Absurdly inane BBC article

[kerbiloid]

32 minutes ago, fredinno said:

what IS SCP ANYWAYS

SCP — Special Containment Procedures or Secure, Contain, Protect.

http://www.scp-wiki.net

Series III (2000-2999)

Series II (1000-1999)

Series I (001-999)

An internet setting/project/pen-game about a fictional worldwide Foundation collecting surrealistic/fictional/anomalous artifacts and protecting the humanity.
A large catalog of the artifact descriptions and short mostly creepy novels about them, with main characters and organizations, crossing between each other.
A bunch of casual computer games/mods, creepy stories and from time to time movies are based/use this setting.

Basic classes of danger.
http://www.scp-wiki.net/object-classes

Classes of personnel (pay attention for D)
http://www.scp-wiki.net/security-clearance-levels

Edited July 18, 2016 by kerbiloid

[fredinno]

8 hours ago, kerbiloid said:

SCP — Special Containment Procedures or Secure, Contain, Protect.

http://www.scp-wiki.net

Series III (2000-2999)

Series II (1000-1999)

Series I (001-999)

An internet setting/project/pen-game about a fictional worldwide Foundation collecting surrealistic/fictional/anomalous artifacts and protecting the humanity.
A large catalog of the artifact descriptions and short mostly creepy novels about them, with main characters and organizations, crossing between each other.
A bunch of casual computer games/mods, creepy stories and from time to time movies are based/use this setting.

Basic classes of danger.
http://www.scp-wiki.net/object-classes

Classes of personnel (pay attention for D)
http://www.scp-wiki.net/security-clearance-levels

So, basically a giant RP?

[kerbiloid]

1 hour ago, fredinno said:

So, basically a giant RP?

If RP - "roleplay", no. A collection of fanfics on the same theme, with moderators, etc. But not a game.

[DDE]

15 hours ago, fredinno said:

 

 

But VASMIR IS worthwhile, just as a conventional ION drive would...

 

 

Lower efficiency (50% vs 70%), requires superconducting magnets and a nuclear power plant that isn't anywhere near the drawing boards and is likely impossible.

http://spacenews.com/vasimr-hoax/

Remember those 'uses' of government financing? It sounds very much like one.

15 hours ago, fredinno said:

Also, relavent

 

 

Just when I can't watch a T-foot vid...

[p1t1o]

16 hours ago, fredinno said:

Why is VTOL bad?

Because you need a TWR significantly greater than 1 to do it, whereas taking off horizontally, you can get away with TWRs that are much lower, 0.2-0.4 could be considered common. And when VTOL-ing, you need to be able to produce your >1TWR at zero velocity, with no airflow, and if a loss of power is encountered, you have no horizontal velocity with which to produce lift or safely glide it out. Basically you have to multiply your margins by some ungainly number, making it hugely inefficient. Frankly, if you have a fusion powered VTOL airliner, what is it doing having wings anyway? Why even have it land at all?

[kerbiloid]

Just now, p1t1o said:

Frankly, if you have a fusion powered VTOL airliner, what is it doing having wings anyway? Why even have it land at all?

Do you keep the gas pedal pressed into the floor all the road driving a car? Or it's mostly moved by inertia?

Edited July 19, 2016 by kerbiloid

[cubinator]

7 hours ago, kerbiloid said:

Do you keep the gas pedal pressed into the floor all the road driving a car? Or it's mostly moved by inertia?

The car is moving horizontally, so if you let go of the accelerator it will keep going for a while. A hovering VTOL will just drop if it does that, hence the extra design requirements.

[kerbiloid]

14 minutes ago, cubinator said:

The car is moving horizontally, so if you let go of the accelerator it will keep going for a while. A hovering VTOL will just drop if it does that, hence the extra design requirements.

Both car and VTOL are saving their engine minimizing its power. One - thanks to the inertia, another - thanks to the lifting force of the air.
VTOL plane can stay in air without wings, but it does the same.

[cubinator]

7 minutes ago, kerbiloid said:

Both car and VTOL are saving their engine minimizing its power. One - thanks to the inertia, another - thanks to the lifting force of the air.
VTOL plane can stay in air without wings, but it does the same.

True, but while the VTOL is 'VTOLing' it has to maintain an impractically high thrust at low airspeed, making it a much less viable option than traditional horizontally-launching planes.

[Emperor of the Titan Squid]

the good thing is that they are actually trying to slove the engineering challenges, instead of just giving up, like what happened with x-33.

[PB666]

6 minutes ago, Emperor of the Titan Squid said:

the good thing is that they are actually trying to slove the engineering challenges, instead of just giving up, like what happened with x-33.

