« Back to Home Page

Hydrogen-Burning Hypersonic Airplane: Going Green at Mach-5

3p Contributor | Tuesday January 29th, 2008 | 17 Comments

a2%20takeoff.jpg
The proposed future of air travel is quite a marvel. Seems unfathomable compared to the pollutant, oil-guzzling airliners of today. With the endless and testing delays, the awkward security, and greenhouse gas-emitting beasts, it’s a wonder why solutions have not yet come to fruition.
It just so turns out, it is all happening rather quickly behind the scenes. One proposed aircraft that seems wildly impossible is actually on the slate for possible funding for testing. The concept hypersonic jet has been developed by Reaction Engine and it is aptly called the A2. It is a Mach-5 (3,400 mph) wicked aircraft capable of holding 300 passengers and produces, get this, ZERO carbon emissions!
The project has been supplemented in part through funding from the European Union’s Long-Term Advanced Propulsion Concepts and Technologies project, otherwise known in short as (Lapcat). Lapcat is in search for an airliner that can cruise from Brussels to Sydney in less than 4 hours. The A2 can meet the expectations without leaving its footprint behind.


Engineers have been re-working the A2 with the Concorde’s short comings in mind. The technical director of the project, Richard Varvill, believes that the Concorde was trashed for a few major reasons, limitations rather. First, it could not fly far enough, the limited range kept it from flying trans-Pacific routes. These routes are where the biggest market potential is for these hypersonic jets. Second, the Concorde’s power plant was only efficient up to its Mach-2 cruising speed. The problem with that was when the jet was restricted to cruise at Mach-0.9 to avoid producing sonic booms; its gas mileage took a dive.
Because of these limitations that sank the Concorde, the A2 has compensated and improved upon the shortfalls. The A2 engine has two modes for efficient cruising which is a combination of ramjet and turbojet propulsion systems. These systems will allow the A2 to be efficient at slow speeds and also give it the power necessary to produce hypersonic very high speeds.
Some interesting twists include the lack of any windows in the design due to the heat the jet will have to mitigate and weight of space shuttle type windows that would be required. Although passengers like to have windows for viewing pleasure and comfort they might be willing to bend on that luxury to get from point A to B in 4 hours rather than the current 22 hour flight time.
The A2 will reach hypersonic speeds in the following manner:
Mode 1- The jet’s four Scimitar engines send incoming air through the bypass ducts to the turbines. These turbines will produce thrust similar to today’s jet engines. The turbine compresses incoming air and mixes it with fuel to generate combustion which is enough to push the jet off the runway and propel it up to Mach-2.5.
Mode 2- Once Mach-2.5 is achieved the A2 switches into high gear and begins to reach its value. The incoming air is rerouted into the engine’s core with enough pressure to sustain combustion at speeds of up to Mach-5. This is the principle behind all ramjet designs, but the A2′s Scimitar system kicks it up a notch by adding a turbine compressor to squash the air far more intensely.
The problem that has foreshadowed this idea is that air-breathing engines cannot use turbines due to the super heated air that enters the blades, some 1,800 degrees F. The Scimitar hopes to overcome this problem with the addition of a cooling system enveloped within the engine which will cool the air enough to allow it to run through a turbine.
The most astounding aspect of this concept is the ZERO “carbon” emissions footprint. The A2 is hydrogen powered so that it discharges only water vapor and nitrous oxide through the exhaust. Even though hydrogen still sounds dangerous to most folks, the fuel is actually no more explosive than normal jet fuel.
Hypersonic propulsion experts say that there is nothing fundamentally unsound in the A2′s plans. However, accomplishing the goal of making it happen is another story. Many obstacles will have to be overcome to perfect the design to the point of production. The heat exchange system is a serious issue and a massive engineering feat. Perhaps one of the biggest challenges is producing large amounts of hydrogen fuel without emitting carbon to do so. This leaves the A2 as not a truly green flying wonder because carbon-free hydrogen production is still a far ways off just yet but it is a radical start in a new direction.


▼▼▼      17 Comments     ▼▼▼

Newsletter Signup
  • Terry Rawlton

    zero *carbon* emissions, you mean. Strictly speaking the plane does indeed have emissions, they happy to be water vapor.

  • Dave

    Um, nitrous oxide does not equal zero emissions. It is a major greenhouse gas. See
    http://www.epa.gov/nitrousoxide/index.html
    and
    http://www.grida.no/climate/ipcc_tar/wg1/248.htm

  • brad

    Yes, saying there are zero emissions is ridiculous. Water vapor is the worst ghg, the difference being that water vapor creates clouds which could reflect more energy than they retain from the earth’s surface. NOx emissions are also nothing to trivialize.
    The question is whether these engines are just as efficient or more efficient than current turbine engines, taking into account all emissions.

