London to Sydney in 4 Hours

[bad company]

I wasn’t sure where to post this, feel free to move it mods.

https://www.google.co.uk/amp/s/www.bbc.com/news/am...

Exciting project???

[andy_s]

https://www.pistonheads.com/gassing/forum.asp?h=0&...

First I've seen of it, looks interesting.

[Frank7]

bad company said:

I wasn’t sure where to post this, feel free to move it mods.

https://www.google.co.uk/amp/s/www.bbc.com/news/am...

Exciting project???

Sounds great, but there’s bound to be some unseen fly in the ointment which the developers haven’t discovered yet, like moving a human that far, that fast, turns them into leprechauns, or something similar.
When my kid lived in Brisbane, I went Business Class on BA once, but even with flat bed seats, and champagne on tap, it was still 22 hours, via Malaysia and Sydney.
If they could have got it down to 9, or 9.5 hours, I’d have gone every 6-9 months, but his wife missed Der Vaterland, so he returned to Germany, and London to Dortmund is between 1h 15 mins, and 1h 40mins, I can do that standing on my head, and in the cheap seats yet.

[Smiljan]

Frank7 said:

Sounds great, but there’s bound to be some unseen fly in the ointment which the developers haven’t discovered yet, like moving a human that far, that fast, turns them into leprechauns.

I'm pretty sure that doesn't happen no matter how fast you fly.

[Frank7]

Smiljan said:

Frank7 said:

Sounds great, but there’s bound to be some unseen fly in the ointment which the developers haven’t discovered yet, like moving a human that far, that fast, turns them into leprechauns.

I'm pretty sure that doesn't happen no matter how fast you fly.

It probably doesn’t, but I meant some kind of adverse affect on a human body, moving at that speed.
Maybe none at all, after all, humans go into space, but would you need some special “space suit” to do London to Sydney in 4 hours?

[Scrump]

Earlier thread here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Recent thread on Reaction Engines:
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Edited by Scrump on Monday 18th March 07:20

[Eric Mc]

It's based on the technology being developed for the Skylon orbital spacecraft - which has been in development for over 20 years. Indeed, if you go back to the original Alan Bond concept, called HOTOL, you are looking at a gestation period of over 30 years.

There is no issue with the affect of such speed on humans. Hundreds of people have travelled faster in rides in and out of earth orbit without any undue effects. Developing the engines has been the main project so far. If and when the engine technology is made to work, the next hurdle is to design and build and airframe that is controllable in the atmosphere at high hypersonic speeds and can withstand the airframe heating that is associated with such speeds. These are problems that aeronautical engineers have been working on since the days of the X-15 and the Space Shuttle.

[CanAm]

Frank7 said:

It probably doesn’t, but I meant some kind of adverse affect on a human body, moving at that speed.
Maybe none at all, after all, humans go into space, but would you need some special “space suit” to do London to Sydney in 4 hours?

I don't think they'd get many passengers unless it was a 'shirt sleeve environment'. Having said that, crews of military aircraft such as the Blackbird do wear virtual 'space suits', and they are flying lower and slower!

[Eric Mc]

CanAm said:

I don't think they'd get many passengers unless it was a 'shirt sleeve environment'. Having said that, crews of military aircraft such as the Blackbird do wear virtual 'space suits', and they are flying lower and slower!

But crews on Space Shuttles between 1984 and the challenger accident started using "shirt sleeve" type flight suits with simple motor cycle helmets. After Challenger, they reverted to SR-71/U-2 based pressure suits - not because of the speed but fear that the might vehicle break up and depressurise due to the rather fragile construction of the Orbiter.

Suits worn on initial Shuttle flights -



Flight suits worn from 1984 to early 1986 -



Later pressure suits used for the remainder of the programme -



Concorde flew at speeds and altitudes where the outside conditions would prove pretty fatal to anybody exposed to them without a pressure suit - so it can be done.

[captain_cynic]

Frank7 said:

Sounds great, but there’s bound to be some unseen fly in the ointment which the developers haven’t discovered yet, like moving a human that far, that fast, turns them into leprechauns.

