Revolutionizing Aviation: Faster Takeoff and Landing Technology Explained

[physior]

hello!

I recently flew from Athens to London, with regular flight.

I noticed that a significant part of the whole travel time is taken by the take off and landing.

Why don't we develop a system, similar to helicopters, in order to achieve the fastest take off and landing?

Also, I wonder why the plane couldn't just fly faster after taking off and before landing. Can't the human sustain such accelerations and velocities? We don't have the technology to fly that fast? What is the problem exactly?

I strongly believe that with current technology it would be possible to diminish the flight duration to a fraction of its current amount.

We already have airoplanes that drive much faster. Also, human body can sustain faster velocities and accelerations I believe. Current accelerations in a regular airoplane are not even noticeable!

Any thoughts?

Thanks!

 

[Doug Huffman]

Nuisance abatement, costs and safety are preeminent considerations.

 

[physior]

I don't see how we cannot meet these with new systems, vertical landing and take off
as for costs, they earn millions!
I don't see why they cannot be safe, in fact, normal landing and take off seem more risky to me!

 

[Ryan_m_b]

I don't see why VTOL would make takeoff and landing any faster, after all you'll still have to get up to cruising speed. As for faster journeys you might want to take a look into Concorde, specifically how uncompetitive it was compared to regular business class, private jets and growing use of telecoms in business.

 

[timthereaper]

hello!
Why don't we develop a system, similar to helicopters, in order to achieve the fastest take off and landing?

Also, I wonder why the plane couldn't just fly faster after taking off and before landing. Can't the human sustain such accelerations and velocities? We don't have the technology to fly that fast? What is the problem exactly?

The real problem is efficiency. Most planes are designed to cruise at a certain speed and going much faster/slower than that affects the performance of the aircraft. It's not a speed limitation; it's a fuel conservation thing.

As far as VTOL, there's a lot of research in it, but it's not reliable yet.

 

[Borg]

Also, I wonder why the plane couldn't just fly faster after taking off and before landing. Can't the human sustain such accelerations and velocities?

So in your world, people with heart conditions wouldn't be allowed to fly?

 

[SteamKing]

Most of the delays encountered at airports are due to the number of flights landing or taking off at any given time. It's not that the planes are that slow landing or taking off, but you've got a pretty complicated 3-D problem trying to manage the flights on the ground and in the air. There are only so many runways and so much airspace which can be safely occupied at anyone time.

 

[physior]

So in your world, people with heart conditions wouldn't be allowed to fly?

in the world YOU are living, people with heart conditions aren't allowed to fly, too

 

[phinds]

in the world YOU are living, people with heart conditions aren't allowed to fly, too

I find that unlikely. Can you cite a solid reference for that information or is it just your opinion?

 

[physior]

I find that unlikely. Can you cite a solid reference for that information or is it just your opinion?

you must not be serious...
scroll down to see a list of contraindications
http://www.patient.co.uk/doctor/flying-with-medical-conditions

 

[phinds]

you must not be serious...
scroll down to see a list of contraindications
http://www.patient.co.uk/doctor/flying-with-medical-conditions

OK, thanks. I was aware of guidelines about not flying if you have had heart surgery or a heart attack within a few weeks but there seem to be even more restriction that I was not aware of.

 

[berkeman]

you must not be serious...
scroll down to see a list of contraindications
http://www.patient.co.uk/doctor/flying-with-medical-conditions

OK, thanks. I was aware of guidelines about not flying if you have had heart surgery or a heart attack within a few weeks but there seem to be even more restriction that I was not aware of.

Those contraindications are generally because of the low O2sat levels involved in flying at altitude. I'm thinking that phinds was referring more to the g-levels that you were implying in shortening the duration of flights...

 

[phinds]

Those contraindications are generally because of the low O2sat levels involved in flying at altitude. I'm thinking that phinds was referring more to the g-levels that you were implying in shortening the duration of flights...

