X-59 supersonic aircraft

https://www.lockheedmartin.com/en-us/products/quesst.html

by belter • 3 years ago

59 60 3 years ago

greesil• 3 years ago

Whither Aerion?

Mistletoe2• 3 years ago

I remember as a kid hearing sonic booms and thinking it was so cool. I guess it was military planes in my area. I wonder how many people now even knows what it sounds like.

The article mentions commercial air flights taking half the time, but I wonder who needs that kind of speed when I see this-

“According to ICCT, supersonic flights would burn up to 9x more fuel per passenger per kilometer than their subsonic flying buddies.“

hamburglar• 3 years ago

When I was a kid, my dad was a naval officer stationed on an aircraft carrier and I got to go on something called the “Dependent’s Day Cruise” where we sailed out offshore and got tours of the ship and they did a full-on airshow for us. Because we were out at sea, they could break the sound barrier with impunity, and it was mind-blowingly cool to have fighter jets flying over low enough that we could see the pilots, absolutely silently until that massive shockwave hit your chest. It’s surreal.

mpweiher• 3 years ago

would burn up to 9x more fuel per passenger per kilometer

That number seems a bit hyperbolic, even for Concorde, which was 1960s technology. Modern supersonics will be far lighter, use turbofans instead of turbojets, not require (or even have) afterburners etc.

They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture.

The truth will probably be somewhere in-between.

heisenbit• 3 years ago

They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture.

This fig leaf is transparent.

carabiner2• 3 years ago

The 9x factor seems in the ballpark when you consider a Mach 2 jetliner will be going 2.5-3x faster than a subsonic one, and drag increases with the square of the airspeed.

hef19898• 3 years ago

The Concorde is still pretty top notch, tech wise. As far as supersonic and supercruise jet engines go, they are all military. Civilian engine development went all in improving noise levels and fuel economy. And without a viable market, no engine OEM will invest the billions needed to develop a civil supersonic engine. So it is either a huge market, or various governments foot the RnD bills. Both of which are far, far away.

All technological promises regarding civilian supersonics only exist in fancy renderings and pitch decks, there is no substance behind. Even less than there is with the various eVTOLs, at least those actually fly. Well, some of them that is...

operatingthetan• 3 years ago

My girlfriend and I were hanging out at a lake east of Issaquah near seattle and suddenly two Growlers came down low over the lake and we were subject to two sonic booms which was amazing. They sounded sort of like a resonant crack of thunder but much louder. They flew over a boat in the middle of the lake and I shit you not someone on it screamed "AMERICA F YEAH." It turned out this lake was one of the ones they filmed for the new Top Gun film, but it was common for Whidbey pilots to buzz it on their way back to the NAS.

rwmj• 3 years ago

I read some contemporary articles in a Private Eye annual from the 1960s and the problem was not really the noise but the structural damage that was (allegedly) being caused. I don't know how real that was, but in the UK concerns over structural damage to buildings was what lead to the ban.

As for this plane, what are the elements of the design that reduce sonic booms? The comically long nose?

Mistletoe2• 3 years ago

I think it is mainly the comically long nose.

https://www.thedrive.com/the-war-zone/44307/behold-the-x-59-...

hansthehorse• 3 years ago

My daughter lives relatively close to Cape Canaveral and hears sonic booms from the returning Spacex first stage quite frequently, as does the surrounding neighborhood.

Yubzzzzz• 3 years ago

I'm curious to see the fuel efficiency. Wind resistance has to be way way higher at these speeds, but it also appears to be flying at much higher elevation so they may cancel out to a certain degree.

usrusr• 3 years ago

Even if fuel economy was somehow better, it would still lead to more fuel getting burned. Because the super rich only have so much time in their lives to spend in the stratosphere or elsewhere and shorter flight times could noticeably shift their trade-off decision about the inconvenience of flying vs the inconvenience of not being where they'd like to be. Outliers in wealth aren't quite as much outliers in ecological footprint because fortunately there's only so much you can consume, but a supersonic revival would help close that gap.

A part of me sure loves the nostalgic idea of technological bigger-better-faster, but the rest is fully aware that this is not the progress we are looking for. It's bad enough when private investors put money into destructive technology like this, but if it was my tax money, I'd be shouting at them.

wkat42422• 3 years ago

Because the super rich only have so much time in their lives to spend in the stratosphere

It's also not a place you'd want to spend too much time considering you're outside of the radiation protection of a large part of the atmosphere.

someweirdperson2• 3 years ago

No eyeballs Mk 1 forward-view?

OJFord3• 3 years ago

Too fast for it to be useful I'd guess, you're reliant on the computer anyway so why have a front window be a design constraint restricting aerodynamics, tough enough glass/plastic (a lot more force on it than the overhead/side window it does have) etc.?

regularfry5• 3 years ago

Mach 1.4 is really not that fast. Slower than Concorde by a fair margin.

willvarfar• 3 years ago

It feels so weird to scroll down and see the product sheet with feet and inches. And is the plane really only 99 inches long?

Is metric used to actually design the plane, or does Skunkworks still use US customary measurements?

darkwizard42• 3 years ago

Weird design I think, I think it means to be 99 ft. long, but the label isn't there...

sakras• 3 years ago

Given that it’s 14ft tall, I’d say no, though I agree they could’ve made it clearer. It says 99’7 In, or 99 feet and 7 inches (ideally, it would be 99’7”).

et-al• 3 years ago

The diagram confusingly lists the length as 99'7 in. Don't know why they mixed the single tick (feet) and written inches notation.