Seriously, that's your justification?

You attempt a new strategy when there is a significant change in base technologies. LfOx systems still have an ISPnax of 445 sec, there is still turbulence problems at Mach 5, and there is been no major improvement in multicompressor ramjet technology in decades, the speed required to orbit is still 17000 MPH at the equator, the height required to get past mach 5 is still well about 100,000 feet, wings still create side drag and lift drag, Gravity still pulls at >9.7 m/s^2 up to well past 200,000 feet.

Until you have a rigid flight bed that can lift something well into the 30 to 60 km range gently push it off, allow it blast itself into the orbit without destroying itself or its lift vehicle, then that vehicle decelerate and safely land on its own landing gear or whatever, its not any better than what space X can currently do.

Frankly I don't think the advantage gained is any better than the current First stage takeoff and land systems. If you think they could reuse the vehicle 10 times in a month, thats nothing but hype.

 

 

 

 

[fredinno]

19 hours ago, DDE said:

Lower efficiency (50% vs 70%), requires superconducting magnets and a nuclear power plant that isn't anywhere near the drawing boards and is likely impossible.

http://spacenews.com/vasimr-hoax/

Remember those 'uses' of government financing? It sounds very much like one.

 

Just when I can't watch a T-foot vid...

Efficiency is not a big deal with ION, since they are so efficient anyways....

And all ION need highly powerful magnets to channel the IONs out of the thrust chamber.

No nuclear power plant is needed if you have big enough solar cells. And all ION drives have the same 'too much energy use' issue...

 

Seriously, this is more "I think ION drives are bad" than "I think VASMIRs are bad". The former has been busted by the use of ION drives extensively in government and commerical satellites to save tons of fuel (and $$$). Ever heard of DAWN?

18 hours ago, p1t1o said:

Because you need a TWR significantly greater than 1 to do it, whereas taking off horizontally, you can get away with TWRs that are much lower, 0.2-0.4 could be considered common. And when VTOL-ing, you need to be able to produce your >1TWR at zero velocity, with no airflow, and if a loss of power is encountered, you have no horizontal velocity with which to produce lift or safely glide it out. Basically you have to multiply your margins by some ungainly number, making it hugely inefficient. Frankly, if you have a fusion powered VTOL airliner, what is it doing having wings anyway? Why even have it land at all?

VTOL are more efficient due to their smaller wings, and the ability for the upper stage to be a lifting body, vastly reducing structural mass.

 

They are also simpler, since unlike HTHL, they use only rocket fuel, not rocket and jet fuel- and if an engine goes out a Mach 5 in the atmosphere, ou're pretty much screwed without an abort system regardless.

 

And the extra margin would increase reliability (in theory). In practice, a HTOL would have very high margins added too, since Skylons are NOT cheap.

6 hours ago, PB666 said:

Seriously, that's your justification?

You attempt a new strategy when there is a significant change in base technologies. LfOx systems still have an ISPnax of 445 sec, there is still turbulence problems at Mach 5, and there is been no major improvement in multicompressor ramjet technology in decades, the speed required to orbit is still 17000 MPH at the equator, the height required to get past mach 5 is still well about 100,000 feet, wings still create side drag and lift drag, Gravity still pulls at >9.7 m/s^2 up to well past 200,000 feet.

Until you have a rigid flight bed that can lift something well into the 30 to 60 km range gently push it off, allow it blast itself into the orbit without destroying itself or its lift vehicle, then that vehicle decelerate and safely land on its own landing gear or whatever, its not any better than what space X can currently do.

Frankly I don't think the advantage gained is any better than the current First stage takeoff and land systems. If you think they could reuse the vehicle 10 times in a month, thats nothing but hype.

You could do 10x a month with enough demand....

X-33 showed it was possible, even with H2 Lox.

[Shpaget]

Are we still talking about the airliner or are we talking about orbital stuff?

VTOL airliners are not going to happen unless we magic up a power source of mind boggling energy density. A fusion reactor of a fraction of the size of current best (paper) designs that somehow doesn't irradiate everything on board, or batteries straight out of a Jedi light saber or Star Trek hand held phaser.

I also don't see airliners using LOX any time soon. For a vehicle to not use the atmospheric oxygen but carry it onboard sounds asinine. Same goes for not using air as reaction mass. Modern turbofan engines rely on air as reaction mass so much that only about 10% of the air that goes through the engine actually goes through the combustion chamber. The other 90% is just pushed around the engine. And we're not talking about small quantities of air either. Rolls Roys Trent XWB engine, for example displaces around 1400kg of air every second. Airbus A350 has two of them.