No, to be fair, I just wasn't aware of the restrictions. I was told after open heart surgery that I shouldn't fly for the next several weeks (and check w/ the cardiologist in any case) but I was not aware that airlines had regulations about it, so I really was wrong. I thought it was just medical guidelines. I guess the airlines don't want anyone dying on their planes

 

[berkeman]

I was surprised at diabetics being on the list, BTW, until I read what the restrictions were. Yeah, there are a lot of subtleties in those contraindications.

BTW @physior -- Have you seen this thread in the Physics forum about VTOL engine sizing? https://www.physicsforums.com/threads/why-must-vtol-engines-be-larger-than-normal-engines.790352/

:-)

 

[physior]

yeah, I was imagining a combination of VTOL and horizontal movement
to the point it becomes hardly noticeable (0.5g?)

now, we get 1g during the take off and after that, we don't feel any acceleration
why not the plane accelerate during the half of its travel? and deccelerating for the rest half

 

[berkeman]

now, we get 1g during the take off and after that, we don't feel any acceleration
why not the plane accelerate during the half of its travel? and deccelerating for the rest half

Because as has been mentioned, it is more efficient to climb steeply and then level off to cruise most of the way. Saves on fuel, etc.

There are lots of great books and learning resources on airplane design and jet engine design. Check out your local library or do some searching on the net. It's a fun subject to study. :-)

 

[Ryan_m_b]

A plane can't accelerate for half the journey due to drag. The faster you go the worse drag becomes meaning you have to burn even more fuel.

 

[russ_watters]

Most of the delays encountered at airports are due to the number of flights landing or taking off at any given time. It's not that the planes are that slow landing or taking off, but you've got a pretty complicated 3-D problem trying to manage the flights on the ground and in the air. There are only so many runways and so much airspace which can be safely occupied at anyone time.

So, ways around this problem:

1. Build more airports. (expensive)
2. Fly planes closer together. (dangerous)
3. Fly larger planes. (possible!)

 

[SteamKing]

So, ways around this problem:

1. Build more airports. (expensive)
2. Fly planes closer together. (dangerous)
3. Fly larger planes. (possible!)

The problem with 3) is that the larger planes are more expensive to purchase and their size and the number of people which they carry can lead to 1) which can handle either the size of these planes, the number of passengers, or both. The size of these planes also means that 2) is not only dangerous, but may be lethal to smaller aircraft flying into or out of the same airports.

The Airbus A380, which is currently the largest commercial passenger plane in production (and the one which can carry the largest number of passengers)

http://en.wikipedia.org/wiki/Airbus_A380

has been reported recently to be ending production due to a variety of reasons.

 

[Borg]

Those contraindications are generally because of the low O2sat levels involved in flying at altitude. I'm thinking that phinds was referring more to the g-levels that you were implying in shortening the duration of flights...

I was referring to the g-forces. The link to airline restrictions is nice but I've never been questioned about medical conditions like that. In general, people aren't dying from heart attacks during takeoff and landing and the airlines are pretty lax about questioning passengers about their health unless they show up in obvious distress. Increasing g-forces significantly would change that equation.

 

[russ_watters]

The problem with 3) is that the larger planes are more expensive to purchase and their size and the number of people which they carry can lead to 1) which can handle either the size of these planes, the number of passengers, or both. The size of these planes also means that 2) is not only dangerous, but may be lethal to smaller aircraft flying into or out of the same airports.

The Airbus A380, which is currently the largest commercial passenger plane in production (and the one which can carry the largest number of passengers)

http://en.wikipedia.org/wiki/Airbus_A380

has been reported recently to be ending production due to a variety of reasons.

Something has to give. More people are going to want to fly every year, so the problem you highlighted (airport congestion) is going to keep getting worse. Yes, I'm aware the A380 isn't doing well because carriers are opting for more flights with smaller planes (particularly, budget, domestic carriers). But I think ultimately if they want to grow and they can't get new airport gates or departure times, they won't have a choice but to start flying progressively bigger and bigger planes.

I understand it is currently not considered a desirable option, but I think it is the least undesirable of the options moving forward.

