[mohansrides]

Originally Posted by AVR

I am a big fan of long-haul flights having done the Dubai-SFO route many times along with the Delhi-New York flights. I am kinda blessed with the ability to sleep for however long I want if I am not at driving so I catch a few drinks - sleep and in a to-and-fro US India trip I end up watching a grand total of 1 movie (first-half in to and second-half in fro) with a long-interval

I sleep 5-6 hours on regular days but my sleep patterns are like camel's eating patterns. Grab as much when you can!

You sir are my new idol!! Of all the superhuman abilities to have, to sleep and wake up at will is hard to beat. If used effectively, it could be an incredibly useful gift.

Unfortunately, I am the exact opposite of you. I struggle to sleep and then I struggle to wake up

Unless I am super exhausted, I cannot sleep. In fact, sometimes I cannot sleep precisely because when I am super exhausted.

[Mohan Mathew A]

Originally Posted by mohansrides

You sir are my new idol!! Of all the superhuman abilities to have, to sleep and wake up at will is hard to beat. If used effectively, it could be an incredibly useful gift.

Unfortunately, I am the exact opposite of you. I struggle to sleep and then I struggle to wake up

Unless I am super exhausted, I cannot sleep. In fact, sometimes I cannot sleep precisely because when I am super exhausted.

I am happy that there are more people like me. To say that I am a fussy sleeper will be an understatement and I cannot sleep on an aircraft (a lie flat business class seat helps but then again is no guarantee). So the ability to sleep 'on demand' is indeed a gift, something which I wish I had. Like Flight duty hours for crew, there should be something similar for passengers (I really mean it).

[RM Motorsports]

World's Longest Flight - Trip Report by CNN

https://www.youtube.com/watch?v=rV1-BF3zh1o

[mohansrides]

Originally Posted by Mohan Mathew A

We should have faster aircrafts.

This line made me smile.

I think that although most of them aren't specifically designed for speed (like say the Concorde), today's flights are plenty fast. Certainly, they are capable of flying faster than they do during their commercial operations. The speeds they choose to fly at are a function of lots of things. At a bare minimum, rules, air traffic, and fuel economy dictate air plane speeds.

[rajeshadd]

How much fuel the aircraft has to carry or will they refuel mid-air as they do for military jets? Good to see that the reliability and endurance of aircraft engines(possible GE or Rolls Royce Trent) have improved so much..

[rajeshadd]

Originally Posted by Mohan Mathew A

The longest I have flown non-stop was Frankfurt-Mexico city. It was something like 13 hours and I hated it. I find anything more than 4 hours a pain. My problem is I can't sleep on flights. We should have faster aircrafts.

Speed, Reliability and Practicality together has to improve. Concorde was stopped due reliability and practicality issues..

[Axe77]

I would factor in another key advantage of flying direct. Less chance of luggage loss / delays. Lol. This is based on my event experience where Lufthansa lost my bags on a trip to Berlin.

[Jeroen]

Originally Posted by mohansrides

I think that although most of them aren't specifically designed for speed (like say the Concorde), today's flights are plenty fast. Certainly, they are capable of flying faster than they do during their commercial operations. The speeds they choose to fly at are a function of lots of things. At a bare minimum, rules, air traffic, and fuel economy dictate air plane speeds.

Actually, they can’t fly much faster than what they do during normal commercial operations (whatever that is). Most airliners cruise at around Mach 0,8-0,86 and they can’t go much above that. It is just a limitation in the design of any commercial jet liner. Going faster gets them into a flight regime where shock wave start to build and create all sort of aerodynamic problems More than Mach .9 is rarely possible for any commercial jet. You need a completely different design to get nearer to Mach 1 and beyond.

Interestingly, current commercial jets tend to fly a tad slower than say those say 20-30 years ago!

Originally Posted by rajeshadd

How much fuel the aircraft has to carry or will they refuel mid-air as they do for military jets? Good to see that the reliability and endurance of aircraft engines(possible GE or Rolls Royce Trent) have improved so much..

No mid air refuelling for commercial aviation. It’s all down to how much fuel you can take and how far that will take a particular aircraft. Which in essence is down to the type of aircraft and it’s engines. Reliability of modern jet engine has not been an issue for the last couple of decades. Twin jets fly all around the world and have been for many years. We have seen some problems with some brand new engines lately. But that should and will be fixed.

Originally Posted by rajeshadd

Speed, Reliability and Practicality together has to improve. Concorde was stopped due reliability and practicality issues..

Why, what is wrong with reliability? See my comments above.

Very few four engine planes left. Everything is twin these days and virtually without any problems. How often do planes crash due to unreliability of a particular component?

Concorde was most of the most reliable commercial planes ever built. The one (very unfortunate) accident had nothing to do with reliability. (it was due to debris on the runway)

According to BA and AirFrance it was becoming economically unfeasible to fly Concorde due to low passenger number and rising maintenance cost.

It would be nice to think at some point in time we will be able to fly faster than the current jet airlines. There are various parties making such claims towards the near future, but I am not holding my breath.

Jeroen

[turbospooler]

Originally Posted by Axe77

I would factor in another key advantage of flying direct. Less chance of luggage loss / delays. Lol. This is based on my event experience where Lufthansa lost my bags on a trip to Berlin.

I echo your thoughts. In fact, it is not only the longer routes that I prefer direct connections to, but the shorter routes as well domestically.
It is just a case of adding up of the probability of losing your baggage every time you make a connection.

