I’ve had the sport wing pack on the shelf for a while. I love the EVA Biplane, but wanted an option for something more sedate. Now things are settling after the move I decided it was time to start building!

Here you can see how small the wing pack is, just a few sheets of balsa. It always amazes me how it transforms into a complex and beautiful structure.

The first step is to build the leading edges. The manual tells you to build one wing first, then build an opposite. I preferred to build them at the same time, constantly checking to make sure I’m building mirror image. It really doesn’t matter how you do it, as long as you don’t end up with two left wings! (or two right ones).

I found the sheet for the leading edge support was slightly thicker than the holes in the leading edge pieces allowed for. A gentle pinch on each tab compressed them enough to allow easy assembly.

Here’s one leading edge assembled. At first the assembly seems to contradict common sense. However the smaller piece to the rear allows a step for the sheeting to sit in. Don’t worry it all works out and can be ‘sanded round’ with ease.

Here’s two of them complete.

Relieving spars and ribs from their carrier sheets came next. One of the sheets had considerable grain variation which meant that the laser had not cut all the way through some parts. This was easily solved with some careful cutting with a scalpel. Also, if the spars were used in the pairs they were cut in I would have had one wing (marginally) heavier than the other. I’ve swapped them about so each wing has one normal spar and one super hard spar.

Here you can see the strengths of a model designed with CAD software and laser cut such as the Mountain Models products. Everything simply interlocks! It takes careful alignment and some gentle wiggling at first but you’ll end up with a strong and true structure.

Here’s two basic skeletons complete.

Next, the plywood doublers for the wing root and carbon wing joiner holes need installing. A word of caution here: hammer the blind nut on a block of scrap wood – it’s wider than the doubler! Look what I did to the laminex on our table :(

Sheeting the leading edge comes next. Be careful to keep the wing straight during this process. It gets very stiff once the bottom sheeting is on. Once the top sheeting is on you will never remove a warp if you’ve built one in.

I’ve read on RCGroups.com that others have tried using (full span) flaperons on their EVA Sports. From memory people reported undesirable pitching effects and negligible benefits. I’ve been wondering what dedicated, smaller inboard flaps would be like so decided to take the plunge. Modifying the wing at this stage will be easier than later on and give a neater finish. To do this I had to fabricate two new servo mounts, two new horns, chop up the existing ailerons and install new cross grain stiffeners where I separated the flaps from the ailerons.

I decided to add some wingtips to the square ends of the standard wing. Designed free hand according to what I thought would look good, I have no idea whether they’ll be any aerodynamic benefit at all. The intention is to make the EVA look a little like bit like the Spacewalker which I’ve always had a soft spot for.

Here are the completed wings, with flaps and ailerons ready for covering. Look, I made a left and a right one!

Finally the money shot. Who can resist a beautifully sheeted and sanded leading edge? I love sanding it round.

Click Here to see the wings Covered and installed.