[bscholl]

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.

[reso]

Given that sonic booms are one of the main reasons the Concorde didn't work, is calling your company "Boom" the best idea? Half-kidding.

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

[dsyko]

Also given the association that "boom" has with explosions, a very bold name choice.

[shrewduser]

i am also perplexed

[pbreit]

I am not even slightly perplexed. It's a great name and great mission and I wish them well.

[bscholl]

Thank you!

[niccolop]

Wasn't one of the issues with Concorde that is was just too expensive as well, in terms of running it (from a fuel stand point) and maintenance?

Notwithstanding the accidents.

[btilly]

Elon Musk says that eventually we will move to VTOL supersonic electric jets, but he is too busy with other projects to implement it.

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.

[schwarrrtz]

The specific energy of kerosene is ~40 MJ/kg [0] while the specific energy of lithium ion batteries is ~1 MJ/kg [1].

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

[mikeyouse]

To be fair to our electric friends, electric motors are >90% efficient while turbofans top out at somewhere near 35% efficiency (as far as I can find).. So what appears to be a 40:1 advantage to kerosene is more like a 15:1 advantage -- substantial but much more accessible with ongoing battery improvements. Though as another commenter mentioned, fuel planes do definitely benefit from shedding weight the entire time they're moving.

[SeoxyS]

A jet engine (e.g. turbofan) relies on combustion in the engine in order to function. The ignition of the fuel from within the engine is key… it is not just there to just create energy to drive rotational force. You would you use an electric motor on a plane without going back to what is essentially a propeller design?

[gruturo]

Actually, a good 80% of a modern airliner's thrust comes from the huge fan in front of the engine.

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...

[lmm]

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.

[pjc50]

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 power:

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

[eloff]

To be fair, you can manufacture kerosene from renewable electricity. If you use carbon from the atmosphere, it's even completely carbon neutral. Think of it as a less cost efficient, but more energy dense battery. I kind of doubt that batteries are the way to go when energy density matters.

[WatchDog]

Plus a conventional airplane sheds weight as it travels.

[flashman]

Nothing that recoverable drop-tank batteries can't solve. I'm mostly kidding.

[foota]

Refueling via amazon drone?

[schiffern]

And yet Musk claims transcontinental range (NY-LA) would be possible with 400 Wh/kg batteries and mid-70% battery mass fraction.

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

[schwarrrtz]

A 70% battery mass fraction seems like a huge engineering challenge for an aircraft. I did a quick calculation of fuel mass fraction for the various Boeing 777 models [0] which ranged from ~13% to ~36%.

Not saying it's impossible. Just hard.

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

[lmm]

I don't see that the engineering is hard. You could just take an existing design and replace most of the cabin with batteries.

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?

[xgbi]

And on top of that, "refueling" wouldn't cost the 250k figure that usually gets thrown in comments. I imagine it being more in the space of a 1-2k$ ; in which case the reduced passenger capacity might still be worth the premium in batteries.

[kuprel]

Specific energy of hydrogen is 142 MJ/kg. Why not a hydrogen fuel cell powered electric jet?

[taneq]

Because hydrogen is very hard to store in any reasonable size or shape, and that's even without focusing on the inefficiency of generating it.

[jessaustin]

Ammonia doesn't have this or several of the other drawbacks of hydrogen, but is otherwise equivalent.

[maaku]

Drag on a bigger airframe.

[bscholl]

exactly

[bscholl]

schwarrrtz and azernik nailed it.

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!

[rdl]

Batteries do make sense on aircraft in place of APUs for backup and start and such, of course, just not thrust.

[azernik]

Unfortunately, aerospace is a place where energy density really really matters. If your car's battery weighs twice as much as equivalent hydrocarbon fuel, that will decrease your range, but probably won't affect your performance or total energy usage all that much.

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.

[diskcat]

Yeah but you are getting 50:1 difference in energy density between hydrocarbon fuel and battery. Also, vertical takeoff is extremely inefficient because a wing can generate a lot of lift compared to drag. this in addition to the fact that a vertical lift system is only used during take off and landing while being dead weight the rest of the trip.

even elon can't override physics

[ungerik]

The big power requirement of VTOL is not the problem in the overall energy budget because the hovering time is very short compared to the total flight time. Main problem is the additional weight of the more powerful engines.

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.

[diskcat]

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

[Xixi]

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...

[lmm]

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

[mathattack]

Great idea. The airline industry needs innovation around product and service to get out of it's current race to mediocrity.

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.

[bscholl]

Speed: Mach 2.2 is the fastest speed possible with known technology already accepted by the FAA. At that speed, you can have good takeoff performance (and comply with airport noise restrictions) and good cruise performance. We'd to build a faster V2 or V3, in due time.

