This Incredible Plane: Otto Celera 500L

Merriam-Webster defines a virtuous cycle as a “chain of events in which one desirable occurrence leads to another.”

In summer 2020, the world was introduced to an unusual looking airplane that sported long, thin, high-aspect-ratio wings, a 12-cylinder diesel engine complete with a five-bladed pusher propeller, and a rotund fuselage that could pass for an elongated egg. 

This glistening white vehicle with its silky-smooth skin is the Otto Celera 500L. 

Unlike many new aircraft concepts introduced to the public before ever turning a wheel, the Celera 500L had already flown 31 test flights out of the former George Air Force Base in Southern California. 

During its public introduction, inventor William Otto explained that the Celera 500L utilized laminar flow in its long, thin wing as well as its egg-shaped fuselage to reduce overall drag by 59 percent. This dramatic drag reduction reduced the power and fuel quantity required and increased the range and performance of the aircraft significantly. 

This meets the definition of a virtuous cycle. So where did this all begin? Like so many overnight success stories, it took well over a decade. 

Otto, a former research scientist at Los Alamos National Laboratory and chief scientist at North American Aviation, formed Otto Aviation in 2008. His goal was to develop a significantly more efficient general aviation-based aircraft, which could compete favorably with business jets. 

Working with a small but dedicated team, the first proof-of-concept vehicle flew in September 2018, powered by a 550 hp Red A03 V-12 turbocharged diesel engine driving a five-blade pusher propeller. This European Union Aviation Safety Agency-and FAA-certified powerplant runs on diesel fuel or jet-A, and its two banks of cylinders, canted at 80 degrees, can operate independently, providing twin-engine redundancy. 

So how does this relatively small powerplant push a six passenger airplane at near business jet speeds and altitudes? 

Laminar flow is not a new concept. The North American P-51 Mustang featured a laminar-flow wing, which allowed its outstanding performance and long range. Several current jets employ laminar-flow wings. 

The Celera 500L took this concept a step further by applying laminar-flow principles to the long, slender wings, as well as the bulbous fuselage. The composite construction of the prototype created the exceptionally smooth surfaces required to sustain laminar flow from nose to tail. 

The reduced fuel capacity required by the thrifty diesel engine allowed all fuel to be contained in the fuselage, which, in turn, allows for a thinner, low-drag wing. The pusher propeller is intentional and allows smooth airflow over the entire airplane. 

The proof-of-concept design featured nearly horizontal flight deck windows and no cabin windows. While plans for follow-on models contained cabin windows, the lack of them on the prototype highlights the fact that laminar flow depends on smooth and undisturbed surfaces. 

The unique Red AO3 powerplant is cooled through two scoops molded into the top of the aft fuselage. These bring in cool air, heat it through the radiators, and exhaust it out the rear, in the same way the P-51 Mustang’s iconic belly-mounted scoop reduces cooling drag. 

The result of this effort is a composite airframe powered by a turbo diesel piston engine, with the potential to carry six people over 4,000 miles at well over 300 knots (400 knots true). By the time flight testing wrapped up in 2021, 51 test flights, totaling 55 hours of flight time, had been completed. 

Then, with the world in the midst of COVID-19, the Celera 500L seemingly disappeared from public view. Rumors surfaced of a production version and two follow-on airframes. Additionally, hydrogen power was considered. The truth is that the Otto Celera 500L was in reality a technology demonstrator. 

As of 2025, Otto Aviation is alive and well. However, this time the laminar-flow fuselage and wings are to be mated to two turbo-fan engines. This next iteration of the Otto design, dubbed the “Phantom 3500” (originally the Celera 800), updates the original design with jet engines and swept wings. 

The spacious egg-shaped fuselage is retained, which allows for more cabin volume and passenger comfort. Once again, the attention to drag reduction allows designers to opt for less thirsty engines, reduced fuel capacity, lower gross weight, and longer range. The piston-powered Celera 500L boasts sub-$400–per-hour operating costs. 

Likewise, the Otto Phantom promises 3,500-mile range, a 3,500-foot balanced field length, and an over 40 percent reduction in fuel consumption. 

As previously noted, the Celera 500L prototype had no cabin windows. Laminar flow is particularly hard to achieve and maintain if the surface is disturbed by protrusions, joints, undulations, or even dirt and debris. 

The Phantom 3500 solves this problem by replacing the passenger cabin windows with large, high-definition, in-cabin video displays. These are not new to commercial aviation, having been used in high-end, first-class cabins, but they resolve the issue of drag and disturbance caused by the cabin window joints. Thankfully, the pilots still get real windows to look for other traffic and for taking off and landing. 

To be sure, the Phantom 3500, currently in the design process, is still a “paper airplane,” and the road to certification of any new aircraft is paved with unexpected costs, delays, and outright failures. It takes a lot of time, money, and patience to succeed. 

However, the piston-powered Otto Celera 500L is the real deal. Looking like something out of a science fiction magazine, it was conceived with GA materials and techniques and exploits the concept of laminar flow to bring entry-level business jet performance to a piston-powered, single-engine airplane. 

The Celera 500L is a working example of imaginative design and a virtuous cycle.