 

[Travis_King]

Takeoff itself takes relatively little wasted time. Conventional takeoff allows the plane to get up to speed and begin it's parabolic ascent/trajectory. What benefit would VTOL give? Getting altitude is the least of the concern, why waste fuel which could be used for horizontal velocity (which creates lift itself) on only vertical lift, which doesn't get you any closer to your destination.

The only benefit of VTOL, maybe, would be the reduction in runway traffic - which is admittedly a huge time waster. But you'd still have to account for air traffic. 200 planes can't just take off in 200 different directions at once...

 

[Doug Huffman]

It is not difficult to think of air travel as having reached some sort of point of diminishing returns, as being saturated. Bigger, faster AC make longer more frequent ground transportation delays at the airports capable of handling them. A common trip is to a regional airport for access to a hub without ground traffic delays.

With other air travel inconveniences and expenses those of us with more time to spare than money may find intracontinental ground travel preferable. I can afford to drive to a bicycling event to which I could not afford to fly my bicycles and for just a fraction more time.

 

[SteamKing]

Airlines seem to have been working overtime to drive passengers away in recent years. More fees, especially on checked baggage, crowded cabins, fewer, if any, amenities during flights, etc.

People used to complain about airline food; on many flights, you're lucky if you get a bag of peanuts.

I used to fly regularly on one of the regional carriers in the US before deregulation. Even without first class, it was a much better experience before deregulation than afterwards. At least, if your flight had a leg which was at least an hour in duration, you got a basic meal with your ticket. Also, this was before the hub concept was adopted wholesale by the airlines. If your flight didn't pass thru one of the congested airports like Atlanta or Chicago, it was a relatively painless experience. Now, unless a flight is relatively short, it's an experience to be endured rather than savored.

 

[physior]

So, ways around this problem:

1. Build more airports. (expensive)
2. Fly planes closer together. (dangerous)
3. Fly larger planes. (possible!)

why not diminish the area needed to land/take off planes, by installing helicopter-like mechanisms to airplanes for taking off and landing?
and diminish the time required to occupy a whole area (landing aisle)? if the airplane lands within seconds, instead of tens of minutes

 

[Ryan_m_b]

why not diminish the area needed to land/take off planes, by installing helicopter-like mechanisms to airplanes for taking off and landing?
and diminish the time required to occupy a whole area (landing aisle)? if the airplane lands within seconds, instead of tens of minutes

Think of it in terms of return on investment. The cost of a VTOL commercial jet is likely to be greater than the available alternatives.

 

[physior]

Think of it in terms of return on investment. The cost of a VTOL commercial jet is likely to be greater than the available alternatives.

ofcourse there is a cost to develop and test and manufacture such an airplane
but don't airflight companies earn very much already? I paid 500 GBP for a flight that regularly costs 150, and all this because it was inflatedly swollen, because of Xmas.
they prefer to increase capitals of the rich people who own and run them, instead of putting them into research and advancing of technology
maybe national and international organisms should research and develop such airplane and force then all the airflight companies to buy that technology, as being safer, faster, perhaps more economical (as flight duration will diminish), but most importantly it will save numerous hours from people's lifes and allow them to enjoy more times with their lives?

 

[SteamKing]

ofcourse there is a cost to develop and test and manufacture such an airplane
but don't airflight companies earn very much already?

It's not clear what you are asking here. Does 'airflight companies' mean the airlines which take passengers from A to B, or are you talking about the makers of the aircraft themselves?

I paid 500 GBP for a flight that regularly costs 150, and all this because it was inflatedly swollen, because of Xmas.

If you book an airline flight last minute or during the holiday rush, you will probably pay a premium for the price of the ticket. High demand during the holidays with only a fixed number of seats means the airlines can charge more for each seat. That's Economics 101, basic supply and demand. Either purchase your ticket several weeks ahead of time or find an alternate means of transportation, in order to avoid bankrupting yourself.

they prefer to increase capitals of the rich people who own and run them, instead of putting them into research and advancing of technology
maybe national and international organisms should research and develop such airplane and force then all the airflight companies to buy that technology, as being safer, faster, perhaps more economical (as flight duration will diminish), but most importantly it will save numerous hours from people's lifes and allow them to enjoy more times with their lives?

