Having said that, I'm a huge Concorde fanboy, and I really hope you guys can make affordable supersonic travel a reality!

Notwithstanding the accidents.

Have you thought about this idea, and in what time frame do you think someone might try to implement it?

Elon's basic idea is that air-breathing jets are limited to altitudes at which oxygen tops out, and then are mostly fighting drag from nitrogen. Electric ones can go to higher altitudes and experience less drag at much higher speeds. However wings designed to do that won't help you get off the ground, therefore you need vertical take off and landing. Which eliminates the need for a large airport, allowing you to locate more conveniently to major cities.

Unsure how much energy you'd save from the difference in drag, but I'd guess that significant improvements in electric energy storage would be required to make an electric plane doable.

[0] https://en.wikipedia.org/wiki/Kerosene#Properties [1] https://en.wikipedia.org/wiki/Lithium-ion_battery

A turbine after the combustion chamber steals some of the energy to move the compressor and the fan. Most of the air (>90%) just goes through the fan and bypasses the engine. You could argue that these engines are _already_ cleverly camouflaged propellers :)

https://en.wikipedia.org/wiki/Turbofan https://www.quora.com/How-much-of-a-jet-engines-thrust-is-de...

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 power:

http://www.nrl.navy.mil/media/news-releases/2014/nrl-fuel-fr...

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.

http://www.aviation.com/general-aviation/elon-musk-toying-de...

Not saying it's impossible. Just hard.

[0] https://en.wikipedia.org/wiki/Boeing_777#Specifications

Building an economically viable mass-market aircraft with a 70% mass fraction might be another question, but if we're just talking about the engineering challenge of building it at all I don't think that's hard?

Today's batteries don't store enough energy for long international flights. There are some battery technologies in the lab (Google Lithium-air batteries) that might make this feasible, but they're not ready yet. Yet alone proven safe to carry passengers.

As fans of speed, we want to bring supersonics to market as quickly as possible. So, we're only using core technologies that have flown on other airplanes and are accepted by regulators.

There's plenty of opportunity for radical innovation in V2 and V3 once V1 is working!

For planes, however, using a more environmentally-friendly but heavier energy storage medium is self-defeating, because you have to spend a lot more energy lifting the extra energy-storage weight. Unfortunate, but it is what it is.

even elon can't override physics

BUT: If you want to fly supersonic, you need very powerful engines anyways, so if you can re-use them for VTOL it's a win win.

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 would be VERY hard indeed and it would be something that has to be seen to be believed.

[1] https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning...

2 questions:

1) Why 2.2 times the speed of sound? (Why not aim higher?)

2) Where will you get the capital? Seems like a very big ask compared to the typical company coming out of YC.

Again - good luck! I would love to clip 4 hours from the SF to NYC flight.

Capital: I can't comment quite yet. (Sorry)

He'd pretty much have to at least take the meeting.

[0] One example is the end of the future oped he wrote. http://www.nationalreview.com/article/278758/end-future-pete...

https://news.ycombinator.com/item?id=11346947

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.

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, will the program be viable with only trans-oceanic flights? (I notice NYC/London highlighted in the marketing materials)

Alternatively, is there a viable way to make supersonic flight quiet enough to fly overland? (That would be a game changer!)

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 will be reversed in the coming years.

Can you elaborate on this? Is there a significant lobbying effort for this or is it something the FAA is considering of their own volition, to stimulate activity in this area?

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!

Imagine if Goldman Sachs were the only bank in NYC with supersonic transport for staff and customers for 5-10y. That might be worth more to them than $5k per seat on every flight. Maybe also to a law firm. Etc.

Exclusivity within a vertical is worth huge practical and status advantages.

That said, if your competitor fields a supersonic option, you have to, too, because you'll just lose business class to your comp, which is worse than losing it to yourself.

Honestly, I'm not even convinced that bit's true. Copying what others are doing is often the least effective way of competing. If supersonic premium carriers actually start eating into your business class demand, the sensible, conservative response is to refit your existing transatlantic fleet with more economy seats, refocus it on new routes or consider shedding an aircraft or two. You lose a stream of profit and a touch of prestige, but don't gain the problem of having to profitably operate new aircraft specialised for a highly volatile market segment. Especially when it's a new airframe programme from a no-name manufacturer.

