The Need For Speed


Latest iteration of the Aerion AS2 (I think. There’ve been a lot).

This is disappointing:

Aerion Corp. today ceased operations, citing a lack of available financing for its plans to bring a family of supersonic aircraft to market. In a statement, the company said it had built an $11.2 billion backlog for the first of that family, the Mach 1.2 AS2 business jet, but “in the current financial environment, it has proven hugely challenging to close on the scheduled and necessary large new capital requirements to finalize the transition of the AS2 into production. Given these conditions, the Aerion Corporation is now taking the appropriate steps in consideration of this ongoing financial environment.”

-AIN Online

Possibly related: last fall, Boeing suspended its NeXT “future innovations” unit. While not directly tied to Aerion, it’s indicative of Boeing’s cash crunch and the need to refocus on its core competencies (that is, building airplanes that don’t crash). Between the 737MAX and COVID, they’re not in a position to throw billions at projects that might never make it to the runway.

I really hoped they could be successful, but it’s also been in development for close to twenty years so it was hard to get too excited.

Making airplanes go faster presents all kinds of technical challenges as you approach Mach 1, and it’s not as simple as adding more wing sweep or bigger engines. One design choice affects other choices downstream, and sometimes those trades can’t be resolved to anyone’s satisfaction. A lot of tradeoffs that are useful for military jets don’t translate well to civil transports and the FAA’s Part 25 certification standards. Adding speed adds complications like wave drag, and the optimum ways to solve it sacrifices performance at lower speeds, which is crucial to controllability in takeoff and landing (and a big focus of those Pt. 25 standards I was talking about). Example: a clipped delta wing is great for high-speed cruise but terrible for takeoff, approach and landing. Maybe you can mitigate this with more power from the engines, but now you’ve created a noise issue that cannot be ignored if you ever want to get the thing certified to fly anywhere civilized.

This really made me wonder about Aerion’s plans for a Mach 4 jet. While that puts it just shy of hypersonic (and the related heating / materials problems), that’s still pretty freaking ambitious when they hadn’t even cut metal on the “slow” Mach 1.2 version.

Finally, before anyone is willing to spend serious money on overcoming the technical challenges, there’s this hurdle: convincing Congress and the FAA to rescind the prohibition on supersonic flight over land. Without that, the business case may never close. It’s a huge chicken-and-egg problem when you consider the newest business jets regularly tickle M.90. Once you’re already at 90% of the speed of sound, adding another 20 or 30% might be too expensive to be worth the trouble. But man would that thing look cool on the ramp.

Having said all that, this is a setback I hate to see. Hopefully Boom doesn’t suffer the same fate.

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