VESNA RES Sailplane

Posted by ultralajt on July 11, 2016 at 6:00 AM Comments comments (0)


This spring I start thinking of a new sailplane, that will not be "just another glider", but it should look nice in spirit of "Golden era of gliding".


I give her name VESNA after Slavic Goddess of Spring.


So, I start with a hand drawn sketch, then CAD drawings and also for the first time I went to 3D model design and extract then parts from it.

All started with idea to build myself a new glider, possible within RES category (Rudder Elevator Spoiler, 2m max wingspan), but not in the spirit of mainstream where mostly large HLG models are build today as RES, but rather a nicely shaped-curved eyecatching nostalgic model!


I draw a sketch to pour my vision on the paper and then I start to do computer design in 3D model. It was my first real attempt of 3D design of the sailplane that I also finished by building it.


Here are some pictures made while process was on the fly...

Photo above: initial hand drawn sketch of new model.

Photo above: Sketch outined by CAD program and sized to 2 m wingspan.

Photo above: 3D computer design of the structure.

Photo above: 3D structure almost finished

Photo above: making drawings for CNC machine, all white poplar plywood 3mm thick.

What is needed to build this sailplane?

What is needed for building this model beside Short KIT:


- Balsa thickness of 1.5mm to cover wing root, torsion nose and fuselage, TE doublers ................ 4 pieces (100x1000mm)

- Balsa 1mm thick for sheeting the tail surfaces and TE doublers.........................2 pieces (100x1000mm)

- Balsa 6mm thick for the leading edges, rudder and fuselage nose .................... 1 pc (100x1000mm)

- Plastic tube of 2mm outer diameter and the associated steel wire 0,8mm .....2 sets

- Transparent covering film .................................................. ....................... 2 meters

- Colored covering film .................................................. ............................... 2.4 meters

- Control surface hinges18x28mm .................................................. .......... 6 pieces

- The guard of the control wire 0,8mm .................................................. .. 4 pieces

- Round magnet round10x1mm .................................................. ............... 1 pair

- Servo extension cord ~ ​​20cm .................................................. .................. 4-6 pcs

- Wing jiuner, steel rod 6mm diameter, L = 165mm ............................. 1 piece

- Carbon strip 3x1mm L = 1000mm .................................................. ........ 4 pieces

** This costs just under € 40, depending on where you purchase .


Various material:


- Clear adhesive tape for sealing control surfaces and air brake course

- Self-adhesive foil for decoration (white for the inscription, black or blue cabin)

- Metal hook for Hi-start

- The sponge or foam-like material to hold battery and receiver

- Lead ballast approx 200g

- Screw M4 x 40 ............................................. .2 piece

- Screw M3 x 15 ..............................................2 piece

- Nut M4 .................................................. ......... 2 pieces

- Nut M3 .................................................. ......... 2 pieces

- White glue for wood

- Universal adhesive for wood and carbon (Super Glue phatic)

- Masking tape (for fixation of certain elements during glueing)

** This is to be found in any average local hobby shop.


Recommended Radio Equipment:


Receiver with at least three channels, preferably, 5 or more, because we have more choices for managing air brake (mixes, etc ..). If spoilers are connected to RX by Y-cable, an servo reverser must be purchased for a spoiler . Spoilers can be coupled to the throttle channel, or to flaps (3 position switch..flight modes) or on the slider.

Receiver battery AA size, flat, 800-2700 mAh

Switch on / off (optional)

A receiver battery voltage indicator (optional)


Spoiler servomotor ................................ 2 pieces (or equivalent)

Elevator and rudder servomotor ................. 2 pieces (or equivalent)

Proposal for tailoring the film to cover the model:


Blue: sheet 60 x 240 cm; white

Red: sheet 60 x 200 cm; transparent

The big day arrived!  I maidened Vesna. She was a bit nose heavy, so yesterday I already remove some nose ballast and test it in the flat field. It was amazing change! Now I am waiting a good day to went on the hill again and fly her.


