Looking for transport of the future

[Michel Kieffer]

Looking for transport of the future

What does the future hold for transport? Will technological developments allow us to move like today? Or will displacement, as we have known it for a few decades, be called into question?

The new documents « CO2 target " and " Airplanes and CO2 * »Offer some answers to these questions (link http://www.hkw-aero.fr/energies.html ou http://www.cocyane.fr/ then click on "hkw").

Good reading

Michel

PS: These are hypotheses… do not hesitate to question one or the other point.

* The document " Aircraft and CO2 Will be available a few days.

[sen-no-sen]

In less than 15 years (depending on the global economy of course) we will experience a major change in our relationship with transport.
The "low cost" air flight will certainly disappear in the short term (besides I have a lot of trouble to understand how investors can still get into this field).
Airlines are going to have to seriously adapt ... or die.
Likewise, planes will have to evolve (flying wings, increased use of jet streams, etc.).
I think the future of fast long distance transport is the ekranoplane or "ground effect plane", boeing is working on it).
For individual transport, the solution will be .... collective transport
and the electric car.
In any case to think that we will be able to continue to move in the same way (cheap oil) is a beautiful illusions!

[oiseautempete]

Likewise, planes will have to evolve (flying wings, increased use of jet streams, etc.).
I think the future of fast long distance transport is the ekranoplane or "ground effect plane", boeing is working on it).
For individual transport, the solution will be .... collective transport
and the electric car.

The flying wings pose a problem of congestion on the ground, already with the A380 it was necessary to enlarge the infrastructures ... The Stream jets? we have been using it for a very long time, but there is not necessarily a jet stream in the direction we want to go ...
The ekranoplane may be a runway, but there is the problem of safety in relation to ships and sailboats, sensitivity to the state of the sea and infrastructure must be created (which will be reminiscent of those that existed for seaplanes ...) ... it is not for nothing in my opinion that the Russians do not insist too much on this after having long used ekranoplanes on the Caspian Sea ...
Public transport is only possible for a concentrated habitat, outside of our countries the tendency is to dispersal because people support less and less the big urban centers ... and who says dispersed habitat, says individual vehicle, but 100 % electric I don't really believe in the current state of the art ... hybrid yes ...

[sen-no-sen]

We have to understand one thing very quickly: the future will hardly give us a choice!
Regarding the flying wing, Boeing and Airbus are working on the concept.
The concept of the tourist transport plane in the shape of a "cigar with wings" will have to evolve one day and it will be done within 30 years.

In the same way for the ekranoplanes which will be able to transport more than 1500 passengers at nearly 600km / h, the Russian "wigs" were abandoned by fault of strategic interests, more the data processing and the flight management system were almost non-existent at the time.

For the car it must be understood that the industrial countries
will have to "share" their resource with developing countries (in 2025: 800 million cars in China )

[Michel Kieffer]

Some theoretical elements

The shape of an airplane and its total wetted surface (SMT) condition its aerodynamic efficiency (see the various presentations on the "hkw aero" site).

The shapes are almost perfect today (very difficult to do better), and the SMTs are almost incompressible: the volume of the fuselage is fixed by the size of the passengers; the surface of the wing is constrained by the minimum lift speed imposed by the regulations: 100 knots (182 km / h) at takeoff or landing (Of ​​course, the plane will always keep a margin compared to this limit).

And this is where the problem arises: the surface of the wings (therefore its contribution to the SMT) is determined by the speed above, by the mass and by the max lift coefficient of the wing (Cz max) . And today, the high lift devices (flaps, spouts ...) are at the top ... so little progress to expect on this side. This makes it possible to affirm that the surface of the wings will hardly change in the future ... of course the "supersonic" designs are tracks in principle illusory.

There are still other tracks with very reduced potential today: reducing masses (difficult to do better), improving engine efficiency (not much to expect on this side) and propulsion efficiency. As for this last point, we have a little room for progress by increasing the dilution rates, which amounts roughly to returning to the propellers or something close to it.

And what about the concept of a flying wing? The problem is identical with perhaps (?) A slight reduction in mass. Slight progress, perhaps, but certainly no revolution to expect on this side.

There remains, however, an attractive solution: reduce speeds and optimize our planes accordingly (wing with large aspect ratio, propellers, etc.). Note that these solutions exist in short haul: see the range of ATR aircraft.

There remains the unstoppable solution: move less… and rediscover what is next .

Michel

[I Citro]

Before studying your new creations in detail, I would like to share Oiseautempête's opinion on ekranoplanes. I do not see these devices developing for wider civilian use. Their safety, their comfort ... make them unsuitable for such use. They will confine themselves to military uses ...

