1/18 scale F-16CJ Fighting Falcon Blk 52 Hellenic Air Force conversion & scratchbuild

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1/18 scale Lockheed Martin F-16CJ Fighting Falcon Block 52 Hellenic Air Force

BBI - Elite Force conversion & scratchbuild

The following article is to describe step by step the 1/18 scale Lockheed Martin F-16CJ Fighting Falcon Block 52, currently flying with Hellenic Air Force, conversion using the BBI - Elite Force toy model kit, bought from the States a couple of years before for less than $60.

Despite my enthusiasm when I finally got this 1/18 model in my hands, as soon as I opened the box which exceeds in length the 3 feet (!!!), I realized that I would face hard time and massive scratch building and I'd need to spend hundreds hours on my hobby bench to make it look descent. In the substance, it is not even a model to assembly but a game for children which could be ready in less than 2 minutes. The detail convinces only if you look the model from a distance while points such as landing gear system, engine nozzle, panel lines etc are real dramatic. Luckily, the model is accurate on dimensions and could possibly be used as a F-16 exhibit model that do not interest on conformity of colors, special details etc.

So, I decide to begin the building from the zero and give life in this 82cm long monster with no detail (comparing to scale models by Hasegawa, Tamiya etc) but however this 1/18 F-16 toy has almost unlimited possibilities of becoming a high detailed scale model. It should be noticed that the model's airframe comes straight from the box already sealed and I had to open it and work it from inside. That's a hard work to do, because the fuselage remains stuck with internal reinforcing possessors and metal supports & screws that I should locate and carefully remove without causing any damage on plastic material.

82cm long beast, immediately after opening of packing box. I am already start thinking about finding the proper window to place this Falcon

By selecting heavy metal on my CD player (in order to I become aggressive and get the "Friday 13th" feeling) and using a saw and a Dremel tool, I opened the fuselage, the basic airframe pieces were cut and useless parts such as landing gear, engine nozzle, a part of the air intake etc were removed and led to the garbage.

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CHAPTER I - Engine's 1st stage blades & afterburner construction

Beginning the construction from behind, I should first scratch build the Pratt & Whitney F100 turbofan engine (F-16CJ Block 52) nozzle, the afterburner compartment etc as detailed as a curious and indiscreet eye could see. Considering the huge dimensions of the model, I should theoretically scratch build almost everything! Using plastic cards, my new X-Acto blade, F-16 related bibliography, photographs and the T.O service manual used for the real F-16, I started.

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Building the engine's air intake & blade fans was quite easy. Using an old 1st aid kit tape cap which just fit on 1/18 diameter engine 1st stage blade fans, I placed carefully plastic blades as shown in the following pictures. Molding some epoxy putty, I build a basic item of a cone, then stuck some steel pins on it and removed them after 20 minutes, as soon as the epoxy putty was solid rock. Spinning the epoxy item with the Dremel tool and sanding as required, I formed in to a cone shape and finally I placed a pitot tube sensor on the top of the cone spinner as shown in the real Pratt & Whitney F100 turbofan engine pictures.

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CHAPTER II – Air intake tube construction

Because the main BBI - Elite Force kit was very poor on detail and had the air intake tube sealed, I had to first open the air intake by cutting the plastic and then build from scratch the approximately 30cm long tube, leading to the engine's 1st stage blades described in detail into previous Chapter I. Just because the F-16's air intake tube is not just a straight line tube, the idea of scale building with plastic card was rejected from the first moment. If you notice, the F-16's air intake tube is curved in both X and Y axes while heading to the engine's 1st stage blades.

Source:

For this reason, I decide that a "negative image" cast of the air intake tube should be made and build the tube model using this cast, with two available & different methods:

• The first method is based on a solid rock (made by balsa, epoxy filler, plastic etc) "negative image" cast of the air intake tube on which I would try to vacum form some air intake tube "half" parts (left-right or upper-lower). Some very thin (and fragile too) plastic parts could be produced, but with doubtful contact between the two "halfs". For sure, the tube "halfs" would leave visible contact line marks across the construction, that should be filled with putty and carefully sanded on a fragile and extra thin plastic material.
  
  
  
  
• The second method is based on a deliberately fragile and hollow "negative image" cast made by soft materials (such as plaster and cardboard), that could easily be decomposed and removed after sinking into water. I decide to follow the second method, knowing that I had only one shot to try, with no mistakes allowed, considering that the cast would be destroyed after use, but I could have one-piece tube as a result, without any marks or lines inside the tube and also avoid unneccessary sanding with doubtful results.
  