Till then, I can show only videos from her first flights (nose heavy), one from ground camera and another from on board camera.

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There will be a Short KIT for this Sailplane model available soon in my webshop!

Hayrack model

Posted by ultralajt on October 4, 2015 at 8:30 AM Comments comments (0)

In my country, for centuries, farmers store hay in very unique hayrack buildings, made totaly from wood, without any metal piece involved in the structure. Usually they were thatched roofs, but in late last century they use tiles.

As modern way of farming dont need hayracks anymore, as grass is stored in silo, such wonderfull wooden objects slowly dissapear from our country scennery....

As explained at Land of hayracks Museum :

"A hayrack is a structure for drying crops standing independently or leaning against another outbuilding. Most frequently made of wood, a hayrack is situated at the homestead or separately on the field or meadow. Grains, hay, corn, flax, hemp, legumes, cuttings of tuberous plants and fern were dried and stored in it. A double hayrack is a particularly suitable place for storing tools, agricultural machinery and wagons as well as other building material and modern vehicles."

I made a small "semiscale" model of such hayrack as an decorative object or just as an chilldrens toy:

And another photo for size reference:

Model is build entirely from 3mm thick poplar plywood on my CNC router.


Posted by ultralajt on July 17, 2015 at 7:00 PM Comments comments (0)

A teaser..... :P

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Posted by ultralajt on June 23, 2015 at 3:20 PM Comments comments (0)

I finally managed to write assembly manual for my newest model MARABU II.

I also prepare SHORT KIT and it will be availale soon in my Webstore.

It is an upgraded model Marabu I build couple of years ago. This time, model is constructed mostly from white poplar plywood cut on my new CNC router.

THERMIC 70 by Frank Zaic

Posted by ultralajt on July 22, 2014 at 1:50 PM Comments comments (0)

Last week I saw a beautiful crafted soarer at nearby RC flying field. My friend build a scaled up Thermic sailplane. It is and old FF design made in 1946 by famous Frank Zaic. Of course, model is R/C and covered by Oralight.

I decided to build for myself original version of Thermic 70. Wing span is 70".

Plans werew downloaded from Internet:

I cut many 3x3mm balsa strips, as these are basic structure of the fuselage.

I made two identical fuselage sides (ladder):

Next I glue some fuselage formers to spread sides to proper distance and to get shape:

Next I add some additional longerons:

And in very short time, fuselage is ready for final sanding:

Of course, I need to instal servo, battery and reciever tray, install elevator and rudder pushrods, install fin ribs and make a removable canopy hatch for RC equippment access.

SideWinder DLG model

Posted by ultralajt on July 25, 2013 at 6:55 AM Comments comments (0)

Couple of days ago, I finally completed my first Discus Launch Glider (DLG). It is a SideWinder DLG from PolecatAeroWorks wing, with of shelve generic fuselage and balsa tail feathers.

Last evening it was maiden flight:

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and this morning I started to throw model higher and higher:

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A am looking forward to catch some thermal bubbles!


Ilindenka 2 original layout

Posted by ultralajt on May 18, 2013 at 4:10 AM Comments comments (0)

I am lucky to have friends, helping me in search for Ilinenka 2 informations.

So, couple of days ago, I recieved scanned 3 view drawing of Ilindenka 2 Sailplane. Based on that 3 view drawing, I made a vectorised drawing of Ilindenka 2 layout.  Now I can finnaly start to make drawings for a scale RC model.

Ilindenka 2 figuring out the shape

Posted by ultralajt on April 29, 2013 at 10:15 AM Comments comments (0)

I made 3D model based on my own 3v wdrawing in order to see how close I am to teh proper shape, and to see what changes shold I do .

Now it is obvious, where changes mst be made:

I need to:

  • lower the wing sweep
  • enlarge the wing dihedral
  • enlarge the wing root chord
  • make more taper of horizontal tail
  • shorten the fuselage forward part
  • to widen wing struts attachment points
  • to make some changes on the turtledeck

Ilindenka 2 Vintage Sailplane

Posted by ultralajt on April 28, 2013 at 2:35 AM Comments comments (1)

Yesterday I started to make plans for a scale model of Yugoslav Vintage Sailplane Ilindenka 2.

I think that proportions of this Sailplane are just such, that will garantee pleasant flight behaviour and performance.

Thinking of 1:4 scale.

Unfortunately there is not much informations about this Trainer Sailplane, So I am just guessing about its layout, based on these two photos above, and  a fact that I have some technical data of previous Ilindenka Sailplane.

Marabu with new motor

Posted by ultralajt on April 24, 2013 at 5:15 AM Comments comments (0)

Now you can feel the power!!

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Marabu motor cowl modified

Posted by ultralajt on April 7, 2013 at 12:10 PM Comments comments (0)

As new motor is larger, it was necessarry to lengthen the motor cowl for about 16mm.

I took only blue color spray can in my workshop and spray over the cowl. It is made from balsa and ply. Original it was covered with blue heat shrinkable covering, but today I didnt want to break my fingers around all roundings, so I just spray blue paint over the filler I sprayed before. The color dont match excatly the blue on the model, but what a heck.. is model for flying, not for showing off.. ;)

I am thinking of adding a spinner....

Tomorrow I will trim rear of the cowl sides and screw it to the fuselage. These days I move Fuselahe a lot form workshop to my cabinet, and covering starts showing wrinkles. I will streech covering shortly.. probably just using hot air gun.

Marabu new motor mount

Posted by ultralajt on April 7, 2013 at 6:30 AM Comments comments (0)

I was thinking about lightweight motor mount made from carbon tubes, but today I just use some 6mm aluminum tubing and bent its ends to get some sort of motor supports.

It seems ugly, but it is solid, simple and it will be hidden inder the engine cover. I will live is as it is.

Marabu minor wing repairment

Posted by ultralajt on April 6, 2013 at 7:50 PM Comments comments (0)

I had a bad landing over the winter, landing on the narrow road, hitting a garden fence pole with very tip of the wing.

I instantly secure broken tip bow with adhesive tape in angry and hurry again into the air to make another landing at the same spot.. this time landing was perfect. Obviously I was superficial at first landing, not take care about narrow place.

Today I decided to fix that wing tip. I cut away a covering between the tip bow and last wing rib. Next I glue broken tip to its original place and reinforce with balsa doublers. I even use a small strip of 0,6mm thick ply to reinforce the bow joint.
Next I apply new covering. I need to make the blue decoration and repairment will be finished. Anyway, model is ready to fly again.


Photo above: damaged wing tip bow. Sheared at both ends.

Photo above: large part of the bow attached to the wing only by covering.

Photo above: removing the covering and salvaging the balsa pieces...

Photo above: Glueing the tip bow and some sheetings at rear spar back on place.

Photo above: parts glued, awaiting for the covering.

Photo above: covering aplied. Only blue decoration jet to be made and repair will be finished.

Marabu minor fuselage changes

Posted by ultralajt on April 6, 2013 at 4:05 PM Comments comments (0)

In wish to get more power for aerotowing sailplanes, i will install new motor. But in order not to pull motor mount out from a white poplar plywood firewall, I reinforce it with a thin carbon fibre plate both sides.

Left new, right old.

Black gold! :D  I need to make four studs for installing the motor and drill many holes in to the firewall. Some for the bolts, some for the wires, and some for cooling air for the ESC and battery.

While epoxy was curing, I play a little with cockpit. I remove the side window to get easier approach to interior. Then I trim an old instrument panel, glue black wire insulation around upper perimeter and use some velcro to attach it onto the front panel.

