Comments on: MACH-5 A2: Fly Sydney to Brussels in 4hrs – Emissions Free!

By: paulfenn

paulfenn — Mon, 12 May 2008 21:25:59 +0000

I noticed here there are some who wonder where we get the electrical current to split the hydrogen away from the oxygen – anyone ever here of fan turbines? With these speeds it would be an easy matter for turbines to use the wind velocities to generate electricity – they can be located and built into the design and they wouldn’t have to be monstrosities either – (an air born windmill)

By: blog

blog — Thu, 28 Feb 2008 12:56:59 +0000

No visions about the future in comments. W Wright , Cooke, etc must have their doubts about the future.Nothing ventured nothing gained.Pessimests are the insecticides of the future.
samoht .

By: popeye

popeye — Wed, 13 Feb 2008 18:15:22 +0000

Tidal power to generate the potential needed for hydrogen seperation, or geothermal, or solar or god forbid nuclear (with GTMHR maybe…) :0

By: Bulldog

Bulldog — Mon, 11 Feb 2008 09:34:48 +0000

I think its great but who controls it? It might crash like concorde though.

By: woozle

woozle — Mon, 11 Feb 2008 09:30:46 +0000

where the heck is the tailfin?!

By: kjb

kjb — Thu, 07 Feb 2008 07:57:15 +0000

It’s not sub-orbital for a very good reason. To do that you need to carry the oxidiser with you and that increases the take-off weight to where a runway capable reusable craft with a reasonable payload becomes problematic.
Also, liquid hydrogen is the probably the only choice of fuel for this due to it specific energy being greater than hydrocarbon fuels.

By: Justin

Justin — Sun, 03 Feb 2008 16:55:01 +0000

Pardon me, Correction, the windows wouldn’t blow out. The surface changes with having windows would put a lot of stress on the airframe at hypersonic speeds. The plane has to be virtually seamless in order to fly without damaging itself.

By: Justin

Justin — Sun, 03 Feb 2008 16:26:35 +0000

I don’t know about you, but I think this is a really cool concept for future airliners, even if the concept itself doesn’t go into production. Honestly though, I wonder why they’re aiming for such a high speed. Mach 5 is a pretty tall order for any aircraft, (Mach 2 or 3 would be more reasonable). The thing I heard about hydrogen not being produced cleanly and having a low energy density per unit of volume; these are all challenges to overcome, but I believe with time and research, these problems can be solved.

Also, if anyone’s wondering, I asked my dad why they didn’t put windows on the plane, even for the cockpit. He said that the forces exerted on an aircraft at those speeds would deform a window so much that it would blow out in flight. (He was in the Air Force as a comm officer on the Looking Glass so he knows this kind of stuff). Save for maybe a bubble canopy in the cockpit, there would be no windows on a hypersonic airliner. Maybe they could put a line of imbedded cameras along both sides that link to flat-screen moniters on the interior so that people could still see outside.

By: Joni

Joni — Fri, 25 Jan 2008 17:58:53 +0000

Looking on their website, it does seem to be from 2005. Has there been any updates up till now?

By: Corey

Corey — Thu, 24 Jan 2008 21:45:11 +0000

Burning hydrogen way up there is far from “green”. When hydrogen is burned it produces water vapor. Water vapor is a greenhouse gas that’s more effective/dangerous than CO2. In other words, this is worse than regular jets for all intents and purposes.

By: Kat

Kat — Thu, 24 Jan 2008 10:31:47 +0000

interesting discussion, although i can’t contribute much, but.. there’s someone in the world named John Scott-Scott? that’s all i got.

By: Rassendyl

Rassendyl — Thu, 24 Jan 2008 07:30:49 +0000

Now thats what I call SPEED.

By: Daemon

Daemon — Thu, 24 Jan 2008 03:20:37 +0000

The engines exist, the have for a bit now (hello X-43), but they’re not likely to look anything like the pictures depicted here… nor is the amusing-to-the-point-of-ludicrous airframe.

One of the big problems with such an airframe that I don’t think has been mentioned yet is acceleration/deceleration and noise pollution. You want it to go Mach 5? When? Not over your house, but the design needs to be very optimized to operate at those speeds so either you accept sonic boom over populated areas as it accels/decels, only fly it where it can do so over water, or figure out a whole field of hypersonics that allows for efficient slow-speed flight. Riiiight. Investors invest when the market is there (which it is), the technology is there (which it mostly is), and the REGULATIONS allow the darn thing to FLY and pay back its investment. Its a pricey lil’ bugger so someone’s gotta foot the bill.

Nice fantasy though, does kinda look like that old Thunderbirds puppet show. The graphics weanie and I had a shared childhood, how sweet… only I grew up to actually do something besides produce ballyhoo navel-gazing pictures that distract from real progress in the field.

Educate yourself: http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/aw031907p2.xml

By: Josh

Josh — Wed, 23 Jan 2008 20:19:45 +0000

@ Rich: In web comments, there is really nothing worse than a good criticism dripping with sarcasm and faux-politeness. Please avoid affectation. Thanks

@ comments about the windows: I hate flying and I hate looking out the window at the wing/engine/ground. Doing everything you can to shorten my trip AND helping me avoid eye contact with what is around me is the biggest favor that the airline industry could do for me. Yay for supersonic beer cans!

By: greg

greg — Wed, 23 Jan 2008 19:33:42 +0000

Good comments. It is nice to see that many recognize that the use of hydrogen as a “fuel” is not, as inhabitat writes, “emissions free.” Someday (ah yes, “someday”) it could be, but hydrogen is not and will not for a long time be an emissions free energy storage medium.

If i ran a deisel generator to pump water up behind a dam and then harvested the hydro energy, would we call that “emissions free?”

If I burned coal to drive a giant fan and then harvested the wind for electricity would we call that “emissions free?”

Until we can generate hydrogen solely and reliably from non-emitting sources, hydrogen use is NOT emissions free.