Virgin Galactic Hypersonic P2P Travel

[FutureSpaceTourist]

As VG are talking about this more now (including the small investment from Boeing) think it’s time for its own thread

https://twitter.com/thesheetztweetz/status/1205888732597030913

Virgin Galactic CEO @gtwhitesides on #hypersonic plans:

-Collecting data from SpaceShipTwo
-Structural work to be done, such as ceramic composites (may find a partner for development)
-Propulsion development will take the longest (won’t be rocket-powered)

Interesting last point - not rocket powered?’

https://www.cnbc.com/amp/2019/12/14/space-investing-becoming-real-morgan-stanley-hosts-second-summit.html

[Eric Hedman]

Interesting last point - not rocket powered?’

Is it a coincidence that Boeing also invested in Reaction engines?

https://www.cnbc.com/2018/04/11/boeing-horizonx-ventures-joins-37-million-reaction-engines-investment.html

A variation of the SABRE engine might fit "not rocket powered."

[FutureSpaceTourist]

I suspect Boeing’s investments in VG and RE are not a co-incidence (as both could potentially produce things of interest to Boeing in ultra high speed transport).

An air breathing engine that can operate from 0 to Mach 5 seems to me like a great propulsion unit for a hypersonic people carrier. Of course you need much more than an engine!

Not clear to me though who will put up the billions needed to develop an airframe etc, even if SABRE is finished and proven. I can’t see VG generating significant further amounts of investment unless/until SS2 is commercially successful.

[FutureSpaceTourist]

https://twitter.com/thesheetztweetz/status/1217832708849774593

Now beginning the Virgin Galactic $SPCE portion of today's conference, with Palermo interviewed by UBS analysts Myles Walton and Jarrod Castle.

Live thread:

https://twitter.com/thesheetztweetz/status/1217839440913141760

UBS: What does the hypersonic landscape look like?

Palermo: We're going to work with partners to develop a door-to-door solution, because we can't just reduce travel time in the air if it still takes you 2 hours to get to the spaceport and 2 hours to get through security.

[Vahe231991]

I suspect Boeing’s investments in VG and RE are not a co-incidence (as both could potentially produce things of interest to Boeing in ultra high speed transport).

An air breathing engine that can operate from 0 to Mach 5 seems to me like a great propulsion unit for a hypersonic people carrier. Of course you need much more than an engine!

Not clear to me though who will put up the billions needed to develop an airframe etc, even if SABRE is finished and proven. I can’t see VG generating significant further amounts of investment unless/until SS2 is commercially successful.

Hypersonic P2P travel is easier at suborbital altitudes. We all know that ramjets cannot work at standstill and that either a rocket engine or a high-performance jet engine similar to the J58 and J93 is required to get the ramjet to ignite at high supersonic or hypersonic speeds. Since Boom Technology has proposed the Overture SST, it is reasonable to believe that Boom could team up with Virgin Galactic to propose a Mach 6 airliner similar to size to the Overture and powered by four packs of RATO boosters under the fuselage for takeoff and rapid climb to altitudes of 50,000 feet and a turbine-based combined-cycle propulsion system whereby the scramjet is largely used in the hypersonic flight regime.

[daedalus1]

Passengers do not want super speed, they want comfort a reasonable speed and an affordable ticket price. Concorde is the proof of that.

[Hog]

Passengers do not want super speed, they want comfort a reasonable speed and an affordable ticket price. Concorde is the proof of that.

Most Concord passengers didn't know how much a ticket cost.

[Thunderscreech]

Passengers do not want super speed, they want comfort a reasonable speed and an affordable ticket price. Concorde is the proof of that.

Most Concord passengers didn't know how much a ticket cost.

Context for anyone who hasn't heard this: During the first few years of operation, British Airways was losing money hand over fist with Concorde and instituted a program to figure out how to fix this.  One of the things they did was started asking Concorde passengers how much they thought their tickets cost.

“Most of them didn’t know. It was their secretaries or travel companies doing the bookings. When they were asked to guess, because they were senior, very important people, they all guessed that the fare was higher.  So very simply, we said, we’ll charge them what they think they are paying. And so we put the fares up””

- Captain Jock Lowe, Concorde resource & Planning Manager.