To be honest, in a hypothetical and unlikely near future in which business class priced supersonic transport exists, subsonic premium services will happily coexist alongside them due to better start times, destinations and connections, even on the few routes actually suited for supersonic transport. But yes, there might be fewer flights and higher coach class ticket prices on a handful of routes.

For the most part major airlines didn't benefit from trying to cannibalise part of their existing business to copy [reliably profitable] low cost carriers, and they'll do just fine without the riskier option of supersonic medium haul all-premium flights.

I think (and I've spoken with considerably more commercial airline fleet planners than the average person) the sales challenge with this concept is even bigger than the engineering challenge, which is saying something.

Yeah, there already was a first in this space, and it went down in flames.

Since then, there has been research on 300 seat Mach 2.4-Mach 3 vehicles, but these are extremely challenging.

To make this happen and happen soon, you have to start much smaller than the established players usually consider. We're at 40 seats—that's the minimum economic size. Supersonics are hard, so it pays to start as small as you can and scale up over time.

Clearly you know more about this than me, but can you elaborate on why my view isn't correct?

With 40 seats and business class prices, the Boom airplane works on many more routes, which means we can make a lot of airplanes and enjoy economies of scale.

Looking into the future, as fuel efficiency further improves, per seat costs come down, and it will make sense to make ever larger aircraft. It's a virtuous cycle that will eventually allow supersonic flight at economy prices.

Your price is way off.

http://www.airliners.net/aviation-forums/general_aviation/re...

That's about $16k when accounting for inflation, so $20k isn't too far off.

Given the existence of business class only BA NY to City of London flights, there probably is a market for expensive supersonic routes, but it's probably still pretty small. International lawyers may value the back and forth in a day, but most people who fly business/first are probably fine with comfortable seating and a nice meal even if it takes a bit longer.

If there are only two equally large competitors left in the market you won't get radical innovation.

Even "conventional" programs like the 787 and the A350 had big problems because they tried out new things. If you screw up a big program, you may loose lot of 50% market share for the next two decades.

Do you actually think most anyone can afford $5000 round trip to London?

That's just the start of course—with more innovation on fuel efficiency the price and emissions both come down.

$5,000 is what a business class ticket NY/London costs today, and many business travelers are able to do that routinely. This compares to up to $20k on Concorde.

We will get the $5,000 way down over time—this is just the start.

Isn't that a bit optimistic? I would think it's closer to 2X. 2.6 times the airspeed, but why would turnaround time at the airport be any lower than for a comparably modern 'slow' airplane?

For example, 6 hour flight plus 1 hour turnaround time versus 2.3 hours plus 1 hour turnaround time is more or less a factor of 2. For longer flights, the ratio goes up a bit, but getting it over 2.5? I doubt it, at "the 2.6 times as fast as a typical passenger jet" level.

$5k is fairly standard for a first class ticket purchased a few weeks out. It's also much cheaper than a private jet and would yield the same, or similar, or possibly better results.

Here's another interesting subtle side effect. People on this plane would see it as an exclusive networking "club".

I can easily see finance professionals and executives loving this the whole concept.

I'm genuinely curious where you got "most anyone" from their marketing copy. I read it as "affordable for people flying business class," but that might be because I was thinking in the context of Concorde pricing.

Edit: Derp, totally glossed over that part of the parent comment.

From the original comment.

What are your goals/timelines with regards to funding (Very different than SAAS)? For a new plane won't you need hundreds of millions of dollars before you even get a prototype flying?

Why haven't Boeing/Lockheed/Northrup built a plane to fly supersonic ?

Is the execution of building a new plane or patents going to be your path to success ?

Wasn't Warren Buffet investing in this space a few years back ?

I have two questions:

1) Can you tell us about your start-up process? Aside from your all-star team, I can't even imagine how you could have brought this to reality. I can't even imagine how much capital and space a prototype would have taken. At what point did you decide that it was time to apply to YC? Were there other investors? How much design work did you have completed/prototyped when you starting talking to investors? (sorry I know this is 5 questions)

2) Are you hiring?

Posted ticket prices are based on what's profitable for airlines with the efficiency and performance of the airplane. Airlines will set the final prices, but we hope they will make tickets as affordable as possible!

Good luck to you - this is a really exciting idea and one that I think we need!

Can you elaborate what computer simulations this is referring to?

EDIT: your answer at https://news.ycombinator.com/item?id=11330935 applies here.

