The guys over at Sonex Aircraft in Oshkosh, Wisconsin, have had a very busy year so far. After starting the year with the announcement of the first engine runs on their single seat DIY jet known as the SubSonex, the company has been busy with the development of another new single-seat airplane and improvements to existing models.

Unfortunately, similar to the development of other recent jet aircraft (787 & Joint Strike Fighter), even the little guys can run into a few hiccups along the way. The SubSonex is no exception.

After firing up the tiny jet engine for the first time last winter, the team at Sonex were excited to make the first flight in their single seater. But initial taxi testing uncovered some stability issues with the ground handling and the engineers went back to the drawing board.

At Airventure in Oshkosh earlier this summer, the SubSonex was back. Now it has a more stable tricycle gear configuration as compared to the single wheel/tail dragger configuration that caused concern during the taxi testing.

Sonex founder John Monnett remains committed to the SubSonex and says the issues facing the new jet are all part of the research and development process. The company runs the project out of its "Hornet's Nest," the R&D side of the hangar, sort of like a small scale Skunkworks.

“The challenges we face with the SubSonex perfectly illustrate our reasoning for unveiling this project under the banner of the Hornets’ Nest Research and Development program" Monnett says. “We have been very deliberate in not publishing timetables for development of the aircraft or guarantees of kit availability because there are no guarantees in R&D, despite our best efforts."

During much of the summer the jet project, which Monnett himself calls his "Walter Mitty" airplane, has been put on the back burner at Sonex while the company focuses on some of its other new projects including a more traditional piston powered, high-performance single seater. And a new turbo charged version of its Volkswagen based engine.

Like the SubSonex, the new OneX features just a single seat and promises a lot of performance. But unlike the jet, which could cost well north of $80,000 (though the company has yet to announce a price), the tiny OneX is expected to cost just $21,000 ready to fly.

Such a low price eliminates one of the main complaints of many pilots and would-be pilots, the cost of buying a fun to fly airplane. Sure there are a fair number of older, used airplanes that could be bought for the same price. But with the OneX you're getting a brand new airplane that is fully aerobatic and capable of cruising at 140 miles per hour.

"Obviously some assembly required," notes Sonex CEO Jeremy Monnett.

Like all Sonex designs, the OneX falls into the experimental category of home-built aircraft and can be flown with a light sport pilot license. The younger Monnett says most of their planes are built in about 700 hours. The single-seat OneX has fewer parts and combined with its smaller size it should take less time to build. Because many of the parts come ready to assemble from the factory, the DIY airplane doesn't require previous experience, Monnett says.

"You have to have a lot of motivation to finish a project like that, but you don't have to have a ton of skills."

The experimental moniker is actually a bit misleading as the airplanes aren't really an experiment. It's simply the term the industry uses to describe aircraft that don't fall under the Federal Aviation Administration's rules for factory-built and certified aircraft. There are tens of thousands of these kinds of experimental aircraft safely flying around the world.

Best of all with the Volkswagen-based Aerovee engine, the low-fuel burn keeps the cost low once you're flying, just four gallons per hour during typical cruise.

"Our airplanes are like little roadsters," says Jeremy Monnett.

The analogy is a good one. Like cars such as a Porsche Boxster or Mazda Miata, the Sonex airplanes are fairly minimalist and don't have any room to bring the family. But they are really well designed to head out and have a lot of fun on your own or with a friend.

And like many of the roadsters cruising the mountain roads and valleys, Sonex is no stranger to boosting the power. The company recently unveiled a turbocharged version of its Aerovee engine.

Still in development, the new turbocharged engine should be welcome news for pilots flying at high altitude or who find themselves needing power during take off on a hot day.

The stock Aerovee engine produces 80 horsepower. No word yet on how much additional power the system will provide.

Photos: Sonex, Jason Paur/Wired.com