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

[vonklaus]

Peter Theil regularly uses lack of aerospace innovation as a yardstick for slowing progress in Technology all the time[0].

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...

[an_account_name]

Okay, I'm assuming you can comment now, but we already know.

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

[mark-r]

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.

[mathattack]

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. :-)

[mark-r]

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.

[Pyxl101]

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, 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!)

[bscholl]

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 will be reversed in the coming years.

[privong]

> 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?

[maaku]

NASA Ames has been doing some great research (in the bay area no less) on boomless supersonic crafts. There are basically two strategies: either modify the fuselage to disrupt the boom wavefront, or redirect the wavefront by going supersonic at a nontraditional attack angle. Both work.

[SeeDave]

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!

[voltagex_]

is SYD -> SFO too far?

[fernly]

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.

[pacaro]

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

[stuaxo]

I thought it was used because they didn't want the brits and french to have the market for these planes.

[rdl]

I wonder if you should just sell exclusivity per company.

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.

[bscholl]

TBH we really don't want to lock people out. I was disappointed that I never got to fly Concorde, not even once, and we want to open this to everyone (eventually make it routine).

[guscost]

That's awesome, but if the GP strategy has a good enough chance of helping you get to your goal sooner than otherwise, totally go for it.

[elliotec]

Thank you for that.

[nharada]

Why do you think that other established players haven't entered this space (i.e. Boeing, etc)?

[theothermkn]

Nobody wants to be first in this space. Because of the fuel costs of supersonic travel (the flow is inherently dissipative above Mach 1), the margins are too tight for anything but business class travel. As soon as you have a supersonic option, you've moved business class out of your subsonic fleet, along with that revenue. With the loss of the effective subsidy of business class, coach costs go up, and the market shrinks due to elasticity of demand.

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.

[notahacker]

> 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.

[searine]

>Nobody wants to be first in this space.

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

[lmm]

One major crash, at an airline with serious maintenance issues. The final cancellation was supposedly on economic grounds but politics factored into it (I have heard it claimed that AF deliberately overstated maintenance costs to prevent BA from continuing to operate Concorde).

[bscholl]

There's a lot of scorched earth in supersonics, since Concorde wasn't an economic success and the Boeing SST project was cancelled.

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.

[pacificmint]

I had always thought that the small size of the Concorde was what made the per seat cost so expensive and held the Concorde back economically. So my expectation was that to be economically successful, you'd have to build a supersonic plane that carried more people.

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

[bscholl]

Actually, Concorde was too big: 100 seats. It worked NY/London but at ~$20k/seat they couldn't fill enough seats several times daily on other routes. Which means you can't have many airplanes, which means no economies of scale.

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.

[jacquesm]

> 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...

[mikedouglas]

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.

[ghaff]

It looks as if the Concorde was roughly $5K each way (or $10K RT) +/- in today's dollars--although I'm not sure a standard CPI inflation calculator is the best way to look at airline ticket price changes.

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.

[pacificmint]

Thanks for explaining that, I had never looked at it that way. And good luck to your venture.

[ungerik]

One word: risk!

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.

[bvi]

Honest / naive question. How do you even start an aerospace company "in your basement"?

[zeckalpha]

It's been done: https://en.wikipedia.org/wiki/Burt_Rutan

[elliotec]

Blueprints, math, models.

[lisper]

Or start by building a small plane, which you can do in a (large) basement.

[elinchrome]

How does the environmental impact per passenger compare to a modern passenger jet?

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

[bscholl]

We have the same gas mileage (fuel per seat mile) as a lay-flat bed in business class. Since the aircraft can do nearly 3X as many trips in the same time, on net it's better.

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.

[Someone]

"Since the aircraft can do nearly 3X as many trips in the same time"

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.

[erikpukinskis]

Boarding should be faster, since it's only 40 seats and, ostensibly, roomier.

[cma]

Same would apply to an all business class lay-flat flight.

[foobarqux]

What is the biggest line item in your costs? Fuel?

[krisoft]

Developing an airplane, I would guess.

[rabidonrails]

I heard it was the little bags of peanuts :P

[foobarqux]

I meant operating costs.

[jonknee]

Yes, fuel is the major operating cost of an airliner...

[mbesto]

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

$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.

[mmcclure]

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

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.

[bscholl]

$5,000 isn't an "everyone every time" price, of course. But it's low enough for routine business travel. With more innovation (this is just V1!), we can improve fuel economy and reduce prices further.

[jacobush]

Wasn't the V1 subsonic and V2 supersonic? Sorry...

[mathieuh]

> Not just as a private jet, but something most anyone can afford to fly

From the original comment.

[Inthenameofmine]

What's your opinion on the Skylon engine? http://www.reactionengines.co.uk/space_skylon.html

[robert_foss]

I'm very curious about this too.

