1/18 scale Tervamaki Engineering JT-9T autogyro

[Nick_Karatzides]

Using an X-acto, I removed the formed fuselage from the styrene sheet and test fitting on the autogyro scale model airframe. Few drops of cyanoacrylate glue applied on the right spots across the fuselage joints to make the contact secure, did some light sanding on the fresh produced thin-skinned right side fuselage to eliminate some tiny marks and as you can see at the following pictures, the nearly transparent result is more than realistic to scale and completely satisfies to me.

 

 

 

 

 

 

 

[Nick_Karatzides]

Do you remember the wooden picture frames I found at the local IKEA store for only 1€ each, securing the styrene plastic sheet to be vacuum formed? I kept these thin plexiglas plates, to use them as required. Continuing the cockpit construction, I had to build the rear cockpit cover, so I placed the autogyro model upside down facing a glass surface, I boxed it by placing the thin plexiglas plates around it, securing in place with modeling clay for kids. Then, I removed the scale model carefully, leaving space between these thin plexiglas plates. Wet white plaster mixture, applied into the gap, between the thin plexiglas plates to fill the area. When the first layer of thinned plaster was dry and hard enough, two or three extra layers of white plaster followed to finally build the basic cast. 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 plaster cast was dry and hardened after few hours, I removed the modeling clay for kids and the thin plexiglas plates. The white plaster cast got shaped into proper dimensions but cutting it with saw, filling with tiny quantities of modeling putty added to close minor scratches and pores on white plaster cast surface, dry sanded and finally sprayed overall with gloss shiny coat.

 

 

 

 

 

Edytowane 4 Listopada 2009 przez Gość

[Nick_Karatzides]

Because I was planning to use smaller wooden frame to secure the styrene plastic sheet (the piece to be vacuum formed is too small, there is no need to spend big plastic card), I had to close the outer holes on the hardboard high-density fibreboard plate. To do so, I cut a plastic bag in shape and covered as required the desired area. I pined a styrene plastic sheet on the wooden frame, insert it into the preheated electric oven as described before and as soon as I noticed that the plastic started drooping down, I removed it on the vacuum former plate, while the vacuum cleaner was already pluged & switched on. The plastic nicely formed around the plaster cast and here is how it looks like.

 

 

 

 

 

 

 

 

As long as the piece looked satisfying to me, I removed the formed plastic from the styrene sheet with a new Nr 11 surgical blade on my cutter, test fitting on the scale model and later start adding internal detail.

 

 

[Nick_Karatzides]

I placed the rear cockpit’s cover in place and secure it with just one or two drops of cyanoacrylate super glue. Then, using a small pencil, I defined the exact line that the rear cockpit cover should be cut in order to let the inside structure visible. Using the mini Dremel tool, I cut and removed the left half part, in a way to look kind artistic.

 

 

[Nick_Karatzides]

My good friend Dimitris Pravinos, who is a WWII German tanks specialist scale modeler, sent me about five hundred (!!!) cups he found and looked ideal to use them for mixing colors, modeling putty etc. Few drops of nitrocellulose lacquer thinner and just a little amount of Humbrol modeling putty, were more than enough to prepare a nice liquid mixture to apply on the rear cockpit cover surface, to ensure that little tiny scratches would disappear.

 

 

 

 

 

 

[Nick_Karatzides]

Few hours later, soft sanding and a quick airbrushing with white color to make mistakes, scratches etc become easy to spot, the rear cockpit cover was finally ready.

 

[Nick_Karatzides]

CHAPTER V - "H" shaped tail construction

 

The Tervamaki Engineering JT-9T autogyro designed by Finnish engineer Mr. Jukka Tervamaki, is equipped with a twin "H" shaped tail. To build this, I started by rolling flexible styrene sheet around a plastic tube and forming as required to look like the real JT-9T autogyro right side elevator main wing - only 18 times smaller. Following, using the sandwich method (placing one plastic sheet over another), cutting carefully and working extensively with sandpaper to form into desired size and aerodynamic shape, I manage to build the right side stabilizer wing. As you understand, the left side elevator wing, the stabilizer and rudder, will be stripped in a way to show the airframe aluminum skeleton.

