you get stuck!

PDF file (11kb)
DXF CAD file (25kb)

Here are a few examples of what others have done with the design... Please send me more examples, especially if they are different or colourful!

They're breeding!
Steve Cook
'Ultimate Bipe'
27.5" swept wing
Trevor's sticker collection
Good info on
Trevor Hewson's
web site
Now that's what I call bright
Hoppy
S280 3.7:1
7x720 NiMHs
hoppy has an eye for colour!
Hoppy


Nice colours
Jerry Brown
Kansas

Charles Fischer
Charles Fischer
EPS-100C

Tiny versions
Andrew Green's
33% and 50% scale
with my 100%
Tiny versions
Laurence and Andrew
Green with 33%
version
Herbert's
Herbert from
Austria
Mabuchi 050
Didier Vanhooren
Special fuz
from Didier
Vanhooren

Build the plane as you see it above, or really push the frontiers of science like club mate David Smith did with floats! It adds an ounce (29g) but flight performance is surprisingly similar. I got mine to take off from water, but only once. It probably needs more power to overcome the friction. Hand launches and landings on water are very successful. A rudder would be a major aid to steering, although if you have a radio which allows your rudder stick to drive the aileron servo in the wrong direction, this 'opposite aileron' has some effect in steering on the ground/water! Trevor Hewson's site has more on this and an excellent write-up on this model and others. It helps if you can disable this mixer once airborne.

We made our floats from 50 x 50 x 520mm blocks of polystryrene foam. The step is about 300mm from the nose and we positioned it roughly on the CG. Taper the rear section from the step, and sand a 10 degree 'V' shape on the bottom from the nose to the step. Carve the nose to resemble the front of a speed boat. Our wings had about 4 degrees of positive incidence relative to the top of the floats; our view is this was probably not enough. The floats appear huge relative to the size of the model, but we progressively increased the size to that mentioned and this now 'feels' close to the correct size (some of the photos below are of the smaller sizes). The outside edges were 260mm apart (the width of the stab) and held with 1.5 or 2mm carbon rods, but this was not far enough apart and the plane tipped over too easily. Add a 'security' string from the motor to the fuz stick as we both lost motors to the murky depths of the river! Wrap cling film around delicate electronic bits if they are dear to you. In theory you should waterproof the fuz stick as it is weakened when wet, and this was the main reason for me loosing my motor (the stick snapped when it nosed over with power on). Please let me know if you try this, and especially if you can improve on the 'formula' as our is not perfect yet.

Dave fishing his treasure from the soggy banks (full size floats)
47 kb
The version we flew off water
12 kb
Dave's model on one of the first flights with smaller floats
13 kb
Dave with an earlier version (smaller floats)
21 kb

'Extra 300'

This model handles wind better than the AndNow (smaller flying surfaces = less drag) and has a very quick roll rate which is really impressive (so 'impressive' that you might like to use a large helping of exponential, especially for take-offs!). It can also handle slow speeds and calm conditions despite the smaller wing. I use two servos and it does not need a working rudder. Bunts and outside loops are really easy.

The plane weighs 175g (6.2oz) with two HS50 servos, GWS Carbon Brush 'B' motor, 8x300mAh NiMHs, 10x4.7 GWS prop, GWS Naro Rx and Schulze 08 ESC. The 'A', 'S1' and 'S2' motors with appropriate props/batteries will be fine too (small prop/faster RPM seems better than large prop/slow RPM for this model). The Extra has the same length and width as AndNow. However, it has a smaller wing area than the AndNow (215 sq in vs 277 sq in) and a profile fuz. A word of warning, however. It needs to be kept light; heavier options than what I have indicated tend to be less successful. Go with the AndNow if your equipment is a bit heavier as that model can handle extra weight.

