Looking for transport of the future

[chatelot16]

yes we are talking about transport of the future

if in the future everyone wants to go to work by plane it will be a big remedy against overpopulation ...

the private plane will never be a mass transport, the sky is not big enough

but we have the right to dream!

[chatelot16]

Chatelot is not an airplane, you need an ULM

there is no longer much difference between microlights and airplanes ...

there are really microlights that land slowly and go very quickly

but this is not the transport of the future: it is luxury toys

[Christophe]

Well I was thinking of the suspended delta plane type ULM that you can fold up in your garage.

There are only those there that you can land in the neighbor's field, right?

[chatelot16]

of course the good old commuter it lands in the fields, but it does not advance and it consumes like a hole ...


there are good microlights like planes which land as slowly as commuters and which fly very fast ... and which are good gliders

for cars I also like the versatile: my Citroen GS drive very fast when the chickens are lying down: go in any path like a 4x4, and load big stuff like a truck or pull trailers much heavier than what is marked on the gray card ...

my vehicle of the future will be an extremely economical 2 wheel, completely streamlined like an airplane, with 2 additional wheels for low speed (like a landing gear)

[oiseautempete]

no it's not the best: 98km / h stall speed is too fast to land in a field around my house

I saw more versatile aircraft than the one

maximum finesse = 16: it is not glorious either

there are small modern planes with finesse better than the real gliders of 20 years ago: when we have the chance to find the good condition we cross France with the engine off ...



but for the jumo junker it was 2 crankshaft 1 at the top and 1 at the bottom with a bunch of cylinder with a piston at each end: it is a very good way to make diesel!


the motor of the jumo junker with its 2 crankshafts was probably well balanced from this point of view

the jumo junkers we continued to fly long after the war: it means that it did not demolish the cells by the vibrations

Indeed the stall speed is very high, but in any case in France it is forbidden for an airplane to land in a field or even a private meadow, whereas it is tolerated in microlight (if the farmer agrees ).
16 finesse is EXCELLENT for a light aircraft or a 3-axis ultralight, the majority revolve around 12 and an autogyro is even in 3-4 (but with a good prelancer, it takes off and lands in a handkerchief. poached...) An aircraft that has 20 finesse is a motor glider, but you should not hope to cross France with that without an engine, you have to type in the competition glider with 40 and more finesse and which can type transitions at more than 200km / h ...
I know a little bit about diesel aircraft engines, but the Junker Jumo 205 is not a very good example because of a fairly primitive and heavy design (the additional crankshaft) ... on the other hand the Clerget 14F engines from 1938-39, whose power = gasoline weight ratio, and reliable, was much better, but the development was stopped by the war and when the studies were resumed it was to be abandoned quickly with the advent of turbomachines, ultra greedy at the time certainly, but very light, using inexpensive fuel and requiring very little maintenance ... Note that the specific consumption of the Clerget was equivalent to that of the Renault-Morane (SMA) aircraft engine which appeared 60 years later ...
http://www.hydroretro.net/etudegh/mazoutdenfer.pdf

[chatelot16]

thank you for these beautiful page on clerget, I knew that clerget had done very interesting work on diesel, and that it had been wasted by the war and lamentably abandoned by snecma

the clergy force was a very good injection system

the strength of the junker was its opposed piston system which I find very interesting, but as it had a less optimized injection it did not turn fast enough so it was heavier for its power

a 2-stroke engine with a good modern HDI type injection will run at 4000rpm and will have an enormous power density

I said well like hdi: that is to say high pressure but not all electronic like the current hdi: rather pump injector that I find more reliable

there is also to think about the choice of the star motor: mechanically it is lighter and perfectly balanced in displacement of mass

the in-line cylinders even if it is a little heavier, it is narrower and allows better aerodynamics of the aircraft

[kistinie]

Some theoretical elements

The shape of an airplane and its total wetted surface (TMS) determine its aerodynamic efficiency (see the various presentations on the site http://www.hkw-aero.fr/ ).

