This is What it Takes to Create a Mini Personal Jet

The heart of John Monnett has always been beating as a jet pilot. Nearing his 50s, the only way he could realize his dream was by building his own aircraft. Fortunately for Monnett, he is the founder and president of Sonex Aircraft, an Oshkosh-based kit builder company.

Some of the popular offerings from Sonex Aircraft include Xenos-B, Sonex-B and OneX.

At the recent Sun ‘n Fun, Monnett was convinced to talk about SubSonex, the single-engine jet kit from the company. It didn’t required much convincing to make him to talk about the making of this new aircraft.

Monnett, goes down his memory lane as he started to talk. His interest in a jet goes back to the early days of airplanes from Jim Bede, including BD-5 Jet. This plane was used in James Bond movie Octopussy in 1983.

The aircraft was beyond the reach of most people, as the cost of engine alone was $150,000 and this was 35 years back, says Monnett. He recalls that BD-5 Jet was a cool machine. A thought came in his mind, that many more pilots would want to own a jet, provided it is within reach.

A few decades later, Sonex just created its first motor glider, Xenos. What else can the company do, he wondered? After some time, Monnett studied about electric propulsion and he along with his co-designer Pete Buck noticed the condition of the present model aircraft industry.

They heard about a jet engine that can put out 150 pounds of thrust, and they starting working on some designs and numbers to make some sense with a jet engine, Monnett recalled.

During that time, there was no way to actually control the engine, but they were almost ready with the airframe. They realized that they are still in the middle on nowhere.

The “Eureka” moment for the Sonex team happened when they heard about a small jet engine from Czech Republic that could produce 250 pounds of thrust. Finally, SubSonex got certified by 2009. Still, there were one or two things missing which was keeping the aircraft short of expectations of thousands of people at Sun ‘n Fun and AirVenture.

To begin with, the aircraft was certified for a single wheel gear, which according to Monnett was one of the dumbest ideas they ever had. When the tail dragger was leveled, it changed the position of fuel tank. Fuel tank baffles were added to overcome this problem.

The second problem was with the high thrust line. The tail would rise early even before the aircraft is ready to fly when takeoff power was added. In such situations, the pilot had little control over the direction of movement of aircraft.

Monnett explained with a big grin that in the beginning he made a number of excursions crossing taxiways, dodging lights, but fortunately with no big damage to the aircraft. It was only on one occasion that a hole was punched in the fuselage.

The Sonex team analyzed that the aircraft required a traditional main gear and a nose wheel. This modification happened just around where the aircraft was punctured by John. Changes in the original design almost resulted in the JSX-2 SubSonex that the company is selling these days.

The single-engine jet from Sonex was the result of Monnett’s dream to fly a jet. When it was time to earn the Letter of Authorization from FAA, the aircraft need to be flown solo, but Monnett had no experience in jets.

Monnett had to convince the FAA that he will safely fly the airplane which has been the outcome of his dream.

Was it worth waiting so long?

Monnett found his make quite easy to fly, even though it was bumpy on the first day. Once the aircraft is off the ground, the ride is pretty comfortable all the way up to 250 knot.

At 92% power, the aircraft cruises at nearly 230 knots. You can be in air for nearly 2.5 hours with a 40 gallon fuel tank. The Fadec controlled engine burns nearly 17 gallons of fuel in an hour.

At present, five SubSonex are already in operation and another nine are in different stages of construction. The price tag for quick-build aircraft kit is $47,000, and for the engine costs $55,000, a few more thousand need to be spent for avionics. You own jet will be ready in around $130,000.

Matters of heart finally realized. Monnett names the SubSonex as “his personal hot rod”. There is only one problem that is not taken care of still. “Flying a jet is really cool. He is so spoiled now that only he wants to fly is a jet.”

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