 

 

 

 

 

 

 

[Nick_Karatzides]

 

 

 

 

[Nick_Karatzides]

CHAPTER VI - Landing gear system construction

 

The single seat JT-9 and the tandem seating JT-9T, are available with tricycle landing gear system with a steerable nose wheel or a taildragger version too. For both types, the type of landing gear is based on the placement of the exact CG position, determined after complete weight calculations according the owner/pilot's personal needs. My 1/18 scale model is designed to be equiped with a tricycle landing gear system with a steerable nose wheel. An utillity free-spinning tail wheel is also placed, to prevent any accidental damage on tail structure if the autogyro raise nose too high while in ground. Feel free to check the diagrams and images found into my first post of this project, back in page 1.

 

Using plastic card, sprue, metal wire, resin tires and brakes fit accurately to 1/18 scale diagrams and few unidentified parts found in the sparebox, I build a realistic looking 1/18 scale main landing gear system with absorbers and a steerable nose gear. I stole a nickel plated button from GF's favorite dress (hope she'll never find out where's the missing button or I'm in real trouble), placed it into a plastic tube piece, covered with with transparent plastic card & add some details to simulate the landing light in scale.

 

 

 

 

 

 

 

 

 

 

 

Yeah, yeah, yeah... I know! I am a button stealer, but let's admit it! We all prefer less buttons on female dresses

[Nick_Karatzides]

CHAPTER VII - Canopy construction

 

The Tervamaki Engineering JT-9T autogyro canopy is made by bented and cold-formed 3mm polycarbonate sheet. The backwards sliding canopy of the single seat JT-9 version, offers the possibility to taxi and fly slowly with the canopy open, a benefit in a hot climate. The trainer / tandem seating JT-9T, has a side opening one piece canopy. Of course, canopy modifications can be done, according the autogyro owner's personal needs or desires.

 

 

 

 

 

I used styrene plastic card to form it as shown into following pictures to give the basic shape of the canopy. Then, a layer of polyester filler applied on the styrene. The specific polyester filler I used, comes with the proper catalyst which provides a solid rock build and approximately 3 to 5 minutes time window to form it into shape. I prefer to use epoxy putty or polyester filler with fiberglass grains for special purposes, because:

• It becomes solid rock within only few minutes or seconds,
  
• it does not shrink and does not crack after months or years,
  
• you can pour to any shape that you want but you need to work fast because as soon as you mix it with catalyst cream approx 5%, you have limited time before becoming solid rock,
  
• you can also put additional layers of epoxy or polyester filler to build up,
  
• you can sand it, you can drill it, you can use any type of scale modeling glue, any type of primer or enamel / acrylic paint on it with no problem,
  
• can be purchased at any good crafts store into 250ml, 500ml, 1lt (comes with a tube of catalyst hardener) or bigger canisters and if you can't find it, fear not and try your local decent hardware store and finally...
  
• it is cheaper than dirt - estimated prices are £3 to £10 depending the canister size, the quality, if contains fiberglass grains for maximum strenght etc.

Keep in mind that the chemical reaction after mixing the polyester filler with the catalyst hardener, produces some heat that possibly effect on thin plastic parts, so test it first before try it on your scale model. I don’t think that the produced heat is more than Fahrenheit 110, but better watchout. Remember that epoxy materials are dangerous when breath or shallow and could result skin, eyes or lungs problems or even cancer when used for long period with no precaution measures. Always keep in mind, that a powerful vacuum system to suck away the epoxy dust should be used all time to keep the workbench area clean while sanding or milling epoxy or resin materials. Using an issued breathing mask and a pair of surgery latex gloves to prevent dust contact with lungs and fingers while sanding or milling epoxy, is also an important matter that you should seriously take care of! My recommendation is to also wear an overall working suit (as I do) to keep your clothes dust free while sanding epoxy. Some people might find it too much, but I wouldn't like to bring epoxy dust & grains from my work bench into living room and my beloved.

 

When the basic canopy shape made by styrene sheet, was fully covered by a a thin layer of polyester filler and had enough time to polymerize and get solid rock, I sand it with wet sandpaper to make the cast curved and shiny. To produce a thin-skinned canopy, the polyester part should be vacuum formed. As described into previous chapters, a transparent plastic 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 plastic nicely formed around the canopy cast following the curves & details as planed. Using an X-acto, I removed the formed canopy buble from the transparent sheet and start adding details, such as canopy's frame. Few drops of cyanoacrylate glue applied on the right spots with great caution. Remember that CA 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.

