Prototype Explorer Displayed at EAA AirVenture Oshkosh 2019


A visiting airplane from Europe was tucked into a corner of the display area at the EAA’s 2019 AirVenture. It wasn’t surrounded by a splashy pavilion nor potted plants and chairs and tables, but this lone aircraft, which made a trans-Atlantic flight just to get to the annual EAA convention, made a big impression on this EAA member and journalist. The NF Explorer is a newly-designed STOL turboprop aircraft equipped for back country flying, and designed by a trio of aviation enthusiasts.

The concept was hatched by Frank Koinzer, a professional European airline pilot who is flying Airbus A-340-600s for a living. He is no stranger to aviation, as he began flying at age 15, and has continued “aviating” ever since. Frank attended his first EAA AirVenture/Convention in 1999, flying his Robin DR40/180 across the Atlantic Ocean from Germany… no small feat for a light single-engined aircraft. Twenty years later, he flew his rugged Explorer prototype across the same seas; after leaving mainland Europe, his stops included the countries of Iceland, Greenland and Canada before arriving at Oshkosh Wisconsin.

Looking to broaden his aviation experiences, he began flying into the “backcountry” of different continents, and planned to visit places like Alaska and other North American frontiers, as well as areas of South America and Africa. He looked at aircraft like the de Havilland Canada DHC-2 Beaver, the larger DHC-3 Otter, and Cessnas like the C206 Stationaire, but they didn’t meet his long range needs for flying into remote, rugged regions. He wanted something that ran on Jet fuel (which is more plentiful in those areas, it seems), STOL capabilities, and a “reasonable cruise speed and a spacious interior cabin”. None of those aforementioned aircraft met all of the needs in one airframe/powerplant combination.

Accordingly, he began to design an aircraft that would meet all of his needs. Soon, he was joined by 2 certified aircraft engineers, Jirka and Hans. Together, they designed a large, high-winged, single engine turboprop plane with plenty of room and short-field capabilities. Part of the complex job of designing an aircraft was a welcome challenge to Frank, as in his own words, he is “addicted to making sophisticated details work, that were not always easy to join”. Looking forward, the design would be certified to FAR 23 requirements, although it would be built as an experimental homebuilt.

The fuselage is built within a mold, and ultimately becomes one large piece. The wings are made separately, and their design was certified by building a concept example, which successfully survived a test to 183% of its design load without failure, at the University of Prague.

Various friends and associates have pitched in their talents and assistance, such as for the custom designed wheel and brake system… the wheels are machined out of a block of aluminum and fitted with a titanium brake caliper.

“Now we almost can’t believe what an extraordinary aircraft we have created, we are overwhelmed by the response from all sides, and we are eager to share that amazing flying machine with other backcountry flying enthusiasts” says Frank.

The aircraft example is the first prototype built, its cockpit instrument panel was installed and fitted with a trio of large multi-function displays. A pair of sleek seats carry two people comfortably, and there’s no control yolk… there are control sticks instead. Two motorbikes were shown in the rear cabin of the aircraft to show how large the interior space of the aircraft is. There were tracks for additional seats, but none were fitted during our visit. Complete with a U.S. registry sponsored by a New Mexico company, this is the first of (hopefully) a number of kits that will be furnished to buyers to complete and customize for themselves.

Aircraft information via NF–aircraft brochure. 

For more information on the new Explorer, you can email Frank Koinzer at: .

Ken Kula

Assignment and Content Editor, writer and photographer A New Englander all of my life, I've lived in New Hampshire since 1981. My passion for all things aviation began at a very early age, and I coupled this with my interest of photography during college in the late 1970s. I spent 32 years in the air traffic control industry, and concurrently, enjoyed my aviation photography and writing adventures, which continue today. I've been quite fortunate to have been mentored by some generous and gifted individuals. I enjoy contributing to this great site, and working with some very knowledgeable and equally passionate aviation followers.

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