  • Dave

    The amount of Nitrous Oxide released is negligible, nothing to raise serious concerns over comparatively. Also, forget not that this concept could take you from New York to London in only 2 hours, that is a remarkable leap in efficiency.
    And water vapor discharge is far more friendly to the skies than carbon emissions, in the classic definition of the term it is slated to be a truly ZERO “carbon” emissions aircraft.
    Nothing can be produced without something being wasted, let’s not get carried away with picking apart truly advanced, higher efficient and significantly more eco-friendly innovations.
    The negativity among many in the green industry is alarming, I say cheers to this concept, I would gladly support something that is far greener than the conventional airliners.

  • http://www.global-risks.com James Haselip

    Indeed this does not appear to propose any radical solutions to the air transport dilemma, not least of all because of the known greenhouse effect of high-altitude water vapour emissions. More importantly (and despite the hype) hydrogen technology is decades away from commercial viability, while solutions will be required over the next 5-10 years.
    From a short to medium term commercial perspective, the drive to develop and test biofuel aviation is likely to prove popular among increasingly ‘carbon conscious’ air passengers. And while biofuel initiates such as those launched by Virgin and Air New Zealand last year are limited to working within the confines of existing technology and a culture of high speed air travel, the mere fact that airlines are seeking to move beyond what is currently an unsustainable industry is a positive step which could lead to a number of as yet unknown future technology options, perhaps radically different from the dominance of today’s jet-engine travel.
    But by thinking bigger, faster and more hi-tech, we may be overlooking more simple technological solutions. For example, a new generation of low-energy airships that could transport passengers and goods at lower altitudes, albeit at slower speeds!
    http://www.global-risks.com

  • Takko

    BRing back the airship! Slower, yes, but sooooo much more comfy

  • Pat

    Just something to think about: While this plane has no carbon emmision, so does the factory that produces the hydrogen liquid. And the emmision of the factory to produce the required hydrogen is greater than what the plane would produce by flying with kerosin. The only thing that “might be better” is that the factory can filter the carbon and then pump it beneath the earth. (Thats how factories store the filtered carbonoxide)

  • Axel H√•ll√©n

    Why is the human race so fixated on flying? There are ways to go 3000 km/h in maglev trains in low pressure tunnels.
    check this link out:
    http://faculty.washington.edu/jbs/itrans/suppes.htm

  • Nadia

    It is as if many of you have not read the fine print. This is a “concept” aircraft, a long ways off from production if ever. With time comes advanced technology, perhaps in time there will be a way to produce hydrogen fuel at low carbon emission price compared to current methods. Happy to see industries and organizations thinking out of the box to improve our world. It is a wonderful idea, great article.

  • http://www.apple-pie.com apple pie recipe

    Zero carbon emissions? Wow. Now if we can only get airlines to adopt it. Thats the problem. Most airlines are cash strapped.

  • anon

    It’s only really zero emission if the hydrogen that’s powering it was created using zero emissions. Otherwise, it’s just transferring the emissions from the plane to the power plant producing the energy required to produce hydrogen.

  • ret

    No more energy is used to make hydrogen than to regular fuel….probably less….and making the aircraft ain’t going to add anything. As airplanes are being manufactured at the present moment it aint adding anything new. Again due to manufacturing developments it might even be less of a carbon problem. Whats not to say spin offs like smaller cheaper hydrogen engine wont happen. Some people wont be happy till we go back to the horse and cart and candles.

  • Frank Eggers

    This may have possibilities, but what about safety?

    The plane would be carrying a large quantity of liquid hydrogen. If the plane crashed, the hydrogen would be released and almost certainly burn. Probably there would be no survivors on the plane, but usually there aren’t survivors with tradtional jet fuel anyway. But what about people on the ground? Would they be in greater danger?

    Would refueling be safe? What about the large liquid hydrogen tanks at airports? Would they be safe?

    It may be that all these problems could be adequately dealt with, but they must be considered.

  • dave

    HI how about the destruction of humans afterall we are parisites to this beloved earth. How about we lower the worlds population thus cutting enormous emissions and polution all together. China rising will do ten times the amount of damage the USA has done. Something to think about. Maybe there is nothing we can do but just sit back and watch our polar caps melt thus destroying the earths axis and putting us in a death spin.

  • Pepito Grillo

    Hydrogen being no more dangerous than common fuel???? Hydrogen at high speeds burns with oxygen just by itself. A crack on a seal on a pressurized tank is enough.
    Anyway I would love to see this thing flying

  • dan

    it is interesting at how smart the human race thinks it is, and how amazingly dumb and lacking in any intellectual idealisms they are, except for the occasional einstien that can truly see through it all.
    why not create a more efficient way to remove hydrogen from water rather than crude oil? it is already being done on smaller scales. then alot of your problems discussed no longer exists
    dan

  • Maxim

    Its an awesome concept, but with no windows? That can be a huge problem, i.e. it can cause motion sickness in some passengers. I believe something must be done about that. Better R&D in the window department is a must.