Celera 500L
Flying|December 2020
Fact or fiction?

For the past three years in the aviation press, occasional spy photos have appeared, showing an unusual blimplike airplane parked at the former George Air Force Base, now Southern California Logistics Airport, near Victorville, California. This oddity has now made its formal debut. Its name is Celera 500L, and it is a product of Otto Aviation.

Otto makes impressive claims for the Celera, notably that it will cruise at 400 knots at 65,000 feet and have a range of at least 3,900 nautical miles. Powered by a diesel engine and burning jet fuel, it’s said to be eight to 10 times more efficient than comparable jets, to achieve a carlike 25 or so miles per gallon and a 22-to-1 glide ratio.

As I write this, very few specifics about the physical characteristics of the airplane have been published—other than that it accommodates 6 passengers in a spacious cabin with a stand-up center aisle. Its circular fuselage is about 78 inches in diameter and 35 feet long and has the profile of a laminar-flow airfoil section (something similar to a NACA 67-018). The aft-mounted engine drives a multibladed propeller whose diameter seems to be about the same as that of the fuselage. It appears that the elliptical wingspans about 55 feet. If the airplane weighs 7,000 pounds—just a guess—it would require at least 210 square feet of wing area to achieve the FAA-mandated 61-knot stalling speed for single-engine airplanes. That implies an aspect ratio of about 14.

The German-manufactured 374-cubic-inch, 12-cylinder Red A03 engine is rated at 500 hp, using jet fuel. The dry weight of the engine is 800 pounds; radiators and accessories would add a hundred pounds. Its specific fuel consumption is 0.35 pounds per horsepower-hour; this represents a 17 percent improvement over the 0.42 of comparable spark-ignition engines, as well as a 47 percent improvement over a Pratt & Whitney PT6. According to Red Aircraft’s website, a version with two stages of turbocharging can operate at up to 50,000 feet, but its critical altitude— the highest altitude at which it develops rated power—is 25,000 feet.

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