This Plane Does Not Fly, It's Ugly Enough to Repel the Ground

We are seeing some interesting claims about the performance of the Celera 500L Aircraft, which is expected to make its first flight in the near future.

They are claiming a cruising speed of in excess of 460 mph and a maximum altitude of at least 65,000 feet, all while achieving something on the order of 30 miles per gallon of fuel.

They plan to achieve this with two 500 hp liquid cooled piston engines.

I call bullsh%$. That sort of performance would require some changes to the laws of aerodynamics, if just because the performance that they are claiming would require :

More than two years after The War Zone was first to report on a mysterious bullet-shaped aircraft appearing at the Southern California Logistics Airport near Victorville, a refined version of the plane has conducted taxi tests and looks to be getting close to its first flight. Even though much about its design and purpose remain unclear, we do know now that the aircraft, which is called the Otto Aviation Celera 500L, is definitely focused on potentially game-changing high-efficiency flight that has the potential to disrupt the aerospace marketplace.

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"Such a transportation system requires a unique aircraft. It must be capable of operation from any current airfield," one of the patent documents says in its background section. "Preferably, it would have operating costs well below current costs and competitive with commercial airliners, cruise at higher system speed than current commercial aircraft, have a longer range with full passenger and luggage load than most current business aircraft, provide passenger comfort comparable to commercial aircraft, and be capable of all weather operation. The plane should also provide for ease of maintenance and require only a single pilot."

The patent goes on to describe a notional aircraft that would cruise between 460 and 510 miles per hour at an altitude of up to 65,000 feet, yielding a fuel efficiency rate of between 30 and 42 miles per gallon. To put this in perspective, the Pilatus PC-12, a popular light, single-engine turboprop aircraft has a service ceiling of 30,000 feet, a cruising speed just under 330 miles per hour, and still burns, on average, 66 gallons of jet fuel per hour, for a fuel economy of roughly five miles to the gallon. Even going to a Learjet 70, which has similar speed performance to what's stated in the Celera patent documents, but still nowhere near as high a ceiling, we are talking about roughly three miles per gallon of gas at cruise. So, Otto Aviation is talking about performance that is at least 10 times more efficient than existing light business jets with similar cruise capabilities.

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One of Otto Aviation's patents also says that the intakes and exhausts we mentioned before are supposed to help leverage this engine design to provide even greater efficiency. The exhaust setup is also supposed to include a novel heat exchanger that combines heated cooling air with exhaust gases provide a small additional boost in thrust. It all remains to be seen whether or not the combination of an A03 optimized for the Celera 500L specifically, together with intercoolers and specialized exhausts, will be enough to get the plane anywhere close to the kind of high-altitude performance Otto is clearly aiming for broadly

Just a few notes from my decidedly non-aerodynamicist  perspective:

• For the speed and altitude that they are targeting, we are looking at about ¾ Mach, which means that you are going to see transonic effects.
• There are no provisions for area ruling to prevent shock wave formation and the resultant drag rise.  (i.e. area ruling)
• The propeller is unswept, and at the speeds that they are talking about, the tips would (again) lose efficiency at high mach numbers.

I can see this as offering similar performance similar to something like the the Piaggio P.180, but that is about 100 mph slower and 20,000 feet lower altitude.  (As an FYI, the fuel sipping P.180 gets about 9 mpg)

Reliability would probably be lower, as pistons are less reliable than turbines, and the payload would likely be less too, as piston engines are also heavier.

The claims are so outrageous that I expect someone on the management team to have a last name of Bede.