The airplane manufacturing companies are more competent at designing and producing aircraft, especially commercial aircraft, than any national or international organization (not organism). A lot of economic analysis goes into working out the performance characteristics of a new plane design to make sure that it is affordable to the customer (the airlines) to purchase and maintain, and to ensure that the aircraft can be operated profitably on its intended route.

It takes an investment of billions of dollars to design, build, test, and certify a new aircraft before it goes into production. Once in production, the manufacturing and development costs for the aircraft must be earned back, otherwise the aircraft producer goes out of business.

Because production volumes for commercial aircraft are so low, and because it takes years to introduce a new aircraft to the market, the economics of airplane construction can turn quickly unfavorable to the producer, which often means heavy losses in capital invested, not to mention reductions in work force to cut costs.

It's currently not technically feasible to combine the VTOL capabilities of a helicopter with the high flight speed of a conventional aircraft. If you try to make such a hybrid aircraft, what little bit of time you save on take-offs and landings will be more than offset by the additional hours you'll spend in the air between airports because your airliner cannot fly as fast as a conventional plane.

 

[Ryan_m_b]

ofcourse there is a cost to develop and test and manufacture such an airplane
but don't airflight companies earn very much already?

Before we discuss how much they earn you should look carefully again at what I said: Return On Investment (ROI). Airline companies want to be able to get the biggest ROI possible, so they want their running costs to be low and their profits high. It seems from what people are saying in this thread and others that the cost of running a VTOL plane will be higher than a normal one. So the return on investment would be lower. Assuming you are right and VTOL allows more planes to come and go in anyone time then it might offset this lower ROI somewhat. This may be easier to understand with a hypothetical (all numbers here are entirely made up for illustration), let's say that:

A normal plane costs $100,000
A VTOL plane costs $500,000

Using a runway a normal plane takesoff/lands every 10 minutes
Using a landing pad a VTOL plane takesoff/lands every 5 minutes

A plane journey of either kind makes a profit of $10,000

If this is true which should an airline invest in? A fleet of normal planes with a runway, or a fleet of VTOLs with a landing pad? I'll let you answer it yourself but the key message is for a VTOL to be worth the investment the increase in turnover has to be great enough to offset the cost of the plane. This is true whether you are talking about an private company looking to make profit or a publicly owned transport system looking to provide the best value for money for the taxpayers.

 

[physior]

I understand what you say
the problem is that some times, and I am saying that this is a good time, we must not act with goal the profit, but the benefit of the society

and don't tell me that it doesn't work like that
how many times government or companies have spent money to do research or technology?
war aircrafts is a good example, I think maybe that technology (VTO) already exists there!

 

[physior]

but this thread is about the future of airflight technology
and I strongly believe that we will see such technology
maybe flying saucepans? who knows

 

[Travis_King]

I doubt it. It's not economical and it makes very little engineering sense. The Harrier jet has this capability, but it's used for a specific purpose during combat missions. VTOL is expensive in fuel and weight, and really doesn't help anything regarding air traffic congestion, so I really don't see where it would be beneficial.

 

[physior]

I doubt it. It's not economical and it makes very little engineering sense. The Harrier jet has this capability, but it's used for a specific purpose during combat missions. VTOL is expensive in fuel and weight, and really doesn't help anything regarding air traffic congestion, so I really don't see where it would be beneficial.

I cannot comment on fuel or weight
but I cannot understand how you cannot see the benefit for air congestion
to be fair, I am not talking about congestion in air, but when landing and taking off only

 

[Ryan_m_b]

I understand what you say
the problem is that some times, and I am saying that this is a good time, we must not act with goal the profit, but the benefit of the society

Of course the pursuit of economic profit is not something we do all the time. Often we do things that have value beyond money. This isn't one of those cases though, here we're discussing if there are any advantages to VTOL planes.