I started by making a cardboard template of the fuz profile. You also use this template to cut the single rib which helps support the wing. The wing and stab are obviously one piece components, and these need to be cut from the dimensions marked on the plans. One easy way to attach the undercarriage is to make it removeable. First hold the pre-formed u/c to the fuz stick with masking or sellotape (with the sticky side out), bind it tightly with thread ('Spiderwire' or Kevlar are the strongest) and saturate carefully with thin Cyano making sure it does not get under the tape (see photo below). You can then remove the u/c from the 'socket', glue the fuz stick to the depron fuz profile, and cut appropriate slots or holes to allow you to re-attach the u/c. For the elevator joiner, I glued the 2mm carbon (or bamboo) to the 1/64 ply plates with Cyano, and then glued this assembly to the depron elevators to ensure they were aligned correctly. I then extended the slot for the stab slightly so that I could thread the elevator assembly through the fuz (see photo). I have the ailerons parallel with the fuz stick. If you tweak this 'reflex' slightly, you can get the model to fly inverted without trim change. The CG is on the wing spar and is at the 25% position (60mm from leading edge). I use water based acrylic paints from craft/DIY stores for painting these models. Either brush it on or dilute with water and spray. The extra weight is barely measureable. Use a permanent marker to neaten up painted edges.

Extra 300
22 kb
Extra 300
29 kb
Extra 300
17 kb
Extra 300
30 kb
Elevator joiner
12 kb
Slot for elevator
19 kb
Removeable undercarriage
16 kb
Extra 300
13 kb

In addition to the CAD drawings, the plans are available in Adobe Acrobat 'PDF' format so anyone can open them. You will need either the 'Letter' or 'A4' paper formats if you want to build the model. They should print on 5 pages which will give you a full size fuz and a smaller top view with dimensions marked. Please note that PDF's print to different sizes on different printers. To get around this, the fuz profile appears 4 times in different colours/sizes. Measure the "100mm reference line" and use the most accurate profile. Email me if this does not work properly. The CAD versions should print accurately if you ensure your program is using metric settings.

PDF full size 'A4' version (22kb)
PDF full size 'Letter' version (22kb)

Zipped TurboCAD file (32kb)
Zipped 'DXF' CAD file (28kb)


Drenalyn

There are many designs for Depron models although not many stand out as being special. Some research led me to this French site... La PAGE OFFICIELLE de la DRENALYN. The play on the word 'adrenalin' and the number of models in one of the group photos (34 colourful models) suggested that this is an IMPORTANT model in France. Plus, any model that has an 'OFFICIELLE' site must be special. Here are some pictures of my model:

Drenalyn
13 kb
Drenalyn
16 kb
Drenalyn
11 kb
Drenalyn
23 kb
Drenalyn
13 kb

I must warn you up front that this model is only nice to fly if it is over-powered. It also suits those who can or want to learn to prop-hang (ie: it's not a beginners model). I have not flown mine a great deal so my advice is fairly limited and you will probably have to experiment a bit.

There are many plans of this model on the web but few on English language web sites. This link will take you to the designer's version (Philippe Jambon). With his permission, I have drawn my own version as I have tried to make changes to suit smaller motors. Mine show three sizes to suit different power options:
1. The standard 600mm wingspan version designed for Speed 300's with 4:1 or 5:1 gearboxes on 7x500 Nicads. You are probably looking at 35 to 50W of power for these.
2. A 500mm version which I built that performs well with a GWS Dx D motor (9.6:1), GWS 12x6 prop and 3x800 Lithium-Ion cells (nice with 25W+). Also performs well on a Speed 300 with 3x1600 Li-Ions.
3. The 400mm version which I believe is getting closer to the correct size for the GWS IPS/150 motors although 300mm (not drawn) may be better (I've not tried these).

Single page 'PDF' file (31kb) This is a one page plan with dimensions marked for three sizes. Scale your own if you want to try the 300mm version. The plans are in Adobe Acrobat which most people should be able to open.

Full size 'PDF' Letter format (82kb) This is an auto-extracting zip file of three full size files (fuz, wing and tail) plus the above single page version (no zip software needed). This will allow you to print the depron components on 13 pages to make cardboard templates to make the plane.

