Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Boom (YC W16) – Supersonic Passenger Airplanes

boom.aero

Post reply on HN
Print view View original

271–280 of 488 posts

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#271

Post by bscholl »

rdl wrote: post #257
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.

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.

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).

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#272

Post by azernik »

btilly wrote: post #240
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.

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 altit…

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.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#273

Post by jonknee »

dantiberian wrote: post #153
partisan wrote: post #77

Earlier quoted context omitted.

> I personally would generally prefer an F cabin + great Ka-band Internet for 14h, vs. a coach/Concorde sized seat for 7h. Agreed. I spent 5 of the most uncomfortable hours of my life on an airplane from JFK to San Diego, being 6'1 and not particularly slim. Thereafter, I upgraded my seats on that flight to Economy Plus. I guess I could stand a 2 hour flight like that, but not too much more. Getting me there faster,…

I can almost guarantee that you will not be cramped in these planes. They're selling it as an alternative to business class.

So was Concorde, but they were very uncomfortable (been on a couple in museums). Concorde feels like coach in a small commuter plane.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#274

Post by bscholl »

schwarrrtz wrote: post #245
btilly wrote: post #240

Earlier quoted context omitted.

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 altit…

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

exactly

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#275

Post by devenson »

bertil wrote: post #250
bscholl wrote: post #204

Earlier quoted context omitted.

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.

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?

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.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#276

Post by jonknee »

mikeryan wrote: post #194
ant6n wrote: post #68

It describes their values as something like 'fly long distance in the morning, do a bunch of meetings there, and be back before the end of the day'. Does it make sense to travel 20,000km on one day to make a bunch of meetings, spending 15,000$? I feel that better tele-presence just makes more sense.

It's hard to buy your client a beer over tele-presence.

"I cared so much about you that I paid 10x the fare just so I could leave as quickly as possible. You better chug that beer!"

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#277

Post by bscholl »

btilly wrote: post #240
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.

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 altit…

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!

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#278

Post by tempestn »

bertil wrote: post #250
bscholl wrote: post #204

Earlier quoted context omitted.

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.

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?

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.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#279

Post by azernik »

ant6n wrote: post #120
ElijahLynn wrote: post #89

Earlier quoted context omitted.

The telepresence rooms we have at our corp. are 100's of thousands for a room. And you have to have another room on the other end. If it will be a consistent meeting then it makes sense to set them up but for one off meetings at different locations then the cost is not justified. I do see a stereoscopic (3D) 360 VR future someday but we have a ways to go to get the 'presence' of that down to realism still.

Startup idea: rentable tele-presence rooms. tele-presence restaurants, tele-presence bars.

Lots of hotels that cater to business customers already to this - go to the local Hilton and pay $XYZ to use their telepresence room for an hour.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#280

Post by schiffern »

schwarrrtz wrote: post #245
btilly wrote: post #240

Earlier quoted context omitted.

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 altit…

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

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...

Post reply on HN