Barry Kennedy and Vladimir Gavrilko explain Spread Tow Carbon
by Lee Estingoy [email protected]
Welcome to the Soaring column. This month, I have some interesting detail from two master builders.
Vladimir Gavrilko, maker of the Blaster, Supra, and Maxa, is now using a new type of carbon material: Spread Tow Carbon (STC), which is essentially a thin mat of carbon fibers. He contributed the following through his US distributor, Barry Kennedy of Kennedy Composites:
“STC was developed to overcome some of the disadvantages of woven carbon-fiber fabric. There is the complete absence of crimp, giving a better surface finish and no place for epoxy to accumulate, lowering the total weight of the composite parts.
“The fiber orientation is superior. The fibers can be lined up for maximum tension, or compressive qualities of the material can be utilized for the part.
“In 2010, we began a series of experiments on the creation of extra-light carbon fabrics. After numerous experiments, we managed to design and make a machine for flattening carbon fibers to the thickness of 0.02 mm. It has allowed us to create a biaxial fabric from extra-strength carbon-fiber tow. We achieved an ultra-light density of 38–40 g/m². We are now also making a triaxial fabric at 58 g/m². We use this fabric to make the parts stronger and highlight small details easily.”
This fabric is used in select versions of the Blaster, Supra, and Maxa models sold by Kennedy Composites. Vladimir, who is based in Ukraine, also sells the material to other modeling companies and firms that make sports equipment.
Jaro Muller
Interview
LE: Jaro, for as long as I can remember, you’ve been the name for exquisite composite airframe work. How long have you been in the business, and how did you get started?
JM: I started with model building in 1961 when I constructed my first airplane as a boy. Since then, I worked my way up to free-fly (FF) models and then to RC models in the ’70s. In 1978, I started to focus on the F3B contest gliders category. Back then, we had to manufacture all parts on our own, whereby I gained great practice in building the airplanes and I learned a lot about construction of models and their technology.
I built my first whole-composite model called Avant in 1985 with the great help of Ralph Decker from Germany. There was a big demand for this model, not only in my home country but also abroad. Avant was followed by Ellipse 1, which I launched in the World Championship of F3B in Paris. That was the breakthrough moment in my model-building career. Ellipse 1 was even more requested on the market than the previous one, which made me think of starting my own business. I launched my company in 1990, and by this the history of my operation in this business was started.
LE: Can you tell us a little about how the advancements of composite materials have changed your way of working or designing airframes?
JM: Composite materials caused a revolution in the model-building world. The whole construction philosophy changed and caused a great leap forward in the development and production of models. It was clear to me that the future would be in composite materials, and therefore I decided as early as 1985 to be among the first to use only this construction. Previously I had produced classical balsa models.
There has been a big advancement in composite materials over the last 20 years of my operation in this business. Much work has been done in the development of technology and the numerous ways of utilizing these materials. I think there is still room for some progress.
LE: How many hours do you estimate that it takes to make a modern Thermal Duration F3J aircraft? How many molds must be built to make a new one?
JM: The development of a model from the first thought till completion takes about two years. The first phase, where the philosophy and technology are created, takes the greatest portion of time—about one year more or less.
My goal is to bring an utterly original model to the market. The whole concept is very well thought out, which makes the development process time-consuming. The creation of a new thing is a long and hard process. The production of the molds and technology is a rather manual, less creative, and less complicated process, but still a full-time job for two people for less than one year.
Many models on the market are technologically similar to each other and they only differ in small details, which do not truly bring novelty. So, if you want to construct a real novelty, you must spend serious time and even be prepared to work in ways some consider old-fashioned. The R&D period—in the case of "copying"—is clearly much shorter. In my case, copying as a method of development is out of the question. I am still a model builder in my heart and not merely a businessman. That is why I don't make it easy for myself.
LE: How do you make the molds these days? Are they CNC? Do you do the CAD work yourself?
JM: I have the molds milled in Germany, including the CAD work. I only provide them with the technical base data.
LE: I remember a technique that you used with the Elita. You used multiple strips of material laid in the wing, running parallel to the span at such an angle that they connected the top and bottom wing skins. What happened to that? Why didn't that catch on in the modeling world?
JM: This technology was unique, but had its disadvantages because it was quite challenging for production. The wings were fairly heavy and crinkled in the heat after some time. We abandoned this technology for these reasons. However, the biggest advantage of this technology was the relative firmness of the wings.
LE: What sort of aerodynamic work do you do in the design of your aircraft?
JM: I try to design my models with the least possible influence from competitors' models. I also try hard to avoid making something very similar to the work of others. The main source of inspiration for me is observing birds. I still think they are one step ahead of us. Other helpers in the creative process are the feeling for model building and experience gained throughout the years. I am not concerned with any specific theories in a particular way.
LE: Where are you located? How big is your shop?
JM: My company is based in a rather small facility. The main building has around 100 square meters and it is the place where the development of new models, the final check of manufactured models, as well as packing and shipping, is carried out. Production is operated separately in a few family-run small businesses. The people who work for me are mostly former model builders.
I create the models, develop the molds and technology, produce the first prototypes, and subsequently hand them to the production companies, which manufacture the individual parts of the model. The final check and finish work of the products, as well as the shipping, is also done by me.
LE: Most Thermal Duration pilots in the US are familiar with the Espada. It is unique in a number of ways. The ones that jump out at me are the fully molded control surfaces and the incredible level of detail (such as servo mounts) that you put into them. What innovations does the new Egida offer?
JM: My goal is to increase the standard of my models, which also includes simplifying the finish work carried out by the customer and preventing any problems with the servo mounts. One reason for this approach is that the new generations of model builders are pilots rather than builders.
In my opinion, Egida is the biggest step ahead in this area. I used my experience from contest modeling. There are many different situations which occur during a contest where servos are damaged and need to be replaced as soon as possible.
I came to the idea of servo mounts as used for Egida. The replacement of a servo takes about one minute. I tried to make every detail as simple as possible, functional, and reliable. It may not look like it at first sight, but the creation of these details costs a lot of time and effort. I think I did well with Egida on this one.
The main goals that I set for myself for the construction of Egida were the following:
- Construct a model for an extreme-speed launch.
- Achieve autostability and easy controllability of the model at the same time.
- Concentrate the maximum achievable weight as close as possible to the CG, which provides autostability and sensitivity of the model to thermal gusts.
- Technologically optimize the model so that materials are used purposefully; for example, the wings are not full carbon—carbon is only applied where necessary.
LE: Do you still enjoy "fun" flying? If so, which airplane is your favorite to play with these days?
JM: Thank God I still have fun piloting the models, despite the fact that model building has been my main job for the last 21 years. Since my childhood, I have always preferred to fly the latest model that I constructed.
LE: What is your favorite airplane of all time—the one that left the biggest impression on you?
JM: Birds.
I have to admit that last answer caught me off guard, but the proof is in the product, and Jaro has quite a legacy of amazing products.
See you at the field!
Sources
Kennedy Composites (972) 602-3144 www.kennedycomposites.com
League of Silent Flight www.silentflight.org
Transcribed from original scans by AI. Minor OCR errors may remain.