Full-size 'PDF' A4 format (82kb) This is an A4 version of the above. Note that 'pdf' files don't always print to the exact same size on different printers so don't be put off if the sizes are not perfectly accurate.

Zipped 'DXF' CAD file (88kb) This is a zipped CAD file which will require zip software to open.

So what's the model like? Well, Pierre describes performance on his 6oz 420mm version as "leisurely" with the Dx A swinging a 9x4.7 on 7x110 NiMHs. I used a similar motor (Dx B), larger prop (10x4.7) and more cells (8x300 NiMHs) to produce about 15W of power for my 500mm version and my model was also uninspiring. Sigh!

However, with 25W of power from 3x800 Lithium-Ion Cells on a Dx D (9.6:1) and 12x6 prop it sparkled! I flew for 15 minutes on my first flight with this combination in a light breeze outdoors and could not stop myself from prop-hanging. Great fun! It took a 7oz model to get me to this level of flying! I've since added a rudder to improve control, and now just have to learn how to control a true 3D model! The plane launches easily by hand with low power levels, but seems to need great amounts of power to bring it to life. Dean in Milwaukee has reported "extremely sporty performance" to almost prop-hang a 400mm version using 2x830mAh Lithium-Ion cells to drive a GWS 'S1' with a 9x7 prop.


Butterfly

It seemed to me when I started flying indoors that a Butterfly was the epitome of a slow flying object. Most people are fascinated by these fragile and colourful creatures. Having discovered the magic of Depron for models like these, I set out to discover the mysteries of the Butterfly. Early versions were challenging to say the least. The CG had to be much further forward than I anticipated, and a rudder was more effective for turns than mixed elevons. The model still has a few quirks, but is very interesting once you understand the control characteristics.

New design
15 kb
In flight
18 kb
Ready for painting
16 kb

The first version (the orange/coral coloured one below) had a 30" span with 408 sq in wing area. It flew well but needed the power of 3 lithium cells working a small GWS harder than is wise. I have now reduced the size to 85% of original and built a new version (the turquoise/blue one above). I have also changed the front wing shape slightly and reduced dihedral. It now has a 26" span with 320 sq in wing area and flies even better. It weighs 5.8oz (166g) which is the same as my AndNow. It is very agile with 8x300 NiMHs and a GWS Dx 'B' (7:1) turning a 10x4.7 prop. It loops easily but I have not tried rolling it. It has plenty of power so I would be very surprised if it did not fly well on 7 cells.

Please note that flying these flat wing models is a little unconventional. A gentle level, but nose slightly high, hand launch at half or 2/3 throttle will get you away smoothly. Too much throttle and it will climb steeply instead of flying away from you. Turns usually require extra power as it has a tendancy to loose speed, stall and pitch nose up. Extra power and down elevator to drop the nose is sometimes then needed. The plane rewards smooth flyers, but initial circuits are likely to be exciting with the plane pitching up and down and spiraling in all directions until you calm down and stop over-correcting. A nice flyer once you've 'got it' with just a smattering of random inconsiderate behaviour to keep you on your toes! (its favourite it to lure you into a corner... )

I use two 6g type servos and a GWS Naro Rx with half length aerial. Everything mounts onto a central 5x5mm spruce spar. You might like (initially) to make this slightly longer than shown to make sure you can get the CG right. The 2mm carbon wing spars plug in to plastic tubes bound to metal dihredral braces with cotton (same concept as on the PicoStick). I've not decided whether more dihedral will be helpful (it turns quite tightly as is), but I don't recommend less (less would reduce stability). You don't really need an undercarriage. I just have a 20mm high balsa belly 'fin' near the CG to help protect the servos and radio gear when I land. Landings are just 'belly flops'; bring it in under low power and cut the throttle as you touch down. So, surf the web, visit the library, but the one thing you have to do is dream up a fancy colour-scheme. Photos please!


