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Boom (YC W16) – Supersonic Passenger Airplanes

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Re: Boom (YC W16) – Supersonic Passenger Airplanes

#481

Post by api_or_ipa »

snaily wrote: post #379
api_or_ipa wrote: post #140

No where does it mention proposed range. This is a big deal: with thirsty supersonic cruise, your fuel mass fraction will exponentially grow according to the Rocket Equation. Simply put, the more fuel you carry, the more fuel you must carry to bring that fuel along. Flying twice the distance will mean >>2x the fuel. LON-NYC might be attainable, but tran-pacific will certainly be difficult.

The rocket equation applies when you're continuously accelerating your fuel to ever higher speeds. The work in supersonic flight is fighting drag, which while many times larger that for subsonic does not have an appreciable weight dependency. Why would flying longer require more than proportionally additional fuel?

My assumption is that drag (esp lift induced) is a function of weight. The more fuel you must carry, the more drag you incur. The more drag you incur, the more fuel you must carry to over-come it.

I know this is certainly true of subsonic flight. How much it affects supersonic flight it unknown to me.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#482

Post by spaceflunky »

azernik wrote: post #291
jandrese wrote: post #252

Earlier quoted context omitted.

A brand new advanced composite supersonic jet flying in a year's time? Color me skeptical. There are literally millions of things that need to be designed for this, and many of them will be bleeding edge. And this is from some tiny startup? A line like that sets off some big flashing red lights for me. Either they're incompetent and have grossly underestimated the amount of work needed to complete this, or it's a sca…

Not quite. According to [1], what they'll be flying is actually a one-third-scale prototype, which I'd imagine is a lot easier to build. And they've already been going for two years. The real issue that I'm not seeing addressed is capital. No investors listed anywhere. [1] http://www.bloomberg.com/news/articles/2016-03-21/this-aeros... EDIT: Forgot to actually include the link.

So I've actually worked on a couple of aviation projects in career as a biz dev person. A usual development technique is to build at small scale and then work your way up.

The problem is that when you get closer to 1:1 scale, new always issues come up with bigger challenges. You solve one problem at 1:5 scale, only to realize that doesn't work at 1:3 and the whole thing needs to be redesigned from the ground up.

The annals of aviation history are littered with aircraft unable to move past 1:n scale.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#483

Post by rwmj »

jessaustin wrote: post #479
rwmj wrote: post #478

Earlier quoted context omitted.

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.

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…

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

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#484

Post by jessaustin »

rwmj wrote: post #483
jessaustin wrote: post #479

Earlier quoted context omitted.

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…

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

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.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#485

Post by devenson »

devenson wrote: post #275
bertil wrote: post #250

Earlier quoted context omitted.

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 z…

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.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#486

Post by bewo001 »

saganus wrote: post #66
themgt wrote: post #3

Sorry but is "Boom" really a good name for an aircraft company? I get it's supersonic, but my first association was an exploding airplane.

If they wanted to associate with a sonic boom.. Maybe.. SonicBee or something cuter? Agreed that Boom is not a name I would immediately associate with sonic boom instead of ka-boom.

Planey McPlaneface?

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#487

Post by bewo001 »

bduerst wrote: post #50
danielschonfeld wrote: post #25

Earlier quoted context omitted.

I believe the problem with those was always the sonic boom created by flying at > 1 Mach. It shattered windows on the ground. Could be wrong tho

Supersonic flight is banned over populated areas. I'm not sure if it's from shattering windows or not.

Grew up in Germany during the Cold War. Sonic booms from military jets were not rare. In the low level flight training areas the population really suffered.

Re: Boom (YC W16) – Supersonic Passenger Airplanes

#488

Post by an_account_name »

bscholl wrote: post #332
mathattack wrote: post #328

Earlier quoted context omitted.

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.

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)

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

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

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