Delta777-XXX
Topic Author
Posts: 940
Joined: Sun Jun 11, 2000 3:50 am

Why Not Make The 747X Go M.95?

Wed Mar 28, 2001 10:42 pm

Lately there have been a lot of rumors about Boeing dropping the 747X for the "M.95 200 seater".

Why can't Boeing just make it's 747X go M.95??

All of the 747s are pretty fast and fuel efficient. Why not add some new technology or something and make them faster and more efficient??

I understand that the airlines may want something smaller, but if Boeing wants something to compete with the A380, that seems to be great.

Any comments??
 
Guest

RE: Why Not Make The 747X Go M.95?

Wed Mar 28, 2001 10:47 pm

Developing this new technology is quite expensive. Since Boeing doesn't think there's a big market for A380 / 747X-sized planes, it probably won't be worth the cost to them, and they'd rather try it on a somewhat smaller aircraft, 757/767-size. Besides, incorporating this technology into the aircraft now would probably mean they'd have to delay it by a couple of years.
 
widebody
Posts: 1107
Joined: Wed Aug 02, 2000 5:08 pm

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 12:35 am

Aerodynamically, with the aircraft travelling at M0.95, the air flow around some parts of the aircraft will go supersonic.....this has to be designed for.......
 
BostonBeau
Posts: 488
Joined: Tue Sep 05, 2000 11:55 pm

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 1:58 am

Isn't there effectively a "speed limit" on the oceanic tracks, dictated by the slowest aircraft on the track? I remember the B747 originally flew faster when first introduced, but was slowed down, both to be considerably more economical, and because some of the other aircraft couldn't keep up. I guess they could dedicate tracks to faster/slower aircraft, but it would seem easier if everyone flew at the same speed I guess.
 
GOT
Posts: 1843
Joined: Sun Dec 31, 2000 6:44 am

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 2:46 am

It's so expensive to develop and it's very hard for the aerodynamics. I don't think it would work.

GOT
Just like birdwatching - without having to be so damned quiet!
 
turbulence
Posts: 876
Joined: Sun Nov 14, 1999 1:33 am

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 3:11 am

The reason is what Widebody said. Some parts of the airplane (specially wing edges) would be going supersonic, and the bigger the wings the worse the effect, mainly structural.

Best turbulences.
 
prebennorholm
Posts: 6447
Joined: Tue Mar 21, 2000 6:25 am

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 5:23 am

Widebody and Turbulence, I think your assumptions are a little wrong. To make a M.95 plane and have supersonic flow around it would be quite stupid. If you have supersonic flow, then better go the full way and make a real supersonic plane.
But it may be just about possible to reach M.95 and still keep the fastest air flow at no more than M.99. I am pretty sure that it's what Boeing is talking about.
But it would be a plane with a dramatically different view compared to ordinary M.8x airliners.
It is a little strange that Boeing hasn't released any information about the plane. But it is quite obvious for aerodynamic people how the poperties of a M.95 plane with max. M.99 airflow must be:
The fuselage must be long, narrow and pointed in both ends, something not very dissimilar to the Concorde.
The pax would call it cramped. The main cabin section of the fuselage would probably not be a straight tube, but instead gradually increase diameter until its thickest point from where it would gradually decrease diameter all way to the tail.
Ordinary windscreens, which the pilots could look out of, would be a difficult subject. To give the pilots some forward view during take-off and landing an artificial view system (TV) would be more likely than the Concorde's drooping nose.
The wing would also have to be different. A wide cord delta wing could be likely.
The only thing, which could come almost off the shelves, would be the engines. Unlike a real supersonic plane a M.95 plane could fly with today's high bypass ratio fan engines without much modification. And since it would not generate a sonic boom, then it can, unlike the supersonic plane, be operated over populated land.
As you see, to make a M.95 airliner is a completely different sort of animal, and it is nothing like putting some more power and some "new technology" on an old 747.

But the main point is that it is so totally unnecessary. If only ground service, baggage handling and traffic imposed delays could be made a lot more efficient, then most of us would gladly travel on a M.50 or M.60 plane instead.

Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs
 
widebody
Posts: 1107
Joined: Wed Aug 02, 2000 5:08 pm

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 5:52 am

Preben,

All of what you said was correct, the question was whether the 747 speed could be ramped up to M0.95, and the answer to that is no.......Boeing could develop a M0.95 plane with no supersonic flow around it, but you'd have that design consideration in mind when desiging it......

Regards,
WB.....
 
prebennorholm
Posts: 6447
Joined: Tue Mar 21, 2000 6:25 am

RE: Why Not Make The 747X Go M.95?

Thu Mar 29, 2001 6:15 am

Exactly, Widebody!
And your last sentence - you'd have that design consideration in mind when desiging it...... means a lot more than most people would normally assume.
Nobody should think about this as just a 10-15% increase in speed. They should rather think about it as 3 times closer to the sound barrier. THREE TIMES CLOSER!!!
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos