1/18 scale Bölkow Bo-102 Helitrainer scratchbuild model

[Nick_Karatzides]

Dark brownish pigments & chalk powder shades, dissolved in water and spread in selected engine block spots gave a better look. When satisfied with the result, I began the tail boom painting process. To do so, I used the Life Color UA140 Yellow RLM 04 FS33538 colour which is actually the colour found into the official Bölkow’s technical order manual. Paint applied over 2-3 very diluted (almost pure water) thin layers, one after another, using a fine brush, keeping in mind that leaving paint marks should be avoided.

 

 

[Nick_Karatzides]

CHAPTER VIII - Tarmac & grass display base construction

I found nice idea to place the Bö-102 Helitrainer on a display base, simulating a concrete ground area. The idea was to establish the picture of an abandoned small airfield in Vlotho, where the Helitrainer used to rest for decades till found and finally donated to the Hubschraubermuseum helicopter museum in Bückeburg, Germany. The museum workshop team, managed to restore it and display it as on of these experimental helicopter training devices. From my local store, I bought a 20x30cm polished wooden picture frame.

 

I add some grams of plaster powder and few drops of water with a syringe into a soft rubber cup to make the right mixture. Materials like plaster, start as a dry powder that is mixed with water to form a paste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after drying and this characteristic make plaster suitable for the job. Keep in mind that adding salt into wet plaster mixture, reduce the plaster's hardening time and adding vinegar into wet plaster mixture, extend the plaster's hardening time. When the first layer of thinned plaster applied on the picture frame, a glass were pushed against the plaster to form a flat basic strong cast. The basic idea, is to produce a totally flat cast and later add some detail or apply extra stuff where is needed.

 

 

 

 

 

I left it few hours to get harden in order to be sure that the cast wouldn't break when I would try to cut it into desired shape. Meanwhile, I took the soft rubber cup which I used to make the plaster mixture, squized it to break the last hardened plaster left inside, so it would be easier for me to clean it afterwards and prepare it for any future mix. That's the reason this soft rubber cup were used for.

 

 

As soon as the plaster cast got harden, cut into shape and the concrete plaques were lined with a scriber, I used my airbrush to paint it. After the polished wooden frame was covered with masking tape, three different acrylic paint layers were applied on the plaster surface. First, mat black colour covered the area and then a light grey applied with airbrush, spraying in almost zero degrees angle, to let the darker areas between the concrete plaques remain naturally dark. The corner was paint with earth tones and as soon as the acrylic colours dried, I tried some drybrushing on selected spots using sand tones.

 

As for he grass & plants, I used different colors of static grass from my local hobby shop, empty them into a plastic box and make a mixture.

 

 

Water based white glue for wood, which becomes transparent when it dries, is just the right for the job. So, I opened a 500gr canister bought for 2€ only, pick a small quantity, add just few drops of water with a syringe into a small metal container to make the right mixture and finally I applied on the desired areas to be filled with grass & plants, using a wet brush. Because the mixture is enriched with water based glue, it is easy to correct possible mistakes.

 

 

 

 

 

As soon as the result was OK, I sprayed over with Humbrol enamel mat coat, to seal the paint and grass, so far. I left it overnight and as soon as the enamel mat coat dried, I add very few light & dust effects with chalk dust and pigments.

[Nick_Karatzides]

CHAPTER IX - Attempting the final assembly

As soon as the individual scale model’s parts were already painted & weathered, I had to conclude the most difficult part. To assembly everything in one piece, without damaging the construction, the paint, the weather effect and of course ,my patience. That’s why I had to constantly monitor and try dry fit tests for each part during each step of this project, to ensure that I will not face any nasty surprises. The landing pad & the wheeled supporting base construction, would be the first to be placed on the tarmac display base. Everything secured in place with hidden pins encased in plaster & glued with CA super glue.

 

 

 

 

[Nick_Karatzides]

CHAPTER X - Clear canopy installation on bubble cabin

The Bö-102’s cabin and one-piece glass bubble canopy, offers wide visibility for the student pilot. The absence of side doors is a benefit in a hot climate and also provides better vocal communication with trainer who sits nest to student pilot. Of course, canopy modifications can be done, as seen Bö-102s with total absence of glass canopy. As written and described into previous “CHAPTER” I, the basic shape of the thin-skinned, right-to-scale bubble typed canopy, was made by vacuum forming 1mm clear polycarbonate sheet, on a solid rock one-piece image cast made of modeling clay and additional layers of epoxy putty & polyester filler with fiberglass grains. To do so, the clear sheet were pined on a wooden frame, preheated into electric oven and as soon as I noticed that it started drooping down, I vacuum formed it. The clear sheet nicely formed around the canopy cast following the curves & details as planed. Using an X-acto knife, I removed the formed canopy bubble from the transparent sheet and start adding details, such as canopy's frame.

 

The clear canopy frame was made by 1mm masking tape. Few drops of CA super glue applied on the right spots with great caution. Remember that CA super glue does fog the transparent parts and this canopy would not be an exception - that's why I placed some very tiny drops of it, just on few spots to secure the installation.

 

 

[Nick_Karatzides]

After placing the clear canopy on cabin and adding few tiny drops of CA super glue just on few spots to secure the installation, small amounts of Squadron MMD green putty filled tiny gaps. Later, the green putty overages sanded lightly and the cabin prepared for airbrushing. The cabin was painted using the Life Color UA025 Light Gull Grey FS36440 acrylic paint and later the lower part was dusted by airbrushing a very light layer of Life Color LC37 Matt Burnt Umber FS3004 acrylic paint.

 

 

[Nick_Karatzides]

CHAPTER XI - Instructor’s bicycle type seat construction

I almost forgot to build the instructor’s bicycle type seat in which he sits, next to the student pilot. Using plasticine, I made an image cast of how I would like seat’s surface to look like. I only had to push the material gently with fingers and got the desired shape - in fact, the process took less than 5 seconds.

 

 

 

Using a small amount of Milliput putty, I made a small ball, dust it with talcum powder and pressed it against the working bench with a roller until it becomes as thin as could get. The use of talcum powder is necessary to avoid Milliput sticking on roller or fingers and get easier to handle without tearing to pieces.

 

 

 

When the Milliput was pretty thin, I lifted it and place it on the plasticine image cast I made earlier, to let it follow the shape and curves of the seat. Using an old wet brush, I let few drops of water on the Milliput sheet, to make it softer and easier to follow the seat shape and left it overnight to get harden. Of course, the same technique can be also used to build blankets, truck covers, etc.

 

 

 

I left the Milliput overnight to get polymerized. As soon as it was got harden, I removed the plasticine image cast and cut the seat, as shown into the following pictures.

 

 

 

Using airbrush, basic blue colour and shades of sand & rusty brown tones sprayed at low pressure to represent the weathering and dusting on the seat and the lower part of the landing pad with supporting base. After a satisfactory weathering result, the scale model was sprayed with mat enamel coat and left 24 hours to dry.

[Nick_Karatzides]

CHAPTER XII - Epilogue

Final details were added and I tried some close-up pictures. Although initially I plan to represent a brand new bright ‘n’ shiny Bölkow Bö-102 Helitrainer, I changed my mind during the building process and finally decide to present as found in an abandoned small airfield in Vlotho, where the Helitrainer used to rest for decades till found and finally donated to the Hubschraubermuseum helicopter museum in Bückeburg, Germany. The museum workshop team, managed to restore it and display it as on of these experimental helicopter training devices. That is why I preferred to add much wear, dust and stains from oil and scorched medals at several points and some rust as example in the exhaust.

 

I tried black paper background (instead of white) & different light conditions. Thank you for following this thread and I hope you enjoyed reading this article.

 

 

 

 

 

 

 

 

 

 

 

[kornik_69]

This looks awesome!

 

Congratulations Nick!

[ShaDow FoX]

Awesome job It's really amazing.

[krosto]

Nick, your "production line" is astonishing! It was real pleasure to watch your work as such an construction activity is hard to find.

I am looking forward for your new ideas being accomplished

 

K

[Czesio]

Man, You`re awesome ! Incredibly good work

[Jic]

Great , Good Job Man ! : )