[Jeroen]

Originally Posted by mohansrides

Certainly, they are capable of flying faster than they do during their commercial operations. The speeds they choose to fly at are a function of lots of things. At a bare minimum, rules, air traffic, and fuel economy dictate air plane speeds.

i already made some general comments regarding the speed of current airliners:

Actually, they can’t fly much faster than what they do during normal commercial operations (whatever that is). Most airliners cruise at around Mach 0,8-0,86 and they can’t go much above that. It is just a limitation in the design of any commercial jet liner. Going faster gets them into a flight regime where shock wave start to build and create all sort of aerodynamic problems More than Mach .9 is rarely possible for any commercial jet. You need a completely different design to get nearer to Mach 1 and beyond.

Today I was doing some simulator work and I captured a few situations to illustrate. All images/data from a 747-400.

Here is the starting situation, a Jumbo Jet in typical cruise mode.



The most relevant information for this topic is on the left side of the left display, the so called Primary Flight Display which sits right in front of each pilot. In the middle the navigation display. It shows the aircraft position, its route, several waypoints along the route. In the top left corner you can also see the ground speed (GS), True Air Speed (TAS) and wind direction and wind speed. the right hand display shows main engine parameters and will also show all alarm and caution annunciations.



You can see that the current speed is identical to the command speed. In this scenario the command speed is set via the Flight Management System. Note the two yellow lines on the speed tape. These are the minimum and maximum manoeuvring speeds. They are constantly measured and calculated. They vary, amongst others, based on aircraft weight, altitude, air temperature etc.

If your speed drops into the lower yellow zone, you will get a low speed alarm to warn you you are about to stall. If your speed accelerates and gets you into the upper yellow zone you are overspending. That might cause bits to break off!.

Now let us speed up. I disconnect the auto throttle and just fire wall the throttles. Note on the right display the caution annunciation of the auto throttle disconnected



The speed is now well into the red zone. There is an overspeed alarm as I am exceeding the maximum speed. (again note, this maximum speed is dynamic based on variables as mentioned before.

So you see that at altitude modern aircraft do not have the capability to change their air speed too much. It needs to stay between the two yellow lines.

Now lets take this aircraft up to a higher altitude and see what happens:



Note how the upper and lower manoeuvring speeds are almost on top of each other? This area is known as the coffin corner. There is very little room for error. A small speed deviation puts you in a low speed or overspeed condition. It is one of the reasons jet liners always fly on auto pilot during cruise at altitude.

If I push the speed up further the whole left side of the PFD will essentially becomes blank. The computers can’t calculate the various parameters any more. And you are in BIG trouble


These speed limits are a direct consequence of current design of swept wing air jet liners. They all have the same limitations.

Hope this helps a bit

Jeroen
A few more images I took along the way:

[sagarpadaki]

Wow! Thanks for the explanation Jeroen.

Can you please tell me which flight simulator is this and on which Operating system is it run on?

[Jeroen]

Originally Posted by sagarpadaki

.
Can you please tell me which flight simulator is this and on which Operating system is it run on?

This is Precision Simulator from Aerowinx: http://www.aerowinx.com/

click on the link to download a demo version of the manual. It will give you some idea on what this piece of software is all about.

It runs on Mac as well as Window machines.

It is a very advanced 747-400 simulator. It does not have any scenery. It is just an incredible detailed and true to life system and process simulator. You can pull a fuse and the systems respond as in true life. Quite a few users hook it up to MS Flight SIM just to get the scenery.

It is not cheap. On average probably around Euro 350. There are probably only a couple of hundred users in the world. Many of them aviation professionals and or pilots themselves.

Have a look at these training video's. The author is very active on the forum and is a former British Airway Training Captain

https://www.team-bhp.com/forum/newre...eply&p=4495528

The forum is outstanding. I have been part of this community for probably some 15-20 years. There is a small group ofsome 20-30 guys that have been part of this forum during all these years and are actively contributing to the add ons, training material etc.

The previous version ran on DOS, but again, for its days incredible piece of software.

Enjoy Jeroen

[mohansrides]

Originally Posted by Jeroen

Today I was doing some simulator work and I captured a few situations to illustrate. All images/data from a 747-400.

Here is the starting situation, a Jumbo Jet in typical cruise mode.....

Hope this helps a bit

Jeroen

Jeroen.... I mean Holy Whatever Man!!! I just made a casual comment; and you go all Ninja on me

Thanks for all that explanation. To tell you the truth, almost all of it went over my head. I am a terrestrial person. More about bikes and cars. Not that into aircrafts and aviation. Still, it was cool to see all that stuff from you.

Mohan

[Jeroen]

Originally Posted by mohansrides

To tell you the truth, almost all of it went over my head. I am a terrestrial person. More about bikes and cars. Not that into aircrafts and aviation. Still, it was cool to see all that stuff from you.

Hi Mohan,
no problem. The gist of it all: Current commercial jet airliners speed is determined and limited by their design. At cruising altitude the band with between minimum and maximum speed is quite narrow. With increasing altitude that bandwidth narrows further.

Effectively they all more or less fly the same (air) speed. They simply can not slow down much, or speed up much.

Note, this is all about air speeds. Ground speed can be very different. Ground speed is air speed plus or minus whatever direction and speed the wind is blowing. Jet stream can easily reach more than 100 mph.

At say, a 6 hour flight that could be almost an hour less (if from dead behind) or an hour more (if straight into it).

Take care and enjoy those bikes and cars!

Jeroen