You yourself have complained about the price of tickets. How would you feel if airliners replaced all their current jets with more expensive VTOLs and had to double, triple or even increase by 10x the price of their tickets? No airliner can run at a loss.

and don't tell me that it doesn't work like that
how many times government or companies have spent money to do research or technology?
war aircrafts is a good example, I think maybe that technology (VTO) already exists there!

The military is vastly different but they still have to consider their ROI. It's just in that case the return they are looking for is the best weapon/logistics. In terms of government spending: let's say the government announced they were going to create their own airline, that would be cheap (like public transport), not overly concerned with making a profit and paid with taxpayers money. Would you, as a taxpayer, prefer they spent that money on a cool but inefficient VTOL fleet or an standard but efficient fleet of normal jets?

 

[Ryan_m_b]

I cannot comment on fuel or weight
but I cannot understand how you cannot see the benefit for air congestion
to be fair, I am not talking about congestion in air, but when landing and taking off only

It's not that people can't see the benefit, it's the idea that the very minor saving in time would be worth the much larger expense of VTOL jets. Which have never been built anywhere near the size of a passenger jet (there are some tiltwings but they are slower and have a lower range than jets). Think of it this way: in a normal jet once it's ready to go it spends on average 10 minutes (in my experience) taxiing to the runway and taking off. Occasionally it takes longer if there is a problem but that's not too common in my experience. I've tried to find if there's any data on average times between planes being ready and taking off but didn't manage to, as this is key to your argument physior why don't you try to look for this? In a hypothetical VTOL jet the only difference is that the jet would take off once it is ready. So the total saving is on the order of 20 minutes, maybe a bit longer on flights that commonly are put into holding patterns whilst they wait for a runway (again it would be useful to have some numbers on this).

Given that do you really think that the expense of developing and introducing, what are likely to be much more expensive, VTOL jets is worth it just for an average saving of 20 minutes?

 

[boneh3ad]

VTOL systems expend considerably more fuel than their standard take-off counterparts in order to take off vertically. It is both more expensive and more environmentally damaging to try and do something like VTOL commercial aircraft. It makes no sense to pursue such an endeavor. The only reason that militaries use VTOL systems is because they have specialized requirements where their aircraft may need to land where no runway exists and/or at makeshift airfields.

The future of aviation is in more efficient designs. Eventually we will likely see something like a blended wing body. With a little bit more research we may see a return to supersonic jetliners as well, but only after we perfect the mitigation of the sonic boom so that they can be certified over land. If they are transoceanic-only aircraft, they will fail for economic reasons just like the Concorde.

 

[Doug Huffman]

Nuisance abatement, costs and safety are preeminent considerations.

And we have come full circle.

 

[Ryan_m_b]

With a little bit more research we may see a return to supersonic jetliners as well, but only after we perfect the mitigation of the sonic boom so that they can be certified over land. If they are transoceanic-only aircraft, they will fail for economic reasons just like the Concorde.

This probably deserves its own thread but I find this a very interesting topic. As it stands I'm not convinced a return to super-sonic commercial flight will occur, other than perhaps toys for wealthy people (supersonic bizjets). As I understand it supersonic flight uses up a lot more fuel per mile than subsonic, necessitating increased ticket prices. Given competition with services like subsonic first class and private jets, as well as telecoms technology obliviating much of the need to send business people quickly round the world, is there a market for a supersonic passenger jet? I've read many articles reporting that speed is a low concern for passengers over comfort and price. I wonder how many people would be willing to pay five times as much (using Concorde as an example) for a ticket for a journey only half as long. Especially given that the same price would get them a luxury seat on subsonic with money to spare.

 

[russ_watters]

Airlines seem to have been working overtime to drive passengers away in recent years. More fees, especially on checked baggage, crowded cabins, fewer, if any, amenities during flights, etc.

People used to complain about airline food; on many flights, you're lucky if you get a bag of peanuts.

Yes, I suppose right now the "something's got to give" is prices. Basic supply and demand says that when demand rises, suppliers have two choices:
1. Increase prices.
2. Increase supply.

Airlines are opting for #1, to drive down (keep from increasing) demand.