[andrewmp1]

Lots of questions here:

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 ?

[big_al337]

Im thrilled to see something like this taking flight, congrats!

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?

[maho]

I'm curious, since you posted a route and a ticket price: Will you be operating Boom as a new airline, or do you plan to sell your plane to other airlines?

[bscholl]

We're teaming with existing and new airlines to bring aircraft into service.

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!

[hguant]

I wish I could share your hope.

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

[bscholl]

Thank you! It's an idea whose time has come...

[designtofly]

From the Bloomberg article: "Boom’s software can also run millions of computer simulations a day on its designs, so the startup doesn’t have to spend months tweaking things in wind tunnels."

Can you elaborate what computer simulations this is referring to?

[bscholl]

There's computational fluid dynamics—which are very good today especially at supersonic conditions. Also, we have some design optimization tools we've built in-house which let us quickly explore many alternatives and zero-in on the best design.

[JoshTriplett]

Obviously, shortening an international flight provides the highest value for your first major route. How well can this scale down to domestic flights? Turning a 3-4 hour flight into a 60-90 minute flight, or a 90 minute flight into a 30 minute flight, appeals quite a bit.

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?

[bscholl]

Supersonics help most on long international flights. So that's the first focus. San Francisco - Los Angeles, so much time is spent on takeoff and landing that faster cruise doesn't help much. Hyperloop, self driving cars can help with these shorter trips.

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.

[kazinator]

> a 90 minute flight into a 30 minute flight, appeals quite a bit.

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.

[jonathankoren]

Wasn't the problem that made the Concorde uneconomical fuel prices? While a barrel of oil is currently trading at around $41, I don't think many economists believe that this is a long term trend, and expect prices to rise back to around $80 - $100. Isn't this a strategic problem?

[nether]

How are you reducing the boom? Are you widening part of the forebody to increase the local air temp & mach no to weaken the shock? What about redirecting the shock?

[bscholl]

Sonic boom physics are subtle and counter-intuitive. High level, you: (1) keep the airplane as small and light as possible (reduces total shock energy) (2) carefully shape the fuselage and wings, so the shocks don't combine as strongly

[dghughes]

NASA and Boeing have a design that has the engines on the upper part of the wings saying it reflects most of the boom upward. (see ninth paragraph) https://www.nasa.gov/aero/centers_tackle_sonic_boom.html

[neurotech1]

What type of intake design are you using? Comparable to the F-22A fixed square intakes?

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

[bscholl]

Really good questions. We aren't sharing the details of the technical design quite yet (but will have more to say as we approach first flight).

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.)

[melvinmt]

How instrumental was YC in the development of Boom (money/advice wise)?

[bscholl]

YC has been awesome and supportive in so many ways, far beyond money. 5 stars, would do again!! :-)

[FLUX-YOU]

What are you looking to build from scratch vs OTS? Anything interesting in the avionics dept?

[schoen]

Are there other areas you or other readers can think of in which a technology that was previously available or in use went away entirely with no replacement?

[JoshTriplett]

For the price you quoted, what will the seating situation be? Comparable to existing international coach, or somewhere between coach and business class? Do you have approximate seating charts and spacing?

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

[bscholl]

We're baselining an experience better than domestic first class. One seat on each side of aisle, so everyone gets a window and aisle. There's more footroom and more headroom than the typical first class on a 737 or A320.

But this is something airlines can customize.

[JoshTriplett]

Ah, I see; it wasn't obvious from the pictures on your site that the plane is significantly smaller, closer to commuter-jet sized than 747-sized.

What's the total plane seat capacity?

[ocdtrekkie]

In case you didn't see earlier comments, they said it was 40 seats.

[rwmj]

Why do you bother having pilots on board? Why not have the majority of the flight directed automatically, perhaps assisted by a ground manager dealing with several planes at once?

[jessaustin]

Savvy passengers might value someone with "skin in the game".

[rwmj]

I think you may mean "naive passengers will be reassured by two men in suits". Savvy passengers would know how pilot error is the main cause of crashes.

[jessaustin]

That will be a fair statement once there are any commercial (or general aviation!) passenger flights for which all flight operations take place without human intervention. We don't live in that world yet. Saddling an already risky endeavor with the additional risk of having to invent a completely new class of control software is really too much to ask.

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.

[rwmj]

Hence why I said "ground manager dealing with several planes at once".

[jessaustin]

So this is like USAF's drone guys in mobile homes out in the Nevada desert? One notes that they don't handle aircraft with passengers either. Your idea isn't bad in general, and someday it will probably be accomplished in some form, but we're not anywhere close to that yet. Independent joint probabilities multiply, so the last thing a highly speculative aircraft needs is a highly speculative pilot arrangement.

