What are Boeing's plans?

"Tom S." wrote in message
...

"Kevin Brooks" wrote in message
...

"Tom S." wrote in message
...

"Kevin Brooks" wrote in message
...

7E7 will offer airlines a new airframe (they can't fly the same old
ones
forever)

No ?

No. Aircraft have definite service lives. Surprised you did not know
that.

What's the service life of a DC-3?

Don't know--how many of them have you seen flying with major airlines of
late?

Why would the number of major airlines be at all relevant?

They are the folks who buy most of the airplanes--you know, the thing we
were talking about here?

Brooks

In article 3523d.323018$Oi.300857@fed1read04,
"Leadfoot" writes:
Boeings take on aircraft service life is that it can be indefinite so long
as the sircraft is maintained properly. There has never been a requirement
to retire a Boeing aircraft after "X" number of whatevers. I suspect the
747 will fare far better than the DC-3 over a 70 year period.

While you're correct about Boeing's take on service life, the fact
remains that, at some point in its life (the end, of course) a 747
will start showing cracks in wing spars, and the fuselage pressure
vessel, and all manner of other areas, and it will become uneconomical
to repair it. That's already happening. the DC-3 series of airplanes
hasn't shown any of these behaviors. That's not too surprising,
really - The DC-3's wing structure is fairly stiff, and it uses Jack
Northrop's multi-cellular construction techniques. There are multiple
load paths there, so individual elements aren't stressed too highly.
It's not pressurized, so you're not inflating and deflating the cabin
on each flight. The 747, and, for that matter, any other jet, is much
more flexible, and has to put up with the stresses and strains of
pressurization, At some point, it's going to give.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

"Tom S." wrote


"Kevin Brooks" wrote
No. Aircraft have definite service lives. Surprised you did not know
that.


What's the service life of a DC-3?

Since all loads in a DC-3 are carried by high strength fittings
and not by "stressed skin", the CD-3 has no specified service
life as do the modern jetliners.
I recall seeing a TV interview with Mr. Douglas in which he explained
that by replacing the bushel basket of fittings that he had brought
with him, any DC-3 airframe could be made good as new.

Bob Moore

"Kevin Brooks" wrote in message
...

"Pooh Bear" wrote in message
Fuel efficiency ( cost per seat-mile ) is what it's about. This factor
is
skewed by amortised cost of old but serviceable a/c - like the 727s I
just
mentioend. Not efficient - but the lease purchase was paid off decades
back.

I tell you what--you want to start up a new low-cost airline here in the
states with 727's, be my guest---but don't be planning on getting many
financial backers.

Question - how efficient is a 727 re-engined with the RR Tay conversion?
These seem popular with the higher end of biz-jet operators.

I think someone on here, though may have been on TV, said that the
difference between cruise speeds on various airliners is to do with the
critical speed of the wing. Above this speed, the thrust required is much
more, so you use much more fuel. The 747 was designed for a faster
speed in this respect so has a higher cruise speed? I think the 727 was
quoted as being quite good at M 0.75 but not at 0.85? Something like
that?

Paul

Kevin Brooks wrote:

7E7 will offer airlines a new airframe (they can't fly the same old ones
forever)

No ?

No. Aircraft have definite service lives.

Some helicopters don't.

--
Fritz

"Fritz" wrote in message
...
Kevin Brooks wrote:

7E7 will offer airlines a new airframe (they can't fly the same old
ones
forever)

No ?

No. Aircraft have definite service lives.

Some helicopters don't.

Point to the modern passenger carrying aircraft that offers infinite cycles
and airframe hours.

Brooks


--
Fritz