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Here are the plans. They are Adobe Acrobat versions comprising 4 pages which you have to glue to cardboard to make templates. I have provided A4 and Letter sizes. As usual, please note that this technology is great for eliminating the need for CAD software, but printed sizes are less predicatable. So, I suggest you measure the 100mm reference line on the printed drawing and sketch a revised version (or use a photocopier) to correct significant errors. Let me know if you want a special size. I've also added a CAD version for those who prefer this format.

A4 'PDF' version (17kb)
Letter 'PDF' version (17kb)
Zipped 'DXF' CAD version (31kb)

Ed Couch in the US has kindly sent me pictures of his Butterfly from these plans. It looks great with the feelers (pipe cleaners) and eyes. GWS 'A' motor with 8 x 120 mAh nicads swinging a 10x4.7 repitched to 10x7. Brian Shaw has also sent me his brightly-coloured version; note the wheels to prevent nose-overs. Brian hails from the West coast of Scotland. Both are of the initial larger version.

Ed Couch's version
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Ed Couch's version
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Ed Couch's version
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Brian Shaw's version
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1913 Curtiss Flying Boat

Speed 300 powered, 3x1600mAh Li-Ions, 40 inch wingspan, 16oz AUW, Depron wings, blue foam hull, scale outline and rigging. The plane takes off from flat water but the wing-tip floats are too small for cross-winds. The plane flies reasonably well in calm conditions, but it is a replica of a 1913 plane so don't expect it to be as nice as a Tiger Moth! Curtiss himself apparently only flew the original in calm conditions and I can confirm that the model is a handful in wind. I never 'finished' the drawings but nevertheless here are DXF (169kb) and DWG (310kb) versions from which I built mine along with some construction photos.

Curtiss Flying Boat
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On water
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Curtiss Flying Boat
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Rear hull halves
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Glass cloth covering
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HS50 (rudder) and HS55 (elevator) servos
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HS55 aileron servo; closed loop controls
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Tail surfaces
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Working aileron
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Bottom view
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Night Flying

AndNow is an ideal plane for night flying, but any light model is likely to be a suitable platform. You can use a spare channel on the Receiver to power some lights with very little weight or power penalty. I now use just two 'extremely high brightness' 5mm LEDs taped to the top of the fin to illuminate the wing. This creates a fairly good three point reference as the LEDs on the tail are usually blindingly obvious and the illuminated wing is clearly visible from the top and bottom as the photos show. The only problem is when flying directly towards yourself when the wing tends to disappear. LEDs strapped to the bottom of the undercarriage legs may be a better option?

I am using the brightest LED's I can find. Mine came from Maplin but any component supplier will have some. They only draw 20 to 30mA each, the same as standard LED's although can cost quite a bit more. They usually operate at 2 to 3v so the 4.8 or 5v from the receiver needs limiting with a small current limiting resistor. The easiest way to size this is to obtain 50, 100 and 150 ohm resistors (or the closest available values). Starting with the highest value, check the current and intensity. I'm running mine at 50mA for two LEDs. There is a formula for determining resistance but you should not need it if you play around with these values a bit. Remember that two or more resistors in 'series' (end to end in line with either the positive or negative lead) will provide more resistance than one and reduce current and intensity. Two or more in 'parallel' will reduce resitance as the current has more paths through which it can flow. The following photos show a top view and one from the bottom. These are 15 degree angle LEDs; 30 degrees may be worth trying to get a broader spread over the wing.


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I have also tried using four 'standard' 3mm LEDs taped to the plane at strategic places. These work OK but are less visible at distance (and impress your friends less - the high intensity LEDs are incredibly bright). If you run these standard LED's off a spare channel of the receiver they will have to be in parallel with a suitable resister. Alternatively, make up a jumper to 'tap' power direct from the flight pack. Once again I run the LEDs in parallel but using a 1k (1000 ohm) trim pot to regulate current and intensity. Note that you can also get 5v LED's which will not need a resistor if run from a receiver channel but I have not found high brightness versions yet. One final comment is to draw your attention to the fact that LEDs have a polarity. They come with two leads, one shorter than the other. The short lead is the negative side (black wire). They also usually have a small 'flat' moulded into the plastic on the same side.


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