[Animats]

1. How much money do you need to get to first flight?

2. How much money do you have?

[astrodust]

Or more accurately: How many cargo containers full of money do you have?

[ADRIANFR]

Is SFO-NYC a feasible route for Boom?

[bscholl]

Unfortunately, there's a ban on supersonic travel over land in the US since the 1970s. When this is reversed, we can fly SFO-JFK in about 2:20.

[bertil]

Would it make sense for you to fly West from SFO, turn around, go super-sonic over the ocean and fly towards NY — then again, decelerate over the Atlantic, and turn back?

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

[sounds]

Everywhere the plane is supersonic, it emits the boom. Your question implies that the only boom is when you "go super-sonic."

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.

[bertil]

Didn’t get down-voted overall so fine on that end.

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.

[devenson]

The sonic boom isn't created when the aircraft transitions through the speed of sound. Although I never hear it explained this way, I believe it is caused when the velocity of the aircraft with respect to the listener transitions the speed of sound. That's when the sound waves approaching the listener bunch up and cause the boom.

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.

[devenson]

slight correction to the above: there is no second boom heard by the listener when the aircraft is flying away from the listener faster than the speed of sound. The listener the would simply hear no sound.

[tempestn]

As others have said, the boom is continuous. However, what you could (and presumably would) do is gain altitude at sub-sonic speed, then go supersonic only once cruising altitude is reached. That should help with volume. Also presumably they would avoid flying over major population centers.

[mark-r]

Is the boom attenuated by flying through much less dense air?

[tempestn]

Possibly! Certainly if the plane was traveling in a vacuum it would produce no boom, so one would assume that the boom would be reduced as the air became less dense. However my understanding is that most of the advantage from altitude comes from the attenuation (or really spreading out) of sound with the square of distance.

[bradleyjg]

Sonic booms are continuous while going faster than the speed of sound. It isn't just something that happens when you cross the barrier.

[jonknee]

... Sonic booms happen anytime you're going supersonic speeds, it's not limited to when you cross the boundary.

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

[JoshTriplett]

What's the regulatory situation in countries other than the US? Europe, Asia, Canada, Mexico, South America?

[bscholl]

It's complicated and unclear, unfortunately. We'll have to see how things unfold when the airplanes are flying.

[TheOtherHobbes]

Might be an idea to spend a little more time on that.

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.

[putzdown]

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 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.

[wallacoloo]

> "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.

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.

[SeeDave]

>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.

[blairanderson]

Please do not tell people what to do. Its a waste of bandwidth. Thank you.

[jessaustin]

Upvoted for irony.

[Bluestrike2]

It's such a silly thing, but I love the name.

[bscholl]

Thanks! :-)

[ocdtrekkie]

This is so exciting. When I was younger, one of my big to-do list items was to someday ride on the Concorde. That dream is no longer possible, but flying on one of your planes might be!

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.

[danohuiginn]

How many of these would you need to sell (or operate) to recover the development costs?

[john61]

What about CO2 emissions?

[briandear]

Are CO2 emissions really a concern? If 5000 of these planes were flying, as a proportion of global CO2, it would be undetectable if they reduced the plane's emissions by 50%. Then you'd have the argument of how much of that CO2 had any measurable effect on climate -- and that would assume that effect was deleterious. A lot of assumptions to bet a revolutionary aircraft design upon.

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.

[john61]

If 1969 the planet would have been at stake because of CO2, it would have been better to not fly to the moon but rather use the resources to save the planet.

[foobarqux]

Who are your investors?

[rsync]

What will your pilots do, just as a for instance, if ... say a lone Cessna asks tower for his ground speed ... and then a bit later a navy F-18 pilot also asks tower for his ground speed ?

What will they do in that situation ?

[bluehawk]

Hilarious context, for those who haven't read it yet: http://oppositelock.kinja.com/favorite-sr-71-story-107912704...

[gregingelmo]

Oh man what hilarious story! Thanks for posting it.

[ceocoder]

specially if the F-18 pilot is making sure that every bug smasher from Mount Whitney to the Mojave knows what true speed is.

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.

[tfe]

There is an ebook version floating around the internet.

[dboreham]

Yikes! I have two copies, having thought that I'd lost mine years ago -- bought a new one -- then found the original again.

[ceocoder]

Are you interested in selling one of them? If so I promise to give it a very good home, I still have books from my childhood in great condition.

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

[kriro]

If you feel like parting with one it would be cool to consider the pilot who posted the story (as he's lamenting that it's too expensive) :D

[schwarrrtz]

i think that depends on how badass the copilot is

[bscholl]

Brian Shul is a steely-eyed missile man. :-)

[rory096]

Nitpick: Walt Watson is the back-seater in question — Brian Shul was just the guy on the stick (and the author of the story, of course).