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Boom (YC W16) – Supersonic Passenger Airplanes

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Re: Boom (YC W16) – Supersonic Passenger Airplanes

#451

Post by lmm »

Xixi wrote: post #449
diskcat wrote: post #441

Earlier quoted context omitted.

To fly supersonic you need an engine that is very powerful at supersonic speed. VTOL requires an engine that is powerful at low speed. The harrier jump jet, a most famous VTOL aircraft, didn't have supersonic capability when all its contemporaries did and can only take off vertically with reduced payload or it would burn all its fuel just taking off. While I don't have the numbers I think VTOL supersonic aircraft wou…

The F35-B is both supersonic and VSTOL [1]: very hard indeed, but done. Just like the Harrier, the F35-B probably doesn't take off vertically with any significant payload though. [1] https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning...

The F-35-B has essentially two different types of engine (the main engines and the lift fan) to make that work.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#452

Post by learc83 »

rohit89 wrote: post #405
nharada wrote: post #142

Earlier quoted context omitted.

I agree, this is an insanely hard problem to solve. There are dozens of companies with tons of capital and massive R&D budgets that haven't already done this, presumably because they either think it's too hard, the regulatory hurdles are too high, or the market is not ready. Why can this startup do what they can't?

...because they really want to do it? If there's one thing I've learnt, looking at what the big companies are doing/didn't do is a really bad metric for things like this. If this was a company started by Elon, perception of this company would have been totally different.

That's partially because Elon was already massively rich and was able to attract even more money because he was investing so much of his own.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#453

Post by designtofly »

jasonwatkinspdx wrote: post #353
jandrese wrote: post #298

Earlier quoted context omitted.

That link didn't make me feel much better. They're planning to "tweak an off the shelf engine for supersonic speed". When I hear off the shelf engines, I think turbofans, but no amount of tweaking is going to make a turbofan work at supersonic speeds. It's possible they can get some military grade afterburning turbojets from somewhere, but it's not something you can buy off of the shelf. Their webpage has a bunch of…

> but no amount of tweaking is going to make a turbofan work at supersonic speeds Sure they can. It's the inlet's job to slow the flow to subsonic. Turbofans have been used on supersonic military aircraft since the 1960's. Go read about intake ramps. Then learn about diverterless supersonic intakes. You're yelling scam pretty loud for someone that clearly doesn't know basics of the topic area. Edit: My guess is the e…

But those intakes don't work for free. You will encounter huge losses and drag penalties. And military jets aren't designed to fly 3500 miles supersonically the entire way. The vast majority of miltiary jets have a maximum supersonic time that can be measured in minutes.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#454

Post by lmm »

nether wrote: post #227
paulmd wrote: post #166

Earlier quoted context omitted.

Seriously. People here are way underestimating the costs to develop and certify a major commercial airframe, especially across the multiple regulatory regimes inherent to international flight. You're probably talking about on the order of a billion dollars even if you're playing it cheap. If you want to start re-engineering components instead of buying off the shelf, that number will go uphill rapidly. This is not a…

How many people did SpaceX start with? Certainly not the thousands of workers it has today. Everything you said about requiring a "national scale corp" was said about launching rockets to orbit as well. Looking at Boom's roster they have some seriously experienced industry vets working for them or advising them. This isn't just fresh grads. They've been through FAA/EASA cert trials of new aircraft, testing and unders…

SpaceX very nearly didn't make it. One more F1 failure and they'd've been out of business.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#455

Post by mark-r »

mathattack wrote: post #450
mark-r wrote: post #401

Earlier quoted context omitted.

SF to NYC seems unlikely; the sonic booms from the transition between subsonic and supersonic are disruptive enough that they're essentially banned over land areas. Edit: I'm informed by other comments that the boom occurs the entire time you're supersonic, not just during the transition. That makes it even worse.

Interesting. I assumed there could be an engineering way around the boom, but it's not my specialty. I'll have to settle for easier access to Honolulu and Tokyo. :-)

As I've read through the thread, I see that there are efforts to make the boom quieter. Physics won't allow it to ever go away completely, but the hope is that it might be taken down to an acceptable level so that the laws banning overland supersonic flight could be retired. Laws don't change easily though, especially when there are entrenched airlines who would not welcome any new competition - they'll be lobbying against it for sure. I wouldn't be in line for a ticket just yet.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#456

Post by pacaro »

fernly wrote: post #334
Pyxl101 wrote: post #203

Earlier quoted context omitted.

Exciting work! I'd be glad if supersonic flight was a reality again. How do you plan to tackle the challenge of opposition to supersonic flight? Overland supersonic flight has been banned in US and Europe because the loud noise of sonic booms annoyed residents that the planes flew over. Coastal residents continued to object to supersonic flight. Is there a path to offering transcontinental flights again, and if not,…

Nostalgia... In the 70s I lived in a London suburb that was under one of the approach paths to Heathrow, and could always tell when Concorde was passing over on final. Its sound was many decibels above a 747 and had a harsh, rock-crushing quality.