 

[boneh3ad]

This probably deserves its own thread but I find this a very interesting topic. As it stands I'm not convinced a return to super-sonic commercial flight will occur, other than perhaps toys for wealthy people (supersonic bizjets). As I understand it supersonic flight uses up a lot more fuel per mile than subsonic, necessitating increased ticket prices. Given competition with services like subsonic first class and private jets, as well as telecoms technology obliviating much of the need to send business people quickly round the world, is there a market for a supersonic passenger jet? I've read many articles reporting that speed is a low concern for passengers over comfort and price. I wonder how many people would be willing to pay five times as much (using Concorde as an example) for a ticket for a journey only half as long. Especially given that the same price would get them a luxury seat on subsonic with money to spare.

Well, yes and no. Sure, the first foray back into supersonic transports will be on the bizjet side of things, and a few companies are working on that now (e.g. Aerion has a relatively mature supersonic business jet concept and Gulfstream has one proposed). The problem is that the aerodynamics change so substantially between subsonic and supersonic flight that what functions as an efficient design in one regime typically doesn't in the other. I don't know what Gulfstream has planned, but Aerion is planning to mitigate this problem at least somewhat by designing the jet for supersonic cruise and incorporating the concept of natural laminar flow on the wings in order to help mitigate the penalties at subsonic velocities. That's probably the most likely initial approach.

NASA and AFRL also have a lot of work ongoing and externally funded with morphing structures. The initial application would be seamless control surfaces, e.g. flaps that don't have any hinges or gaps and operate by the actual trailing edge of the wing bending smoothly downward. Ultimately, though, you might imagine there would be the ability to morph the airfoil profile such that it performs well at multiple Mach number ranges.

Still, it won't be very economical or impactful on the general public unless they can get such an aircraft certified over land as well. Mitigating sonic booms for this purpose is another active area of research. I know Lockheed and Boeing have both had at various points programs for this kind of development. I don't know a whole lot about them, though.

Either way, I think eventually will will probably find our way back into the realm of supersonic transport aircraft provided we don't develop anything else superior first.

 

[Ryan_m_b]

So essentially it's a no-go on efficiency without some very big advances in materials science and noise reduction? Do you have any links on these morphing materials? Sounds interesting, if quite far off.

 

[boneh3ad]

So essentially it's a no-go on efficiency without some very big advances in materials science and noise reduction? Do you have any links on these morphing materials? Sounds interesting, if quite far off.

It's not as far off as you might thing, at least in terms of replacing flaps with flexible structures. I am sure it will be a while before we see it on any commercial aircraft, of course, but UAVs and then military aircraft may use the technology within a generation or two. I think these two videos show what is really the current state of the art, though I am not really sure. This isn't my area of expertise. As you'll see from the video, the current approach is to use elastic materials of some sort to allow the morphing. I think ultimately the goal is to move toward shape memory alloys, but I may have imagined that.





Interestingly, I just found this page at NASA that talks about a few of the things I mentioned previously as the future of aviation. In particular, note that they predict that planes will get smaller and more efficient, not larger, especially for the commuter type flights. Ultimately, if you want to reduce congestion, you end up using smaller, more efficient planes that can use an array of smaller airports. Then travelers aren't all trying to fly in and out of the same few airports.

For larger planes, the future is likely the blended wing body. It is substantially more efficient while holding more people. We could do that now, but the problem is they don't fit at traditional airport gates. Most likely, we will have to wait to see those until the military adopts them for cargo transport and forces infrastructure to slowly adapt. Until then, even if Boeing built one, no airline would buy it since there is no infrastructure for them.

http://www.nasa.gov/audience/foreducators/9-12/features/F_Can_You_Imagine.html

 

[SteamKing]

I think that unless the new technology for SSTs includes significant fuel economy improvements, it will all remain a pipe dream, whether the SST is for general commercial aviation or the specialized bizjet market.