Do you have concrete plans to change those regulations? Do you have solutions for the problems addressed by those regulations (e.g. noise)? Will this scale down well if you have to reach a certain altitude first?

As far as regulations, our first aircraft is much quieter than Concorde, and it will get quieter with future iterations. Altitude helps, but quieting the boom is mostly about nuances of aircraft shape.

Eventually, when you can get from San Fran to Tokyo faster than San Fran to New York, the rules will get updated.

It does appeal, but then you have to factor in the travel to and from the airports on both ends, and various additional inherent delays.

Are you using current turbofan engines (GE F110?) or something exotic?

Regarding engines: our first prototype (1/3 scale) flies with an off-the-shelf GE engine. For the product airplane, we're taking an existing subsonic engine and adapting it for supersonic flight. (Sorry, I know that's vague—much more to say about this in due time.)

Will that vary by airline, or do you plan to standardize it?

But this is something airlines can customize.

What's the total plane seat capacity?

If you think this will be easy, why not just start by outfitting e.g. simple four-passenger Cessnas with your amazing new software that obviates pilots? There's got to be a market there, for something that works. Then when you've got that handled, move up to bigger and faster planes.

2. How much money do you have?

i.e. what is the distance from the shore you can boom?

http://physics.stackexchange.com/questions/68354/is-a-sonic-...

Would a Mach 1 plane hear a boom if overtaken by a Mach 3 plane?

http://aviation.stackexchange.com/questions/17243/does-a-mac...

I understand why you got downvoted, but I don't think the question was actually repellant. If it were at the top of the thread it would be annoying but here I find it a fun thought experiment.

I actually never though of the existence of a continuous cone of focus outside of the plane — the graph I had seen were all focused on the whether the plane heard it.

I guess an alternative option would be to find routes above the polar circle, or through the narrow of Central america — but the increased distance would make it less interesting at “just” Mach 2.2.

When the aircraft is directly above a listener on the ground, the relative velocity is zero, so you can see how the velocity changes from greater-than-sound to less-than-sound (twice) as the aircraft is approaching and then departing with respect to the listener. Thus the listener hears 2 booms.

The boom is usually explained in terms of shock waves emanating from the aircraft, but I think my description explains the phenomenon just as well, but more intuitively.

https://en.wikipedia.org/wiki/Sonic_boom

The engineering is not the hard part here.

Without regulatory support and approval you don't have a product or a market, so "Let's worry about that after we get the prototype working" may not be a fully viable strategy.

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 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'd have to disagree. The way I associate these words causes me to think of something "revolutionary" when I hear "boom". i.e., it's shaking up the market. Contrary to that, "glide" and "zip" (I know these are just examples) sound more soothing and definitely not attention-grabbing. If the aim of the company were to provide luxurious flight, then maybe that would be fitting. But as I see it, the company really does mean to shake things up, in which case their name is already fitting.

Obviously, everyone has their own opinions, but I thought sharing an opposing perspective would be useful in showing that it's definitely not a one-sided topic.

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.

I was amazed to see the regression in flight technology from cancelling the only supersonic passenger plane without a successor. Glad to see someone taking up the reins.

Adding CO2 reduction engineering to an already difficult project means less resources available to actually get the thing to work.

Imagine if The Apollo program had to worry about CO2 emissions on top of just trying to get a rocket to launch.

You also could argue some economy of scale efficiencies. If one flight on this plane caused just 3 passengers to forego a private jet trip for the same distance, you'd save 3 private jet's worth of flights. Given the time savings, this project would certainly disrupt a segment of the private jet market.

A 777 burns 1680 gallons per hour with 365 maximum passengers. A Gulfstream G650 burns about 865 gallons per hour.. holding a max of 18 passengers. So the G650 is burning 48 gallons per hour, per passenger while the 777 is doing 4.6 gallons per hour per passenger. We're assuming fully loaded for comparison but we all know that a G650 is rarely flying a 18 pax capacity, generally it's in an 11 seat configuration.

So as you can see, even if the fuel efficiency were half of a 777, it would still be a massive efficiency compared to a G650 and thus a net gain for those concerned about CO2.

What will they do in that situation ?

I've read and re-read that story so many times, each reading results in a fresh batch of goosebumps. I'd love to read the book (Sled Driver, I think?), but it is over $500 on Amazon. I wish they either ordered another print OR published as an ebook.

Someone emailed me a pdf (thank you!) but I'd love to be able to have a physical copy too.