Your question did make me think of the Boom XB-1; a scaled down version of a passenger jet that I'm skeptical will ever fly commercially.

justinator• 3 years ago

Ah! I think I've seen that in person! This plane?

https://www.instagram.com/p/Cp-YjLNDUf6/

knifie_spoonie• 3 years ago

And is the plane really only 99 inches long?

I'm guessing it should read 99ft 7in. That would put it at just over 3m, which still seems pretty small to me.

pmuk• 3 years ago

99ft 7in is 30.353m

bee_rider• 3 years ago

My trick to convert to meters from feet is: just convert it to yards and ignore the difference.

SideburnsOfDoom• 3 years ago

I'm guessing it should read 99ft 7in.

Yep.

That would put it at just over 3m

Nope.

nixass• 3 years ago

It's better than football fields ar least

unwind• 3 years ago

Nah, 1,383/5,000th football fields (US) should be pretty clear to most people.

dcl• 3 years ago

I thought exactly the same thing.

nocoiner• 3 years ago

And is the plane really only 99 inches long?

Can it fly from New York’s Idlewild Airport to the Belgian Congo in 17 minutes?

supernova87a• 3 years ago

Is there a rule / scaling relationship about the maximum passenger volume + payload of a supersonic aircraft and the fuel burn? Just wondering if by physical law, these transports are destined to be only ever extremely premium / luxury travel.

carabiner2• 3 years ago

Energy argument follows: higher speed = higher drag (increases with square of speed) = higher thrust to overcome that drag = more fuel = more weight = more structure overall (larger wings etc.).

credit_guy3• 3 years ago

Everyone repeats this argument, but it's wrong.

Higher speed -> you reduce the angle of attack -> lower cross-section. The drag per unit of area increases, but the area decreases. Overall, you still have higher drag, but you get faster to where you need to get. It is not pre-ordained that you need to burn more fuel overall.

In fact, you can end up burning less, not more fuel.

Here's why: drag per se doesn't matter. What matters is the lift-to-drag ratio [1]. To keep the plane at a constant altitude, the lift needs to be equal to the gravitational force acting on the plane. To keep the plane at constant speed, the thrust needs to equal the drag. If the lift-to-drag ratio is 10, the thrust needs to be one tenth of the weight of the plane.

Now, the fuel consumption per second is roughly proportional to the thrust. If you double the speed and the lift-to-drag ratio gets cut in half, your overall fuel consumption is the same. But here's the thing: in supersonic regime, the lift-to-drag ratio does not get cut in half. The empirical lift-to-drag ratio is 4(v+3)/v, where v is expressed in Mach number. For example at Mach 3 you get LTD ratio = 8 and at Mach 6 you get 5.33.

Of course, things are not that rosy: on one hand the airplane needs to be sturdier, because it needs to withstand higher vibrations. On another hand, even if in cruise mode you may save fuel, it's difficult to optimize the plane in a very wide range of velocities. Concorde was horrible at low speeds, so it was burning a lot of fuel at take-off; it is quite obvious that a plane is the heaviest at take-off, so if you burn more fuel at that point, you really burn more fuel.

But design has made huge advances in 50 years. We may be able to optimize better an airplane now than we could when the fastest supercomputer was slower than the iPhone in your pocket.

Bottom line: it is not at all obvious that a supersonic plane needs to burn a lot of fuel, and it may be that it could actually burn less than a subsonic one.

[1]https://en.wikipedia.org/wiki/Lift-to-drag_ratio

wkat42422• 3 years ago

"Creates a sound as loud as a car door closing" -> I assume this means at ground level? I can't imagine even the propulsion being that quiet let alone the sonic boom.

rnabel• 3 years ago

Yes, the noise level is measured on the ground directly below the flight path of the plane.

Interestingly, it’s not just the volume but also the pattern of the boom that can be altered by changing the design of the plane. There’s a great discussion of this here: https://www.elidourado.com/p/50-years-supersonic-ban (Scroll down to the images of the sound wave)

nevermindiguess• 3 years ago

It’s nice when they put it like that. Now imagine you trying to relax or concentrate in your home and hearing a “car door closing”, every minute, regularly, all day. And if in the end it sounds more like the car’s tire blowing up - well… “we are looking at ways to resolve the issue”, “we are aware of the issue and working on it”, “you are the only one complaining”, “it looks you may be too sensitive to noise”, and so on. Who cares in the end. It’s just people.

sand500• 3 years ago

Noise complaint got supersonic flights banned in the first place. Even now, most airports have noise abatement procedures.

https://www.faa.gov/newsroom/supersonic-flight

gwnywg• 3 years ago

Unrelated but... My brain can't tell me if 14 foot is a lot or not... I can't imagine how is it possible to do CAD design in imperial measures, it was always making me think why is not whole world moving to metric- is it not a de-facto standard now?

senectus1• 3 years ago

I don't understand imperial at all, only metric.

But I know I'm just over 6 foot tall, I know a foot is about the length of a ruler.

Acres are completely alien to me, same with lbs and oz's

X-59 supersonic aircraft

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