737-700

[louis]

Hi,

Recently I was in a 737-700 during my trip. I noticed that the
landing speed was quite high. Anyone know what the normal landing
speed is for this aircraft?
Also, I noticed that there was another way to slow down the aircraft
after touching down. Was it reverse thrust of the engines? I am
confused because reverse thrust would cause engine overheating (that
is, there would be no air flowing through the engine but pushed out by
the reverse pitch of the blades).

Louis

[Robert Moore]

(louis) wrote
> Recently I was in a 737-700 during my trip. I noticed that the
> landing speed was quite high. Anyone know what the normal landing
> speed is for this aircraft?

Could be around 120-130 kts

> Also, I noticed that there was another way to slow down the aircraft
> after touching down. Was it reverse thrust of the engines? I am
> confused because reverse thrust would cause engine overheating (that
> is, there would be no air flowing through the engine but pushed out by
> the reverse pitch of the blades).

Three ways to slow a jetliner, wheel brakes, reverse thrust, and
ground spoilers on top of the wing.
The "blades" do not change pitch, the exhaust out the rear of the
engine is turned around by deflectors.

Bob Moore
ATP B-727 B-707

[Andrew Crane]

"louis" > wrote in message
om...
> Hi,
>
> Also, I noticed that there was another way to slow down the aircraft
> after touching down. Was it reverse thrust of the engines? I am
> confused because reverse thrust would cause engine overheating (that
> is, there would be no air flowing through the engine but pushed out by
> the reverse pitch of the blades).

ROFL - this is a troll, right :-)

Regards
Andrew


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[John Hilt]

On 4 Mar 2004 07:34:35 -0800 louis
wrote in news:rec.aviation.misc

>Recently I was in a 737-700 during my trip. I noticed that the
>landing speed was quite high. Anyone know what the normal landing
>speed is for this aircraft?

110 - 150 knots air speed, depending on weight an flap setting.
The ground speed may seem high with no wind.

>Also, I noticed that there was another way to slow down the aircraft
>after touching down. Was it reverse thrust of the engines? I am
>confused because reverse thrust would cause engine overheating (that
>is, there would be no air flowing through the engine but pushed out by
>the reverse pitch of the blades)

The CFM56 core air flow is not affected during fan air flow deflection
and reversal. Older models with JT8 engines reversed all the air using
bucket deflectors, without overheating. Compressor and fan blade pitch
can't be adjusted on jet engines, only stator blade angle of attack.

--
_/_/_/ -=jh=-

[CFLav8r]

> Three ways to slow a jetliner, wheel brakes, reverse thrust, and
> ground spoilers on top of the wing.
> The "blades" do not change pitch, the exhaust out the rear of the
> engine is turned around by deflectors.
>
> Bob Moore
> ATP B-727 B-707
>
Actually you forgot the fourth and fifth way... 4: Drag, 5: Obstacles.

Capt. Dan
L10-A-Lemon, Diesel-9

[David Lesher]

> Three ways to slow a jetliner, wheel brakes, reverse thrust, and
> ground spoilers on top of the wing.

I'd always assumed the ground spoilers were to kill lift, thus making
the brakes much more effective. Do they make a sizeable direct
contribution as well?
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[Robert Moore]

David Lesher wrote

> I'd always assumed the ground spoilers were to kill lift, thus making
> the brakes much more effective. Do they make a sizeable direct
> contribution as well?

Well... I've certainly been able to steer Boeing Jetliners even
at taxi speeds by using the spoilers.

Bob Moore

[Tamas Feher]

>Three ways to slow a jetliner, wheel brakes, reverse
>thrust, and ground spoilers on top of the wing.

Braking parachute
Runway end catching net

I wonder how Flight 1420 went off the runway end? Did they deploy the
braking chute?

[pacplyer]

(louis) wrote in message >...
> Hi,
>
> Recently I was in a 737-700 during my trip. I noticed that the
> landing speed was quite high. Anyone know what the normal landing
> speed is for this aircraft?
> Also, I noticed that there was another way to slow down the aircraft
> after touching down. Was it reverse thrust of the engines? I am
> confused because reverse thrust would cause engine overheating (that
> is, there would be no air flowing through the engine but pushed out by
> the reverse pitch of the blades).
>
> Louis

Louis,

Lots of things can cause a high groundspeed at touchdown. Many
airlines use reduced flap settings (for mtc savings and x-winds) and
bug up to 20kts on top of the "normal speed" for things like wind
gusts and shears. Or you could have had a ten knot tailwind. A flaps
up procedure if they are jammed, can result in an approach speed of up
to 160 kts on some widebodies. Most engines now use the "cascade"
type-reverser (developed by a mechanic from Western Airlines,) as
opposed to old-style clamshell reverser doors (Alas, I really miss
those old midevil mousetraps...) Overheating due to bad airflow was a
problem in the P&W JT9D-70A. EGT would take off without warning in
reverse sometimes and the S/O was authorized to reach up and announce
that he was "Shuting down number X" engine to save the companys' five
million dollar engine. But new engines have better stall/surge
performance. About 140kts was a typical speed for the 737-200.

pacplyer