[p1t1o]

3 hours ago, fredinno said:

VTOL are more efficient due to their smaller wings, and the ability for the upper stage to be a lifting body, vastly reducing structural mass.

Hmm? We are talking airliners here aren't we? Its not going to have smaller wings if it needs to fly at all, in fact larger wings would capture more ground effect and rebounded exhaust, increasing lift in the VTOL mode. No reason why any craft cant have lifting body characteristics either.

 

3 hours ago, fredinno said:

They are also simpler, since unlike HTHL, they use only rocket fuel, not rocket and jet fuel- and if an engine goes out a Mach 5 in the atmosphere, ou're pretty much screwed without an abort system regardless.

Are you talking about an SSTO?

About aborts, this isn't necessarily the case. For example, the concorde apparently had quite benign characteristic even if two engine went out on the same side at Mach 2. This was due to the way air was dumped from beneath the engine, countering the loss of lift and reducing the increase in drag.

[SinBad]

53 minutes ago, Shpaget said:

Are we still talking about the airliner or are we talking about orbital stuff?

VTOL airliners are not going to happen unless we magic up a power source of mind boggling energy density.

Even with awesome power densities, for an atmospheric craft aerodynamic lift designs will always be more efficient than VTOL (barring any hoopdedoo future tech antigravioli propulsion devices) just because it takes less energy to generate X amount of lifting force by propelling a wing forward than it does to have the engine provide lift directly. Even helicopters use their powerplants this way, its a rotating aerodynamic lifting surface. Airliners are already a business running tight profit margins, every extra bit of lost efficiency turns into lost profit. Which is why i am of the opinion that vtol will not be used in a commercial transport role where it can be avoided. (The company next door to my old job was a helo operator that mostly serviced oil rigs, hard to htol on those)

[YNM]

On " Why is VTOL bad ? Maybe we can in one point" :

Why waste propellant/fuel for takeoff when you can use the airflow for that ? I mean, the design for this fictional aircraft is blended wing right ? Unless you get problems with space (like on most carriers) or with stresses (like fighters) where large wings are detrimental, VTOL are just not worth it. Harriers, the only operational VTOL aircraft today, only have tiny wingspan for it's length.

On 7/18/2016 at 11:18 PM, fredinno said:

IN any case, we don't even have a Concorde 2.0. I wonder why. Was noone using it?

Many says rivarly. Others say economics. I say, nobody is impressed for the shorter time, as well as safety. Luxury things aren't relevant anymore - the bargaining point today is to create the cheapest.

Edited July 20, 2016 by YNM

[PB666]

1 hour ago, YNM said:

On " Why is VTOL bad ? Maybe we can in one point" :

Why waste propellant/fuel for takeoff when you can use the airflow for that ? I mean, the design for this fictional aircraft is blended wing right ? Unless you get problems with space (like on most carriers) or with stresses (like fighters) where large wings are detrimental, VTOL are just not worth it. Harriers, the only operational VTOL aircraft today, only have tiny wingspan for it's length.

Many says rivarly. Others say economics. I say, nobody is impressed for the shorter time, as well as safety. Luxury things aren't relevant anymore - the bargaining point today is to create the cheapest.

Concorde 1.9 was expensive to develope and was not safe tontake off,mit would have been more expensive to make it safe, there were only four flights. It was a very space age idea, but it was not fully developed. 

[DDE]

11 hours ago, fredinno said:

Efficiency is not a big deal with ION, since they are so efficient anyways....

And all ION need highly powerful magnets to channel the IONs out of the thrust chamber.

No nuclear power plant is needed if you have big enough solar cells. And all ION drives have the same 'too much energy use' issue...

 

 

VASIMR is not an ion thruster, it's a wholly different family, electromagnetic (pondermotive, to be precise) as opposed to electrostatic. No, the magnets aren't the element accelerating remass in a Hall-effect thruster. Therefore your appeal to Dawn is invalid.

Efficiency is always a big deal, because the requirement for a reactor results in your propulsion system mass bloating; sure, you can have high ISP, but the hit to the ship's mass ratio still results in your dV tanking, pun intended.

No, there appears to be no way to power a VASIMR with solar panels; or, if there is, it is even heavier than a reactor.

[magnemoe]

9 minutes ago, DDE said:

VASIMR is not an ion thruster, it's a wholly different family, electromagnetic (pondermotive, to be precise) as opposed to electrostatic. No, the magnets aren't the element accelerating remass in a Hall-effect thruster. Therefore your appeal to Dawn is invalid.