  
  
  

By selecting the second way, which was more desired and realistic for me, I finally produced one solid rock one-piece air intake tube, very accurate on scale, following exactly the real air intake tube curves and present to fellow modelers a mighty unconventional way of scale building to keep in their mind for any future projects of their own. That's why, I present the project with step-by-step pictures, to provide any possible help to understand how did it. After all, I believe that scale modeling is not just cutting plastic parts straight from the kit box or maybe use some resin accessories already checked to fit perfect into models, but combining arts, skills, techniques and finally use our brain to invent new methods in order to have a realistic result.

Having the official F-16 Block 52 blueprints copied from the T.O manual, I got the exact dimensions of the air intake tube, print them down on a cutaway image and using scissor and simple cardboard, I create a the "negative image" of the air intake tube, basic spine. As soon as the spine made by cardboard was set on a straight line, it was wrapped around with a cloth net found into the 1st aid kit. Small quantities of plaster, highly thinned with water, applied on the cloth net with a brush, to build the first layer of a hollow plaster cast, which would become the "negative image" of the air intake tube.

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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 can be easily manipulated with metal tools or even sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material and that exactly is what I'm looking for on this air intake tube construction. 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 net was dry and hard enough to hold the basic spine made by cardboard, a second thin layer of plaster was applied to form the curves of the air intake tube, following the lines of the pre-cutting cardboard. The basic idea, is to keep this plaster cast hollow, accurate on scale and as thin as possible trying not to apply extra stuff where is no needed. When the plaster cast was dry and hardened, tiny quantities of modeling putty added to close minor scratches and pores on plaster cast surface, brushed with water based clue, painted in black color, dry sanded and finally sprayed overall with gloss shiny coat.

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Johnson's baby oil (thin layers of vaseline based mixtures can be used also) brushed as a segregative material for later purpose and generous quantities of polyester filler applied on the plaster cast. The specific polyester filler I used, is enriched with fiberglass grains to enforce the final construction. The filler should be always used with the proper catalyst which provides a solid rock build and approximately 5 to 10 minutes time window to form it into shape.

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When the plaster cast used as a "negative image" of the air intake tube, was fully covered with a 3-4 mm thick layer of polyester filler enriched with fiberglass grains and had enough time to polymerize and get solid rock, it was sunk into water and stayed wet overnight, in order to let the enclosed cast made by cardboard and plaster get moistened and decomposed.

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Being underwater for few hours, waiting for the enclosed cast made by cardboard and plaster to get decomposed and become soft, mixed pieces of cloth net, thinned plaster and moistened cardboard were removed with caution.

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By the time all the thinned plaster, dissolved cardboard pieces and cloth net remains were removed, the tube was sanded properly, washed and attached by using cyanoacrylic glue on the F-16 lower fuselage "mouth" housing. Epoxy putty and polyester filler used to close the huge gaps.

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omg..this is awesome....excellent work so far...i'll definately be watching this as it progresses

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After proper sanding, this is how the air intake looks like

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Using plastic card, I formed a 1 inch wide ring and placed it to the air intake tube's end, in order to fit perfectly the Pratt & Whitney F100 turbofan engine's 1st stage blade fans structure, which displayed earlier. Epoxy putty filled the gaps and formed the tube's end diameter to a perfect circle.

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As it is well known, the Block 52 F-16s (using the Pratt & Whitney F100-PW 229 afterburning turbofan engine) air intake shapes are not the same with older "big mouth" F-16 versions such as Block 30 and Block 50 (using the General Electric F110-GE 100 afterburning turbofan engine) also used by the Hellenic Air Force Squadrons. The newest Block 52s have a larger nose tire which required the intake to be reshaped to accomodate the new tires size. For this reason, the Block 52 F-16's newer air intake have a noticeable bump about 4 feet in on the lower surface.

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CHAPTER III - Engine's afterburner area construction

Starting to work behind the engine's last stage blades and the afterburner's spoked frame, I had to simulate in scale the inner embossed detail on the afterburner's area. Following the exact blueprint plans of the T.O service manual used for the real F-16 and after converting numbers to 1/18 scale, I did calculate the AB area dimensions, cut a piece of plastic card, fold it to cylinder and reinforce it externally with plastic bands, to ensure that it'll keep in shape. This cylinder is the base to host the inner embossed detail on the afterburner's area. As soon as the base cylinder was ready, I opened randomly more than 30 holes, using a 2mm drill - the reason will be explained into following lines.

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Having a couple of different methods in mind to simulate in scale the inner embossed detail on the afterburner's area, but knowing that the following method is much accurate to scale and easier to re-do if something goes wrong, I tried a visit into my local PC store and searched for a cable tape used into PCs to connect the motherboard with the HDs or CD/DVDs etc and transfer data between them. I found a plenty of PC cable tapes, but I finally got one with intense embossed detail between the cable lines. After calculating the base cylinder's inner circumference, I cut the brand new cable tape on exact length, sprayed it with light gray base coat and placed it carefully into the cylinder, trying to avoid folding marks on the cable tape surface.