Indeed. I lived in Reading from 79-82 and remember that school essentially paused everytime that Concorde passed overhead because you couldn't hear anything that was being said in the classroom for a couple of minutes

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#457

Post by SeeDave »

bscholl wrote: post #208
Pyxl101 wrote: post #203

Earlier quoted context omitted.

Exciting work! I'd be glad if supersonic flight was a reality again. How do you plan to tackle the challenge of opposition to supersonic flight? Overland supersonic flight has been banned in US and Europe because the loud noise of sonic booms annoyed residents that the planes flew over. Coastal residents continued to object to supersonic flight. Is there a path to offering transcontinental flights again, and if not,…

Thanks! We are very excited to be doing this. We're starting out focused on long flights that are mostly over water, like New York - London or San Francisco - Shanghai. Around an airport, our airplane will be about as quiet as other new aircraft. The sonic boom will also be much quieter—and we'll continue to make future iterations even quieter. It's hard to say exactly when, but I expect the supersonic overland ban w…

Curious about next steps once you've built the plane. It seems that you're core mission is commingled somewhere between "building Concorde 2.0" and "offering incredibly fast trans-ocean travel."

Many personal questions that you can ignore at your leisure:

Do you plan on operating an airline? If not, will you work with GECAS and/or ILFC directly or offer vendor financing? Are you open to partnering with an unconventional such as Virgin, Southwest to build out their international capacity, or a startup airline? It would be amusing (in a good way) to see Ohanian leverage his experience in travel at Hipmunk into operating a fleet of your jets.

Your idea is amazing and I have complete confidence in your ability to build a ridiculously fast jet. Looking forward to seeing your next steps in putting passengers in seats!

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#458

Post by SeeDave »

putzdown wrote: post #319
bscholl wrote: post #192

Hi - I'm Blake, Founder/CEO at Boom. After watching no tangible progress in supersonics since Concorde was shut down, I started Boom because I want supersonic flight in our lifetime. Not just as a private jet, but something most anyone can afford to fly. Will try to answer as many questions here as I can.

Terrific premise; I hope you succeed. But advice: 1. "boom" is not the right name. Explosions. Annoying/scary sonic boom. These are not the associations you're looking for. Try "glide," "zip"—something along those lines. 2. In your very first team picture I see a grumpy-looking fellow with hands in pockets. A few images on he's still there, now joined by another grump with crossed arms. These people look disengaged a…

>2. In your very first team picture I see a grumpy-looking fellow with hands in pockets. A few images on he's still there, now joined by another grump with crossed arms. These people look disengaged and/or disgruntled. Call me shallow, but it just doesn't look right for a team supposedly revolutionizing aviation. Ask your team to look engaged when taking PR photos. Or if there's a deeper attitude/team dynamics issue there, man fix it now. I don't want my life "booming" into oblivion because some guy was fed up.

I too have found that grumpiness and negativity are so toxic, counterproductive, and worse than useless that they are up there in terms of dealbreakers.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#459

Post by Retric »

pjc50 wrote: post #438
lmm wrote: post #429

Earlier quoted context omitted.

An engine is just a mechanism for converting stored energy into forward motion - the details are, well, details. There's nothing wrong with propellers (probably impellers will be more efficient), and those efficiency numbers are (presumably) including that.

No, the details are completely critical to making it work! I'm kind of surprised that Elon Musk, who clearly knows his stuff in rocketry, is handwaving the difficulties of an electric jet. Personally I see it as far more likely that we'll continue to use conventional aircraft but start synthesising fuel from renewable energy. The US Navy is already looking at doing this to make jet fuel from spare carrier nuclear pow…

You can get supersonic by having air intake, expansion chamber, blade, high pressure chamber, exhaust port.

Think something like this:

Importantly the air flows through the compression chamber at Subsonic speeds.

PS: While simplified this is the general approach for low mach speeds as burning stuff in a supersonic combustion chamber is much more difficult.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#460

Post by aninhumer »

mikedouglas wrote: post #383
jacquesm wrote: post #343

Earlier quoted context omitted.

> It worked NY/London but at ~$20k/seat they couldn't fill enough seats several times daily on other routes. Your price is way off. http://www.airliners.net/aviation-forums/general_aviation/re...

From the link: "In the late 1990s I paid $11,000US each for several round trips." That's about $16k when accounting for inflation, so $20k isn't too far off.

Without qualification, I'd assume they were quoting historical prices. It would be pretty confusing to present any kind of adjusted figures without clarifying them.
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