Aircraft like the Concorde and the Boeing 2707 were designed in a era where the price of fuel was less than US $0.50 / gal and remained stable in price. Currently, when Jet A is selling for about US1.50 a gallon (and was almost US$3.00/gal six months ago), the economics of SSTs are now wholly different. It might be profitable to fly supersonic today, but six months from now, who knows? Airlines would be justifiably wary about taking a big jump into the unknown like that. Also, the pool of pilots with significant experience flying supersonic must be quite limited, more so than pilots with subsonic jet experience.

 

[boneh3ad]

That was my point about morphing wings and NLF. Technologies such as those could help push the cost of flying supersonic more into the same realm as conventional jetliners. We shall see, I suppose. Who knows, maybe someone will develop a Star Trek teleporter next year.

 

[SteamKing]

That was my point about morphing wings and NLF. Technologies such as those could help push the cost of flying supersonic more into the same realm as conventional jetliners. We shall see, I suppose. Who knows, maybe someone will develop a Star Trek teleporter next year.

A transporter might be cheaper to use than morphing materials.

 

[boneh3ad]

A transporter might be cheaper to use than morphing materials.

I might be inclined to agree with you except for the the fact that we now know that NASA and AFRL are pretty far along on the first generation of such materials and wings. If they've gotten it to the point of actually testing it on a business jet type airplane, then it's not just a pipe dream. A couple of years ago I might have chuckled at the idea, though.

 

[.Scott]

Also, I wonder why the plane couldn't just fly faster after taking off and before landing. Can't the human sustain such accelerations and velocities?

It's not clear what you mean by "fly faster after taking off and before landing". The cruise speed is a matter of fuel economy and avoiding any sonic boom.
If you mean accelerating and decelerating to cruise speed, there are other factors. Immediately after rotation, the jet will accelerate to some airspeed below either 200 KTS or 250 KTS depending on whether the airport is in Class B or Class C airspace (http://ww1.jeppesen.com/download/aopa/jul-aopa.pdf). At that point, the pilots primary objective is to rapidly gain altitude - so he will pitch up enough to keep to his chosen speed with maximum or near-maximum thrust.

The deceleration is also limited by the class of airspace - but more importantly by the design of the aircraft. There are a series of aircraft reconfigurations that occur once the airplane is on final approach - changes to flaps, slats, landing gear, and/or air brakes. When the jet is configured for cruise flight, it will be fuel efficient at fairly high altitudes. However, it cannot make a normal landing in that configuration because it needs to maintain too high a speed for contact with the runway. The landing configuration occurs in stages with the aircraft reconfiguring as the airspeed is reduced - all the way until touchdown.

Obviously, it is possible to accelerate and decelerate faster. Takeoffs and landing on an aircraft carrier are the best examples. And some those aircraft are capable of supersonic flight. But the economics in protecting a Naval fleet are different from commercial air transport.

The airspeed restrictions for class B and C airspace are set for two reasons: aircraft maneuvering distances and how long it takes for air traffic control to to communicate with and effectively redirect aircraft.

 

[montoyas7940]

I noticed that a significant part of the whole travel time is taken by the take off and landing.

My experience has shown parking, check-in, security/TSA, baggage handling, rental cars and delays or cancellations to be the inefficiencies of commercial airline travel.

My prediction for the future is small pilotless aircraft with point to point travel into tiny airports.

 

[physior]

My experience has shown parking, check-in, security/TSA, baggage handling, rental cars and delays or cancellations to be the inefficiencies of commercial airline travel.

My prediction for the future is small pilotless aircraft with point to point travel into tiny airports.

with same accelerations/deccelerations as todays aircrafts? with the same take off and landing methods as todays aircrafts?

 

[montoyas7940]

Keep in mind predictions of the future are usually wrong...

ATC speed limits would probably be relaxed with the advent of more automation and high speeds could be carried into the approach. Also the approaches could be greatly abbreviated since there would be little or no human involvement. Basically drop in like a rock and throw out some high drag devices for a short landing. A stabilized approach for safety would be pointless.

The VTOL efficiency issues might be solved, but much later I would imagine. The aircraft could drop into an air cushion generated by equipment installed on the ground.

For takeoff IDK, an aircraft carrier on land? Maybe.