I plan to instal a pair of seats (made from depron and painted) to get some "scale look".
I will rearange all servo wires and hidden those that goes up into the wing.

Pilot Overall Sewing Tutorial

Posted by ultralajt on March 10, 2013 at 12:15 PM Comments comments (1)

Okay, now I gather enough photos and video clips of making scale pilot Overalls, that I can make a Photo/Video Tutorial!

I choose old fashion vintage Pilot Overals for my CIRUS HS-62 Vintage Sailplane, as I saw such Overals on the photo from 1962.

First, we mark using paper patterns, all parts and then cut them from linen fabric:

After the pars are cut from fabric, we need to make all folds on the pockets, using a Liquid glue.

Folds just need to be glued so much, that will stay in place while sewing. Othervise, they can easily "drift" away.

On the upper part of the pocket, that will create a "flap" over it, folds must be folded to the other side.

Now you sewn pockets on their place.. both front pieces of the Overall.

Next we pay attention to the derails on the sleeves:

Next we sewn both back parts in the upper half. From the crouch up to the neck:

Next we prepare edged ot the fron parts. Edges on the button line. Then we sew together front pieces from the grouch to the bottom end of the "button line" :

Next we can sewn back and front together. We start at grouch towards one trousers end, and once again to the oposite leg. Next we sew outside edges of body and legs part, and also the seam at shoulders top:

Now we can turn Overall inside out, to check the seams:

Next we sew the edges of the sleeves:

Next, we sew sleeves on the body parts. We start at bottom seam.

And al last, we sew collar::

To close "button line" on the Overall sew a thin ribbon of velcro to the inner side of the Overall.

In a day or two, I will add video clips of all sewing operations.

Paterns preview:

Patterns available for FREE Download!

MARABU CNC - 4 portable laser cutters

Posted by ultralajt on January 29, 2013 at 5:30 AM Comments comments (0)

I recieved some feedback about Marabu CNC files. Some CNC laser shops own machines with smaller working area, for instance 30 x 50 cm, can not handle the largest mmarabu parts. They must be "spliced" to be made on small working size machine.

I am working in this direction, to add also a version of files that will be made on 300 x 500 mm machine working area.

Hopefully I will manage to do  that over the next weekend.


Posted by ultralajt on January 27, 2013 at 11:45 AM Comments comments (4)

I prepared DXF file for all parts that are suitable for making them using CNC Router ot Laser cutting machines.

There is an action going right now, that will end on 4th of February 2013. Each buyer of Marabu plans will recieve also free DXF 4 CNC file.

Preview of the DXF 4 CNC file:

Notes and matrerial borders are drawn on the separate layer, so they can be turned off if necessarry.

Material type and thickness is written on each upper left corner. Some of the parts are named for easier placement ar the model assembly. This DXF file doesnt held any of simple balsa strips, dowels and other simple parts. These must modeller carve by himself. A balsa trip cutter is a very handy tool at Marabu manufacturing.

FRAUD-Casa da Balsa Plantas de aeromodelo

Posted by ultralajt on December 2, 2012 at 11:40 AM Comments comments (2)

I have just discovered a website named that sell GUPPY plans for 19$.

These plans are the first published plans of my Guppy that were freely available years ago on the web and my website. As you can see file size is 1,8MB, while my original plans at my webstore are more than 5MB!

Plans for Guppy as I sell them are more advanced, redrawn and consists all necessarry informations.

I think that guy behind that Casa da Balsa website is cheeter as it sells my made plans for 19$.

More sophisticated plans for the same version of Guppy you can get at my webstore for only 5$!



Posted by ultralajt on November 11, 2012 at 3:15 AM Comments comments (0)


I am working on the design of imaginary oldtimer glider "Alpenflieger".

Wing span 3,25m

This is a design of cockpit removable hatch:

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Marabu Plans

Posted by ultralajt on October 30, 2012 at 4:25 PM Comments comments (2)

Almost finished! :D