I don't think Leprechaunification is a serious issue with Sub Orbital Transport. the biggest problem is that you've got to get up there, there being 100KM (62 mi) above sea level. Jet engines stop working when the atmosphere gets too thin (about 10 miles up from memory), multi-engine setups are too complex and heavy which is why we still use rockets to shoot stuff into orbit.

Once you're up there going 5000 MPH is ridiculously easy due to less resistance from the atmosphere. Other problems exist when returning to earth, but mainly the same as the first, you need a reusable, efficient engine that can be used in all stages of ascent or decent.

Space planes will be a thing (assuming we don't blow ourselves up before then) but it'll still take some time.

[Tango13]

Having read Milton Thompsons book on flying the X-15 I'm curious as to how the passengers and crew are going to handle the 'G' loads on take off and descent?

The Shuttle would pull about 3G on takeoff and iirc correctly the X-15 could sustain 4G in the climb phase which is enough that you can feel your internal organs move, the X-15 landing involved the lovely sensation of feeling like your eyeballs were going to pop out of your head.

Whilst I doubt any space liner won't be that extreme I'd be interested to know how many 'G's the takeoff and landing will involve.

[boxst]

[stevesingo]

Tango13 said:

Having read Milton Thompsons book on flying the X-15 I'm curious as to how the passengers and crew are going to handle the 'G' loads on take off and descent?

The Shuttle would pull about 3G on takeoff and iirc correctly the X-15 could sustain 4G in the climb phase which is enough that you can feel your internal organs move, the X-15 landing involved the lovely sensation of feeling like your eyeballs were going to pop out of your head.

Whilst I doubt any space liner won't be that extreme I'd be interested to know how many 'G's the takeoff and landing will involve.

London to Sydney is 17000km. To cover this distance in 4hrs you need to average 4250kph.

From 0kph to 5000kph (Mach 4.7 at 60k feet) takes 16min 40sec at 0.5g average which is not really that uncomfortable.

[bad company]

stevesingo said:

From 0kph to 5000kph (Mach 4.7 at 60k feet) takes 16min 40sec at 0.5g average which is not really that uncomfortable.

It might cause some first class passengers to spill their g&t’s.

[Mansells Tash]

bad company said:

It might cause some first class passengers to spill their g&t’s.

...Straws

[Eric Mc]

stevesingo said:

London to Sydney is 17000km. To cover this distance in 4hrs you need to average 4250kph.

From 0kph to 5000kph (Mach 4.7 at 60k feet) takes 16min 40sec at 0.5g average which is not really that uncomfortable.

This craft would be reaching altitudes way in excess of 60,000 - more like 300,000 to 400,000 feet. It needs to get above most of the atmosphere to reduce the heat loads on the airframe.

[andy_s]

Mansells Tash said:

bad company said:

It might cause some first class passengers to spill their g&t’s.

...Straws

Paper ones, think of the environment...

[Tango13]

Eric Mc said:

stevesingo said:

London to Sydney is 17000km. To cover this distance in 4hrs you need to average 4250kph.

From 0kph to 5000kph (Mach 4.7 at 60k feet) takes 16min 40sec at 0.5g average which is not really that uncomfortable.

This craft would be reaching altitudes way in excess of 60,000 - more like 300,000 to 400,000 feet. It needs to get above most of the atmosphere to reduce the heat loads on the airframe.

Mach 4.7 at 60,000ft isn't possible, the sustained thermal loading would turn the airframe to jelly. The SR71 had to fly around 90,000ft to hit Mach 3.5 so as Eric rightly posted you need to be at 300,000ft+ and to get that high quick enough involves more 'G' than the average passenger would be comfortable with. On the way back down from that sort of altitude you've got a large mass travelling very fast which means an awful lot of energy to deal with. Either a long shallow low 'G' descent with a very, very high thermal load or a short eyeball popping descent with a relatively low thermal load.

[Blib]

captain_cynic said:

I don't think Leprechaunification is a serious issue with Sub Orbital Transport.

If only it was. I'd watch a live stream.

[Munter]

I think people would be prepared to put up with quite a bit if they can get between London and Sydney in 4 hours compared to the alternative.

Oh course if one is really rich, one doesn't need to rush and would take the yacht.