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

Initially, moving less quickly is indeed a "formidable" solution to reduce the cost of all transport.

As a reminder, the friction force varies between V * V and V * V * V in water.

Unless you do like the military and exploit the MHD.
Thus an underwater torpedo exceeds MACH3 in the water
Thus an airplane passes MACH6 in the air.

So while you stay in your hut, we'll turn you around!

Lol!

http://fr.wikipedia.org/wiki/Acc%C3%A9l%C3%A9rateur_MHD
http://fr.wikipedia.org/wiki/Aurora_%28avion%29
http://jnaudin.free.fr/lifters/main.htm

Enjoy!

[oiseautempete]

a 2-stroke engine with a good modern HDI type injection will run at 4000rpm and will have an enormous power density



there is also to think about the choice of the star motor: mechanically it is lighter and perfectly balanced in displacement of mass

the in-line cylinders even if it is a little heavier, it is narrower and allows better aerodynamics of the aircraft

The 2-stroke diesel system + compressor is used in aviation on Wilksch engines (120 and 160hp) and a few other less known ...
The star engine is a good solution, very simple and for a side-by-side two-seater ulm, a star engine up to 100hp would hardly degrade the aerodynamics because it would remain quite small in diameter ... (for 100hp at 2400tr it would need ~ 3 liters of displacement on 5 cylinders, significantly less displacement if the engine is supercharged ...)

[bernardd]

To Michel Kieffer:

Compared to your very synthetic documents on the prospective of future transport, we see that the only 2 means of fast long distance transport, the plane and the train, both face the same obstacle: air.

Because, moreover, in terms of speed, they almost meet: train records reach 600km / h, limited by catenary problems. It is slower than a plane cruising, but without the inconvenience of the take-off and landing phases, and the location of airports.

In both cases, a solution seems obvious: circulate a vehicle in a sealed vacuum tube.

The smaller the vehicle, the easier the tube is to make: the size of 1 or 2m2 of section would be perfect, so we could almost use urban vehicles, with external propulsion. Otherwise the technical ideal would be a sealed life capsule, where you stay in the most comfortable sitting / lying position for accelerations, with all the means of communication possible today: 3D ocular projection at more than 180 °. ..

This solution would have a lot of advantage:

- low floor space and unlimited crossing capacity,
- mass displaced reduced to a minimum, with energy transmitted by the rails, or even motors on the rails, like a roller coaster,
- very low energy loss by friction, with upper or lower rails and without air, therefore very high speed possible,
- maintaining a vacuum of 1 bar consumes little once the tube has been emptied, the technologies are well mastered (see 30 km vacuum tube from the CERN LHC, much more complex because it is also kept at very low temperature). The most complex part would be the airlocks.
- automatic piloting therefore low operating cost, vehicles can travel in trains,
- insensitivity to meteorology,
- possibility of building with a cover for the recovery of solar energy, which makes this means of transport self-sufficient.

At first glance, the cost of constructing such a tube would be much lower than that of a road or a railroad, because the mass to be supported is low. It could even cross liquid volumes with simple tunnels.

I do not see any theoretical difficulty with such a means of transport.

Such a means of transport would really be complementary to a solution of small vehicles for the short distance, of the type of small urban vehicles envisaged elsewhere, for example in “free” rental.

[bernardd]

Besides the definition of its own vocabulary, I cannot resist this pearl:

To call an internal combustion engine a compressed air engine is a misnomer because in a compressed air engine we do not use the thermal expansion of the air but just its reserve pressure, itself created by borrowing from a another source of energy, all with a lamentable return ...

So what presses on a piston of the engine of my car, it is not the pressure of the gas mixture, it is its "thermal expansion" ...

Great, I learned something today! And what is the unit in the international system, "thermal expansion"?

Ok, it's off topic, it should be in the humor topic, excuse me