 

 

 

 

 

 

 

[Nick_Karatzides]

It’s sad! Obviously, voodoo curses came from the unspeakable dirty Viper snake, got real and the final varnish finishes on the model suffered what the Americans call as FUBAR - F@cked Up Beyond All Recognition.

 

 

In brief words, the color layers popped and “cracked” everywhere on the model’s surface, just before the final touch. For some mysterious reason, the color looked peeled off and an unexpected chipping (I would never succeed this by purpose) appeared! The scale modeling accidents committee is expected to investigate the possible reasons within following days, but unconfirmed sources report "pilot’s error" - OK, I made a rookie’s mistake, while using old colors or coat varnish.

 

Meanwhile, the following actions took place:

• Garlic cloves were hanged across the workbench to keep away evil curses, vampires and “snakes” (or those who claim themselves as “snakes”),
  
• The scale model were covered with a thick layer of ModelStrip product, locked tightly in a plastic bag and left overnight to let the chemical work.

[Nick_Karatzides]

It’s sad! Obviously, voodoo curses came from the unspeakable dirty Viper snake, got real and the final varnish finishes on the model suffered what the Americans call as FUBAR - F@cked Up Beyond All Recognition.

CHAPTER VIII - Live After Death

 

When I started building the model, I did not expect to present the CHAPTER VIII under this title. Bus as all the sad & bad situations in life, it was unexpected and accompanied by great frustration because suddenly I saw months effort to dissolve in only few minutes. The old colours (or bad white spirit solvent) that I used, have led to drying crack. Unfortunately, I ignored all the warning signs such as thick grains left by the white colour in which I primed the scale model before the final painting. Having as target to make this model alive again, just like Iron Maiden Eddie’s Live After Death, I decided to try a full reset – after all, I had nothing to lose! The scale model was already FUBAR.

 

 

The following photos show the unsuccessful paint process. The problems appeared marked inside the red circles. Unfortunately, I have no photos of the model while looked completely written-off, because at that time I was not in a mood to take pictures!

 

 

 

 

 

 

 

ModelStrip, was the first thing came up as the most conventional solution to try paint removing. Following the instructions on the box, a generous stuff applied on the model, wrap it with airtight plastic bag to prevent drying and wait about 15 hours to let the chemical work. Opening the bag next day and checking the results, the colour (or rather the colour layers) were soft and could be removed by rubbing vigorously with an old toothbrush. Unfortunately, using the brush on some very delicate spots (even with careful use), had as result to break / or ruin a couple of plastic pieces. Moreover, the paint could not be removed through narrow points and difficult locations.

 

 

At this point and while I’ve already used all the ModelStrip material without being satisfied with the outcome, I decide to change tactics to something more unconventional, such as oven cleaner.

 

 

Following the product’s directions as always, I sprayed the model with the material, wrap it with airtight plastic bag to prevent drying and wait about 15 hours to let the chemical work. Testing results next day, the oven cleaner failed no more than ModelStrip. I noticed that the colour could be removed but only when pressure and persistent rubbing with brush and that was prohibitive for some parts of the model. Not having another solution, I approached the most unconventional method and visit a science specialist - my local grocery store!

• - Hey man! I need something really strong to clean up kitchen’s oven?
  - Really strong? Use this!

…and he gives me a dust covered 1lt plastic bottle found in an almost unreachable shelf. Reading the bottle’s label, I found out that it contains sodium hydroxide also known as lye (corrosive alkaline substance) or caustic soda and is a caustic metallic base. It is used in many industries, mostly as a strong chemical base with chemical type NaOH.

 

 

 

• - Are you sure that this will work? Are you sure that this is safe to use?
  - Trust me. It’s gonna clean up the kitchen’s oven like a nuclear bomb!
  - How much?
  - 3.50 € . Take it or leave it.

Thinking about a possible failure, I filled a plastic bowl with the milky liquid contained in the bottle and threw all the model pieces inside. As long as the autogyro model was already FUBAR, I had nothing to loose to try. I sealed the bowl with a cover and leave the sodium hydroxide to act for 20-30 minutes while the instructions sets out to wipe the sodium hydroxide chemical liquid after 10 minutes. Opening the plastic bowl’s cover, a nice surprise followed...

