The high-pressure turbine (HPT) disk is the hottest and most critical rotating jet engine component. Designed for the highest cruise temperatures of any commercial engine, HPT is critical for Symphony. ⚙️🔥🧵

Warning - thread contains previously-unreleased hotsection pr0n For this first prototype, we're using Inconel 718-a nickel based superalloy.  Used everywhere from cryogenic tanks to Merlin rocket engines, this metal will survive the limited life expected in our first test article (for production we’re working on something even stronger)

Why do we think supersonic flight will work at scale on @boomaero Overture when it didn't on Concorde?

Here's the business case for supersonic—and a never-before-seen piece of Overture's design. 🧵👇

Only 14 Concordes >1,000 Overtures planned
Concorde failed because it was simply too expensive to reach a large market. 100 uncomfortable seats, $20k tickets. Even on the most popular route—NY-London—it flew on average half empty. Particularly with 80s/90s travel volumes, it was too big and too expensive.

Boom! We cracked it! Today we are introducing Boomless Cruise—supersonic flights up to 50% faster with no audible sonic boom.

We quietly (har har) demo'd this on XB-1's first supersonic flight—three times actually. 🧵👇 How did that work? It's actually well-known physics called Mach cutoff.
When an aircraft breaks the sound barrier at a sufficiently high altitude, the boom refracts in the atmosphere and curls upward without reaching the
ground. It makes a U-turn before anyone can hear it.

What's the connection between XB-1 and Overture? 🧵👇

How it's starting How it'll go
Early in @boomaero history, we sketched out the design for Overture. It was originally a ~32 passenger trijet.

But we knew we didn't know what we didn't know, and we wanted the opportunity to learn and iterate before building a full-scale supersonic passenger airliner.

1/ When I lived in California, I was in a neighborhood with particularly unreliable electricity. There were often outages affecting the whole street. 2/ When the power went out, everyone would go out on their front porch, look left and right and see if it was just them or the whole street.

1/ Heard about a Bell Labs researcher who went around asking his colleagues two questions:
1) What is the most important problem in your field?
2) Are you working on it?

These are good questions, and too often the answer to the second is “no.” 2/ hypothesis: there’s a bystander effect in how people choose their work: People ignore the most obvious approaches to the biggest problems—because they assume that someone else must already be taking care of them

1/ At tonight’s employee rollout celebration I asked @boomaero employees what they thought our odds of success were on the day they joined 2/ the answers ranged from 5% to 100%.

For me... I thought we had well under one chance in ten. At founding, I feared I’d never manage to assemble a team. Then I feared we’d never raise the money to accomplish anything.

1/ RIP, Steve. I’ve watched your interviews and keynotes so many times you feel like the mentor I never met. I hope you passed knowing you’d continue to inspire for years to come. 2/ Preparing for XB-1 rollout this week, I’ve thought often of the grandmaster of product introductions

1/ In the pre-founding days of @boomaero I worried “what do *I*—an Internet prod/eng guy—bring to the table?” 2/ My aerospace knowledge was limited to a private pilot’s license. I didn’t have the resume for the job—not even close.

A student emailed me "how do you build the future?" My response:

1/ Choose an important problem worth solving. Many large, unsolved problems are hiding in plain sight. We are so used to them we are blinded. Slow air travel. Jammed highways. Unaffordable health care. 2/ Invest your passion in the problem, not any particular idea of how to solve it; your first idea might not be right.