They then doubled the fares and the tickets still kept selling out.

[daedalus1]

Passengers do not want super speed, they want comfort a reasonable speed and an affordable ticket price. Concorde is the proof of that.

Most Concord passengers didn't know how much a ticket cost.

Context for anyone who hasn't heard this: During the first few years of operation, British Airways was losing money hand over fist with Concorde and instituted a program to figure out how to fix this.  One of the things they did was started asking Concorde passengers how much they thought their tickets cost.

“Most of them didn’t know. It was their secretaries or travel companies doing the bookings. When they were asked to guess, because they were senior, very important people, they all guessed that the fare was higher.  So very simply, we said, we’ll charge them what they think they are paying. And so we put the fares up””

- Captain Jock Lowe, Concorde resource & Planning Manager.

They then doubled the fares and the tickets still kept selling out.

But my point is, it doesn't matter what the ticket price was, Concorde is not around anymore.

[Thunderscreech]

But my point is, it doesn't matter what the ticket price was, Concorde is not around anymore.

Roger roger, I think the person to whom you responded was speaking solely to the ticket price conundrum part of the thread and referenced an interesting element of the Concorde story that I wanted to expand on because it’s neat and I thought some folks who didn’t know it might be interested. 

[CameronD]

Maybe it isn't as tangible as Concorde, but you have to admit it's still a very pretty paper aeroplane:

[Vahe231991]

Maybe it isn't as tangible as Concorde, but you have to admit it's still a very pretty paper aeroplane:

This rendering is pretty cool. Any hypersonic airliner design capable of Mach 6 and an altitude of 200,000 feet with a capacity for 100 passengers that Boom jointly envisages with the SpaceShip Company would have to use titanium and a minimal amount of titanium carbide ceramics b/c of heat friction at Mach 3.

[CameronD]

Maybe it isn't as tangible as Concorde, but you have to admit it's still a very pretty paper aeroplane:

This rendering is pretty cool. Any hypersonic airliner design capable of Mach 6 and an altitude of 200,000 feet with a capacity for 100 passengers that Boom jointly envisages with the SpaceShip Company would have to use titanium and a minimal amount of titanium carbide ceramics b/c of heat friction at Mach 3.

Perhaps you mean unobtainium??  Whatever breakthrough material they use, if it ever actually makes it off the drawing board this will be one incredibly expensive aircraft to build and operate and, perhaps like it's predecessor, that means uneconomic from the get-go.

[Vahe231991]

Hermeus Aerospace is currently working on a hypersonic airliner design, named Halcyon, which is to fly at speeds of Mach 5 at an altitude of 90,000 feet with a seating capacity for 20 passengers over 125 trans-oceanic routes. Because Rolls-Royce declined to develop a new supersonic engine (all but putting into doubt the prospects for Virgin Galactic's Mach 3 airliner proposal entering full-scale development), which was why Boom Aerospace opted last year to develop an engine of its own for the Overture supersonic airliner, I don't find it implausible that Virgin Galactic could express interest in ordering the Halcyon if the Quarterhorse and Darkhorse are built and successfully flown considering that Hermeus Aerospace, like Boom Aerospace, has designed a hypersonic air-breathing engine of its own.

[CameronD]

Hermeus Aerospace is currently working on a hypersonic airliner design, named Halcyon, which is to fly at speeds of Mach 5 at an altitude of 90,000 feet with a seating capacity for 20 passengers over 125 trans-oceanic routes. Because Rolls-Royce declined to develop a new supersonic engine (all but putting into doubt the prospects for Virgin Galactic's Mach 3 airliner proposal entering full-scale development), which was why Boom Aerospace opted last year to develop an engine of its own for the Overture supersonic airliner, I don't find it implausible that Virgin Galactic could express interest in ordering the Halcyon if the Quarterhorse and Darkhorse are built and successfully flown considering that Hermeus Aerospace, like Boom Aerospace, has designed a hypersonic air-breathing engine of its own.