 

 

 

 

 

 

 

 

The truth is I was delighted! Styrene pieces simply and magically totally striped off the enamel colour layers! Absolutely success, without even apply brush cleaning! Amazing product - incredible grocer! Just because I couldn’t believe it and I wanted to make sure that the colour striped off because of the sodium hydroxide chemical (and not the previous used ModelStrip product or the kitchen oven cleaner), I decide to experiment. I threw in a bowl, already filled with the chemical, a 1/18 scale female figure that I was about to convert for a future project. The specific 1/18 scale female figure, is made by Fast Women brand and can be found by clicking HERE). The results after just 15 minutes in the sodium hydroxide chemical - Perfect! The following pictures, show the "before" and the "after".

 

 

 

 

 

Keep in mind that the sodium hydroxide is (and thus should be considered) a strong caustic base. This means that:

 

• Throughout the impregnation of the model parts into sodium hydroxide, you should take all the necessary protective measures (like mentioned in the warnings on the bottle’s label) and is certainly to use disposable surgical gloves made by latex and breathing mask with appropriate filters to protect against possible fumes.
  
• The colour stripped plastic parts must be rinsed with soft acid to neutralize the caustic base and produce salt and water. Dunking the colour striped parts in plastic container filled with cooking vinegar and then rinsing with plenty of lukewarm water, plastic is now safe to handle with bare hands.

[Nick_Karatzides]

Under the above "adventure" circumstances and considering that all these years dealing with the scale modeling I've tried many color striping methods (including ModelStrip, kitchen oven cleaners, blue alcohol, brake fluid, nitro laquer disolvent, etc), I think that sodium hydroxide NaOH is the best method so far, for the following reasons:

• Kitchen oven cleaners in spray canisters, can do the job, but they cost 3 - 4 € for a 300ml product in which also includes the propellant gas. On the other hand, the NaOH in liquid form is a pure substance, much less price, taking for 1lt bottle, which equals 3.3+ times more product! Using the liquid form NaOH (which you can fill a plastic bowl), you can sink several plastic pieces, same time!
  
• The brake fluid may be effective and remove paint, but it is not plastic friendly plastic and is likely to convert the scale model into a blob of molten plastic. It is clearly more expensive and as far it is highly toxic, flammable and hardly to manege, I will not recommended it for scale modeling use.
  
• Nitric acid laquer disolvent, could be a nice solution for metal figures paint striping, but it is not the best for the plastic. Just like the brake fluid, it does melt and damage plastic parts.

[Nick_Karatzides]

 

 

 

 

 

 

 

 

 

 

 

[Marudek]

Hi!

 

I've been admiring your challenge with this project ever since I discovered it on our forum. I love scratch building and I respect those who dare trying it. Coming back to your project it seems the paint work didn't improve much. Bearing in mind the scale of your autogyro it would be a shame to leave it like that. The effect reminds me armour modeling technique which gives an impression of cast metal. Don't get me wrong, I understand all that painting and further stripping is time consuming and costs a lot of effort. But maybe giving it another chance would advantage in better effect. I'm not the expert but if I were in your shoes I would check the airbrush. It splits the paint particles around the painted area. The photograph depicting you highlight the frame pattern (pic. 6) on the side of autogyro shows it the most. If the airbrush is OK than maybe the paint is too thick. Furthermore when you apply the red (pic. 5) it looks like you paint the same spot until it turns totally red. Instead I would recommend applying thin (transparent) layers all over the model without building paint in one spot. After applying one layer wait until it dries and then apply another one. You can also polish the layers between application and after paint job is finished. I'm sure my colleagues who build model cars would be of help regarding super finish effect.

 

Awaiting further progress I shall admire what you showed so far.

[Nick_Karatzides]

I placed small slips of paper between the frame and the sheet of the fuselage, to protect the red colour that was already applied, covered by a gloss varnish and dried. Next, I masked areas not to be painted and sprayed with the interior green colour.

 

 

 

 

 

 

[Nick_Karatzides]

After the interior colour dried, the slips of paper and adhesive masking tape removed and minor corrections were made in 1-2 spots with a fine brush. The result was sprayed with gloss varnish, to apply washing on certain points.