I see more changes in the reduction of operating costs, through the limitation of masses and powers ...
From memory, the wing loading of current aircraft is around 600kg / m². Current aircraft are therefore irons that only fly because they are overpowered ...

Am i wrong?

[chatelot16]

the economic transport of the future is not the plane

the most economical transport was by train some ten years ago

Today the train tries to go as fast as the plane: TGV too fast to be economical ... too expensive for the one who is not in a hurry ...

the plane is complicated: it eats the energy to stay in the air: to consume the possible month you have to stay in the air as short as possible so go fast!

it's like the car: there are a lot of accidents, to reduce the risk you have to go very fast to be in danger for as short a time as possible ...


the worst part is that i work in an airport! I would like the air transport to continue!

my passion for gasifier and cogeneration will not make planes work but will become my new activity if there is not enough plane left

[Michel Kieffer]

Response to the question formulated by Citro

First of all, a big hello to everyone on this forum.

Question formulated by Citro: what is the impact of the load per m2 (500 - 600 kg for a transport aircraft) on the consumption of the aircraft?

The power, therefore its consumption, is conditioned by the parasitic drag (or shaped drag) and by the drag induced by the lift. These 2 streaks add up. See for this purpose:
- the equation page 10 of the document http://www.hkw-aero.fr/pdf/avion_electrique.pdf
- the layout on page 10 of the document http://www.hkw-aero.fr/pdf/design_techno_perfo.pdf
- note that the above equation is the same for cars or trains, except drag induced by lift which is replaced by drag. And we add the term which takes acceleration into account. See the equation on page 11 of the document http://www.hkw-aero.fr/pdf/energie_utile_voiture.pdf

This recalled, imagine a transport aircraft whose wing load would not be 600 kg per m2 but half, or 300 kg per m2.

The consequence would actually be a reduction in induced drag (cf. equation above), but… the increase in the wing area would lead to degrading the parasitic drag and the mass. Consequently, the plane would be heavier, which would require more power, which would require increasing power and the amount of fuel, which would amount to re-increasing the load per m2… and here we are starting a good start divergent spiral (which we all fear!). See the spiral on page 4 of the document http://www.hkw-aero.fr/pdf/comment_atte ... ectifs.pdf .

To sum up, our transport aircraft finds its optimum with high wing loads.

And that's where you realize the performance: 600 kg / m2 at low speed, you have to do it. The solution, you have all seen it on an AIRBUS or BOEING wing with all high-lift devices deployed (on landing). See for example http://fr.wikipedia.org/wiki/Dispositif ... stentateur or, on a much more modest scale, the 3rd photo on the page http://www.hkw-aero.fr/projet.html .

Michel

[I Citro]

Response to the question formulated by Citro
what is the impact of the load per m2 (500 - 600 kg for a transport aircraft) on the consumption of the aircraft?

... This recalled, imagine a transport aircraft whose wing load would not be 600 kg per m2 but half, or 300 kg per m2.

The consequence would actually be a reduction in induced drag (cf. equation above), but… the increase in the wing area would lead to degrading the parasitic drag and the mass. Consequently, the plane would be heavier, which would require more power, which would require increasing power and the amount of fuel, which would amount to re-increasing the load per m2… and here we are starting a good start divergent spiral (which we all fear!). See the spiral on page 4 of the document http://www.hkw-aero.fr/pdf/comment_atte ... ectifs.pdf .

To sum up, our transport aircraft finds its optimum with high wing loads.

Thank you Michel, you couldn't be more clear.

[oiseautempete]

the surface of the wing is constrained by the minimum lift speed imposed by the regulations: 100 knots (182 km / h) at takeoff or landing (Of ​​course, the plane will always keep a margin compared to this limit).


There remains, however, an attractive solution: reduce speeds and optimize our planes accordingly (wing with large aspect ratio, propellers, etc.). Note that these solutions exist in short haul: see the range of ATR aircraft.

This 100kt limitation is undoubtedly "all out" in the landing configuration, because the takeoff rotation speed at full load is much higher, around 145-150 kt ... note that no commercial aircraft can be land with a full load: either it poses slowly with a fairly high vertical speed and goes crazy, or it poses fast and goes off the track ... suddenly, in the event of a problem that would force you to rest with the full, it must first activate its "vacuum quickly" to lighten the plane before landing ...
Speed ​​reduction is indeed a solution, and no need to bump it down much: a Tupolev 95 flies at more than 800 km / h with propellers, on the other hand it will be necessary to optimize the latter so as not to have too much noise: for example , it suffices to compare the noise level of the Antonov 70 and that of the A400M to understand ... (but except for this detail, the AN70 is clearly superior to the A400M ... and for half the price. ..)