Efficiency is always a big deal, because the requirement for a reactor results in your propulsion system mass bloating; sure, you can have high ISP, but the hit to the ship's mass ratio still results in your dV tanking, pun intended.

No, there appears to be no way to power a VASIMR with solar panels; or, if there is, it is even heavier than a reactor.

As I understand it was thoughts of installing an vasmir on the IIS for the lifting burns and to prove the technology, this was canceled but would have used the stations solar panels for power
And yes they are heavy. If you could scale vasmir down to something more fitting on an probe rater than an manned interplanetary ship power demands would be lower but its probably an lower limit on power it will need. 

[Shpaget]

Oh, one more thing... Has any of you ever been in a Concorde?

I was. And I was really unimpressed. That thing is tiny. In a world where airlines advertise "Extra room", they really are left behind.

Edited July 20, 2016 by Shpaget

[DDE]

2 hours ago, magnemoe said:

As I understand it was thoughts of installing an vasmir on the IIS for the lifting burns and to prove the technology, this was canceled but would have used the stations solar panels for power
And yes they are heavy. If you could scale vasmir down to something more fitting on an probe rater than an manned interplanetary ship power demands would be lower but its probably an lower limit on power it will need. 

Yeah, but I haven't seen good info on how well it scales down. There are very few reasons to use it over current electrostatic thrusters. I mean, do you really want to deal with liquid hydrogen or liquid lithium when compressed xenon does the job well enough? Not to mention the ISPs can be forced through the roof (~12000 sec).

Also, VASIMR isn't being developed for probes. It's touted as a manned interplanetary craft engine, possibly because it overcomes the inherent thrust limitations of ion thrusters (although it's not fully clear why an array of a few thousand of them is off the table).

[magnemoe]

10 hours ago, SinBad said:

Even with awesome power densities, for an atmospheric craft aerodynamic lift designs will always be more efficient than VTOL (barring any hoopdedoo future tech antigravioli propulsion devices) just because it takes less energy to generate X amount of lifting force by propelling a wing forward than it does to have the engine provide lift directly. Even helicopters use their powerplants this way, its a rotating aerodynamic lifting surface. Airliners are already a business running tight profit margins, every extra bit of lost efficiency turns into lost profit. Which is why i am of the opinion that vtol will not be used in a commercial transport role where it can be avoided. (The company next door to my old job was a helo operator that mostly serviced oil rigs, hard to htol on those)

This you want too avoid vtol if possible. Aircrafts operate from airports anyway, and would outside of premium charter and private planes even if vtol was an free feature. Its not and pointless on something long range outside military and special use

 

[Emperor of the Titan Squid]

23 hours ago, PB666 said:

Seriously, that's your justification?

You attempt a new strategy when there is a significant change in base technologies. LfOx systems still have an ISPnax of 445 sec, there is still turbulence problems at Mach 5, and there is been no major improvement in multicompressor ramjet technology in decades, the speed required to orbit is still 17000 MPH at the equator, the height required to get past mach 5 is still well about 100,000 feet, wings still create side drag and lift drag, Gravity still pulls at >9.7 m/s^2 up to well past 200,000 feet.

Until you have a rigid flight bed that can lift something well into the 30 to 60 km range gently push it off, allow it blast itself into the orbit without destroying itself or its lift vehicle, then that vehicle decelerate and safely land on its own landing gear or whatever, its not any better than what space X can currently do.

Frankly I don't think the advantage gained is any better than the current First stage takeoff and land systems. If you think they could reuse the vehicle 10 times in a month, thats nothing but hype.

 

 

 

 

I get the point, but its good that people are trying to make things happen, instead of just giving up. 

[PB666]

2 hours ago, DDE said:

Yeah, but I haven't seen good info on how well it scales down. There are very few reasons to use it over current electrostatic thrusters. I mean, do you really want to deal with liquid hydrogen or liquid lithium when compressed xenon does the job well enough? Not to mention the ISPs can be forced through the roof (~12000 sec).

Also, VASIMR isn't being developed for probes. It's touted as a manned interplanetary craft engine, possibly because it overcomes the inherent thrust limitations of ion thrusters (although it's not fully clear why an array of a few thousand of them is off the table).

Because like VASIMR, they need a GW of electric power and currently no feasible source in space. Solve the electric power problem, and the radiation problem cheaply then you have a choice.

[pxi]

Dumb question but, asides from all the technical issues, do we really want to go sticking fission reactors on planes?  What exactly happens when a fission reactor has a high-speed encounter with the ground?

(This may explain why I'm unqualified to write for the BBC.)

Edited July 21, 2016 by pxi