DarkAero’s Composite Kitplane to Flight Test in Spring 2020

Wisconsin’s Karl Brothers planning big things for DarkAero in 2020.

DarkAero 1 prototype
Keegan, River, and Ryley Karl with their DarkAero 1 prototype at Dane County Regional Airport, Wisconsin.DarkAero

The three-brother team of Keegan, River, and Ryley Karl came up with the idea to develop a better composite kitplane several years ago while helping Ryley to construct a Cozy Mark IV kit airplane shortly after graduation from college. All three have degrees in the fields of aerospace, electrical or mechanical engineering, and they were working full-time as engineers between 2014 and 2017 before quitting their jobs and launching DarkAero, their kitplane company.

DarkAero’s first model, their DarkAero 1 kit, is nearing completion now and will begin flight testing in Spring 2020. Not only is the kit designed for speed and range, much thought has gone into making the kit an easier, more efficient build, eliminating many of the barriers that composites can present when used in airplane construction.

“Through frustrations and long days of sanding on Ryley’s Cozy, we had a desire for an aircraft that was more refined, efficient, and optimized using the best materials for the job," said Keegan Karl. “We also had a desire to improve the build experience, as composite kits have so many advantages as a material for aircraft performance, but the approach for constructing them as a builder felt dated and inefficient.”

Keegan Karl explained some of the big things that excite the brothers about the aircraft beyond its performance. “The manufacturability of it and ease of build for the customer is important,” he said. “On the builder end, we are eliminating the filling and sanding work that is typically found with composite kits. All the layups and tricky composite work are done by our team. The builder is just responsible for bonding, bolting, or riveting sections together, and it won't require any special jigs/fixtures. We developed an approach we call Hollow Grid, creating our own carbon fiber honeycomb panels in house to make the internal structures for the ribs, shear webs, and fuselage bulkheads.”

The two-passenger DarkAero 1 is a tricycle, retractable-gear airplane designed to have a cruise speed of 275 mph with 1,700-sm range and a 750-pound useful load. The airplane will be G-rated to +6/-3 G, and will offer a 2,500-ft/min rate of climb behind the 200-hp UL Power UL520iS engine. “The airframe of the DarkAero 1 is designed specifically around the UL520iS engine, because it is significantly lighter and smaller than traditional aircraft engines of the same horsepower. The engine’s low weight and tight packaging make for a light aircraft with very little drag,” Keegan Karl said.

The brothers are EAA AirVenture regular attendees and began “flying” early in life when their dad would take them to Ace Hardware in town to buy balsa-wood airplanes. “We grew up on a farmhouse out in the country, and when you live out in the country, you need a way to stay entertained and excited, so airplanes and aviation became an outlet for us. During our many visits to EAA AirVenture, we were always looking for new kit aircraft attempting to push the limits of speed, range, and efficiency by leveraging the latest tools, materials, and technology. However, we never saw anything that caught our eye. It was there that our desire to begin DarkAero and design our own kitplane originated,” Keegan Karl said.

DarkAero is 100% owned and funded by the Karl brothers, a conscious decision designed to maintain control of the company vision and to “help fuel risk-taking, creativity, and attempting new things that hadn't been seen or tried before with kit aircraft.” As engineers, they have manufactured much of the large production equipment themselves, including a 24-foot cure oven for curing the airframe components up to high temperatures. “We looked first at buying an oven, but after we got the quote, we decided to just build one ourselves. The cure oven is a good example of how we have been able to self-fund. By doing nearly all of the R&D, production mold manufacturing, and even large production equipment builds ourselves, we've been able to keep costs low,” Keegan Karl explained.

The projected price for the DarkAero 1 kit is set at $79,900, which includes the airframe, canopy, engine mount, landing gear, and control hardware plus fittings and fasteners. Once the UL Power 520iS engine, avionics, propeller, wheels, brakes, and paint are added, DarkAero said the completed cost is expected to be $140,000 to $160,000.