Twin take off on one engine?

On Sep 3, 3:47*pm, Clark wrote:
"Flaps_50!" wrote in news:d7b4faf4-4167-46cd-8692-
:



According to the data I can find, the 747 can't climb on one engine so
how can it take off?
Cheers

Hmmm, empty weight is about 360,000 lbs plus a little fuel and 50,000 lbs of
thrust. It aught to work. I suspect your data are in error or perhaps you're
considering a loaded 747.

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Yeah, but how *long* would the runway have to be assuming ideal
conditions of say 68 F at sea level and head wind of 20mph? Its not
just the weight, it's the rolling resistance of the mains as well.
What's the longest runway in the world? (Edwards, Groom Lake,
Bonneville salt flats notwithstanding).

I googled the heck out of it and could not find any thing single
engine take off of a 747.

On Thu, 3 Sep 2009 17:42:52 -0700 (PDT), Richard wrote in
:

... I googled the heck out of it and could not find any thing single
engine take off of a 747.

I couldn't find anything I thought was reliable--some
claims and counterclaims on groups or forums like this.

What is clear is that the 747 can and has done lots of
ferry flights with one of the four engines inoperative.

If you're already up in the air with decent altitude
and a light payload, one engine might keep you in
the air.

My personal bet is that one engine won't do for liftoff.
Two would probably be OK. Three--people have done it,
so there's no doubt about it.

Marty
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On Sep 4, 3:26*pm, "Martin X. Moleski, SJ"
wrote:
On Thu, 3 Sep 2009 17:42:52 -0700 (PDT), Richard wrote in
:

... I googled the heck out of it and could not find any thing single
engine take off of a 747.

I couldn't find anything I thought was reliable--some
claims and counterclaims on groups or forums like this.

What is clear is that the 747 can and has done lots of
ferry flights with one of the four engines inoperative.

If you're already up in the air with decent altitude
and a light payload, one engine might keep you in
the air.


Wasn't there was a case of a single engine landing with no go around
being possible?
Cheers

On Sep 3, 3:47*pm, Clark wrote:
"Flaps_50!" wrote in news:d7b4faf4-4167-46cd-8692-
:



According to the data I can find, the 747 can't climb on one engine so
how can it take off?
Cheers

Hmmm, empty weight is about 360,000 lbs plus a little fuel and 50,000 lbs of
thrust. It aught to work. I suspect your data are in error or perhaps you're
considering a loaded 747.

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there should be a "sig" here

Here's some good relevent reading:

http://www.airliners.net/aviation-fo...ead.main/69428

On Sep 4, 8:47*am, Clark wrote:
"Flaps_50!" wrote in news:d7b4faf4-4167-46cd-8692-
:



According to the data I can find, the 747 can't climb on one engine so
how can it take off?
Cheers

Hmmm, empty weight is about 360,000 lbs plus a little fuel and 50,000 lbs of
thrust. It aught to work. I suspect your data are in error or perhaps you're
considering a loaded 747.


It comes from the certification requirements of a commercial 747
climbing on 3 engines. The excess thrust is calculated from the rate
of climb in that condition and knowing that 1 HP is 33,000 ft lbs /
rminute. Perhaps my math is wrong but I don't calculate an excess
thrust of 120,000 lbs... What do you get?

Cheers

"Clark" wrote in message
...
"Flaps_50!" wrote in news:2ce85d20-5c84-4425-a1bf-
:

On Sep 4, 8:47 am, Clark wrote:
"Flaps_50!" wrote in news:d7b4faf4-4167-46cd-8692-
:



According to the data I can find, the 747 can't climb on one engine so
how can it take off?
Cheers

Hmmm, empty weight is about 360,000 lbs plus a little fuel and 50,000
lbs
of
thrust. It aught to work. I suspect your data are in error or perhaps
you
're
considering a loaded 747.


It comes from the certification requirements of a commercial 747
climbing on 3 engines. The excess thrust is calculated from the rate
of climb in that condition and knowing that 1 HP is 33,000 ft lbs /
rminute. Perhaps my math is wrong but I don't calculate an excess
thrust of 120,000 lbs... What do you get?

Cheers

What I get is that I suspect your numbers are at gross weight. I suggest
looking at the problem as stated rather than making up your own
conditions.


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there should be a "sig" here

What I get is the latest successfull troll: please ignore him.

On Sep 11, 1:02*am, "Peter Dohm" wrote:
"Clark" wrote in message

...



"Flaps_50!" wrote in news:2ce85d20-5c84-4425-a1bf-
:

On Sep 4, 8:47 am, Clark wrote:
"Flaps_50!" wrote in news:d7b4faf4-4167-46cd-8692-
:

According to the data I can find, the 747 can't climb on one engine so
how can it take off?
Cheers

Hmmm, empty weight is about 360,000 lbs plus a little fuel and 50,000
lbs
*of
thrust. It aught to work. I suspect your data are in error or perhaps
you
're
considering a loaded 747.

It comes from the certification requirements of a commercial 747
climbing on 3 engines. The excess thrust is calculated from the rate
of climb in that condition and knowing that 1 HP is 33,000 ft lbs /
rminute. Perhaps my math is wrong but I don't calculate an excess
thrust of 120,000 lbs... What do you get?

Cheers

What I get is that I suspect your numbers are at gross weight. I suggest
looking at the problem as stated rather than making up your own
conditions.

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there should be a "sig" here

What I get is the latest successfull troll: *please ignore him.

I see, discussion using physics and aeronautics about real aircraft
performance is a troll to you. You clearly prefer BS.
The 747 figures I used: empty weight 403,000 #, MTOW 870,000 #.
Minimum fuel 70,000 #, thrust available 60,000 #. That gave me TOW of
473,000 # which is quite a bit more than Clark 'estimated' so the drag
would be proportionally higher. In the absence of any ref to the
claimed actual takeoff on one engine, it sounds like urban piloting
myth.