 

 

 

 

 

[Nick_Karatzides]

The steps are slow, but I prefer steady progress rather than hastily. Unfortunately, the problems are not missed. Although I do not think myself as awkward, after the incident with the (voluntarily flying) autogyro model scaffolding under my sleeve and threw (launched to be precise) on its own initiative, brought about 4 or 5 spin turns and finally abnormal landed about 5 feet away and 3 feet lower, I begin to believe that this model has been seriously voodoo curses. Despite the delicate structure of the fuselage, the use of CA glue and maybe a miracle, were the main reasons that the model escaped having suffered only a broken landing gear, scratchbuilt again.

 

 

After the scale model was masked & sprayed with primary colors as described above, the same methodology followed for the canopy, scratchbuilt by transparent plastic on a vacuum former. After the acrylic paint and mat enamel coat dried, I removed the masking tape and I saw the following:

 

 

 

The masking tape that I had used, had left noticeable marks on the transparent part of the canopy - something that had never done before! Beeing sure now that this scale model is indeed cursed, I dropped by the local grocery store around the corner from where I returned with few garlic cloves. Not having a similar experience before and fearing that if I try to clean the masking tape glue marks using White Spirit will make the things worse with a huge dull hood, I tried to rub the clear plastic part with alcohol which although more friendly to transparent plastics, had to pass crash test first. Dipping a cotton swab in alcohol and water solution and vigorously rubbing the hood, the masking tape glue marks, finally removed as if it was gum.

 

 

 

 

With my heart beating on normal levels again and using airbrush, light tones of basic colours and shades of sand sprayed at low pressure to represent the weathering and dusting on LG and the lower part of airframe. After a satisfactory weathering result, the scale model was sprayed with mat enamel coat. I left it 24 hours to dry and the individual parts of the scale model were test assembled (no glue), so that the autogyro model start to look like a united construction and please the eye.

 

 

 

 

 

 

Having now left the last part of the assembly of the individual already dyed parts of the model, such as the rotor blades, the cockpit flight & engine controls, the cables, the seat belts and other necessary details, I begin to hope that perhaps this model might be ready in 2010.

[Ironkamil]

Hi

Great project! Engine and another details is awesome I am waiting for another chapters.

Great Job

[Nick_Karatzides]

Some update pictures after washing / weathering / colour fading. Control cables are already installed. Still remain to be added:

• The canopy,
  
• Both propellers,
  
• The radio device & GPS,
  
• The engine control levers,
  
• The windshield and windscreen wiper,

and also paint some details such as engine cables etc.

 

 

 

 

 

 

 

 

 

[Nick_Karatzides]

Details on rotor blades and the engine. The rotor blades are made of sterene sheet softened in boiling water to strech 'n' turn in a way to look realistic. Soft sanding applyied on the blade's leading eadge to be shaped as it should be. The spinner cone was made of an old 1/48 scale fuel tank tip, found in sparebox.

 

 

 

 

[Nick_Karatzides]

The JT-9T model posing for the camera...

 

 

 

[Nick_Karatzides]

CHAPTER X - Epilogue

 

Final details were added. VHF radio with headphones in the cockpit, mobile phone, seat belt buckles, main rotor control bars, cables, etc. To break the monotony of red, a toolbox and a tow added into rear storage area. At last, transparent plastic card were placed to simulate the wind shield glasses and of course the canopy in the open position.

 

Close-ups of scratchbuild engine. Although initially I plan to represent a brand new bright and shiny engine I discovered that it would not fit the with a faded, dusty and weathered autogyro. That is why I preferred to add much wear, stains from oil and scorched medals at several points and some rust as example in the exhaust.

 

 

 

 

 

The controls in this two-seater model autogyro, as with any trainer aircraft, perform the same movements. Feel free to notice the rudder pedals and you will see that the front and the back seat, right pedal is pressed to full FOR, bringing the left full AFT. This has resulted in turning the nose wheel to the right and turning the rudder of the tail in such a way as to twist the autogyro to right as defined by the position of the rudder pedals. Also notice that the throttle lever of back seat is attached on a bar connecting to the front seat engine throttle so to move simultaneously. The engine's power transmission is made with a wire, launched by the front seat throttle lever and lead the assembly of the engine. Finally, the control sticks are fallen slightly forward, which of course means that the elevators are set in a similar position.

 

 

 

 

 

 

 

 

 

 

 

 

[_iceboy]

Amaizing scratch !

[hanadam]

Great Job, Perfectly detailed and very realistic ! Big Ouzo to You!