Whether or not Hermeus's plans succeed where others didn't, only time will tell - but the physics involved tells us it isn't going to be easy or cheap (or simply fuel-up-and-go at the end of each flight) using materials currently available to modern science.  Even if one or more of these companies actually succeed in developing a Mach 5 airliner there is no guarantee it will be commercially feasible.

Assuming we all agree Concorde (M2.04 @ 60kft) is a fair comparison and that money is no factor, looking at some numbers for M5.0 @ 90kft:
* Air pressure: At 60kft the air pressure is ~1psi.. at 90kft it's roughly a quarter of that.  Assuming the cabin altitude  is maintained at the usual 6-8kft that means maybe 4 times the stress on the shell than Concorde, meaning a lifespan significantly shorter than an equivalent aircraft at 60kft.  Essentially the 'Titan' in reverse..
* Climb Rate:  Assuming 4kft/min is reasonable, that's approx. 22 minutes to cruising altitude at either end to Concorde's 15.  Having farther to go to breathable air from that altitude, you have to descend a lot faster in an emergency to ensure your shirt-sleeve passengers stay alive.
* Fuel burn:  Who knows what the fuel consumption of these hypersonic engines will be, but for sure it will be an awful lot for those 22 minutes to altitude - and you still need some left to get down at the other end.  That fuel (whatever it is) has to be stored somewhere and that's really what sets your vehicle design, size and range.  By comparison, SS2 only needs fuel for the trip up and glides back for everything else, so it doesn't have that problem.  To function at all, this hypersonic airliner would glide like a brick.

Perhaps I'm pointing out the obvious, but as much as I (and many others I'm sure) would love to be able to get to the other side of the world faster than M0.95, I really don't see how that's possible in a Concorde-like variant with a VG logo on the tail - but that doesn't mean it isn't fascinating watching them try.   
 

[daedalus1]

Again, if Concorde couldn't make a profit and died then no prospect of any other exotic faster than sound transport will be successful. It's fantasy.

[TrevorMonty]

Again, if Concorde couldn't make a profit and died then no prospect of any other exotic faster than sound transport will be successful. It's fantasy.

Concorde might of been profitable if it hadn't been locked out of USA market.

[daedalus1]

Again, if Concorde couldn't make a profit and died then no prospect of any other exotic faster than sound transport will be successful. It's fantasy.

Concorde might of been profitable if it hadn't been locked out of USA market.

Why would you think any other faster than sound wouldn't also be locked out.
The most profitable routes were transatlantic and even with the development costs written off by the French and British governments it still wasn't profitable. That's why all we have is subsonic transport.

[tbellman]

* Air pressure: At 60kft the air pressure is ~1psi.. at 90kft it's roughly a quarter of that.  Assuming the cabin altitude  is maintained at the usual 6-8kft that means maybe 4 times the stress on the shell than Concorde, meaning a lifespan significantly shorter than an equivalent aircraft at 60kft.  Essentially the 'Titan' in reverse..

Are you trying to say that just the change in outside air pressure between 18 km and 27 km altitude would increase the wall tension stress of the pressure vessel by a factor four?  That's not how it works.  What matters is the gauge pressure, i.e. the difference in pressure between the inside and the outside.  And that would change from 80 kPa - 14 kPa = 66 kPa, to 80 kPa - 3 kPa = 77 kPa, which is only a 17% increase, not a 300% increase.  Even going to perfect vacuum on the outside would only be a 21% increase.

The stresses from flying at Mach 5 instead of Mach 2, though, even at the higher altitude and thus lower air density, is going to be quite significant.

[Vahe231991]

Again, if Concorde couldn't make a profit and died then no prospect of any other exotic faster than sound transport will be successful. It's fantasy.

Concorde might of been profitable if it hadn't been locked out of USA market.

The US airline industry had a number of orders for the Concorde, but they were canceled in the early 1970s due to worries about environmental and noise pollution and cost of purchasing and operating (the same factors that doomed the Boeing 2707 to cancellation without ever being built even though that aircraft had been redesigned in 1968 with delta wings due to the weight penalty incurred by the hinges for swinging the wings of the Boeing 2707-100 and -200 designs for a VG wing supersonic airliner).